JDBC入门学习
Introduction
What's JDBC
JDBC stands for Java Database Connectivity, which is a standard Java API for database-independent connectivity between the Java programming language and a wide range of databases.
JDBC library (includes APIs)的主要用途包括
Making a connection to a database. 连接数据库
Creating SQL or MySQL statements. 创建SQL或者MySQL语句
Executing SQL or MySQL queries in the database. 执行SQL或者MySQL查询
Viewing & Modifying the resulting records. 查看或者修改结果
JDBC架构
JDBC支持两层或者三层处理逻辑。但是一般,包括两层结构
JDBC API: This provides the application-to-JDBC Manager connection.
JDBC Driver API: This supports the JDBC Manager-to-Driver Connection.
JDBC drivers实现了JDBC APIs定义的接口。
JDBC连接
连接JDBC通常有四个简单的步骤
Import JDBC Packages: Add import statements to your Java program to import required classes in your Java code.
Register JDBC Driver: This step causes the JVM to load the desired driver implementation into memory so it can fulfill your JDBC requests.
Database URL Formulation: This is to create a properly formatted address that points to the database to which you wish to connect.
Create Connection Object: Finally, code a call to the DriverManagerobject's getConnection( ) method to establish actual database connection.
注册JDBC driver
注册JDBC driver有两种方法:
Approach 1: Class.forName() 自动将driver相关class加载到内存
try {
Class.forName("oracle.jdbc.driver.OracleDriver");
}
catch(ClassNotFoundException ex) {
System.out.println("Error: unable to load driver class!");
System.exit(1);
}
Approach 2: DriverManager.registerDriver() 如果使用的是 non-JDK compliant JVM
try {
Driver myDriver = new oracle.jdbc.driver.OracleDriver();
DriverManager.registerDriver( myDriver );
}
catch(ClassNotFoundException ex) {
System.out.println("Error: unable to load driver class!");
System.exit(1);
}
Database URL formulation
加载完driver之后,可以用DriverManager.getConnection()建立连接。
下面是常用数据库与connection URL的映射表
RDBMS | JDBC driver name | URL format |
---|---|---|
MySQL | com.mysql.jdbc.Driver | jdbc:mysql://hostname/ databaseName |
ORACLE | oracle.jdbc.driver.OracleDriver | jdbc:oracle:thin:@hostname:port Number:databaseName |
DB2 | COM.ibm.db2.jdbc.net.DB2Driver | jdbc:db2:hostname:port Number/databaseName |
Sybase | com.sybase.jdbc.SybDriver | jdbc:sybase:Tds:hostname: port Number/databaseName |
JDBC statement,PreparedStatement & CallableStatement
根据不同的需用,可以选择不同的statement接口。
Interfaces | Recommended Use |
---|---|
Statement | Use for general-purpose access to your database. Useful when you are using static SQL statements at runtime. The Statement interface cannot accept parameters. |
PreparedStatement | Use when you plan to use the SQL statements many times. The PreparedStatement interface accepts input parameters at runtime. |
CallableStatement | Use when you want to access the database stored procedures. The CallableStatement interface can also accept runtime input parameters. |
Statement
创建statement
Statement stmt = null;
try {
stmt = conn.createStatement( );
. . .
}
catch (SQLException e) {
. . .
}
finally {
. . .
}
执行statement
创建完statement object之后,可以用来执行SQL语句
boolean execute (String SQL): Returns a boolean value of true if a ResultSet object can be retrieved; otherwise, it returns false. Use this method to execute SQL DDL statements or when you need to use truly dynamic SQL.
int executeUpdate (String SQL): Returns the number of rows affected by the execution of the SQL statement. Use this method to execute SQL statements for which you expect to get a number of rows affected - for example, an INSERT, UPDATE, or DELETE statement.
ResultSet executeQuery (String SQL): Returns a ResultSet object. Use this method when you expect to get a result set, as you would with a SELECT statement.
关闭statement
如果close connection节省数据库资源一样,close statement可以确保资源的合理回收。
Statement stmt = null;
try {
stmt = conn.createStatement( );
. . .
}
catch (SQLException e) {
. . .
}
finally {
stmt.close();
}
JDBC 批处理
批处理(batch processing)允许一次执行多条SQL语句。由于JDBC drivers并没有要求实现这个功能,因此使用前先用 DatabaseMetaData.supportsBatchUpdates() 检测目标数据库是否支持批处理。
Statement对象的批处理
Create a Statement object using either createStatement() methods.
Set auto-commit to false using setAutoCommit().
Add as many as SQL statements you like into batch using addBatch()method on created statement object.
Execute all the SQL statements using executeBatch() method on created statement object.
Finally, commit all the changes using commit() method.
// Create statement object
Statement stmt = conn.createStatement(); // Set auto-commit to false
conn.setAutoCommit(false); // Create SQL statement
String SQL = "INSERT INTO Employees (id, first, last, age) " +
"VALUES(200,'Zia', 'Ali', 30)";
// Add above SQL statement in the batch.
stmt.addBatch(SQL); // Create one more SQL statement
String SQL = "INSERT INTO Employees (id, first, last, age) " +
"VALUES(201,'Raj', 'Kumar', 35)";
// Add above SQL statement in the batch.
stmt.addBatch(SQL); // Create one more SQL statement
String SQL = "UPDATE Employees SET age = 35 " +
"WHERE id = 100";
// Add above SQL statement in the batch.
stmt.addBatch(SQL); // Create an int[] to hold returned values
int[] count = stmt.executeBatch(); //Explicitly commit statements to apply changes
conn.commit();
PreparedStatement对象的批处理
// Create SQL statement
String SQL = "INSERT INTO Employees (id, first, last, age) " +
"VALUES(?, ?, ?, ?)"; // Create PrepareStatement object
PreparedStatemen pstmt = conn.prepareStatement(SQL); //Set auto-commit to false
conn.setAutoCommit(false); // Set the variables
pstmt.setInt( 1, 400 );
pstmt.setString( 2, "Pappu" );
pstmt.setString( 3, "Singh" );
pstmt.setInt( 4, 33 );
// Add it to the batch
pstmt.addBatch(); // Set the variables
pstmt.setInt( 1, 401 );
pstmt.setString( 2, "Pawan" );
pstmt.setString( 3, "Singh" );
pstmt.setInt( 4, 31 );
// Add it to the batch
pstmt.addBatch(); //add more batches
.
.
.
.
//Create an int[] to hold returned values
int[] count = stmt.executeBatch(); //Explicitly commit statements to apply changes
conn.commit();
References
http://www.tutorialspoint.com/jdbc/jdbc-where-clause.htm
http://stackoverflow.com/questions/2839321/connect-java-to-a-mysql-database
JDBC入门学习的更多相关文章
- mysql的jdbc入门学习小结
转自:专注JavaWeb开发 http://www.javaweb1024.com/data/MySQL/2015/04/25/618.html 一.jdbc基本概念jdbc : Java Datab ...
- MyBatis入门学习教程-使用MyBatis对表执行CRUD操作
上一篇MyBatis学习总结(一)--MyBatis快速入门中我们讲了如何使用Mybatis查询users表中的数据,算是对MyBatis有一个初步的入门了,今天讲解一下如何使用MyBatis对use ...
- MyBatis入门学习(二)
在MyBatis入门学习(一)中我们完成了对MyBatis简要的介绍以及简单的入门小项目测试,主要完成对一个用户信息的查询.这一节我们主要来简要的介绍MyBatis框架的增删改查操作,加深对该框架的了 ...
- Jdbc入门
JDBC入门 l 导jar包:驱动! l 加载驱动类:Class.forName(“类名”); l 给出url.username.password,其中url背下来! l 使用DriverMa ...
- JDBC 接口学习
说明:文章所有内容皆选自实验楼教程[JDBC 入门教程],想要学习更多JDBC,可以点击教程进行学习~ JDBC 简介 JDBC 的全称是 Java Database Connectivity,叫做 ...
- day17(JDBC入门&jdbcUtils工具介绍)
day17 JDBC整体思维导图 JDBC入门 导jar包:驱动! 加载驱动类:Class.forName("类名"); 给出url.username.password,其中url ...
- Mybatis基础入门学习
Mybatis基础入门学习 mybatis架构分析 搭建测试mybatis架构 )下载并导入mybatis3.2.7.jar(架构),mysql-connector-java-5.1.7-bin.ja ...
- JDBC的学习 3-1
JDBC的学习 3-1 JDBC基本概念 快速入门 对JDBC中各个接口和类详解 JDBC : 概念 :Java DateBase Connectivity java数据库连接,Java语言操作数据库 ...
- vue入门学习(基础篇)
vue入门学习总结: vue的一个组件包括三部分:template.style.script. vue的数据在data中定义使用. 数据渲染指令:v-text.v-html.{{}}. 隐藏未编译的标 ...
随机推荐
- codeforces 597C C. Subsequences(dp+树状数组)
题目链接: C. Subsequences time limit per test 1 second memory limit per test 256 megabytes input standar ...
- AC日记——最小的N个和 codevs 1245
1245 最小的N个和 时间限制: 1 s 空间限制: 128000 KB 题目等级 : 钻石 Diamond 题解 查看运行结果 题目描述 Description 有两个长度为 N ...
- WWW读取安卓外部音乐文件
需求分析 使用Everyplay(2121-1540版本)录屏,在升级SDK之后,遇到个问题,调用安卓原生的mediaplay进行播放音乐,在录屏时无法录制到声音,所以想到的解决办法是在Unity中播 ...
- 谈c++ pb_ds库(一)rope大法好
参考资料 1)官方说明 支持 sorry,cena不支持rope 声明 1)头文件 #include<ext/rope> 2)调用命名空间 using namespace __gnu_cx ...
- 安全测试 - CSRF攻击及防御
CSRF(Cross-site request forgery跨站请求伪造) 尽管听起来像跨站脚本(XSS),但它与XSS非常不同,并且攻击方式几乎相左.XSS利用站点内的信任用户,而CSRF则通过伪 ...
- Python mock
在测试过程中,为了更好地展开单元测试,mock一些数据跟对象在所难免,下面讲一下python的mock的简单用法. 关于python mock,网上有很多资料,这里不会讲的特别深,但一定会是实用为主, ...
- [LeetCode] Unique Substrings in Wraparound String 封装字符串中的独特子字符串
Consider the string s to be the infinite wraparound string of "abcdefghijklmnopqrstuvwxyz" ...
- [LeetCode] Construct Binary Tree from Preorder and Inorder Traversal 由先序和中序遍历建立二叉树
Given preorder and inorder traversal of a tree, construct the binary tree. Note:You may assume that ...
- Android/Linux下CGroup框架分析及其使用
1 cgroup介绍 CGroup是control group的简称,它为Linux kernel提供一种任务聚集和划分的机制,可以限制.记录.隔离进程组(process groups)所使用的资源( ...
- web兼容学习分析笔记-margin 和padding浏览器解析差异
二.margin 和padding浏览器解析差异 只有默认margin的元素 <body>margin:8px margin:15px 10px 15px 10px(IE7) <b ...