java中的JSON对象的使用

申明：没工作之前都没听过JSON，可能是自己太菜了。可能在前台AJAX接触到JSON，这几天要求在纯java的编程中，返回JSON字符串形式。

网上有两种解析JSON对象的jar包：JSON-lib.jar和json.jar,这里主要介绍JSON-lib.jar。

jar包地址如下：

json-lib-2.4-jdk15.jar所需全部JAR包.rar

一、JSON-lib.jar还依赖以下jar包：

1. commons-lang.jar
2. commons-beanutils.jar
3. commons-collections.jar
4. commons-logging.jar
5. ezmorph.jar
6. json-lib-2.2.2-jdk15.jar

二、应用

　　JSON也是以key-value形式存在的。key是字符串，value可以是基本类型、JSONArray、JSONObject.

　　JSONArray:[],望文生义也知道，他是数组形式，又可要放多个JSON

　　JSONObject:{}就放一个JSON。

　　由于他们的他们可以嵌套形式就比较多。

三、输出JSON实例考虑到对[]、{}进行对比，区别重复的变量，对变量名进行了首字母大写，显得不规范了。

import net.sf.json.JSONArray;
import net.sf.json.JSONObject;
public class JSONTest {

    public static void main(String[] args) {
        JSONObject container1 = new JSONObject();
        container1.put("ClassName", "高三一班");
        System.out.println(container1.toString());

        JSONArray className = new JSONArray();
        className.add("高三一班");
        container1.put("className", className);
        System.out.println(container1.toString());

        JSONObject classInfo = new JSONObject();
        classInfo.put("stuCount", 50);
        classInfo.put("leader", "rah");
        container1.put("classInfo", classInfo);
        System.out.println(container1);

        JSONObject ClassInfo = new JSONObject();
        JSONArray stuCount = new JSONArray();
        stuCount.add(50);
        JSONArray leader = new JSONArray();
        leader.add("rah");
        ClassInfo.put("stuCount", stuCount);
        ClassInfo.put("leader", leader);
        container1.put("ClassInfo", ClassInfo);
        System.out.println(container1);

        JSONArray students = new JSONArray();
        JSONObject studentOne = new JSONObject();
        studentOne.put("name", "张麻子");
        studentOne.put("sex", "男");
        studentOne.put("age", 12);
        studentOne.put("hobby", "java develop");

        JSONObject studentTwo = new JSONObject();
        studentTwo.put("name", "王瘸子");
        studentTwo.put("sex", "男");
        studentTwo.put("age", 13);
        studentTwo.put("hobby", "C/C++ develop");

        students.add(studentOne);
        students.add(studentTwo);
        container1.put("students", students);
        System.out.println(container1);

        JSONArray Students = new JSONArray();
        JSONObject StudnetOne = new JSONObject();
        JSONArray name1 = new JSONArray();
        name1.add("张麻子");
        JSONArray sex1 = new JSONArray();
        sex1.add("男");
        JSONArray age1= new JSONArray();
        age1.add("12");
        JSONArray hobby1 = new JSONArray();
        hobby1.add("java develop");
        StudnetOne.put("name", name1);
        StudnetOne.put("sex", sex1);
        StudnetOne.put("age", age1);
        StudnetOne.put("hobby", hobby1);

        JSONObject StudnetTwo = new JSONObject();
        JSONArray name2 = new JSONArray();
        name2.add("王瘸子");
        JSONArray sex2 = new JSONArray();
        sex2.add("男");
        JSONArray age2= new JSONArray();
        age2.add("13");
        JSONArray hobby2 = new JSONArray();
        hobby2.add("C/C++ develop");
        StudnetTwo.put("name", name2);
        StudnetTwo.put("sex", sex2);
        StudnetTwo.put("age", age2);
        StudnetTwo.put("hobby", hobby2);

        Students.add(StudnetOne);
        Students.add(StudnetTwo);
        container1.put("Students", Students);
        System.out.println(container1);

        JSONArray teachers = new JSONArray();
        teachers.add(0,"王老师");
        teachers.add(1,"李老师 ");
        container1.put("teachers", teachers);
        System.out.println(container1);

        JSONArray Teachers = new JSONArray();
        JSONObject teacher1 = new JSONObject();
        teacher1.put("name", "小梅");
        teacher1.put("introduce","他是一个好老师");

        JSONObject teacher2 = new JSONObject();
        teacher2.put("name", "小李");
        teacher2.put("introduce","他是一个合格的老师");

        Teachers.add(0,teacher1);
        Teachers.add(1,teacher2);
        container1.put("Teachers", Teachers);
        System.out.println(container1);
    }
}

运行结果：

{"ClassName":"高三一班"}
{"ClassName":"高三一班","className":["高三一班"]}
{"ClassName":"高三一班","className":["高三一班"],"classInfo":{"stuCount":50,"leader":"rah"}}
{"ClassName":"高三一班","className":["高三一班"],"classInfo":{"stuCount":50,"leader":"rah"},"ClassInfo":{"stuCount":[50],"leader":["rah"]}}

{"ClassName":"高三一班","className":["高三一班"],"classInfo":{"stuCount":50,"leader":"rah"},"ClassInfo":{"stuCount":[50],"leader":["rah"]},"students":[{"name":"张麻子","sex":"男","age":12,"hobby":"java develop"},{"name":"王瘸子","sex":"男","age":13,"hobby":"C/C++ develop"}]}

{"ClassName":"高三一班","className":["高三一班"],"classInfo":{"stuCount":50,"leader":"rah"},"ClassInfo":{"stuCount":[50],"leader":["rah"]},"students":[{"name":"张麻子","sex":"男","age":12,"hobby":"java develop"},{"name":"王瘸子","sex":"男","age":13,"hobby":"C/C++ develop"}],"Students":[{"name":["张麻子"],"sex":["男"],"age":["12"],"hobby":["java develop"]},{"name":["王瘸子"],"sex":["男"],"age":["13"],"hobby":["C/C++ develop"]}]}

{"ClassName":"高三一班","className":["高三一班"],"classInfo":{"stuCount":50,"leader":"rah"},"ClassInfo":{"stuCount":[50],"leader":["rah"]},"students":[{"name":"张麻子","sex":"男","age":12,"hobby":"java develop"},{"name":"王瘸子","sex":"男","age":13,"hobby":"C/C++ develop"}],"Students":[{"name":["张麻子"],"sex":["男"],"age":["12"],"hobby":["java develop"]},{"name":["王瘸子"],"sex":["男"],"age":["13"],"hobby":["C/C++ develop"]}],"teachers":["王老师","李老师 "]}

{"ClassName":"高三一班","className":["高三一班"],"classInfo":{"stuCount":50,"leader":"rah"},"ClassInfo":{"stuCount":[50],"leader":["rah"]},"students":[{"name":"张麻子","sex":"男","age":12,"hobby":"java develop"},{"name":"王瘸子","sex":"男","age":13,"hobby":"C/C++ develop"}],"Students":[{"name":["张麻子"],"sex":["男"],"age":["12"],"hobby":["java develop"]},{"name":["王瘸子"],"sex":["男"],"age":["13"],"hobby":["C/C++ develop"]}],"teachers":["王老师","李老师 "],"Teachers":[{"name":"小梅","introduce":"他是一个好老师"},{"name":"小李","introduce":"他是一个合格的老师"}]}

四、遍历JSON实例

以上面的输出的JSON字符串进行按顺序给它遍历

　　　　 String ClassName1 = (String) container1.get("ClassName");
        System.out.println("ClassName data is: " + ClassName1);

        JSONArray className1 = container1.getJSONArray("className");
        System.out.println("className data is: " + className1);

        JSONObject classInfo1 = container1.getJSONObject("classInfo");
        System.out.println("classInfo data is: " + classInfo1);

        JSONObject ClassInfo1 = container1.getJSONObject("ClassInfo");
        System.out.println("ClassInfo data is: " + ClassInfo1);

        JSONArray students1 = container1.getJSONArray("students");
        System.out.println("students data is： " + students1);

        JSONArray Students1 = container1.getJSONArray("Students");
        System.out.println("Students data is: " + Students1);

        JSONArray teachers1 = container1.getJSONArray("teachers");
        for(int i=0; i < teachers1.size(); i++){
            System.out.println("teahcer " + i + " is: "+ teachers1.get(i));
        }

        JSONArray Teachers1 = container1.getJSONArray("Teachers");
        for(int i=0; i < Teachers1.size(); i++){
            System.out.println("Teachers " + i + " is: "+ Teachers1.get(i));
        }

遍历结果：

ClassName data is: 高三一班
className data is: ["高三一班"]
classInfo data is: {"stuCount":50,"leader":"rah"}
ClassInfo data is: {"stuCount":[50],"leader":["rah"]}
students data is： [{"name":"张麻子","sex":"男","age":12,"hobby":"java develop"},{"name":"王瘸子","sex":"男","age":13,"hobby":"C/C++ develop"}]
Students data is: [{"name":["张麻子"],"sex":["男"],"age":["12"],"hobby":["java develop"]},{"name":["王瘸子"],"sex":["男"],"age":["13"],"hobby":["C/C++ develop"]}]
teahcer 0 is: 王老师
teahcer 1 is: 李老师
Teachers 0 is: {"name":"小梅","introduce":"他是一个好老师"}
Teachers 1 is: {"name":"小李","introduce":"他是一个合格的老师"}

上面包括了大部份的JSON的嵌套形式，可能有忽略的也可以参考上面的内容。