Springboot-数据序列化与反序列化

 首先我们的Java对象要实现接口Serializable(序列化)

package com.example.pojo;

import com.baomidou.mybatisplus.annotation.*;

import java.io.Serializable;
import java.time.LocalDateTime;
import java.util.Date;
import lombok.Data;

/**
 * 
 * @TableName user
 */
@TableName(value ="user")
@Data
public class User implements Serializable {

    @TableId(value = "id", type = IdType.AUTO)
    private Long id;


    @TableField(value = "name")
    private String name;

    @TableField(value = "age")
    private Integer age;

    @TableField(value = "staus")
    @TableLogic
    private Integer staus;


    @TableField(value = "creat_time",fill = FieldFill.INSERT)
    private LocalDateTime creatTime;

    @TableField(value = "update_time",fill = FieldFill.INSERT_UPDATE)
    private LocalDateTime updateTime;
    
    @TableField(exist = false)
    private static final long serialVersionUID = 1L;
}

JacksonObjectMapper.java，序列化与反序列化的一些操作（消息转换器）

package com.example.common;

import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.module.SimpleModule;
import com.fasterxml.jackson.databind.ser.std.ToStringSerializer;
import com.fasterxml.jackson.datatype.jsr310.deser.LocalDateDeserializer;
import com.fasterxml.jackson.datatype.jsr310.deser.LocalDateTimeDeserializer;
import com.fasterxml.jackson.datatype.jsr310.deser.LocalTimeDeserializer;
import com.fasterxml.jackson.datatype.jsr310.ser.LocalDateSerializer;
import com.fasterxml.jackson.datatype.jsr310.ser.LocalDateTimeSerializer;
import com.fasterxml.jackson.datatype.jsr310.ser.LocalTimeSerializer;

import java.math.BigInteger;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;
import java.time.format.DateTimeFormatter;

import static com.fasterxml.jackson.databind.DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES;

/**
 * 对象映射器:基于jackson将Java对象转为json，或者将json转为Java对象
 * 将JSON解析为Java对象的过程称为 [从JSON反序列化Java对象]
 * 从Java对象生成JSON的过程称为 [序列化Java对象到JSON]
 */
public class JacksonObjectMapper extends ObjectMapper {

    public static final String DEFAULT_DATE_FORMAT = "yyyy-MM-dd";
    public static final String DEFAULT_DATE_TIME_FORMAT = "yyyy-MM-dd HH:mm:ss";
    public static final String DEFAULT_TIME_FORMAT = "HH:mm:ss";

    public JacksonObjectMapper() {
        super();
        //收到未知属性时不报异常
        this.configure(FAIL_ON_UNKNOWN_PROPERTIES, false);

        //反序列化时，属性不存在的兼容处理
        this.getDeserializationConfig().withoutFeatures(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);


        SimpleModule simpleModule = new SimpleModule()
                //前端传入后端的反序列化--Json转换为Java对象
                .addDeserializer(LocalDateTime.class, new LocalDateTimeDeserializer(DateTimeFormatter.ofPattern(DEFAULT_DATE_TIME_FORMAT)))
                .addDeserializer(LocalDate.class, new LocalDateDeserializer(DateTimeFormatter.ofPattern(DEFAULT_DATE_FORMAT)))
                .addDeserializer(LocalTime.class, new LocalTimeDeserializer(DateTimeFormatter.ofPattern(DEFAULT_TIME_FORMAT)))
                //后端传出前端的序列化--Java对象转为Json
                .addSerializer(BigInteger.class, ToStringSerializer.instance)
                //Java转Json后，Long数据精度只有16位，所以将Long转为Sting类型
                .addSerializer(Long.class, ToStringSerializer.instance)
                .addSerializer(LocalDateTime.class, new LocalDateTimeSerializer(DateTimeFormatter.ofPattern(DEFAULT_DATE_TIME_FORMAT)))
                .addSerializer(LocalDate.class, new LocalDateSerializer(DateTimeFormatter.ofPattern(DEFAULT_DATE_FORMAT)))
                .addSerializer(LocalTime.class, new LocalTimeSerializer(DateTimeFormatter.ofPattern(DEFAULT_TIME_FORMAT)));

        //注册功能模块 例如，可以添加自定义序列化器和反序列化器
        this.registerModule(simpleModule);
    }
}

把我们的消息转换器注册到Springboot

@Configuration注解，项目启动就调用

package com.example.config;


import com.example.common.JacksonObjectMapper;
import lombok.extern.slf4j.Slf4j;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport;

import java.util.List;

@Slf4j
@Configuration
public class WebMvcConfig extends WebMvcConfigurationSupport {

 
    /**
     * 扩展mvc框架的消息转换器
     *
     * @param converters
     */
    @Override
    protected void extendMessageConverters(List> converters) {
        log.info("扩展消息转换器...");
        //创建消息转换器对象
        MappingJackson2HttpMessageConverter messageConverter = new MappingJackson2HttpMessageConverter();
        //设置对象转换器，底层使用Jackson将Java对象转为json
        messageConverter.setObjectMapper(new JacksonObjectMapper());
        //将上面的消息转换器对象追加到mvc框架的转换器集合中
        converters.add(0, messageConverter);
    }

}

然后我们写个controller测试下

    @Autowired
    private UserService userService;

    @RequestMapping("/test1")
    public R test1(@RequestBody User user) {
        LambdaQueryWrapper queryWrapper = new LambdaQueryWrapper<>();
        queryWrapper
                .eq(user.getAge() != null, User::getAge, user.getAge())
                .eq(StringUtils.isNullOrEmpty(user.getName()), User::getName, user.getName());
        User user1 = userService.getOne(queryWrapper);
        return R.success(user1);
    }

结果，Long(id)序列化了，时间也序列化了