springboot使用jackson序列化返回Long类型，j

js整数范围：
var biggestInt = Number.MAX_SAFE_INTEGER;
//9007199254740991
var smallestInt = Number.MIN_SAFE_INTEGER;
//-9007199254740991

1、问题复现

package com.example.demo.pojo;

import lombok.Builder;
import lombok.Data;

import java.io.Serializable;

/**
 * @author xuzhipeng
 * @date 2022/2/22
 */
@Data
@Builder
public class TestLong implements Serializable {

    private static final long serialVersionUID = 550833284250857846L;

    private Long amount;

    private Long age;
}

package com.example.demo.controller;

import com.example.demo.pojo.TestLong;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * @author xuzhipeng
 * @date 2022/2/22
 */
@RestController
public class TestController {

    @GetMapping("/testLong")
    public TestLong testLong(){
        return TestLong.builder().amount(12340551560724503L).age(30L).build();
    }
}

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2、配置自定义Long序列化

package com.example.demo.config;

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.annotation.JacksonStdImpl;
import com.fasterxml.jackson.databind.ser.std.StdSerializer;

import java.io.IOException;

/**
 * jackson long 序列化
 * @author xuzhipeng
 * @date 2022/2/22
 */
@JacksonStdImpl
@SuppressWarnings("serial")
public class CustomizedLongSerializer extends StdSerializer<Object> {

    private static final long JS_MAX_SAFE_INTEGER = 9007199254740991L;
    private static final long JS_MIN_SAFE_INTEGER = -9007199254740991L;

    public final static CustomizedLongSerializer INSTANCE = new CustomizedLongSerializer();

    public CustomizedLongSerializer() { super(Object.class); }

    @Override
    public void serialize(Object value, JsonGenerator gen, SerializerProvider serializerProvider) throws IOException {
        if(value instanceof Long){
            Long val = (Long) value;
            if(val <= JS_MAX_SAFE_INTEGER && val >= JS_MIN_SAFE_INTEGER){
                gen.writeNumber(val);
            }else{
                gen.writeString(value.toString());
            }
        }else{
            gen.writeString(value.toString());
        }
    }
}

package com.example.demo.config;

import com.fasterxml.jackson.databind.JsonSerializer;
import org.springframework.boot.autoconfigure.jackson.Jackson2ObjectMapperBuilderCustomizer;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import java.util.HashMap;
import java.util.Map;

/**
 * jackson配置
 * @author xuzhipeng
 * @date 2022/2/22
 */
@Configuration
public class JacksonConfig {

    @Bean("jackson2ObjectMapperBuilderCustomizer")
    public Jackson2ObjectMapperBuilderCustomizer jackson2ObjectMapperBuilderCustomizer() {
        Map<Class<?>, JsonSerializer<?>> map = new HashMap<>(2);
        map.put(Long.class, CustomizedLongSerializer.INSTANCE);
        map.put(Long.TYPE, CustomizedLongSerializer.INSTANCE);
        return builder -> builder.serializersByType(map);
    }

}

image.png