全栈开发指南

在之前的实体中，我们设置了createTime和updateTime，但是返回的时间格式不是我们需要的，因为我们需要对时间格式在进行自定义的处理。

java
package com.cghbh.entity;

import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.time.LocalDateTime;

@Data
@NoArgsConstructor
@AllArgsConstructor
@TableName("dept")
public class Dept {
    @TableId(type = IdType.AUTO)
    private Integer id;
    private String name;
    private Integer status;
    private LocalDateTime createTime;
    private LocalDateTime updateTime;
}

在qk-entity的pom.xml文件中增加下面的依赖配置，这个依赖是Mybatisplus默认的内部依赖，版本已经默认锁定了，因为我们不需要指定版本。

xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>com.cghbh</groupId>
        <artifactId>qk-parent</artifactId>
        <version>1.0-SNAPSHOT</version>
    </parent>

    <artifactId>qk-entity</artifactId>


    <dependencies>
        <!--时间格式化需要增加的配置的起始点-->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-annotations</artifactId>
        </dependency>
        <!--时间格式化需要增加的配置的结束点-->
    </dependencies>
</project>

局部设置 ​

java
package com.cghbh.entity;

import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import com.fasterxml.jackson.annotation.JsonFormat;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.time.LocalDateTime;

@Data
@NoArgsConstructor
@AllArgsConstructor
@TableName("dept")
public class Dept {
    @TableId(type = IdType.AUTO)
    private Integer id;
    private String name;
    private Integer status;
    private LocalDateTime createTime;
    // 设置的时间格式化
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    private LocalDateTime updateTime;
}

全局设置 ​

在qk-management的config包下新建一个配置文件如下所示：

配置的代码内容如下：

java
package com.cghbh.config;

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 org.springframework.boot.autoconfigure.jackson.Jackson2ObjectMapperBuilderCustomizer;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

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

// 做统一的时间格式输出
@Configuration
public class JacksonTimeConfig {

    // 定义格式
    private static final String DATE_TIME_PATTERN = "yyyy-MM-dd HH:mm:ss";
    private static final String DATE_PATTERN = "yyyy-MM-dd";
    private static final String TIME_PATTERN = "HH:mm:ss";

    @Bean
    public Jackson2ObjectMapperBuilderCustomizer jackson2ObjectMapperBuilderCustomizer() {
        return builder -> {
            // LocalDateTime 序列化/反序列化
            builder.serializerByType(LocalDateTime.class,
                    new LocalDateTimeSerializer(DateTimeFormatter.ofPattern(DATE_TIME_PATTERN)));
            builder.deserializerByType(LocalDateTime.class,
                    new LocalDateTimeDeserializer(DateTimeFormatter.ofPattern(DATE_TIME_PATTERN)));

            // LocalDate
            builder.serializerByType(LocalDate.class,
                    new LocalDateSerializer(DateTimeFormatter.ofPattern(DATE_PATTERN)));
            builder.deserializerByType(LocalDate.class,
                    new LocalDateDeserializer(DateTimeFormatter.ofPattern(DATE_PATTERN)));

            // LocalTime
            builder.serializerByType(LocalTime.class,
                    new LocalTimeSerializer(DateTimeFormatter.ofPattern(TIME_PATTERN)));
            builder.deserializerByType(LocalTime.class,
                    new LocalTimeDeserializer(DateTimeFormatter.ofPattern(TIME_PATTERN)));
        };
    }
}

然后上面的配置会默认对数据库中设置的时间格式进行自动的格式化处理。

使用总结

全局 Jackson 配置优先级低于字段上的 @JsonFormat：

  • 不加注解 → 走全局默认格式 yyyy-MM-dd HH:mm:ss
  • 字段上加 @JsonFormat(pattern = "xxx") → 这个字段单独用自定义格式，覆盖全局