json使用

1.使用Map集合建立JSON

/**
     * 1 、使用Map建立json
     */
    public static void createJSONByMap() {
        Map<String, Object> map = new LinkedHashMap<String, Object>();
        map.put("name", "老王");
        map.put("age", 35);
        map.put("height", 1.73);
        map.put("major", new String[] { "理发", "挖掘机" });
        map.put("hasGirlFriend", false);
        map.put("car", null);
        JSONObject json = new JSONObject(map);
        System.out.println("方法名:createJSONByMap()---" + json);
    }


运行结果：

方法名:createJSONByMap()---{"major":["理发","挖掘机"],"name":"老王","hasGirlFriend":false,"age":35,"height":1.73}

2.使用javaBean建立JSON

package com.hjw.maven.jsonTest;

import java.util.Arrays;

public class Person {
    
    private String name;
    private int age;
    private double height;
    private String[] major;
    private boolean hasGirlFriend;
    
    
    
    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 double getHeight() {
        return height;
    }
    public void setHeight(double height) {
        this.height = height;
    }
    public String[] getMajor() {
        return major;
    }
    public void setMajor(String[] major) {
        this.major = major;
    }
    public boolean isHasGirlFriend() {
        return hasGirlFriend;
    }
    public void setHasGirlFriend(boolean hasGirlFriend) {
        this.hasGirlFriend = hasGirlFriend;
    }
    @Override
    public String toString() {
        return "Person [name=" + name + ", age=" + age + ", height=" + height
                + ", major=" + Arrays.toString(major) + ", hasGirlFriend="
                + hasGirlFriend + "]";
    }
    
    

}

 

/**
     * 二、经过javaBean建立json
     */
    public static void createJSONByBean() {
        Person person = new Person();
        person.setName("老王");
        person.setAge(35);
        person.setHasGirlFriend(false);
        person.setHeight(17.2);
        person.setMajor(new String[] { "厨师", "编程" });
        System.out.println("方法名：createJSONByBean()---" + new JSONObject(person));

    }

 3.经过JSONObject建立JSON

 /**
     * 一、经过JSONObject来建立json
     */
    public static void createJSON() {
        JSONObject json = new JSONObject();
        Object objNull = null;
        json.put("name", "老王");
        json.put("age", 35);
        json.put("height", 1.73);
        json.put("major", new String[] { "理发", "挖掘机" });
        json.put("hasGrilFriend", false);
        System.out.println("方法名:createJSON1()---" + json);
    }

 4.读取文件建立JSONObject

在maven项目src/main/resource中建立laowang.json文件，而后引入commons-io的maven坐标

laowang.json
{
    "hasGrilFriend": false,
    "major": [
        "理发",
        "挖掘机"
    ],
    "name": "老王",
    "age": 35,
    "height": 1.73
}

 

 /**
     * 四、读取文件获取json
     * 
     * @throws IOException
     */
    public static void createJsonByFile() throws IOException {
        File file = new File(JsonDemo.class.getResource("/laowang.json")
                .getFile());
        String content = FileUtils.readFileToString(file);
        JSONObject json = new JSONObject(content);
        System.out.println("name=" + json.getString("name"));
        System.out.println("age=" + json.getInt("age"));
        System.out.println("height=" + json.getDouble("height"));
        System.out.println("hasGirlFriend=" + json.getBoolean("hasGirlFriend"));
        System.out.print("major=[");
        for (Object str : json.getJSONArray("major")) {
            System.out.print(str + ",");
        }
        System.out.println("]");
    }


运行结果:
name=老王
age=35
height=1.73
hasGirlFriend=false
major=[理发,挖掘机,]

 5.经过JSONObject建立json文件

  /**
     * 建立josn文件
     * 
     * @throws IOException
     */
    public static void createJsonFileByWriter() throws IOException {
        Map<String, Object> map = new LinkedHashMap<String, Object>();
        map.put("name", "老王");
        map.put("age", 35);
        map.put("height", 1.73);
        map.put("major", new String[] { "理发", "挖掘机" });
        map.put("hasGrilFriend", false);
        JSONObject json = new JSONObject(map);
        URL url=JsonDemo.class.getResource("/");
        String path=url.getPath();
        path=path.substring(0, path.indexOf("jsonTest"));
        File file = new File(path+"/jsonTest/src/main/resource/laowang1.json");
        if (!file.exists()) {
            file.createNewFile();
        }
        FileWriter fw = new FileWriter(file.getAbsoluteFile());
        BufferedWriter bw = new BufferedWriter(fw);
        json.write(bw);
        bw.close();
        System.out.println("end");
    }

 代码运行后会自动在maven项目中的resource路径下生产一个名为laowang1.json的文件，其中jsonTest为项目名