json-lib --->入门

Posted 2020-07-12 vmkash

 

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JSONObject 这个对象可以看作是一个Map

两个构造方法:

JSONObject jo = new JSONObject();

JSONObject jo = JSONObject.fromObject(这里需要一个map对象或javabean对象);

转化成json串: String json = jo.toString();

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JSONArray 这个对象可以看做是一个List

两个构造方法:

JSONArray ja = JSONArray.fromObject();

JSONArray ja = JSONArray.fromObject(这里需要一个collection集合对象);

转化成json串: String json = ja.toString();

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案例分析:

--->实体类 Person.java

要求:①必须public修饰②有getter和setter方法

 1 package json;
 2 
 3 public class Person {
 4     private String name;
 5     private int age;
 6     private String sex;
 7     
 8     public String getName() {
 9         return name;
10     }
11     public void setName(String name) {
12         this.name = name;
13     }
14     public int getAge() {
15         return age;
16     }
17     public void setAge(int age) {
18         this.age = age;
19     }
20     public String getSex() {
21         return sex;
22     }
23     public void setSex(String sex) {
24         this.sex = sex;
25     }
26     public Person() {}
27     public Person(String name, int age, String sex) {
28         super();
29         this.name = name;
30         this.age = age;
31         this.sex = sex;
32     }
33 
34 }

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--->测试类 TestJson.java

 1 package json;
 2 
 3 import java.util.ArrayList;
 4 import java.util.HashMap;
 5 import java.util.List;
 6 import java.util.Map;
 7 
 8 import net.sf.json.JSONArray;
 9 import net.sf.json.JSONObject;
10 
11 import org.junit.Test;
12 
13 public class TestJson {
14 
15     @Test
16     public void fun(){
17         JSONObject jo = new JSONObject();//创建map对象
18         jo.put("name", "张三");
19         jo.put("age", 23);
20         jo.put("sex", "male");
21         String json = jo.toString();
22         //{"name":"张三","age":23,"sex":"male"}
23         System.out.println(json);        
24     }
25     @Test
26     public void fun1(){
27         Person p1 = new Person("李四",24,"male");
28         Person p2 = new Person("王五",25,"female");
29         Map<String,Person> map = new HashMap<String,Person>();
30         map.put("1", p1);
31         map.put("2", p2);
32         
33         JSONObject mapJson = JSONObject.fromObject(map);//创建mapJson
34         
35 //{"2":{"age":25,"name":"王五","sex":"female"},"1":{"age":24,"name":"李四","sex":"male"}}
36         System.out.println(mapJson.toString());
37         
38         
39         Person person = new Person("LiSi", 18, "female");
40         JSONObject beanJson = JSONObject.fromObject(person);//创建beanJson
41         
42         //{"age":18,"name":"LiSi","sex":"female"}
43         System.out.println(beanJson.toString());
44         
45     }
46     
47     @Test
48     public void fun2(){
49         Person p1 = new Person("李四",24,"male");
50         Person p2 = new Person("王五",25,"female");
51         List<Person> list  = new ArrayList<Person>();
52         list.add(p1);
53         list.add(p2);
54         JSONArray ja = JSONArray.fromObject(list);//从list中创建对象
55         String json = ja.toString();
56 //[{"age":24,"name":"李四","sex":"male"},{"age":25,"name":"王五","sex":"female"}]
57         System.out.println(json);    
58         
59         JSONArray jsonList = new JSONArray();
60         jsonList.add(p1);
61         jsonList.add(p2);
62 //[{"age":24,"name":"李四","sex":"male"},{"age":25,"name":"王五","sex":"female"}]
63         System.out.println(jsonList.toString());
64     }
65 
66 }