{"0":"192.168.1.100","1":"192.168.1.101"} 是Map

{"0":"192.168.1.100","1":"192.168.1.101"}  我一看到，我就觉得这什么json数据啊，这怎么解析成java对象啊，原来它是Java中的Map对象。

下面是JSON的笔记

先定义一个Student类，如下
package com.dashuai.json;

// 标准的JavaBean： 所有属性都有get和set。必须有一个默认的构造方法
public class Student {

private String name;
private int age;

public Student() {
// TODO Auto-generated constructor stub
}

public Student(String name, int age) {
super();
this.name = name;
this.age = age;
}

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;
}

@Override
public String toString() {
return "Student [name=" + name + ", age=" + age + "]";
}

// @Override
// public String toString() {
// return "{\"name\":\"" + name + "\", \"age\":" + age + "}";
// }

}
下面是测试类
package com.dashuai.json;

import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;

import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;

public class Test3 {

public static void main(String[] args) {

Student student = new Student("zhangsan", 25);

Gson gson = new Gson();

String json = gson.toJson(student);

System.out.println(json);

Student stu1 = gson.fromJson(json, Student.class);

System.out.println(stu1);

List<Student> list = new ArrayList<Student>();

for(int i=0;i<5;i++){
list.add(new Student("lisi"+i, 23+i));
}

json = gson.toJson(list);

System.out.println(json);

// List<Student> list2 = gson.fromJson(json, List<?>.class);

Type listType = new TypeToken<List<Student>>() {}.getType();

List<Student> list2 = gson.fromJson(json, listType);

for(Student s:list2){
System.out.println(s);
}

Map<Integer,String> map = new HashMap<Integer,String>();

for(int i=0;i<5;i++){
map.put(i, "192.168.1.10"+i);
}

json = gson.toJson(map);
System.out.println(json);

Type mapType = new TypeToken<Map<Integer,String>>() {}.getType();
Map<Integer,String> map2 = gson.fromJson(json, mapType);

Set<Integer> set = map2.keySet();

for(Integer i:set){
System.out.println("key"+i+",value:"+map2.get(i));
}

}

}

运行结果：

{"name":"zhangsan","age":25}
Student [name=zhangsan, age=25]
[{"name":"lisi0","age":23},{"name":"lisi1","age":24},{"name":"lisi2","age":25},{"name":"lisi3","age":26},{"name":"lisi4","age":27}]
Student [name=lisi0, age=23]
Student [name=lisi1, age=24]
Student [name=lisi2, age=25]
Student [name=lisi3, age=26]
Student [name=lisi4, age=27]
{"0":"192.168.1.100","1":"192.168.1.101","2":"192.168.1.102","3":"192.168.1.103","4":"192.168.1.104"}
key0,value:192.168.1.100
key1,value:192.168.1.101
key2,value:192.168.1.102
key3,value:192.168.1.103
key4,value:192.168.1.104