JsonPath入门教程

有时候需要从json里面提取相关数据，必须得用到如何提取信息的知识，下面来写一下

语法格式

JsonPath	描述
$	根节点
@	当前节点
.or[]	子节点
..	选择所有符合条件的节点
*	所有节点
[]	迭代器标示，如数组下标
[,]	支持迭代器中做多选
[start:end:step]	数组切片运算符
?()	支持过滤操作
()	支持表达式计算

json格式的数据：

{ "store": {
    "book": [
      { "category": "reference",
        "author": "Nigel Rees",
        "title": "Sayings of the Century",
        "price": 8.95
      },
      { "category": "fiction",
        "author": "Evelyn Waugh",
        "title": "Sword of Honour",
        "price": 12.99,
        "isbn": "0-553-21311-3"
      }
    ],
    "bicycle": {
      "color": "red",
      "price": 19.95
    }
  }
}

测试代码：

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import com.jayway.jsonpath.JsonPath;

import java.util.List;

/*
{ "store": {
    "book": [
      { "category": "reference",
        "author": "Nigel Rees",
        "title": "Sayings of the Century",
        "price": 8.95
      },
      { "category": "fiction",
        "author": "Evelyn Waugh",
        "title": "Sword of Honour",
        "price": 12.99,
        "isbn": "0-553-21311-3"
      }
    ],
    "bicycle": {
      "color": "red",
      "price": 19.95
    }
  }
}
 */

public class JsonPathTest {
    private static String jsonStr="{ \"store\": {\n" +
            "    \"book\": [ \n" +
            "      { \"category\": \"reference\",\n" +
            "        \"author\": \"Nigel Rees\",\n" +
            "        \"title\": \"Sayings of the Century\",\n" +
            "        \"price\": 8.95\n" +
            "      },\n" +
            "      { \"category\": \"fiction\",\n" +
            "        \"author\": \"Evelyn Waugh\",\n" +
            "        \"title\": \"Sword of Honour\",\n" +
            "        \"price\": 12.99,\n" +
            "        \"isbn\": \"0-553-21311-3\"\n" +
            "      }\n" +
            "    ],\n" +
            "    \"bicycle\": {\n" +
            "      \"color\": \"red\",\n" +
            "      \"price\": 19.95\n" +
            "    }\n" +
            "  }\n" +
            "}";

    public static void main(String[] args) {
        JSONObject json = JSON.parseObject(jsonStr);//调用自定义的jsonTest()方法获得json对象，生成上面的json

        //输出book[0]的author值
        String author = JsonPath.read(json, "$.store.book[0].author");
        System.out.println(author);
        List<String> authorList = JsonPath.read(json, "$.store.book[*].author");
        for(String authors:authorList){
            System.out.println(authors);
        }

    }
}

　　测试结果

C:\JAVAS\jdk\bin\java "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2017.3.4\lib\idea_rt.jar=19319:C:\Program Files\JetBrains\IntelliJ IDEA 2017.3.4\bin" -Dfile.encoding=UTF- -classpath C:\JAVAS\jdk\jre\lib\charsets.jar;C:\JAVAS\jdk\jre\lib\deploy.jar;C:\JAVAS\jdk\jre\lib\ext\access-bridge-.jar;C:\JAVAS\jdk\jre\lib\ext\cldrdata.jar;C:\JAVAS\jdk\jre\lib\ext\dnsns.jar;C:\JAVAS\jdk\jre\lib\ext\jaccess.jar;C:\JAVAS\jdk\jre\lib\ext\jfxrt.jar;C:\JAVAS\jdk\jre\lib\ext\localedata.jar;C:\JAVAS\jdk\jre\lib\ext\nashorn.jar;C:\JAVAS\jdk\jre\lib\ext\sunec.jar;C:\JAVAS\jdk\jre\lib\ext\sunjce_provider.jar;C:\JAVAS\jdk\jre\lib\ext\sunmscapi.jar;C:\JAVAS\jdk\jre\lib\ext\sunpkcs11.jar;C:\JAVAS\jdk\jre\lib\ext\zipfs.jar;C:\JAVAS\jdk\jre\lib\javaws.jar;C:\JAVAS\jdk\jre\lib\jce.jar;C:\JAVAS\jdk\jre\lib\jfr.jar;C:\JAVAS\jdk\jre\lib\jfxswt.jar;C:\JAVAS\jdk\jre\lib\jsse.jar;C:\JAVAS\jdk\jre\lib\management-agent.jar;C:\JAVAS\jdk\jre\lib\plugin.jar;C:\JAVAS\jdk\jre\lib\resources.jar;C:\JAVAS\jdk\jre\lib\rt.jar;C:\Users\admin\diamond4\java-lesson2\lesson2-start\target\classes;D:\mvn_repository\org\springframework\boot\spring-boot-starter-web\1.5..RELEASE\spring-boot-starter-web-1.5..RELEASE.jar;D:\mvn_repository\org\springframework\boot\spring-boot-starter-tomcat\1.5..RELEASE\spring-boot-starter-tomcat-1.5..RELEASE.jar;D:\mvn_repository\org\apache\tomcat\embed\tomcat-embed-core\8.5.\tomcat-embed-core-8.5..jar;D:\mvn_repository\org\apache\tomcat\embed\tomcat-embed-el\8.5.\tomcat-embed-el-8.5..jar;D:\mvn_repository\org\apache\tomcat\embed\tomcat-embed-websocket\8.5.\tomcat-embed-websocket-8.5..jar;D:\mvn_repository\org\hibernate\hibernate-validator\5.3..Final\hibernate-validator-5.3..Final.jar;D:\mvn_repository\javax\validation\validation-api\1.1..Final\validation-api-1.1..Final.jar;D:\mvn_repository\org\jboss\logging\jboss-logging\3.3..Final\jboss-logging-3.3..Final.jar;D:\mvn_repository\com\fasterxml\classmate\1.3.\classmate-1.3..jar;D:\mvn_repository\com\fasterxml\jackson\core\jackson-databind\2.8.\jackson-databind-2.8..jar;D:\mvn_repository\com\fasterxml\jackson\core\jackson-annotations\2.8.\jackson-annotations-2.8..jar;D:\mvn_repository\com\fasterxml\jackson\core\jackson-core\2.8.\jackson-core-2.8..jar;D:\mvn_repository\org\springframework\spring-web\4.3..RELEASE\spring-web-4.3..RELEASE.jar;D:\mvn_repository\org\springframework\spring-webmvc\4.3..RELEASE\spring-webmvc-4.3..RELEASE.jar;D:\mvn_repository\org\springframework\spring-expression\4.3..RELEASE\spring-expression-4.3..RELEASE.jar;D:\mvn_repository\org\springframework\boot\spring-boot-starter-aop\1.5..RELEASE\spring-boot-starter-aop-1.5..RELEASE.jar;D:\mvn_repository\org\springframework\spring-aop\4.3..RELEASE\spring-aop-4.3..RELEASE.jar;D:\mvn_repository\org\aspectj\aspectjweaver\1.8.\aspectjweaver-1.8..jar;D:\mvn_repository\org\springframework\boot\spring-boot-starter-mail\1.5..RELEASE\spring-boot-starter-mail-1.5..RELEASE.jar;D:\mvn_repository\org\springframework\spring-context\4.3..RELEASE\spring-context-4.3..RELEASE.jar;D:\mvn_repository\com\sun\mail\javax.mail\1.5.\javax.mail-1.5..jar;D:\mvn_repository\javax\activation\activation\1.1\activation-1.1.jar;D:\mvn_repository\org\springframework\spring-test\4.3..RELEASE\spring-test-4.3..RELEASE.jar;D:\mvn_repository\jfree\jfreechart\1.0.\jfreechart-1.0..jar;D:\mvn_repository\jfree\jcommon\1.0.\jcommon-1.0..jar;D:\mvn_repository\com\alibaba\boot\dubbo-spring-boot-starter\0.1.\dubbo-spring-boot-starter-0.1..jar;D:\mvn_repository\com\alibaba\dubbo\2.5.\dubbo-2.5..jar;D:\mvn_repository\org\javassist\javassist\3.21.-GA\javassist-3.21.-GA.jar;D:\mvn_repository\org\jboss\netty\netty\3.2..Final\netty-3.2..Final.jar;D:\mvn_repository\org\apache\zookeeper\zookeeper\3.4.\zookeeper-3.4..jar;D:\mvn_repository\log4j\log4j\1.2.\log4j-1.2..jar;D:\mvn_repository\jline\jline\0.9.\jline-0.9..jar;D:\mvn_repository\io\netty\netty\3.10..Final\netty-3.10..Final.jar;D:\mvn_repository\org\apache\curator\curator-framework\2.12.\curator-framework-2.12..jar;D:\mvn_repository\org\apache\curator\curator-client\2.12.\curator-client-2.12..jar;D:\mvn_repository\com\alibaba\boot\dubbo-spring-boot-autoconfigure\0.1.\dubbo-spring-boot-autoconfigure-0.1..jar;D:\mvn_repository\com\alibaba\boot\dubbo-spring-boot-actuator\0.1.\dubbo-spring-boot-actuator-0.1..jar;D:\mvn_repository\mysql\mysql-connector-java\5.1.\mysql-connector-java-5.1..jar;D:\mvn_repository\com\google\guava\guava\22.0\guava-22.0.jar;D:\mvn_repository\com\google\code\findbugs\jsr305\1.3.\jsr305-1.3..jar;D:\mvn_repository\com\google\errorprone\error_prone_annotations\2.0.\error_prone_annotations-2.0..jar;D:\mvn_repository\com\google\j2objc\j2objc-annotations\1.1\j2objc-annotations-1.1.jar;D:\mvn_repository\org\codehaus\mojo\animal-sniffer-annotations\1.14\animal-sniffer-annotations-1.14.jar;D:\mvn_repository\org\apache\commons\commons-lang3\3.5\commons-lang3-3.5.jar;D:\mvn_repository\org\apache\httpcomponents\httpclient\4.5.\httpclient-4.5..jar;D:\mvn_repository\org\apache\httpcomponents\httpcore\4.4.\httpcore-4.4..jar;D:\mvn_repository\commons-logging\commons-logging\1.2\commons-logging-1.2.jar;D:\mvn_repository\commons-codec\commons-codec\1.10\commons-codec-1.10.jar;D:\mvn_repository\commons-io\commons-io\2.5\commons-io-2.5.jar;D:\mvn_repository\com\alibaba\fastjson\1.2.\fastjson-1.2..jar;D:\mvn_repository\org\quartz-scheduler\quartz\2.2.\quartz-2.2..jar;D:\mvn_repository\c3p0\c3p0\0.9.1.1\c3p0-0.9.1.1.jar;D:\mvn_repository\org\slf4j\slf4j-api\1.7.\slf4j-api-1.7..jar;D:\mvn_repository\org\quartz-scheduler\quartz-jobs\2.2.\quartz-jobs-2.2..jar;D:\mvn_repository\com\jayway\jsonpath\json-path\2.2.\json-path-2.2..jar;D:\mvn_repository\net\minidev\json-smart\2.2.\json-smart-2.2..jar;D:\mvn_repository\net\minidev\accessors-smart\1.1\accessors-smart-1.1.jar;D:\mvn_repository\org\ow2\asm\asm\5.0.\asm-5.0..jar;D:\mvn_repository\org\codehaus\groovy\groovy-all\2.1.\groovy-all-2.1..jar;D:\mvn_repository\org\projectlombok\lombok-maven-plugin\1.16.18.1\lombok-maven-plugin-1.16.18.1.jar;D:\mvn_repository\org\projectlombok\lombok\1.16.\lombok-1.16..jar;D:\mvn_repository\org\sonatype\plexus\plexus-build-api\0.0.\plexus-build-api-0.0..jar;D:\mvn_repository\org\codehaus\plexus\plexus-utils\1.5.\plexus-utils-1.5..jar;D:\mvn_repository\org\springframework\boot\spring-boot-configuration-processor\1.5..RELEASE\spring-boot-configuration-processor-1.5..RELEASE.jar;D:\mvn_repository\com\vaadin\external\google\android-json\0.0..vaadin1\android-json-0.0..vaadin1.jar;D:\mvn_repository\org\jsoup\jsoup\1.9.\jsoup-1.9..jar;D:\mvn_repository\org\springframework\boot\spring-boot-starter-freemarker\1.5..RELEASE\spring-boot-starter-freemarker-1.5..RELEASE.jar;D:\mvn_repository\org\springframework\boot\spring-boot-starter\1.5..RELEASE\spring-boot-starter-1.5..RELEASE.jar;D:\mvn_repository\org\springframework\boot\spring-boot-starter-logging\1.5..RELEASE\spring-boot-starter-logging-1.5..RELEASE.jar;D:\mvn_repository\ch\qos\logback\logback-classic\1.1.\logback-classic-1.1..jar;D:\mvn_repository\ch\qos\logback\logback-core\1.1.\logback-core-1.1..jar;D:\mvn_repository\org\slf4j\jcl-over-slf4j\1.7.\jcl-over-slf4j-1.7..jar;D:\mvn_repository\org\slf4j\jul-to-slf4j\1.7.\jul-to-slf4j-1.7..jar;D:\mvn_repository\org\slf4j\log4j-over-slf4j\1.7.\log4j-over-slf4j-1.7..jar;D:\mvn_repository\org\yaml\snakeyaml\1.17\snakeyaml-1.17.jar;D:\mvn_repository\org\freemarker\freemarker\2.3.-incubating\freemarker-2.3.-incubating.jar;D:\mvn_repository\org\springframework\spring-context-support\4.3..RELEASE\spring-context-support-4.3..RELEASE.jar;D:\mvn_repository\org\springframework\spring-beans\4.3..RELEASE\spring-beans-4.3..RELEASE.jar;D:\mvn_repository\org\apache\poi\poi-ooxml\3.17\poi-ooxml-3.17.jar;D:\mvn_repository\org\apache\poi\poi\3.17\poi-3.17.jar;D:\mvn_repository\org\apache\commons\commons-collections4\4.1\commons-collections4-4.1.jar;D:\mvn_repository\org\apache\poi\poi-ooxml-schemas\3.17\poi-ooxml-schemas-3.17.jar;D:\mvn_repository\org\apache\xmlbeans\xmlbeans\2.6.\xmlbeans-2.6..jar;D:\mvn_repository\stax\stax-api\1.0.\stax-api-1.0..jar;D:\mvn_repository\com\github\virtuald\curvesapi\1.04\curvesapi-1.04.jar;D:\mvn_repository\com\squareup\okhttp3\okhttp\3.2.\okhttp-3.2..jar;D:\mvn_repository\com\squareup\okio\okio\1.6.\okio-1.6..jar;D:\mvn_repository\org\springframework\spring-core\4.3..RELEASE\spring-core-4.3..RELEASE.jar;D:\mvn_repository\org\springframework\boot\spring-boot-devtools\1.5..RELEASE\spring-boot-devtools-1.5..RELEASE.jar;D:\mvn_repository\org\springframework\boot\spring-boot\1.5..RELEASE\spring-boot-1.5..RELEASE.jar;D:\mvn_repository\org\springframework\boot\spring-boot-autoconfigure\1.5..RELEASE\spring-boot-autoconfigure-1.5..RELEASE.jar com.longteng.lesson2.service.JsonPathTest
::59.081 [main] DEBUG com.jayway.jsonpath.internal.path.CompiledPath - Evaluating path: $['store']['book'][]['author']
Nigel Rees
::59.096 [main] DEBUG com.jayway.jsonpath.internal.path.CompiledPath - Evaluating path: $['store']['book'][*]['author']
Nigel Rees
Evelyn Waugh

Process finished with exit code