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：
- commons-lang.jar
- commons-beanutils.jar
- commons-collections.jar
- commons-logging.jar
- ezmorph.jar
- 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。