[javase][json]fastJson在java后台转换json格式数据探究--处理数组/List/Map

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本文介绍使用 FastJSON 库将 Java 对象如数组、列表和 Map 转换为 JSON 格式字符串的方法，并展示了如何反向操作，即将 JSON 字符串转换回 Java 对象。

原文地址:http://blog.youkuaiyun.com/hu_shengyang/article/details/8447787

直接给代码：

[java]view plaincopy 
   
 package fastJson.test;  
   
 import java.util.ArrayList;  
 import java.util.HashMap;  
 import java.util.List;  
 import java.util.Map;  
   
 import com.alibaba.fastjson.JSON;  
 import com.alibaba.fastjson.JSONArray;  
   
 public class FastJsonTest1  
 {  
   
     /** 
      * 数组转json格式字符串 
      */  
     public void array2Json(){  
         String[] arr = {"bill","green","maks","jim"};  
         String jsonText = JSON.toJSONString(arr, true);  
         System.out.println("array2Json()方法：jsonText=="+jsonText);  
         // 输出结果：jsonText==["bill","green","maks","jim"]  
     }  
   
     /** 
      * json格式字符串转数组 
      */  
     public void json2Array(){  
         String jsonText = "[\"bill\",\"green\",\"maks\",\"jim\"]";  
         JSONArray jsonArr = JSON.parseArray(jsonText);  
         System.out.println("json2Array()方法：jsonArr=="+jsonArr);  
         // 输出结果：jsonArr==["bill","green","maks","jim"]  
     }  
       
     /** 
      * 数组转json格式字符串 
      */  
     public void array2Json2(){  
         User user1 = new User("P001","TOM",16);  
         User user2 = new User("P002","JACKSON",21);  
         User user3 = new User("P003","MARTIN",20);  
         User[] userArr = {user1,user2,user3};  
         String jsonText = JSON.toJSONString(userArr, true);  
         System.out.println("array2Json2()方法：jsonText=="+jsonText);  
         //输出结果：jsonText==[{"age":16,"id":"P001","name":"TOM"},{"age":21,"id":"P002","name":"JACKSON"},{"age":20,"id":"P003","name":"MARTIN"}]  
     }  
       
     /** 
      * json格式字符串转数组 
      */  
     public void json2Array2(){  
         String jsonText = "[{\"age\":16,\"id\":\"P001\",\"name\":\"TOM\"},{\"age\":21,\"id\":\"P002\",\"name\":\"JACKSON\"},{\"age\":20,\"id\":\"P003\",\"name\":\"MARTIN\"}]";  
         JSONArray jsonArr = JSON.parseArray(jsonText);  
         System.out.println("json2Array2()方法：jsonArr=="+jsonArr);  
         // 输出结果：jsonArr==[{"age":16,"id":"P001","name":"TOM"},{"age":21,"id":"P002","name":"JACKSON"},{"age":20,"id":"P003","name":"MARTIN"}]  
     }  
       
     /** 
      * list集合转json格式字符串 
      */  
     public void list2Json(){  
         List list = new ArrayList();  
         User user1 = new User("L001","TOM",16);  
         list.add(user1);  
         User user2 = new User("L002","JACKSON",21);  
         list.add(user2);  
         User user3 = new User("L003","MARTIN",20);  
         list.add(user3);  
         String jsonText = JSON.toJSONString(list, true);  
         System.out.println("list2Json()方法：jsonText=="+jsonText);  
         //输出结果：jsonText==[{"age":16,"id":"L001","name":"TOM"},{"age":21,"id":"L002","name":"JACKSON"},{"age":20,"id":"L003","name":"MARTIN"}]  
     }  
       
     /** 
      * list集合转json格式字符串 
      */  
     public void list2Json2(){  
         List list = new ArrayList();  
         Address address1 = new Address("广东省","深圳市","科苑南路","580053");  
         User user1 = new User("L001","TOM",16,address1);  
         list.add(user1);  
         Address address2 = new Address("江西省","南昌市","阳明路","330004");  
         User user2 = new User("L002","JACKSON",21,address2);  
         list.add(user2);  
         Address address3 = new Address("陕西省","西安市","长安南路","710114");  
         User user3 = new User("L003","MARTIN",20,address3);  
         list.add(user3);  
         String jsonText = JSON.toJSONString(list, true);  
         System.out.println("list2Json2()方法：jsonText=="+jsonText);  
         //输出结果：jsonText==[{"address":{"city":"深圳市","post":"580053","province":"广东省","street":"科苑南路"},"age":16,"id":"L001","name":"TOM"},{"address":{"city":"南昌市","post":"330004","province":"江西省","street":"阳明路"},"age":21,"id":"L002","name":"JACKSON"},{"address":{"city":"西安市","post":"710114","province":"陕西省","street":"长安南路"},"age":20,"id":"L003","name":"MARTIN"}]  
     }  
   
     /** 
      * map转json格式字符串 
      */  
     public void map2Json(){  
         Map map = new HashMap();  
         Address address1 = new Address("广东省","深圳市","科苑南路","580053");  
         map.put("address1", address1);  
         Address address2 = new Address("江西省","南昌市","阳明路","330004");  
         map.put("address2", address2);  
         Address address3 = new Address("陕西省","西安市","长安南路","710114");  
         map.put("address3", address3);  
         String jsonText = JSON.toJSONString(map, true);  
         System.out.println("map2Json()方法：jsonText=="+jsonText);  
         //输出结果：jsonText=={"address1":{"city":"深圳市","post":"580053","province":"广东省","street":"科苑南路"},"address2":{"city":"南昌市","post":"330004","province":"江西省","street":"阳明路"},"address3":{"city":"西安市","post":"710114","province":"陕西省","street":"长安南路"}}  
     }  
       
       
       
     public static void main(String[] args)  
     {  
         FastJsonTest1 test = new FastJsonTest1();  
         //数组转json格式字符串  
         test.array2Json();  
           
         //json格式字符串转数组  
         test.json2Array();  
           
         //数组转json格式字符串  
         test.array2Json2();  
           
         //json格式字符串转数组  
         test.json2Array2();  
           
         //list集合转json格式字符串  
         test.list2Json();  
           
         //list集合转json格式字符串  
         test.list2Json2();  
           
         //map转json格式字符串  
         test.map2Json();  
     }  
 }  

控制台输出结果：

[html]view plaincopy 
   
 array2Json()方法：jsonText==["bill","green","maks","jim"]  
 json2Array()方法：jsonArr==["bill","green","maks","jim"]  
 array2Json2()方法：jsonText==[{  
     "age":16,  
     "id":"P001",  
     "name":"TOM"  
 },{  
     "age":21,  
     "id":"P002",  
     "name":"JACKSON"  
 },{  
     "age":20,  
     "id":"P003",  
     "name":"MARTIN"  
 }]  
 json2Array2()方法：jsonArr==[{"age":16,"id":"P001","name":"TOM"},{"age":21,"id":"P002","name":"JACKSON"},{"age":20,"id":"P003","name":"MARTIN"}]  
 list2Json()方法：jsonText==[  
     {  
         "age":16,  
         "id":"L001",  
         "name":"TOM"  
     },  
     {  
         "age":21,  
         "id":"L002",  
         "name":"JACKSON"  
     },  
     {  
         "age":20,  
         "id":"L003",  
         "name":"MARTIN"  
     }  
 ]  
 list2Json2()方法：jsonText==[  
     {  
         "address":{  
             "city":"深圳市",  
             "post":"580053",  
             "province":"广东省",  
             "street":"科苑南路"  
         },  
         "age":16,  
         "id":"L001",  
         "name":"TOM"  
     },  
     {  
         "address":{  
             "city":"南昌市",  
             "post":"330004",  
             "province":"江西省",  
             "street":"阳明路"  
         },  
         "age":21,  
         "id":"L002",  
         "name":"JACKSON"  
     },  
     {  
         "address":{  
             "city":"西安市",  
             "post":"710114",  
             "province":"陕西省",  
             "street":"长安南路"  
         },  
         "age":20,  
         "id":"L003",  
         "name":"MARTIN"  
     }  
 ]  
 map2Json()方法：jsonText=={"address1":{  
     "city":"深圳市",  
     "post":"580053",  
     "province":"广东省",  
     "street":"科苑南路"  
 },"address2":{  
     "city":"南昌市",  
     "post":"330004",  
     "province":"江西省",  
     "street":"阳明路"  
 },"address3":{  
     "city":"西安市",  
     "post":"710114",  
     "province":"陕西省",  
     "street":"长安南路"  
 }}  

附：javabean类 User.java

[java]view plaincopy 
   
 package fastJson.test;  
   
 import java.io.Serializable;  
   
 public class User implements Serializable {  
       
     private static final long serialVersionUID = 1L;  
       
     private String id;  
     private String name;  
     private int age;  
     private Address address;  
       
     public User() {  
         super();  
     }  
   
     public User(String id, String name, int age) {  
         super();  
         this.id = id;  
         this.name = name;  
         this.age = age;  
     }  
       
     public User(String id, String name, int age, Address address)  
     {  
         super();  
         this.id = id;  
         this.name = name;  
         this.age = age;  
         this.address = address;  
     }  
   
     public int getAge() {  
         return age;  
     }  
   
     public void setAge(int age) {  
         this.age = age;  
     }  
   
     public String getId() {  
         return id;  
     }  
   
     public void setId(String id) {  
         this.id = id;  
     }  
   
     public String getName() {  
         return name;  
     }  
   
     public void setName(String name) {  
         this.name = name;  
     }  
   
     public Address getAddress()  
     {  
         return address;  
     }  
   
     public void setAddress(Address address)  
     {  
         this.address = address;  
     }  
       
 }  

Address.java

[java]view plaincopy 
   
 package fastJson.test;  
   
 import java.io.Serializable;  
   
 public class Address implements Serializable  
 {  
     private static final long serialVersionUID = 1L;  
       
     private String province;  
     private String city;  
     private String street;  
     private String post;  
       
     public Address()  
     {  
         super();  
     }  
       
     public Address(String province, String city, String street, String post)  
     {  
         super();  
         this.province = province;  
         this.city = city;  
         this.street = street;  
         this.post = post;  
     }  
   
     public String getCity()  
     {  
         return city;  
     }  
   
     public void setCity(String city)  
     {  
         this.city = city;  
     }  
   
     public String getPost()  
     {  
         return post;  
     }  
   
     public void setPost(String post)  
     {  
         this.post = post;  
     }  
   
     public String getProvince()  
     {  
         return province;  
     }  
   
     public void setProvince(String province)  
     {  
         this.province = province;  
     }  
   
     public String getStreet()  
     {  
         return street;  
     }  
   
     public void setStreet(String street)  
     {  
         this.street = street;  
     }  
       
 }  