日志——JSON的相关方法

http://www.cnblogs.com/henryxu/archive/2013/03/10/2952738.html

JSON  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

 /**
       * 从json数组中得到相应java数组
       * JSONArray下的toArray()方法的使用
       * @param str
       * @return
       */
       public static Object[] getJsonToArray(String str) {
           JSONArray jsonArray = JSONArray.fromObject(str);
           return jsonArray.toArray();
       }

    public static void main(String[] args) {
         JSONArray jsonStrs = new JSONArray();
         jsonStrs.add(0, "cat");
         jsonStrs.add(1, "dog");
         jsonStrs.add(2, "bird");
         jsonStrs.add(3, "duck");

         Object[] obj=getJsonToArray(jsonStrs.toString());
         for(int i=0;i<obj.length;i++){
               System.out.println(obj[i]);
         }
     }

 package jsontest;

 import net.sf.json.JSONArray;
 import net.sf.json.JSONObject;

 public class JSONObjectSample {

     // 创建JSONObject对象
     private static JSONObject createJSONObject() {
         JSONObject jsonObject = new JSONObject();
         jsonObject.put("username", "huangwuyi");
         jsonObject.put("sex", "男");
         jsonObject.put("QQ", "413425430");
         jsonObject.put("Min.score", new Integer(99));
         jsonObject.put("nickname", "梦中心境");
         return jsonObject;
     }

     public static void main(String[] args) {
         JSONObject jsonObject = JSONObjectSample.createJSONObject();//静待方法，直接通过类名+方法调用
         // 输出jsonobject对象
         System.out.println("jsonObject：" + jsonObject);

         // 判读输出对象的类型
         boolean isArray = jsonObject.isArray();
         boolean isEmpty = jsonObject.isEmpty();
         boolean isNullObject = jsonObject.isNullObject();
         System.out.println("是否为数组:" + isArray + "， 是否为空:" + isEmpty
                 + "， isNullObject:" + isNullObject);

         // 添加属性，在jsonObject后面追加元素。
         jsonObject.element("address", "福建省厦门市");
         System.out.println("添加属性后的对象：" + jsonObject);

         // 返回一个JSONArray对象
         JSONArray jsonArray = new JSONArray();
         jsonArray.add(0, "this is a jsonArray value");
         jsonArray.add(1, "another jsonArray value");
         jsonObject.element("jsonArray", jsonArray);
         //在jsonObject后面追加一个jsonArray
         JSONArray array = jsonObject.getJSONArray("jsonArray");
         System.out.println(jsonObject);

         System.out.println("返回一个JSONArray对象：" + array);
         // 添加JSONArray后的值
         // {"username":"huangwuyi","sex":"男","QQ":"413425430","Min.score":99,"nickname":"梦中心境","address":"福建省厦门市","jsonArray":["this is a jsonArray value","another jsonArray value"]}
         System.out.println("结果=" + jsonObject);

         // 根据key返回一个字符串
         String username = jsonObject.getString("username");
         System.out.println("username==>" + username);

         // 把字符转换为 JSONObject
         String temp = jsonObject.toString();
         JSONObject object = JSONObject.fromObject(temp);
         // 转换后根据Key返回值
         System.out.println("qq=" + object.get("QQ"));

     }

 }

JAVA解析JSON数据

在网页中想后台传递多个数据时，有时数据还是多个动态列表，数据很复杂时，JavaScript程序员喜欢把他们作为json串进行处理，后台收到后需要对json字符串进行解析，幸好有JSON-lib，这个Java类包用于把bean,map和XML转换成JSON并能够把JSON转回成bean和DynaBean。
下载地址:http://json-lib.sourceforge.net/

 public class Test {

 /**

 * @param args

 * @author wen

 */

 public static void main(String[] args) {

 //            test1();

 //            test2();

 String json = “{1:{1:{jhinfo:['计划一','亲亲宝宝','www.wenhq.com'],jhrate:['1-5:10.0','6-100:5.0/1']},2:{jhinfo:['计划二','亲亲宝宝','www.wenhq.com'],jhrate:['1-100:100.0']},3:{jhinfo:['计划三','亲亲宝宝','www.wenhq.com'],jhrate:['1-100:150.0/7']}},2:{4:{jhinfo:['年计划','亲亲宝宝','www.wenhq.com'],jhrate:['365-365:1000.0']}}}”;

 try {

 JSONObject jsonObject = JSONObject.fromObject(json);

 String name = jsonObject.getString(“1″);

 String address = jsonObject.getString(“2″);

 System.out.println(“name is:” + name);

 System.out.println(“address is:” + address);

 Iterator it=jsonObject.keys();

 while (it.hasNext()){

 System.out.println(jsonObject.get(it.next()));

 }

 } catch (JSONException e) {

 e.printStackTrace();

 }

 }

 /**

 * json对象字符串转换

 * @author wen

 */

 private static void test2() {

 String json = “{‘name’: ‘亲亲宝宝’,'array’:[{'a':'111','b':'222','c':'333'},{},{'a':'999'}],’address’:'亲亲宝宝’}”;

 try {

 JSONObject jsonObject = JSONObject.fromObject(json);

 String name = jsonObject.getString(“name”);

 String address = jsonObject.getString(“address”);

 System.out.println(“name is:” + name);

 System.out.println(“address is:” + address);

 JSONArray jsonArray = jsonObject.getJSONArray(“array”);

 for (int i = 0; i < jsonArray.size(); i++) {

 System.out.println(“item ” + i + ” :” + jsonArray.getString(i));

 }

 } catch (JSONException e) {

 e.printStackTrace();

 }

 }

 /**

 * json数组 转换，数组以[开头

 * @author wen

 */

 private static void test1() {

 boolean[] boolArray = new boolean[]{true,false,true};

 JSONArray jsonArray1 = JSONArray.fromObject( boolArray );

 System.out.println( jsonArray1 );

 // prints [true,false,true]

 List list = new ArrayList();

 list.add( “first” );

 list.add( “second” );

 JSONArray jsonArray2 = JSONArray.fromObject( list );

 System.out.println( jsonArray2 );

 // prints ["first","second"]

 JSONArray jsonArray3 = JSONArray.fromObject( “['json','is','easy']” );

 System.out.println( jsonArray3 );

 // prints ["json","is","easy"]

 }

创建JSONArray的常用四种方法

1.从头或者从零开始，创建一个JSONArray(Creating a JSONArray from scratch) 
实例1：

Java代码  
JSONArray jsonArray = new JSONArray().element("JSON").element("1").element("2.0").element("true");   
assertEquals("JSON", jsonArray.getString(0));   
assertEquals(1, jsonArray.getInt(1));   
assertEquals(2.0d, jsonArray.getDouble(2), 0d);   
assertTrue(jsonArray.getBoolean(3));

3.使用一个Collection来创建一个JSONArray(Creating a JSONArray from a Collection) 
实例1：

Java代码  
List list = new ArrayList();  
list.add( "JSON" );   
list.add( "1" );   
list.add( "2.0" );   
list.add( "true" );   
JSONArray jsonArray = (JSONArray) JSONSerializer.toJSON( list ); assertEquals( "JSON", jsonArray.getString(0) );   
assertEquals( 1, jsonArray.getInt(1) );   
assertEquals( 2.0d, jsonArray.getDouble(2), 0d );   
assertTrue( jsonArray.getBoolean(3) );

4.使用一个Array来创建一个JSONArray(Creating a JSONArray from an array) 
实例1：

Java代码  
Object[] array = new Object[] { "JSON", 1, 2.0, true };   
JSONArray jsonArray = (JSONArray) JSONSerializer.toJSON(array); assertEquals("JSON", jsonArray.getString(0));  
assertEquals(1, jsonArray.getInt(1));   
assertEquals(2.0d, jsonArray.getDouble(2), 0d);   
assertTrue(jsonArray.getBoolean(3));   
  
//实例2：   
Object[] array = new Object[] { "JSON", 1, 2.0, true };   
JSONArray jsonArray = JSONArray.fromObject(array);   
assertEquals("JSON", jsonArray.getString(0));   
assertEquals(1, jsonArray.getInt(1));   
assertEquals(2.0d, jsonArray.getDouble(2), 0d);   
assertTrue(jsonArray.getBoolean(3));

由此可见，无论要转换的源是哪种类型，都可以使用(JSONArray) JSONSerializer.toJSON()或JSONArray.fromObject()来转换;

常用的三种扩展功能

1.使用一个JSON格式化字符串来创建一个JSONFunction(JavaScript functions)  
实例：

Java代码  
String str = "{func: function( param ){ doSomethingWithParam(param); }}";   
JSONObject jsonObject = (JSONObject) JSONSerializer.toJSON(str); JSONFunction func = (JSONFunction) jsonObject.get("func"); ArrayAssertions.assertEquals(new String[] { "param" }, func.getParams());   
assertEquals("doSomethingWithParam(param);", func.getText());

注：函数的写法要注意function(){},参数param是可选的！

2.排除一个JSON格式化字符串的某些属性(Exclude properties) 
实例：

Java代码  
String str = "{'string':'JSON', 'integer': 1, 'double': 2.0, 'boolean': true}";   
JsonConfig jsonConfig = new JsonConfig();   
jsonConfig.setExcludes(new String[] { "double", "boolean" }); JSONObject jsonObject = (JSONObject) JSONSerializer.toJSON(str, jsonConfig);   
assertEquals("JSON", jsonObject.getString("string"));   
assertEquals(1, jsonObject.getInt("integer"));  
assertFalse(jsonObject.has("double"));   
assertFalse(jsonObject.has("boolean"));

3.排除一个JSON格式化字符串的某些属性,使用过滤器(Exclude properties (with filters) 
实例： 
Java代码  
String str = "{'string':'JSON', 'integer': 1, 'double': 2.0, 'boolean': true}";  
JsonConfig jsonConfig = new JsonConfig(); jsonConfig.setJsonPropertyFilter(new PropertyFilter() {   
   public boolean apply(Object source, String name, Object value) {  
         if ("double".equals(name) || "boolean".equals(name))   
          { return true; }  
              return false; } });   
JSONObject jsonObject = (JSONObject) JSONSerializer.toJSON(str, jsonConfig);   
assertEquals("JSON", jsonObject.getString("string"));   
assertEquals(1, jsonObject.getInt("integer"));   
assertFalse(jsonObject.has("double"));   
assertFalse(jsonObject.has("boolean"));

JSONObject-Java常用的四种用法 
1.JSONObject to DynaBean

Java代码  
String json = "{name=\"json\",bool:true,int:1,double:2.2}"; JSONObject jsonObject = JSONObject.fromObject(json); //抽象的写法：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

Java代码  
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);

3.JSONArray to List

Java代码  
String json = "[\"first\",\"second\"]";   
JSONArray jsonArray = (JSONArray) JSONSerializer.toJSON(json);  
List output = (List) JSONSerializer.toJava(jsonArray);

4.JSONArray to array

Java代码  
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);

理论上，这样就可以了，但时，有异常Caused by: java.lang.NoSuchMethodException: com.json.Json$UserBean.<init>() 
   
2.使用一个JSON格式化字符串来创建一个JSONArray(Creating a JSONArray from a JSON formatted string)  
实例1：

Java代码  
String str = "['JSON', 1, 2.0, true]"; //注意该字符串的格式"[ , ]" JSONArray jsonArray = (JSONArray) JSONSerializer.toJSON( str ); assertEquals( "JSON", jsonArray.getString(0) );   
assertEquals( 1, jsonArray.getInt(1) );   
assertEquals( 2.0d, jsonArray.getDouble(2), 0d );   
assertTrue( jsonArray.getBoolean(3) );

Java代码  
List<String> list = new ArryList<String>(); list.add("a"); list.add("b"); Map<String,List<String>> map = new HashMap<String,List<String>>(); map.put("list",list); MessageUtils.outputJSONResult(JSONObject.fromObject(map).toString(), response); public class MessageUtils { public static void outputJSONResult(String result, HttpServletResponse response) { try { response.setHeader("ContentType", "text/json"); response.setCharacterEncoding("utf-8"); PrintWriter pw = response.getWriter(); pw.write(result); pw.flush(); pw.close(); } catch (IOException e) { e.printStackTrace(); } }