4.使用fastjson进行json字符串和List的转换

转自：https://blog.csdn.net/lipr86/article/details/80833952 

使用fastjson进行自定义类的列表和字符串转换

  1.环境

  jdk1.8,fastjson

  2.pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>co.neutron.json</groupId>
    <artifactId>fastjson</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>fastjson</name>
    <url>http://maven.apache.org</url>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.8</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.12</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>1.7.2</version>
        </dependency>
    </dependencies>
</project>

  3.实体类

package co.neutron.json.fastjson.entity;

public class User {
    private int id;
    private String name;
    private int age;

    public User() {
        super();
    }

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

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    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 "User [id=" + id + ", name=" + name + ", age=" + age + "]";
    }

}

  4.测试类

package co.neutron.json.fastjson;

import java.util.ArrayList;
import java.util.List;

import org.junit.Assert;
import org.junit.Test;

import com.alibaba.fastjson.JSON;

import co.neutron.json.fastjson.entity.User;

public class ArrayListTest {

    /*
     * 测试内容如下
     * 1.将User类型数组转换成json字符串
     * 2.将json字符串转换成为User数组
     */
    @Test
    public void testArray2StringAndString2List() {
        User user1 = new User(1, "张1", 11);
        User user2 = new User(2, "张2", 12);
        User user3 = new User(3, "张3", 13);
        User user4 = new User(4, "张4", 14);
        User[] users = {user1, user2, user3, user4};

        /*
         * 将数组转换为Json字符串
         * result:
         * [{"age":11,"id":1,"name":"张1"},{"age":12,"id":2,"name":"张2"},
         * {"age":13,"id":3,"name":"张3"},{"age":14,"id":4,"name":"张4"}]
         */
        String userStr = JSON.toJSONString(users);

        /*
         * 将Json字符串转换为List
         * result
         * User [id=1, name=张1, age=11]
           User [id=2, name=张2, age=12]
           User [id=3, name=张3, age=13]
           User [id=4, name=张4, age=14]
         */
        List<User> userList = JSON.parseArray(userStr, User.class);
        userList.stream().forEach(System.err::println);
    }

    /**
     * 测试包装类型的List转换为json字符串
     */
    @Test
    public void testList2String() {
        List<Long> longs = new ArrayList<Long>();
        longs.add(1L);
        longs.add(2L);
        longs.add(3L);
        String actual = JSON.toJSONString(longs);
        Assert.assertEquals("[1,2,3]", actual);
    }

}