Jackson Convert JSON array string to List

摘要: Few Jackson examples to convert a JSON array string to a List

Few Jackson examples to convert a JSON array string to a List

	// JSON array string
	// [{"name":"mkyong", "age":37}, {"name":"fong", "age":38}]
	ObjectMapper mapper = new ObjectMapper();
	String json = "[{\"name\":\"mkyong\", \"age\":37}, {\"name\":\"fong\", \"age\":38}]";
	// 1. convert JSON array to Array objects
	Person[] pp1 = mapper.readValue(json, Person[].class);
	// 2. convert JSON array to List of objects
	List<Person> ppl2 = Arrays.asList(mapper.readValue(json, Person[].class));
pom.xml
	<dependency>
		<groupId>com.fasterxml.jackson.core</groupId>
		<artifactId>jackson-databind</artifactId>
		<version>2.9.8</version>
	</dependency>

P.S Tested with Jackson 2.9.8

1. Convert JSON array string to List

1.1 JSON array string

[{"name":"mkyong", "age":37}, {"name":"fong", "age":38}]

1.2 Create an object to map the above JSON fields.

package com.mkyong;
public class Person {
    String name;
    Integer age;
    //getters and setters

1.3 Convert the JSON array string to a List

JacksonArrayExample.java
package com.mkyong;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.io.IOException;
import java.util.Arrays;
import java.util.List;
public class JacksonArrayExample {
    public static void main(String[] args) {
        ObjectMapper mapper = new ObjectMapper();
        String json = "[{\"name\":\"mkyong\", \"age\":37}, {\"name\":\"fong\", \"age\":38}]";
        try {
            // 1. convert JSON array to Array objects
            Person[] pp1 = mapper.readValue(json, Person[].class);
            System.out.println("JSON array to Array objects...");
            for (Person person : pp1) {
                System.out.println(person);
            // 2. convert JSON array to List of objects
            List<Person> ppl2 = Arrays.asList(mapper.readValue(json, Person[].class));
            System.out.println("\nJSON array to List of objects");
            ppl2.stream().forEach(x -> System.out.println(x));
            // 3. alternative
            List<Person> pp3 = mapper.readValue(json, new TypeReference<List<Person>>() {});
            System.out.println("\nAlternative...");
            pp3.stream().forEach(x -> System.out.println(x));
        } catch (IOException e) {
            e.printStackTrace();

Output

1. JSON array to Array objects...
Person{name='mkyong', age=37}
Person{name='fong', age=38}
2. JSON array to List of objects
Person{name='mkyong', age=37}
Person{name='fong', age=38}
3. Alternative...
Person{name='mkyong', age=37}
Person{name='fong', age=38}

上一篇: Jackson How to ignore null fields
下一篇: Gson How to parse JSON
 评论 ( What Do You Think )
名称
邮箱
网址
评论
验证
   
 

 


  • 微信公众号

  • 我的微信

站点声明:

1、一号门博客CMS,由Python, MySQL, Nginx, Wsgi 强力驱动

2、部分文章或者资源来源于互联网, 有时候很难判断是否侵权, 若有侵权, 请联系邮箱:summer@yihaomen.com, 同时欢迎大家注册用户,主动发布无版权争议的 文章/资源.

3、鄂ICP备14001754号-3, 鄂公网安备 42280202422812号