Lucene入门及实际项目应用场景
导入maven依赖
<dependency>
<groupId>org.apache.lucene</groupId>
<artifactId>lucene-core</artifactId>
<version>5.3.1</version>
</dependency>
<dependency>
<groupId>org.apache.lucene</groupId>
<artifactId>lucene-queryparser</artifactId>
<version>5.3.1</version>
</dependency>
<dependency>
<groupId>org.apache.lucene</groupId>
<artifactId>lucene-analyzers-common</artifactId>
<version>5.3.1</version>
</dependency>
Helloword实现
生成索引
目的:索引数据目录,在指定目录生成索引文件
1、构造方法 实例化IndexWriter
获取索引文件存放地址对象
获取输出流
设置输出流的对应配置
给输出流配置设置分词器
2、关闭索引输出流
3、索引指定路径下的所有文件
4、索引指定的文件
5、获取文档(索引文件中包含的重要信息,key-value的形式)
6、测试
package com.liuwenwu.lucene; import java.io.File;
import java.io.FileReader;
import java.nio.file.Paths; import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.TextField;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.store.FSDirectory; /**
* 配合Demo1.java进行lucene的helloword实现
* @author Administrator
*
*/
public class IndexCreate {
private IndexWriter indexWriter; /**
* 1、构造方法 实例化IndexWriter
* @param indexDir
* @throws Exception
*/
public IndexCreate(String indexDir) throws Exception{
// 获取索引文件的存放地址对象
FSDirectory dir = FSDirectory.open(Paths.get(indexDir));
// 标准分词器(针对英文)
Analyzer analyzer = new StandardAnalyzer();
// 索引输出流配置对象
IndexWriterConfig conf = new IndexWriterConfig(analyzer);
indexWriter = new IndexWriter(dir, conf);
} /**
* 2、关闭索引输出流
* @throws Exception
*/
public void closeIndexWriter() throws Exception{
indexWriter.close();
} /**
* 3、索引指定路径下的所有文件
* @param dataDir
* @return
* @throws Exception
*/
public int index(String dataDir) throws Exception{
File[] files = new File(dataDir).listFiles();
for (File file : files) {
indexFile(file);
}
return indexWriter.numDocs();
} /**
* 4、索引指定的文件
* @param file
* @throws Exception
*/
private void indexFile(File file) throws Exception{
System.out.println("被索引文件的全路径:"+file.getCanonicalPath());
Document doc = getDocument(file);
indexWriter.addDocument(doc);
} /**
* 5、获取文档(索引文件中包含的重要信息,key-value的形式)
* @param file
* @return
* @throws Exception
*/
private Document getDocument(File file) throws Exception{
Document doc = new Document();
doc.add(new TextField("contents", new FileReader(file)));
// Field.Store.YES是否存储到硬盘
doc.add(new TextField("fullPath", file.getCanonicalPath(),Field.Store.YES));
doc.add(new TextField("fileName", file.getName(),Field.Store.YES));
return doc;
}
} package com.liuwenwu.lucene; /**
* 生成索引测试
* @author Administrator
*
*/
public class Demo1 {
public static void main(String[] args) {
// 索引文件将要存放的位置
String indexDir = "F:\\y2\\lucene\\demo1";
// 数据源地址
String dataDir = "F:\\y2\\lucene\\demo1\\data";
IndexCreate ic = null;
try {
ic = new IndexCreate(indexDir);
long start = System.currentTimeMillis();
int num = ic.index(dataDir);
long end = System.currentTimeMillis();
System.out.println("检索指定路径下"+num+"个文件,一共花费了"+(end-start)+"毫秒");
} catch (Exception e) {
e.printStackTrace();
}finally {
try {
ic.closeIndexWriter();
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
结果:
使用索引
从索引文件中拿数据
1、获取输入流(通过dirReader)
2、获取索引搜索对象(通过输入流来拿)
3、获取查询对象(通过查询解析器来获取,解析器是通过分词器获取)
4、获取包含关键字排前面的文档对象集合
5、可以获取对应文档的内容
package com.liuwenwu.lucene; import java.nio.file.Paths; import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.queryparser.classic.QueryParser;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.store.FSDirectory; /**
* 配合Demo2.java进行lucene的helloword实现
* @author Administrator
*
*/
public class IndexUse {
/**
* 通过关键字在索引目录中查询
* @param indexDir 索引文件所在目录
* @param q 关键字
*/
public static void search(String indexDir, String q) throws Exception{
FSDirectory indexDirectory = FSDirectory.open(Paths.get(indexDir));
// 注意:索引输入流不是new出来的,是通过目录读取工具类打开的
IndexReader indexReader = DirectoryReader.open(indexDirectory);
// 获取索引搜索对象
IndexSearcher indexSearcher = new IndexSearcher(indexReader);
Analyzer analyzer = new StandardAnalyzer();
// 查询解析器
QueryParser queryParser = new QueryParser("contents", analyzer);
// 获取符合关键字的查询对象
Query query = queryParser.parse(q); long start=System.currentTimeMillis();
// 获取关键字出现的前十次
TopDocs topDocs = indexSearcher.search(query , 10);
long end=System.currentTimeMillis();
System.out.println("匹配 "+q+" ,总共花费"+(end-start)+"毫秒"+"查询到"+topDocs.totalHits+"个记录"); for (ScoreDoc scoreDoc : topDocs.scoreDocs) {
int docID = scoreDoc.doc;
// 索引搜索对象通过文档下标获取文档
Document doc = indexSearcher.doc(docID);
System.out.println("通过索引文件:"+doc.get("fullPath")+"拿数据");
} indexReader.close();
}
}
package com.liuwenwu.lucene; /**
* 查询索引测试
* @author Administrator
*
*/
public class Demo2 {
public static void main(String[] args) {
// 索引文件地址
String indexDir = "F:\\y2\\lucene\\demo1";
// 搜索条件
String q = "EarlyTerminating-Collector";
try {
IndexUse.search(indexDir, q);
} catch (Exception e) {
e.printStackTrace();
}
}
}
结果:
构建索引
package com.liuwenwu.lucene; import java.nio.file.Paths; import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.StringField;
import org.apache.lucene.document.TextField;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.index.Term;
import org.apache.lucene.store.FSDirectory;
import org.junit.Before;
import org.junit.Test; /**
* 构建索引
* 对索引的增删改
* @author Administrator
*
*/
public class Demo3 {
private String ids[]={"1","2","3"};
private String citys[]={"qingdao","nanjing","shanghai"};
private String descs[]={
"Qingdao is a beautiful city.",
"Nanjing is a city of culture.",
"Shanghai is a bustling city."
};
private FSDirectory dir; /**
* 每次都生成索引文件
* @throws Exception
*/
@Before
public void setUp() throws Exception {
dir = FSDirectory.open(Paths.get("F:\\y2\\lucene\\demo2\\indexDir"));
IndexWriter indexWriter = getIndexWriter();
for (int i = 0; i < ids.length; i++) {
Document doc = new Document();
doc.add(new StringField("id", ids[i], Field.Store.YES));
doc.add(new StringField("city", citys[i], Field.Store.YES));
doc.add(new TextField("desc", descs[i], Field.Store.NO));
indexWriter.addDocument(doc);
}
indexWriter.close();
} /**
* 获取索引输出流
* @return
* @throws Exception
*/
private IndexWriter getIndexWriter() throws Exception{
Analyzer analyzer = new StandardAnalyzer();
IndexWriterConfig conf = new IndexWriterConfig(analyzer);
return new IndexWriter(dir, conf );
} /**
* 测试写了几个索引文件
* @throws Exception
*/
@Test
public void getWriteDocNum() throws Exception {
IndexWriter indexWriter = getIndexWriter();
System.out.println("索引目录下生成"+indexWriter.numDocs()+"个索引文件");
} /**
* 打上标记,该索引实际并未删除
* @throws Exception
*/
@Test
public void deleteDocBeforeMerge() throws Exception {
IndexWriter indexWriter = getIndexWriter();
System.out.println("最大文档数:"+indexWriter.maxDoc());
indexWriter.deleteDocuments(new Term("id", "1"));
indexWriter.commit(); System.out.println("最大文档数:"+indexWriter.maxDoc());
System.out.println("实际文档数:"+indexWriter.numDocs());
indexWriter.close();
} /**
* 对应索引文件已经删除,但是该版本的分词会保留
* @throws Exception
*/
@Test
public void deleteDocAfterMerge() throws Exception {
// https://blog.csdn.net/asdfsadfasdfsa/article/details/78820030
// org.apache.lucene.store.LockObtainFailedException: Lock held by this virtual machine:indexWriter是单例的、线程安全的,不允许打开多个。
IndexWriter indexWriter = getIndexWriter();
System.out.println("最大文档数:"+indexWriter.maxDoc());
indexWriter.deleteDocuments(new Term("id", "1"));
indexWriter.forceMergeDeletes(); //强制删除
indexWriter.commit(); System.out.println("最大文档数:"+indexWriter.maxDoc());
System.out.println("实际文档数:"+indexWriter.numDocs());
indexWriter.close();
} /**
* 测试更新索引
* @throws Exception
*/
@Test
public void testUpdate()throws Exception{
IndexWriter writer=getIndexWriter();
Document doc=new Document();
doc.add(new StringField("id", "1", Field.Store.YES));
doc.add(new StringField("city","qingdao",Field.Store.YES));
doc.add(new TextField("desc", "dsss is a city.", Field.Store.NO));
writer.updateDocument(new Term("id","1"), doc);
writer.close();
}
}
新增索引
控制台
删除索引
控制台输出
合并前
合并后
注意:
大数据时用合并前的删除,知识给索引文件打标,定时清理打标的索引文件。
数据量不是特别大的时候,可以及时删除索引文件。
修改索引
通过可视化工具可发现
注意:5.3的版本修改前的分词不会消失。
文档域加权
相关代码
package com.liuwenwu.lucene; import java.nio.file.Paths; import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.StringField;
import org.apache.lucene.document.TextField;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.index.Term;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.TermQuery;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.FSDirectory;
import org.junit.Before;
import org.junit.Test; /**
* 文档域加权
* @author Administrator
*
*/
public class Demo4 {
private String ids[]={"1","2","3","4"};
private String authors[]={"Jack","Marry","John","Json"};
private String positions[]={"accounting","technician","salesperson","boss"};
private String titles[]={"Java is a good language.","Java is a cross platform language","Java powerful","You should learn java"};
private String contents[]={
"If possible, use the same JRE major version at both index and search time.",
"When upgrading to a different JRE major version, consider re-indexing. ",
"Different JRE major versions may implement different versions of Unicode,",
"For example: with Java 1.4, `LetterTokenizer` will split around the character U+02C6,"
}; private Directory dir;//索引文件目录 @Before
public void setUp()throws Exception {
dir = FSDirectory.open(Paths.get("F:\\y2\\lucene\\demo3\\indexDir"));
IndexWriter writer = getIndexWriter();
for (int i = 0; i < authors.length; i++) {
Document doc = new Document();
doc.add(new StringField("id", ids[i], Field.Store.YES));
doc.add(new StringField("author", authors[i], Field.Store.YES));
doc.add(new StringField("position", positions[i], Field.Store.YES)); TextField textField = new TextField("title", titles[i], Field.Store.YES); // Json投钱做广告,把排名刷到第一了
if("boss".equals(positions[i])) {
textField.setBoost(2f);//设置权重,默认为1
} doc.add(textField);
// TextField会分词,StringField不会分词
doc.add(new TextField("content", contents[i], Field.Store.NO));
writer.addDocument(doc);
}
writer.close(); } private IndexWriter getIndexWriter() throws Exception{
Analyzer analyzer = new StandardAnalyzer();
IndexWriterConfig conf = new IndexWriterConfig(analyzer);
return new IndexWriter(dir, conf);
} @Test
public void index() throws Exception{
IndexReader reader = DirectoryReader.open(dir);
IndexSearcher searcher = new IndexSearcher(reader);
String fieldName = "title";
String keyWord = "java";
Term t = new Term(fieldName, keyWord);
Query query = new TermQuery(t);
TopDocs hits = searcher.search(query, 10);
System.out.println("关键字:‘"+keyWord+"’命中了"+hits.totalHits+"次");
for (ScoreDoc scoreDoc : hits.scoreDocs) {
Document doc = searcher.doc(scoreDoc.doc);
System.out.println(doc.get("author"));
}
} }
文档域加权前结果
文档域加权后结果变成
注意:关键字加权有利于排名的提升。
索引搜索功能
特定项搜索
代码
package com.liuwenwu.lucene; import java.io.IOException;
import java.nio.file.Paths; import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.Term;
import org.apache.lucene.queryparser.classic.ParseException;
import org.apache.lucene.queryparser.classic.QueryParser;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.NumericRangeQuery;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.TermQuery;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.store.FSDirectory;
import org.junit.Before;
import org.junit.Test; /**
* 特定项搜索
* 查询表达式(queryParser)
* @author Administrator
*
*/
public class Demo5 {
@Before
public void setUp() {
// 索引文件将要存放的位置
String indexDir = "F:\\y2\\lucene\\demo4";
// 数据源地址
String dataDir = "F:\\y2\\lucene\\demo4\\data";
IndexCreate ic = null;
try {
ic = new IndexCreate(indexDir);
long start = System.currentTimeMillis();
int num = ic.index(dataDir);
long end = System.currentTimeMillis();
System.out.println("检索指定路径下" + num + "个文件,一共花费了" + (end - start) + "毫秒"); } catch (Exception e) {
e.printStackTrace();
} finally {
try {
ic.closeIndexWriter();
} catch (Exception e) {
e.printStackTrace();
}
}
} /**
* 特定项搜索
*/
@Test
public void testTermQuery() {
String indexDir = "F:\\y2\\lucene\\demo4"; String fld = "contents";
String text = "indexformattoooldexception";
// 特定项片段名和关键字
Term t = new Term(fld , text);
TermQuery tq = new TermQuery(t );
try {
FSDirectory indexDirectory = FSDirectory.open(Paths.get(indexDir));
// 注意:索引输入流不是new出来的,是通过目录读取工具类打开的
IndexReader indexReader = DirectoryReader.open(indexDirectory);
// 获取索引搜索对象
IndexSearcher is = new IndexSearcher(indexReader); TopDocs hits = is.search(tq, 100);
// System.out.println(hits.totalHits);
for(ScoreDoc scoreDoc: hits.scoreDocs) {
Document doc = is.doc(scoreDoc.doc);
System.out.println("文件"+doc.get("fullPath")+"中含有该关键字"); }
} catch (IOException e) {
e.printStackTrace();
}
} /**
* 查询表达式(queryParser)
*/
@Test
public void testQueryParser() {
String indexDir = "F:\\y2\\lucene\\demo4";
// 获取查询解析器(通过哪种分词器去解析哪种片段)
QueryParser queryParser = new QueryParser("contents", new StandardAnalyzer());
try {
FSDirectory indexDirectory = FSDirectory.open(Paths.get(indexDir));
// 注意:索引输入流不是new出来的,是通过目录读取工具类打开的
IndexReader indexReader = DirectoryReader.open(indexDirectory);
// 获取索引搜索对象
IndexSearcher is = new IndexSearcher(indexReader); // 由解析器去解析对应的关键字
TopDocs hits = is.search(queryParser.parse("indexformattoooldexception") , 100);
for(ScoreDoc scoreDoc: hits.scoreDocs) {
Document doc = is.doc(scoreDoc.doc);
System.out.println("文件"+doc.get("fullPath")+"中含有该关键字"); }
} catch (IOException e) {
e.printStackTrace();
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} }
控制台结果
Lucene查看工具
查询表达式(queryParser)
/**
* 查询表达式(queryParser)
*/
@Test
public void testQueryParser() {
String indexDir = "F:\\y2\\lucene\\demo4";
// 获取查询解析器(通过哪种分词器去解析哪种片段)
QueryParser queryParser = new QueryParser("contents", new StandardAnalyzer());
try {
FSDirectory indexDirectory = FSDirectory.open(Paths.get(indexDir));
// 注意:索引输入流不是new出来的,是通过目录读取工具类打开的
IndexReader indexReader = DirectoryReader.open(indexDirectory);
// 获取索引搜索对象
IndexSearcher is = new IndexSearcher(indexReader); // 由解析器去解析对应的关键字
TopDocs hits = is.search(queryParser.parse("indexformattoooldexception") , 100);
for(ScoreDoc scoreDoc: hits.scoreDocs) {
Document doc = is.doc(scoreDoc.doc);
System.out.println("文件"+doc.get("fullPath")+"中含有该关键字"); }
} catch (IOException e) {
e.printStackTrace();
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
注意:与特定项搜索结果一样的。但是,特定项搜索是没有指定分词器的。
分页功能
方案一
一次全部查出来到session中,分页的时候从session中那集合截取显示。优势是只要查询一次,缺陷是占用内存。并发的可能性很高。得到命中文档数组,通过下标拿命中文档,从而获取内容。
方案二
每次上一页下一页都是一次查询,占用时间。但是通常少有人点击下一页、得到命中文档数组,通过下标拿命中文档,从而获取内容。
推荐:使用第二种方案
其他查询方法
指定数字范围查询(numbericRangeQuery)
package com.liuwenwu.lucene; import java.nio.file.Paths; import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.IntField;
import org.apache.lucene.document.StringField;
import org.apache.lucene.document.TextField;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.index.Term;
import org.apache.lucene.search.BooleanClause;
import org.apache.lucene.search.BooleanQuery;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.NumericRangeQuery;
import org.apache.lucene.search.PrefixQuery;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.store.FSDirectory;
import org.junit.Before;
import org.junit.Test; /**
* 指定数字范围查询
* 指定字符串开头字母查询(prefixQuery)
* @author Administrator
*
*/
public class Demo6 {
private int ids[]={1,2,3};
private String citys[]={"qingdao","nanjing","shanghai"};
private String descs[]={
"Qingdao is a beautiful city.",
"Nanjing is a city of culture.",
"Shanghai is a bustling city."
};
private FSDirectory dir; /**
* 每次都生成索引文件
* @throws Exception
*/
@Before
public void setUp() throws Exception {
dir = FSDirectory.open(Paths.get("F:\\y2\\lucene\\demo2\\indexDir"));
IndexWriter indexWriter = getIndexWriter();
for (int i = 0; i < ids.length; i++) {
Document doc = new Document();
doc.add(new IntField("id", ids[i], Field.Store.YES));
doc.add(new StringField("city", citys[i], Field.Store.YES));
doc.add(new TextField("desc", descs[i], Field.Store.YES));
indexWriter.addDocument(doc);
}
indexWriter.close();
} /**
* 获取索引输出流
* @return
* @throws Exception
*/
private IndexWriter getIndexWriter() throws Exception{
Analyzer analyzer = new StandardAnalyzer();
IndexWriterConfig conf = new IndexWriterConfig(analyzer);
return new IndexWriter(dir, conf );
} /**
* 指定数字范围查询
* @throws Exception
*/
@Test
public void testNumericRangeQuery()throws Exception{
IndexReader reader = DirectoryReader.open(dir);
IndexSearcher is = new IndexSearcher(reader); NumericRangeQuery<Integer> query=NumericRangeQuery.newIntRange("id", 1, 2, true, true);
TopDocs hits=is.search(query, 10);
for(ScoreDoc scoreDoc:hits.scoreDocs){
Document doc=is.doc(scoreDoc.doc);
System.out.println(doc.get("id"));
System.out.println(doc.get("city"));
System.out.println(doc.get("desc"));
}
} /**
* 指定字符串开头字母查询(prefixQuery)
* @throws Exception
*/
@Test
public void testPrefixQuery()throws Exception{
IndexReader reader = DirectoryReader.open(dir);
IndexSearcher is = new IndexSearcher(reader); PrefixQuery query=new PrefixQuery(new Term("city","n"));
TopDocs hits=is.search(query, 10);
for(ScoreDoc scoreDoc:hits.scoreDocs){
Document doc=is.doc(scoreDoc.doc);
System.out.println(doc.get("id"));
System.out.println(doc.get("city"));
System.out.println(doc.get("desc"));
}
} /**
* 组合查询
* @throws Exception
*/
@Test
public void testBooleanQuery()throws Exception{
IndexReader reader = DirectoryReader.open(dir);
IndexSearcher is = new IndexSearcher(reader); NumericRangeQuery<Integer> query1=NumericRangeQuery.newIntRange("id", 1, 2, true, true);
PrefixQuery query2=new PrefixQuery(new Term("city","n"));
BooleanQuery.Builder booleanQuery=new BooleanQuery.Builder();
booleanQuery.add(query1,BooleanClause.Occur.MUST);
booleanQuery.add(query2,BooleanClause.Occur.MUST);
TopDocs hits=is.search(booleanQuery.build(), 10);
for(ScoreDoc scoreDoc:hits.scoreDocs){
Document doc=is.doc(scoreDoc.doc);
System.out.println(doc.get("id"));
System.out.println(doc.get("city"));
System.out.println(doc.get("desc"));
}
}
}
指定字符串开头字母查询(prefixQuery)
/**
* 指定字符串开头字母查询(prefixQuery)
* @throws Exception
*/
@Test
public void testPrefixQuery()throws Exception{
IndexReader reader = DirectoryReader.open(dir);
IndexSearcher is = new IndexSearcher(reader); PrefixQuery query=new PrefixQuery(new Term("city","n"));
TopDocs hits=is.search(query, 10);
for(ScoreDoc scoreDoc:hits.scoreDocs){
Document doc=is.doc(scoreDoc.doc);
System.out.println(doc.get("id"));
System.out.println(doc.get("city"));
System.out.println(doc.get("desc"));
}
}
组合查询(booleanQuery)重点
Must、must not、should
/**
* 组合查询
* @throws Exception
*/
@Test
public void testBooleanQuery()throws Exception{
IndexReader reader = DirectoryReader.open(dir);
IndexSearcher is = new IndexSearcher(reader); NumericRangeQuery<Integer> query1=NumericRangeQuery.newIntRange("id", 1, 2, true, true);
PrefixQuery query2=new PrefixQuery(new Term("city","n"));
BooleanQuery.Builder booleanQuery=new BooleanQuery.Builder();
booleanQuery.add(query1,BooleanClause.Occur.MUST);
booleanQuery.add(query2,BooleanClause.Occur.MUST);
TopDocs hits=is.search(booleanQuery.build(), 10);
for(ScoreDoc scoreDoc:hits.scoreDocs){
Document doc=is.doc(scoreDoc.doc);
System.out.println(doc.get("id"));
System.out.println(doc.get("city"));
System.out.println(doc.get("desc"));
}
}
中文分词&&高亮显示
private Integer ids[]={1,2,3};
private String citys[]={"青岛","南京","上海"};
private String descs[]={
"青岛是个美丽的城市。",
"南京是个有文化的城市。",
"上海市个繁华的城市。"
};
为了查看高亮显示效果
南京是一个文化的城市南京,简称宁,是江苏省会,地处中国东部地区,长江下游,濒江近海。全市下辖11个区,总面积6597平方公里,2013年建成区面积752.83平方公里,常住人口818.78万,其中城镇人口659.1万人。[1-4] “江南佳丽地,金陵帝王州”,南京拥有着6000多年文明史、近2600年建城史和近500年的建都史,是中国四大古都之一,有“六朝古都”、“十朝都会”之称,是中华文明的重要发祥地,历史上曾数次庇佑华夏之正朔,长期是中国南方的政治、经济、文化中心,拥有厚重的文化底蕴和丰富的历史遗存。[5-7] 南京是国家重要的科教中心,自古以来就是一座崇文重教的城市,有“天下文枢”、“东南第一学”的美誉。截至2013年,南京有高等院校75所,其中211高校8所,仅次于北京上海;国家重点实验室25所、国家重点学科169个、两院院士83人,均居中国第三。[8-10] 。",
使用标准分词器对中文进行分词的结果如下
把每个字都当作了一个词,并没有达到我们想要的效果,也就是说标准分词器StandardAnalyzer已经不能满足我们的开发需要了。
中文分词
依赖
<dependency>
<groupId>org.apache.lucene</groupId>
<artifactId>lucene-analyzers-smartcn</artifactId>
<version>5.3.1</version>
</dependency>
将标准分词器换成中文分词器
结果如下:
高亮显示
依赖
<dependency>
<groupId>org.apache.lucene</groupId>
<artifactId>lucene-highlighter</artifactId>
<version>5.3.1</version>
</dependency>
高亮显示的步奏:
1、通过查询对象,获取查询得分对象
2、通过得分对象,获取对应的片段
3、实例化一个html格式化对象
4、通过html格式化实例和查询得分实例,来实例化Lucene提供的高亮显示类对象。
5、将前面获取到的得分片段,设置到高亮显示的的实例对象中。
6、通过分词器获取TokenStream令牌流对象
7、通过令牌和原有的片段,去拿高亮展示后的片段
相关代码:
package com.liuwenwu.lucene; import java.io.StringReader;
import java.nio.file.Paths; import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.cn.smart.SmartChineseAnalyzer;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.IntField;
import org.apache.lucene.document.StringField;
import org.apache.lucene.document.TextField;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.queryparser.classic.QueryParser;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.search.highlight.Highlighter;
import org.apache.lucene.search.highlight.QueryScorer;
import org.apache.lucene.search.highlight.SimpleHTMLFormatter;
import org.apache.lucene.search.highlight.SimpleSpanFragmenter;
import org.apache.lucene.store.FSDirectory;
import org.junit.Before;
import org.junit.Test; /**
* 中文分词器
* 高亮显示
* @author ASUS
*
*/
public class Demo7 {
private Integer ids[] = { 1, 2, 3 };
private String citys[] = { "青岛", "南京", "上海" };
// private String descs[]={
// "青岛是个美丽的城市。",
// "南京是个有文化的城市。",
// "上海市个繁华的城市。"
// };
private String descs[] = { "青岛是个美丽的城市。",
"南京是一个文化的城市南京,简称宁,是江苏省会,地处中国东部地区,长江下游,濒江近海。全市下辖11个区,总面积6597平方公里,2013年建成区面积752.83平方公里,常住人口818.78万,其中城镇人口659.1万人。[1-4] “江南佳丽地,金陵帝王州”,南京拥有着6000多年文明史、近2600年建城史和近500年的建都史,是中国四大古都之一,有“六朝古都”、“十朝都会”之称,是中华文明的重要发祥地,历史上曾数次庇佑华夏之正朔,长期是中国南方的政治、经济、文化中心,拥有厚重的文化底蕴和丰富的历史遗存。[5-7] 南京是国家重要的科教中心,自古以来就是一座崇文重教的城市,有“天下文枢”、“东南第一学”的美誉。截至2013年,南京有高等院校75所,其中211高校8所,仅次于北京上海;国家重点实验室25所、国家重点学科169个、两院院士83人,均居中国第三。[8-10]",
"上海市个繁华的城市。" }; private FSDirectory dir; /**
* 每次都生成索引文件
*
* @throws Exception
*/
@Before
public void setUp() throws Exception {
dir = FSDirectory.open(Paths.get("F:\\y2\\lucene\\demo2\\indexDir"));
IndexWriter indexWriter = getIndexWriter();
for (int i = 0; i < ids.length; i++) {
Document doc = new Document();
doc.add(new IntField("id", ids[i], Field.Store.YES));
doc.add(new StringField("city", citys[i], Field.Store.YES));
doc.add(new TextField("desc", descs[i], Field.Store.YES));
indexWriter.addDocument(doc);
}
indexWriter.close();
} /**
* 获取索引输出流
*
* @return
* @throws Exception
*/
private IndexWriter getIndexWriter() throws Exception {
// Analyzer analyzer = new StandardAnalyzer();
Analyzer analyzer = new SmartChineseAnalyzer();
IndexWriterConfig conf = new IndexWriterConfig(analyzer);
return new IndexWriter(dir, conf);
} /**
* luke查看索引生成
*
* @throws Exception
*/
@Test
public void testIndexCreate() throws Exception { } /**
* 测试高亮
*
* @throws Exception
*/
@Test
public void testHeight() throws Exception {
IndexReader reader = DirectoryReader.open(dir);
IndexSearcher searcher = new IndexSearcher(reader); SmartChineseAnalyzer analyzer = new SmartChineseAnalyzer();
QueryParser parser = new QueryParser("desc", analyzer);
// Query query = parser.parse("南京文化");
Query query = parser.parse("南京文明");
TopDocs hits = searcher.search(query, 100); // 查询得分项
QueryScorer queryScorer = new QueryScorer(query);
// 得分项对应的内容片段
SimpleSpanFragmenter fragmenter = new SimpleSpanFragmenter(queryScorer);
// 高亮显示的样式
SimpleHTMLFormatter htmlFormatter = new SimpleHTMLFormatter("<span color='red'><b>", "</b></span>");
// 高亮显示对象
Highlighter highlighter = new Highlighter(htmlFormatter, queryScorer);
// 设置需要高亮显示对应的内容片段
highlighter.setTextFragmenter(fragmenter); for (ScoreDoc scoreDoc : hits.scoreDocs) {
Document doc = searcher.doc(scoreDoc.doc);
String desc = doc.get("desc");
if (desc != null) {
// tokenstream是从doucment的域(field)中抽取的一个个分词而组成的一个数据流,用于分词。
TokenStream tokenStream = analyzer.tokenStream("desc", new StringReader(desc));
System.out.println("高亮显示的片段:" + highlighter.getBestFragment(tokenStream, desc));
}
System.out.println("所有内容:" + desc);
} } }
控制台结果:
南京文明结果:
高亮显示的片段:城镇人口659.1万人。[1-4] “江南佳丽地,金陵帝王州”,<span color='red'><b>南京</b></span>拥有着6000多年<span color='red'><b>文明</b></span>史、近2600年建城史和近500年的建都史,是中国四大古都之一,有“六朝古都”、“十朝都会”之称,是中华<span color='red'><b>文明</b></span>的
所有内容:南京是一个文化的城市南京,简称宁,是江苏省会,地处中国东部地区,长江下游,濒江近海。全市下辖11个区,总面积6597平方公里,2013年建成区面积752.83平方公里,常住人口818.78万,其中城镇人口659.1万人。[1-4] “江南佳丽地,金陵帝王州”,南京拥有着6000多年文明史、近2600年建城史和近500年的建都史,是中国四大古都之一,有“六朝古都”、“十朝都会”之称,是中华文明的重要发祥地,历史上曾数次庇佑华夏之正朔,长期是中国南方的政治、经济、文化中心,拥有厚重的文化底蕴和丰富的历史遗存。[5-7] 南京是国家重要的科教中心,自古以来就是一座崇文重教的城市,有“天下文枢”、“东南第一学”的美誉。截至2013年,南京有高等院校75所,其中211高校8所,仅次于北京上海;国家重点实验室25所、国家重点学科169个、两院院士83人,均居中国第三。[8-10]
Lucene中各个核心类的作用:https://blog.csdn.net/kevinelstri/article/details/52317977
综合案例
核心代码
<properties>
<httpclient.version>4.5.2</httpclient.version>
<jsoup.version>1.10.1</jsoup.version>
<!-- <lucene.version>7.1.0</lucene.version> -->
<lucene.version>5.3.1</lucene.version>
<ehcache.version>2.10.3</ehcache.version>
<junit.version>4.12</junit.version>
<log4j.version>1.2.16</log4j.version>
<mysql.version>5.1.44</mysql.version>
<fastjson.version>1.2.47</fastjson.version>
<struts2.version>2.5.16</struts2.version>
<servlet.version>4.0.1</servlet.version>
<jstl.version>1.2</jstl.version>
<standard.version>1.1.2</standard.version>
<tomcat-jsp-api.version>8.0.47</tomcat-jsp-api.version>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>${junit.version}</version>
<scope>test</scope>
</dependency> <!-- jdbc驱动包 -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>${mysql.version}</version>
</dependency> <!-- 添加Httpclient支持 -->
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
<version>${httpclient.version}</version>
</dependency> <!-- 添加jsoup支持 -->
<dependency>
<groupId>org.jsoup</groupId>
<artifactId>jsoup</artifactId>
<version>${jsoup.version}</version>
</dependency> <!-- 添加日志支持 -->
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>${log4j.version}</version>
</dependency> <!-- 添加ehcache支持 -->
<dependency>
<groupId>net.sf.ehcache</groupId>
<artifactId>ehcache</artifactId>
<version>${ehcache.version}</version>
</dependency> <dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>${fastjson.version}</version>
</dependency> <dependency>
<groupId>org.apache.struts</groupId>
<artifactId>struts2-core</artifactId>
<version>${struts2.version}</version>
</dependency> <dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>${servlet.version}</version>
<scope>provided</scope>
</dependency> <dependency>
<groupId>org.apache.lucene</groupId>
<artifactId>lucene-core</artifactId>
<version>${lucene.version}</version>
</dependency>
<dependency>
<groupId>org.apache.lucene</groupId>
<artifactId>lucene-queryparser</artifactId>
<version>${lucene.version}</version>
</dependency>
<!-- <dependency> <groupId>org.apache.lucene</groupId> <artifactId>lucene-analyzers-common</artifactId>
<version>${lucene.version}</version> </dependency> --> <dependency>
<groupId>org.apache.lucene</groupId>
<artifactId>lucene-analyzers-smartcn</artifactId>
<version>${lucene.version}</version>
</dependency> <dependency>
<groupId>org.apache.lucene</groupId>
<artifactId>lucene-highlighter</artifactId>
<version>${lucene.version}</version>
</dependency> <!-- 5.3、jstl、standard -->
<dependency>
<groupId>jstl</groupId>
<artifactId>jstl</artifactId>
<version>${jstl.version}</version>
</dependency>
<dependency>
<groupId>taglibs</groupId>
<artifactId>standard</artifactId>
<version>${standard.version}</version>
</dependency> <!-- 5.4、tomcat-jsp-api -->
<dependency>
<groupId>org.apache.tomcat</groupId>
<artifactId>tomcat-jsp-api</artifactId>
<version>${tomcat-jsp-api.version}</version>
</dependency>
</dependencies>
package com.liuwenwu.blog.web; import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map; import javax.servlet.http.HttpServletRequest; import org.apache.lucene.analysis.cn.smart.SmartChineseAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.queryparser.classic.QueryParser;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.search.highlight.Highlighter;
import org.apache.lucene.store.Directory;
import org.apache.struts2.ServletActionContext; import com.liuwenwu.blog.dao.BlogDao;
import com.liuwenwu.blog.util.LuceneUtil;
import com.liuwenwu.blog.util.PropertiesUtil;
import com.liuwenwu.blog.util.StringUtils; /**
* IndexReader
* IndexSearcher
* Highlighter
* @author Administrator
*
*/
public class BlogAction {
private String title;
private BlogDao blogDao = new BlogDao(); public String getTitle() {
return title;
} public void setTitle(String title) {
this.title = title;
} public String list() {
try {
HttpServletRequest request = ServletActionContext.getRequest();
if (StringUtils.isBlank(title)) {
List<Map<String, Object>> blogList = this.blogDao.list(title, null);
request.setAttribute("blogList", blogList);
}else {
Directory directory = LuceneUtil.getDirectory(PropertiesUtil.getValue("indexPath"));
DirectoryReader reader = LuceneUtil.getDirectoryReader(directory);
IndexSearcher searcher = LuceneUtil.getIndexSearcher(reader);
SmartChineseAnalyzer analyzer = new SmartChineseAnalyzer();
// 拿一句话到索引目中的索引文件中的词库进行关键词碰撞
Query query = new QueryParser("title", analyzer).parse(title);
Highlighter highlighter = LuceneUtil.getHighlighter(query, "title"); TopDocs topDocs = searcher.search(query , 100);
//处理得分命中的文档
List<Map<String, Object>> blogList = new ArrayList<>();
Map<String, Object> map = null;
ScoreDoc[] scoreDocs = topDocs.scoreDocs;
for (ScoreDoc scoreDoc : scoreDocs) {
map = new HashMap<>();
Document doc = searcher.doc(scoreDoc.doc);
map.put("id", doc.get("id"));
String titleHighlighter = doc.get("title");
if(StringUtils.isNotBlank(titleHighlighter)) {
titleHighlighter = highlighter.getBestFragment(analyzer, "title", titleHighlighter);
}
map.put("title", titleHighlighter);
map.put("url", doc.get("url"));
blogList.add(map);
} request.setAttribute("blogList", blogList);
}
} catch (Exception e) {
e.printStackTrace();
}
return "blogList";
}
}
package com.liuwenwu.blog.web; import java.io.IOException;
import java.nio.file.Paths;
import java.sql.SQLException;
import java.util.List;
import java.util.Map; import org.apache.lucene.analysis.cn.smart.SmartChineseAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.StringField;
import org.apache.lucene.document.TextField;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.FSDirectory; import com.liuwenwu.blog.dao.BlogDao;
import com.liuwenwu.blog.util.PropertiesUtil; /**
* 构建lucene索引
* @author Administrator
* 1。构建索引 IndexWriter
* 2、读取索引文件,获取命中片段
* 3、使得命中片段高亮显示
*
*/
public class IndexStarter {
private static BlogDao blogDao = new BlogDao();
public static void main(String[] args) {
IndexWriterConfig conf = new IndexWriterConfig(new SmartChineseAnalyzer());
Directory d;
IndexWriter indexWriter = null;
try {
d = FSDirectory.open(Paths.get(PropertiesUtil.getValue("indexPath")));
indexWriter = new IndexWriter(d , conf ); // 为数据库中的所有数据构建索引
List<Map<String, Object>> list = blogDao.list(null, null);
for (Map<String, Object> map : list) {
Document doc = new Document();
doc.add(new StringField("id", (String) map.get("id"), Field.Store.YES));
// TextField用于对一句话分词处理 java培训机构
doc.add(new TextField("title", (String) map.get("title"), Field.Store.YES));
doc.add(new StringField("url", (String) map.get("url"), Field.Store.YES));
indexWriter.addDocument(doc);
} } catch (IOException e) {
e.printStackTrace();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}finally {
try {
if(indexWriter!= null) {
indexWriter.close();
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
package com.liuwenwu.blog.util; import java.io.IOException;
import java.nio.file.Paths;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.index.IndexWriterConfig.OpenMode;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.highlight.Formatter;
import org.apache.lucene.search.highlight.Highlighter;
import org.apache.lucene.search.highlight.QueryTermScorer;
import org.apache.lucene.search.highlight.Scorer;
import org.apache.lucene.search.highlight.SimpleFragmenter;
import org.apache.lucene.search.highlight.SimpleHTMLFormatter;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.FSDirectory;
import org.apache.lucene.store.RAMDirectory; /**
* lucene工具类
* @author Administrator
*
*/
public class LuceneUtil { /**
* 获取索引文件存放的文件夹对象
*
* @param path
* @return
*/
public static Directory getDirectory(String path) {
Directory directory = null;
try {
directory = FSDirectory.open(Paths.get(path));
} catch (IOException e) {
e.printStackTrace();
}
return directory;
} /**
* 索引文件存放在内存
*
* @return
*/
public static Directory getRAMDirectory() {
Directory directory = new RAMDirectory();
return directory;
} /**
* 文件夹读取对象
*
* @param directory
* @return
*/
public static DirectoryReader getDirectoryReader(Directory directory) {
DirectoryReader reader = null;
try {
reader = DirectoryReader.open(directory);
} catch (IOException e) {
e.printStackTrace();
}
return reader;
} /**
* 文件索引对象
*
* @param reader
* @return
*/
public static IndexSearcher getIndexSearcher(DirectoryReader reader) {
IndexSearcher indexSearcher = new IndexSearcher(reader);
return indexSearcher;
} /**
* 写入索引对象
*
* @param directory
* @param analyzer
* @return
*/
public static IndexWriter getIndexWriter(Directory directory, Analyzer analyzer) {
IndexWriter iwriter = null;
try {
IndexWriterConfig config = new IndexWriterConfig(analyzer);
config.setOpenMode(OpenMode.CREATE_OR_APPEND);
// Sort sort=new Sort(new SortField("content", Type.STRING));
// config.setIndexSort(sort);//排序
config.setCommitOnClose(true);
// 自动提交
// config.setMergeScheduler(new ConcurrentMergeScheduler());
// config.setIndexDeletionPolicy(new
// SnapshotDeletionPolicy(NoDeletionPolicy.INSTANCE));
iwriter = new IndexWriter(directory, config);
} catch (IOException e) {
e.printStackTrace();
}
return iwriter;
} /**
* 关闭索引文件生成对象以及文件夹对象
*
* @param indexWriter
* @param directory
*/
public static void close(IndexWriter indexWriter, Directory directory) {
if (indexWriter != null) {
try {
indexWriter.close();
} catch (IOException e) {
indexWriter = null;
}
}
if (directory != null) {
try {
directory.close();
} catch (IOException e) {
directory = null;
}
}
} /**
* 关闭索引文件读取对象以及文件夹对象
*
* @param reader
* @param directory
*/
public static void close(DirectoryReader reader, Directory directory) {
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
reader = null;
}
}
if (directory != null) {
try {
directory.close();
} catch (IOException e) {
directory = null;
}
} } /**
* 高亮标签
*
* @param query
* @param fieldName
* @return
*/ public static Highlighter getHighlighter(Query query, String fieldName)
{
Formatter formatter = new SimpleHTMLFormatter("<span style='color:red'>", "</span>");
Scorer fragmentScorer = new QueryTermScorer(query, fieldName);
Highlighter highlighter = new Highlighter(formatter, fragmentScorer);
highlighter.setTextFragmenter(new SimpleFragmenter(200));
return highlighter;
}
}
Lucene入门及实际项目应用场景的更多相关文章
- [转帖]kafka入门:简介、使用场景、设计原理、主要配置及集群搭建
kafka入门:简介.使用场景.设计原理.主要配置及集群搭建 http://www.aboutyun.com/thread-9341-1-1.html 还没看完 感觉挺好的. 问题导读: 1.zook ...
- 微信小程序初体验,入门练手项目--通讯录,部署上线(二)
接上一篇<微信小程序初体验,入门练手项目--通讯录,后台是阿里云服务器>:https://www.cnblogs.com/chengxs/p/9898670.html 开发微信小程序最尴尬 ...
- 微信小程序初体验,入门练手项目--通讯录,后台是阿里云服务器(一)
内容: 一.前言 二.相关概念 三.开始工作 四.启动项目起来 五.项目结构 六.设计理念 七.路由 八.部署线上后端服务 同步交流学习社区: https://www.mwcxs.top/page/4 ...
- 推荐:一个适合于Python新手的入门练手项目
随着人工智能的兴起,国内掀起了一股Python学习热潮,入门级编程语言,大多选择Python,有经验的程序员,也开始学习Python,正所谓是人生苦短,我用Python 有个Python入门练手项目, ...
- C#游戏开发高速入门 2.1 构建游戏场景
C#游戏开发高速入门 2.1 构建游戏场景 假设已经计划好了要编写什么样的游戏,在打开Unity以后.要做的第一件事情就是构建游戏场景(Scene).游戏场景就是玩家游戏时,在游戏视图中看到的一切. ...
- 《区块链DAPP开发入门、代码实现、场景应用》笔记5——区块链福利彩票的设计
笔者一直强调,一定要利用区块链的特点来解决行业存在的问题,并且该问题最好用区块链解决或者说只能用区块链解决.彩票行业就是个例子. 在讲解代码之前,首先讲解一下业务设计,如图6.15所示. 图6.15 ...
- 《区块链DAPP开发入门、代码实现、场景应用》笔记4——Ethereum Wallet中部署合约
账号创建完成之后,账号余额是0,但是部署合约是需要消耗GAS的,因此需要获取一定的以太币才能够继续本次实现.在测试网中获取以太币可以通过挖矿的方式,在开发菜单中可以选择打开挖矿模式,但是这需要将Syn ...
- 《区块链DAPP开发入门、代码实现、场景应用》笔记3——Ethereum Wallet的安装
以太坊官方网站可以下载最新版本的Ethereum Wallet,用户无需选择,浏览器会根据访问者操作系统版本自动展现合适的版本,点击DOWNLOAD按钮下载即可安装,如图2.9所示,其下载网址: ht ...
- 《区块链DAPP开发入门、代码实现、场景应用》笔记2——Solidity实现简单的智能合约
本节仅以一个简单的智能合约示例,介绍智能合约的基本组成元素,本合约定义一个uint类型的变量,以及对应这个变量的读写函数. 01 pragma solidity >=0.4.0 <0.6. ...
随机推荐
- .NET 6 预览版 5 发布
很高兴.NET 6 预览版5终于跟大家见面了.我们现在正处于.NET 6 的后半部分,开始整合一些重要的功能. 例如.NET SDK 工作负载,它是我们.NET 统一愿景的基础,可以支持更多类型的应用 ...
- chanakya
仅供个人娱乐 参考http://www.saulgoodman.cn/HA-Chanakya.html 靶机信息 https://www.vulnhub.com/entry/ha-chanakya,3 ...
- QT经验(一)——按钮长按事件分析
引言 最近在做qt项目,需要对button按钮添加一个长按事件(比如点击按钮,开始运动.松开按钮,运动停止).查了些许资料,(差点误把QPushButton的press信号和长按事件混淆)在此记录一下 ...
- ;~ 并发运行的AutoHotkey脚本真机实际测试模板参考20191010.ahk
;~ 并发运行的AutoHotkey脚本真机实际测试模板参考20191010.ahk;~ 2019年10月10日;~ 徐晓亮(aahk6188);~ 操作系统测试环境: Windows 7 专业版 3 ...
- Java 反射(二)运行时获取类的信息
目录 一.获得类的运行时结构 1. 获得类的名字 2. 获得类的属性 获取属性列表 获取指定属性 3. 获取类的方法 获得类的方法列表 获得指定方法 4. 获得的构造器 获得构造器列表 获得指定构造器 ...
- 大写字母与小写字母 相差 一个 空格 A = 65 a = 97 空格 = 32
1 //大写字母与小写字母 相差 一个 空格 A = 65 a = 97 空格 = 32 2 3 #include <stdio.h> 4 int main() 5 { 6 7 char ...
- 通读BadCode
简介 就是旋哥的BadCode系列,这次好好通读下,然后我在旋哥的注释上又加了一些,函数原型等. 项目地址:https://github.com/Rvn0xsy/BadCode 第一课 主要介绍了下c ...
- 阿里面试Redis常考问题
一提到Redis缓存,我们不得不了解的三个问题就是:缓存雪崩.缓存击穿和缓存穿透.这三个问题一旦发生,会导致大量的请求直接请求到数据库层.如果并发压力大,就会导致数据库崩溃.那p0级的故障是没跑了. ...
- 使用账号密码来操作github? NO!
目录 简介 背景介绍 创建令牌 使用令牌 缓存令牌 使用GCM 总结 简介 最近在更新github文件的时候,突然说不让更新了,让我很是困惑,原因是在2021年8月13号之后,github已经不让直接 ...
- 温故知新,微软官方推荐的Visual Studio源代码管理之Git Ignore清单,开启新项目必备宝书
什么是Git Ignore清单 https://git-scm.com/docs/gitignore 简单来说,在Git进行源代码管理中,我们可以通过建立.gitignore来实现一个忽略的黑名单管理 ...