使用jackson自定義序列化

1.導入maven

一共有三個：

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.9.4</version>
</dependency>
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-annotations</artifactId>
    <version>2.9.4</version>
</dependency>
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-core</artifactId>
    <version>2.9.4</version>
</dependency>

2.新建一個實體類Person

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.springframework.data.annotation.Id;

@Data
@NoArgsConstructor
@AllArgsConstructor
public class Person {
    @Id
    private Long id;
    private String name;
    private int age;
    private boolean sex;
}

3.新建一個統一返回的對象類ResponseJson

import com.example.demo.config.ResponseJsonConfig;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@NoArgsConstructor
@AllArgsConstructor
@JsonSerialize(using = ResponseJsonConfig.class)
public class ResponseJson {

    private int statusCode;
    private Object data;
    private String time;
    private String message;

    public ResponseJson(Object data)
    {
        this.data = data;
    }
}

4.新建一個自定義序列化配置的ResponseJsonConfig類

import com.example.demo.utils.ResponseJson;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.ser.std.StdSerializer;

import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;

public class ResponseJsonConfig extends StdSerializer<ResponseJson> {

    public ResponseJsonConfig()
    {
        super(ResponseJson.class);
    }

    @Override
    public void serialize(ResponseJson responseJson, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException
    {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        String time = sdf.format(new Date());
        jsonGenerator.writeStartObject();
        jsonGenerator.writeNumberField("statusCode",responseJson.getStatusCode());
        jsonGenerator.writeStringField("message",responseJson.getMessage() == null? "" : responseJson.getMessage());
        jsonGenerator.writeObjectField("data",responseJson.getData() == null? "" : responseJson.getData());
        jsonGenerator.writeStringField("time",time);
        jsonGenerator.writeEndObject();
    }
}

5.寫一個controller來測試一下

import com.example.demo.test.Person;
import com.example.demo.utils.ResponseJson;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
@RequestMapping("/test")
public class TestController {

    @ResponseBody
    @RequestMapping(value = "/serializer",produces = "application/json;charset=UTF-8")
    public Object testSerializer()
    {
        return new ResponseJson(new Person(1L,"張三",21,true));
    }
}

6.運行測試一下

成功！