在JAVA中使用JSONObject生成json

JSON是一種輕量級的數據交換格式，在現在的web開發中，是非常常見的。在沒有方便的工具之前，我們或許會使用拼字符串的形式來生成json數組，今天我們使用一個json-lib.jar包來為我們實現生成json的功能。

所必須的包有：

commons-httpclient-3.1.jar

commons-lang-2.4.jar

commons-logging-1.1.1.jar

json-lib-2.4-jdk15.jar

ezmorph-1.0.6.jar

commons-collections-3.2.1.jar

 

 1、bean轉為Json

User u = new User(); u.setAge(22);

u.setUsername("hzucmj"); u.setEnabled(true);

JSONObject json = JSONObject.fromObject(u);

System.out.println(json.toString());

//結果為：

{"enabled":true,"username":"hzucmj","age":22}

2、List轉為Json

User u1 = new User(); u1.setAge(22);

u1.setUsername("hzucmj");

u1.setEnabled(true);

 User u2 = new User();

u2.setAge(20); u2.setUsername("ctf");

u2.setEnabled(true);

      List<Object> list = new ArrayList<Object>();

          list.add(u1);

          list.add(u2);

  JSONArray json = JSONArray.fromObject(list);

System.out.println(json.toString());

//結果為：

[{"enabled":false,"username":"ctf","age":20},{"enabled":false,"username":"","age":0}]

3、Map轉為Json

HashMap<String, Comparable> map = new HashMap<String, Comparable>();

map.put("name", "hzucmj"); map.put("age", 22);

JSONObject json = JSONObject.fromObject(list);

System.out.println(json.toString());

//結果為：

{"name":"hzucmj","age":22}

 

 

基於json-lib.jar包 JSONObject-Java常用的四種用法

基於json-lib.jar包Json

實例程序 1.

JSONObject to DynaBean String json = "{name=\"json\",bool:true,int:1,double:2.2}";

JSONObject jsonObject = JSONObject.fromObject(json);

//抽象的寫法：

DynaBean bean = (DynaBean) JSONSerializer.toJava( jsonObject );

Object bean = JSONObject.toBean(jsonObject);

//Object bean1 = JSONSerializer.toJava(jsonObject);

assertEquals(jsonObject.get("name"), PropertyUtils.getProperty(bean, "name"));

assertEquals(jsonObject.get("bool"), PropertyUtils.getProperty(bean, "bool"));

assertEquals(jsonObject.get("int"), PropertyUtils.getProperty(bean, "int"));

assertEquals(jsonObject.get("double"), PropertyUtils.getProperty(bean, "double"));

2.JSONObject to JavaBean String json = "{name:\"zhangsan\",age:25,hight:1.72,sex:true}";

JSONObject jsonObject = JSONObject.fromObject(json);

UserBean bean = (UserBean) JSONObject.toBean(jsonObject, UserBean.class);

System.out.println(jsonObject);

理論上，這樣就可以了，但時，有異常Caused by: java.lang.NoSuchMethodException: com.json.Json$UserBean.<init>()

3.JSONArray to List String json = "[\"first\",\"second\"]";

JSONArray jsonArray = (JSONArray) JSONSerializer.toJSON(json);

List output = (List) JSONSerializer.toJava(jsonArray);

4.JSONArray to array String json = "[\"first\",\"second\"]";

JSONArray jsonArray = (JSONArray) JSONSerializer.toJSON(json);

JsonConfig jsonConfig = new JsonConfig();

jsonConfig.setArrayMode(JsonConfig.MODE_OBJECT_ARRAY);

Object[] output = (Object[]) JSONSerializer.toJava(jsonArray, jsonConfig);

Object[] expected = new Object[] { "first", "second" };

ArrayAssertions.assertEquals(expected, output);