json-lib --->入门

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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

package json;

public class Person {
    private String name;
    private int age;
    private String sex;
    
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public String getSex() {
        return sex;
    }
    public void setSex(String sex) {
        this.sex = sex;
    }
    public Person() {}
    public Person(String name, int age, String sex) {
        super();
        this.name = name;
        this.age = age;
        this.sex = sex;
    }

}

---

--->测试类 TestJson.java

package json;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

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

import org.junit.Test;

public class TestJson {

    @Test
    public void fun(){
        JSONObject jo = new JSONObject();//创建map对象
        jo.put("name", "张三");
        jo.put("age", 23);
        jo.put("sex", "male");
        String json = jo.toString();
        //{"name":"张三","age":23,"sex":"male"}
        System.out.println(json);        
    }
    @Test
    public void fun1(){
        Person p1 = new Person("李四",24,"male");
        Person p2 = new Person("王五",25,"female");
        Map<String,Person> map = new HashMap<String,Person>();
        map.put("1", p1);
        map.put("2", p2);
        
        JSONObject mapJson = JSONObject.fromObject(map);//创建mapJson
        
//{"2":{"age":25,"name":"王五","sex":"female"},"1":{"age":24,"name":"李四","sex":"male"}}
        System.out.println(mapJson.toString());
        
        
        Person person = new Person("LiSi", 18, "female");
        JSONObject beanJson = JSONObject.fromObject(person);//创建beanJson
        
        //{"age":18,"name":"LiSi","sex":"female"}
        System.out.println(beanJson.toString());
        
    }
    
    @Test
    public void fun2(){
        Person p1 = new Person("李四",24,"male");
        Person p2 = new Person("王五",25,"female");
        List<Person> list  = new ArrayList<Person>();
        list.add(p1);
        list.add(p2);
        JSONArray ja = JSONArray.fromObject(list);//从list中创建对象
        String json = ja.toString();
//[{"age":24,"name":"李四","sex":"male"},{"age":25,"name":"王五","sex":"female"}]
        System.out.println(json);    
        
        JSONArray jsonList = new JSONArray();
        jsonList.add(p1);
        jsonList.add(p2);
//[{"age":24,"name":"李四","sex":"male"},{"age":25,"name":"王五","sex":"female"}]
        System.out.println(jsonList.toString());
    }

}