SpringBoot--LocalDateTime--全局格式转换/前端入参__springboot localdatetime转json

简介

说明

项目我们经常会有前后端时间转换的场景，比如：创建时间、更新时间等。一般情况下，前后端使用时间戳或者年月日的格式进行传递。

如果后端收到了前端的参数每次都手动转化为想要的格式，后端每次将数据传给前端时都手动处理为想要的格式实在是太麻烦了。

基于如上原因，本文用示例介绍SpringBoot全局格式配置，将前端传过来的时间自动转化为LocalDateTime。（本文只介绍年月日格式的转化方法，例如：2021-09-16 21:13:21 => LocalDateTime。时间戳转化为LocalDateTime的方法类似）。

方案简介

要分两种情景进行配置（根据 Content-Type 的不同）：

application/x-www-form-urlencoded 和 multipart/form-data

本处将此种情况记为：不使用@RequestBody

application/json

即：使用@RequestBody的接口
本处将此种情况记为：使用@RequestBody

备注

有人说，可以这样配置：

spring:

jackson:

date-format: yyyy-MM-dd HH:mm:ss

time-zone: GMT+8

serialization:

write-dates-as-timestamps: false

这种配置只适用于Date这种，不适用于LocalDateTime等。

Date序列化/反序列化时都是用的这种格式："2020-08-19T16:30:18.823+00:00"。

不使用@RequestBody

方案1：@ControllerAdvice+@InitBinder

配置类

package com.example.config;

import org.springframework.web.bind.WebDataBinder;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.InitBinder;

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

@ControllerAdvice
public class LocalDateTimeAdvice {
    @InitBinder
    protected void initBinder(WebDataBinder binder) {
        binder.registerCustomEditor(LocalDateTime.class, new PropertyEditorSupport() {
            @Override
            public void setAsText(String text) throws IllegalArgumentException {
                setValue(LocalDateTime.parse(text, DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));
            }
        });

        binder.registerCustomEditor(LocalDate.class, new PropertyEditorSupport() {
            @Override
            public void setAsText(String text) throws IllegalArgumentException {
                setValue(LocalDate.parse(text, DateTimeFormatter.ofPattern("yyyy-MM-dd")));
            }
        });

        binder.registerCustomEditor(LocalTime.class, new PropertyEditorSupport() {
            @Override
            public void setAsText(String text) throws IllegalArgumentException {
                setValue(LocalTime.parse(text, DateTimeFormatter.ofPattern("HH:mm:ss")));
            }
        });
    }
}

Entity

package com.example.business.entity;

import lombok.AllArgsConstructor;
import lombok.Data;

import java.time.LocalDateTime;

@Data
@AllArgsConstructor
public class User {
    private Long id;

    private String userName;

    private LocalDateTime createTime;
}

Controller

package com.example.business.controller;

import com.example.business.entity.User;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("user")
public class UserController {
    @PostMapping("save")
    public User save(User user) {
        System.out.println("保存用户：" + user);
        return user;
    }
}

测试

postman访问：http://localhost:8080/user/save?userName=Tony&createTime=2021-09-16 21:13:21

postman结果：

SpringBoot--LocalDateTime--全局格式转换/前端入参_java

后端结果：

SpringBoot--LocalDateTime--全局格式转换/前端入参_LocalDateTime_02

方案2：自定义参数转换器（Converter）

实现 org.springframework.core.convert.converter.Converter，自定义参数转换器。

配置类

package com.example.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.convert.converter.Converter;

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

@Configuration
public class LocalDateTimeConfig {

    @Bean
    public Converter<String, LocalDateTime> localDateTimeConverter() {
        return new LocalDateTimeConverter();
    }

    public static class LocalDateTimeConverter implements Converter<String, LocalDateTime> {
        @Override
        public LocalDateTime convert(String s) {
            return LocalDateTime.parse(s, DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
        }
    }
}

Entity

package com.example.business.entity;

import lombok.AllArgsConstructor;
import lombok.Data;

import java.time.LocalDateTime;

@Data
@AllArgsConstructor
public class User {
    private Long id;

    private String userName;

    private LocalDateTime createTime;
}

Controller

package com.example.business.controller;

import com.example.business.entity.User;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("user")
public class UserController {
    @PostMapping("save")
    public User save(User user) {
        System.out.println("保存用户：" + user);
        return user;
    }
}

测试

postman访问：http://localhost:8080/user/save?userName=Tony&createTime=2021-09-16 21:13:21

postman结果：

SpringBoot--LocalDateTime--全局格式转换/前端入参_spring_03

后端结果

SpringBoot--LocalDateTime--全局格式转换/前端入参_SpringBoot_04

使用@RequestBody

方案1：配置ObjectMapper

法1：只用配置类

本方法只配置ObjectMapper即可，Entity不需要加@JsonFormat。

配置类

package com.example.common.config;

import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.deser.std.DateDeserializers;
import com.fasterxml.jackson.databind.ser.std.DateSerializer;
import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
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 lombok.SneakyThrows;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import java.text.SimpleDateFormat;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;
import java.time.format.DateTimeFormatter;
import java.util.Date;

@Configuration
public class JackSonConfig {
    @Bean
    public ObjectMapper ObjectMapper() {
        ObjectMapper objectMapper = new ObjectMapper();
        JavaTimeModule javaTimeModule = new JavaTimeModule();

        // 序列化
        javaTimeModule.addSerializer(
                LocalDateTime.class,
                new LocalDateTimeSerializer(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));
        javaTimeModule.addSerializer(
                LocalDate.class,
                new LocalDateSerializer(DateTimeFormatter.ofPattern("yyyy-MM-dd")));
        javaTimeModule.addSerializer(
                LocalTime.class,
                new LocalTimeSerializer(DateTimeFormatter.ofPattern("HH:mm:ss")));
        javaTimeModule.addSerializer(
                Date.class,
                new DateSerializer(false, new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")));

        // 反序列化
        javaTimeModule.addDeserializer(
                LocalDateTime.class,
                new LocalDateTimeDeserializer(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));
        javaTimeModule.addDeserializer(
                LocalDate.class,
                new LocalDateDeserializer(DateTimeFormatter.ofPattern("yyyy-MM-dd")));
        javaTimeModule.addDeserializer(
                LocalTime.class,
                new LocalTimeDeserializer(DateTimeFormatter.ofPattern("HH:mm:ss")));
        javaTimeModule.addDeserializer(Date.class, new DateDeserializers.DateDeserializer(){
            @SneakyThrows
            @Override
            public Date deserialize(JsonParser jsonParser, DeserializationContext dc){
                String text = jsonParser.getText().trim();
                SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
                return sdf.parse(text);
            }
        });

        objectMapper.registerModule(javaTimeModule);
        return objectMapper;
    }

}

Entity

package com.example.business.entity;

import lombok.Data;

import java.time.LocalDateTime;

@Data
public class User {
    private Long id;

    private String userName;

    private LocalDateTime createTime;
}

Controller

package com.example.business.controller;

import com.example.business.entity.User;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("user")
public class UserController {
    @PostMapping("save")
    public User save(@RequestBody User user) {
        System.out.println("保存用户：" + user);
        return user;
    }
}

测试

SpringBoot--LocalDateTime--全局格式转换/前端入参_SpringBoot_05

后端结果

保存用户：User(id=null, userName=Tony, createTime=2021-09-16T21:13:21)

法2：配置类+@JsonFormat

本方法需要配置ObjectMapper，Entity也需要加@JsonFormat。

配置类

package com.example.common.config;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.datatype.jdk8.Jdk8Module;
import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
import com.fasterxml.jackson.module.paramnames.ParameterNamesModule;
import org.springframework.boot.jackson.JsonComponent;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class JacksonConfig {

    @Bean
    public ObjectMapper serializingObjectMapper() {
        ObjectMapper objectMapper = new ObjectMapper();
        // 自动扫描并注册相关模块
        objectMapper.findAndRegisterModules();

        // 手动注册相关模块
        // objectMapper.registerModule(new ParameterNamesModule());
        // objectMapper.registerModule(new Jdk8Module());
        // objectMapper.registerModule(new JavaTimeModule());
        return objectMapper;
    }

}

Entity

package com.example.business.entity;

import com.fasterxml.jackson.annotation.JsonFormat;
import lombok.Data;

import java.time.LocalDateTime;

@Data
public class User {
    private Long id;

    private String userName;

    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
    private LocalDateTime createTime;
}

Controller

package com.example.business.controller;

import com.example.business.entity.User;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("user")
public class UserController {
    @PostMapping("save")
    public User save(@RequestBody User user) {
        System.out.println("保存用户：" + user);
        return user;
    }
}

测试

SpringBoot--LocalDateTime--全局格式转换/前端入参_spring_06

后端结果

保存用户：User(id=null, userName=Tony, createTime=2021-09-16T21:13:21)

mysql的rowid的作用 mysql的row_number

为每组记录添加行号设置一个变量SET @row_number = 0;在mysql中每次都累加代码如下SET @row_number = 0; SELECT (@row_number:=@row_number + 1) AS num, firstName, lastName employees LIMIT 5;为每个分组的数据都打上连续的id设置一个变量