Alibaba / popular JSON parsing open source project fastjson2

One 、 Introduce

FASTJSON v2 yes FASTJSON Important upgrade of the project , The goal is to provide a high-performance platform for the next decade JSON library . Through the same set of API,
GitHub Address ： https://github.com/alibaba/fastjson2

• Support JSON/JSONB Two protocols ,JSONPath First class citizen .
• Support full resolution and partial resolution .
• Support Java Server side 、 client Android、 Big data scenario .
• Support kotlin

1. Use maven Add dependency

<dependency>
    <groupId>com.alibaba.fastjson2</groupId>
    <artifactId>fastjson2</artifactId>
    <version>2.0.3</version>
</dependency>

2. fastjson v1 Compatible modules

If you used fastjson 1.2.x edition , Compatible packages can be used , Compatibility packages do not guarantee 100% compatible , Please test carefully to verify , If you find any problems, please give feedback in time .

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>2.0.3</version>
</dependency>

Two 、 Easy to use

1. Create entity class objects

package com.janson.demo.fastjson;

import lombok.Data;

/** * @Author Janson * @Date 2022/5/16 9:05 * @Version 1.0 */
@Data
public class DemoData {
    
    private Integer id;
    private String name;
    private Integer age;
    private String sex;
}

2. Three methods commonly used in testing JSON.toJSONString(JavaBean),JSON.parseObject(str, DemoData.class);JSON.parseArray(str, DemoData.class);

• Methods to introduce ：

  • JSON.parseObject(str, DemoData.class) take JSON It can be interpreted as JSONObject
  • JSON.parseArray(str, DemoData.class); take JSON It can be interpreted as JSONArray
  • JSON.toJSONString(JavaBean), take Java Object serialization to JSON

package com.janson.demo.fastjson;

import com.alibaba.fastjson2.JSON;
import java.util.List;
/** * @Author Janson * @Date 2022/5/16 9:03 * @Version 1.0 */
public class TestFastjson {
    
    public static void main(String[] args) {
    
        System.out.println("-----JSON.toJSONString()----- test javaBean To json character string ---------------");
        DemoData demoData = new DemoData();
        demoData.setAge(18);
        demoData.setId(11108);
        demoData.setName(" Frenchman Zhang San ");
        demoData.setSex(" male "); //
        String stoJSONString = JSON.toJSONString(demoData);
        System.out.println(stoJSONString);
        System.out.println("----------- End of test --------------\n");

        System.out.println("-----JSON.parseObject(s, DemoData.class);----- test json String to javaBean---------------");
        DemoData demoDataparseObject = JSON.parseObject(stoJSONString, DemoData.class);
        System.out.println(demoDataparseObject.getAge() + " "  + demoDataparseObject.getName()+" " + demoDataparseObject.getId() + " "+demoDataparseObject.getSex());
        System.out.println("----------- End of test --------------\n");

        System.out.println("-----JSON.parseArray(str, DemoData.class);----- Test a group json String to javaBean Set （list）---------------");
        String str = "[{\"age\":18,\"id\":11108,\"name\":\" Frenchman Zhang San \",\"sex\":\" male \"},{\"age\":80,\"id\":188808,\"name\":\" Outlaw Trump \",\"sex\":\" Unknown \"}]";
        List<DemoData> demoDataparseArray = JSON.parseArray(str, DemoData.class);
        int i = 0;
        for (DemoData demoDataList: demoDataparseArray) {
    
            System.out.println(" Set index ：" + i+ " Aggregate data " + demoDataList);
            i++;
        }
        System.out.println("----------- End of test --------------");
    }
}

3、 ... and 、 Advanced use Use JSONB (JSONB finger JSON Byte[])

3.1 take JavaBean Object serialization JSONB =>

• Method JSONB.toBytes(JavaBean)
• take JSONB The data is parsed as JavaBean ：JSONB.parseObject(bytes,DemoData.class)

System.out.println("-----JSONB.toBytes()----- test javaBean serialize JSONB, Byte array --------------");
DemoData demoData1 = new DemoData();
demoData1.setAge(18);
demoData1.setId(11108);
demoData1.setName(" Frenchman Zhang San ");
demoData1.setSex(" male ");
byte[] bytes = JSONB.toBytes(demoData1);
System.out.println(bytes.length);
for (int b = 0;b<bytes.length;b++) {
    
    System.out.println( b +" "+ bytes[b]);
}
System.out.println("----------- End of test --------------\n");

System.out.println("-----JSONB.parseObject(bytes,DemoData.class)----- test JSONB It can be interpreted as javaBean--------------");
DemoData demoDataJSONB = JSONB.parseObject(bytes,DemoData.class);
System.out.println(demoDataJSONB.getId() + " "+ demoDataJSONB.getName() + " "
        + demoDataJSONB.getAge() + " "+demoDataJSONB.getSex());
System.out.println("----------- End of test --------------\n");


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