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(); } }