基于json-lib.jar包 创建JSONObject的四个常用方法

基于json-lib.jar包Json实例程序1.从头或者从零开始，创建一个JSONObject(Creating a JSONObject from scratch)实例1：   JSONObject jsonObject = new JSONObject();   jsonObject.element("name", "周星星");   jsonObject.element("sex", "male");   jsonObject.element("age", 18);   jsonObject.element("job", "student");   System.out.println(jsonObject.get("name"));// 周星星   System.out.println(jsonObject.get("job"));// student   System.out.println(jsonObject.getString("sex"));// male   System.out.println(jsonObject.getInt("age"));// 18实例2：   JSONObject jsonObject = new JSONObject().element("string", "JSON").element("integer", "1").element("double", "2.0").element("boolean", "true");   assertEquals("JSON", jsonObject.getString("string"));   assertEquals(1, jsonObject.getInt("integer"));   assertEquals(2.0d, jsonObject.getDouble("double"), 0d);   assertTrue(jsonObject.getBoolean("boolean"));   注：这是对实例1的一个简化版  2.使用一个JSON格式化字符串来创建一个JSONObject(Creating a JSONObject from a JSON formatted string)  实例1：   String json = "{name:\"周星星\",sex:\"male\",age:18,job:\"student\"}";   JSONObject jsonObject = JSONObject.fromObject(json);   //或者使用 JSONObject jsonObject = (JSONObject) JSONSerializer.toJSON(json);   System.out.println(jsonObject.get("name"));// 周星星   System.out.println(jsonObject.get("job"));// student   System.out.println(jsonObject.getString("sex"));// male   System.out.println(jsonObject.getInt("age"));// 18实例2：   String str = "{'string':'JSON', 'integer': 1, 'double': 2.0, 'boolean': true}";   JSONObject jsonObject = (JSONObject) JSONSerializer.toJSON(str);   assertEquals("JSON", jsonObject.getString("string"));   assertEquals(1, jsonObject.getInt("integer"));   assertEquals(2.0d, jsonObject.getDouble("double"), 0d);   assertTrue(jsonObject.getBoolean("boolean"));  3.使用一个Map来创建一个JSONObject(Creating a JSONObject from a Map)实例1：   Map map = new HashMap();     map.put( "string", "JSON" );     map.put( "integer", "1" );     map.put( "double", "2.0" );     map.put( "boolean", "true" );     JSONObject jsonObject = (JSONObject) JSONSerializer.toJSON( map );     assertEquals( "JSON", jsonObject.getString("string") );           assertEquals( 1, jsonObject.getInt("integer") );           assertEquals( 2.0d, jsonObject.getDouble("double"), 0d );           assertTrue( jsonObject.getBoolean("boolean") );4.使用一个JavaBean来创建一个JSONObject(Creating a JSONObject from a JavaBean)实例1：public class Mybean {   private String string;   private int integer;   private double dooble;   private boolean bool;   // getters & setters}Mybean bean = new Mybean();bean.setString("JSON");bean.setInteger(1);bean.setDooble(2.0d);bean.setBool(true);JSONObject jsonObject = (JSONObject) JSONSerializer.toJSON(bean);assertEquals("JSON", jsonObject.getString("string"));assertEquals(1, jsonObject.getInt("integer"));assertEquals(2.0d, jsonObject.getDouble("dooble"), 0d);assertTrue(jsonObject.getBoolean("bool"));由此可见，无论要转换的源是哪种类型，都可以使用(JSONObject) JSONSerializer.toJSON()或JSONObject.fromObject()来转换;