LocalDateTime与mysql日期类型的交互（基于mybatis）

众所周知，在实体Entity里面，可以使用Java.sql.Date、java.sql.Timestamp、java.util.Date来映射到数据库的date、timestamp、datetime等字段，但是，java.sql.Date、java.sql.Timestamp、java.util.Date这些类都不好用，很多方法都过时了。

Java8里面新出来了一些API，LocalDate、LocalTime、LocalDateTime 非常好用，默认的情况下，在mybatis里面不支持java8的时间、日期。直接使用，会报如下错误

Caused by: java.lang.IllegalStateException: No typehandler found for property createTime  
    at org.apache.ibatis.mapping.ResultMapping$Builder.validate(ResultMapping.java:151)  
    at org.apache.ibatis.mapping.ResultMapping$Builder.build(ResultMapping.java:140)  
    at org.apache.ibatis.builder.MapperBuilderAssistant.buildResultMapping(MapperBuilderAssistant.java:382)  
    at org.apache.ibatis.builder.xml.XMLMapperBuilder.buildResultMappingFromContext(XMLMapperBuilder.java:378)  
    at org.apache.ibatis.builder.xml.XMLMapperBuilder.resultMapElement(XMLMapperBuilder.java:280)  
    at org.apache.ibatis.builder.xml.XMLMapperBuilder.resultMapElement(XMLMapperBuilder.java:252)  
    at org.apache.ibatis.builder.xml.XMLMapperBuilder.resultMapElements(XMLMapperBuilder.java:244)  
    at org.apache.ibatis.builder.xml.XMLMapperBuilder.configurationElement(XMLMapperBuilder.java:116)  
    ... 81 common frames omitted  

 导入依赖

<dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>tk.mybatis</groupId>
            <artifactId>mapper-spring-boot-starter</artifactId>
            <version>2.0.2</version>
        </dependency>
        <!-- mybatis数据库字段类型映射，此处是重点 -->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-typehandlers-jsr310</artifactId>
            <version>1.0.1</version>
        </dependency>
        <!-- MYSQL驱动包 -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

属性配置

spring.datasource.url=jdbc:mysql://localhost:3306/dev?useUnicode=true&characterEncoding=UTF-8&zeroDateTimeBehavior=convertToNull&allowMultiQueries=true&useSSL=false
spring.datasource.username=root
spring.datasource.password=123456
# 如果想看到mybatis日志需要做如下配置
logging.level.com.carry=DEBUG
######### Mybatis 自身配置 ##########
mybatis.mapper-locations=classpath:com/carry/mapper/*Mapper.xml
mybatis.type-aliases-package=com.carry.dto
# 驼峰命名规范 如：数据库字段是  order_id 那么 实体字段就要写成 orderId
mybatis.configuration.map-underscore-to-camel-case=true
######### 通用Mapper ##########
# 主键自增回写方法,默认值MYSQL,详细说明请看文档
mapper.identity=MYSQL
mapper.mappers=tk.mybatis.mapper.common.Mapper
# 设置 insert 和 update 中，是否判断字符串类型!=''
mapper.not-empty=true
# 枚举按简单类型处理
mapper.enum-as-simple-type=true

建表SQL

CREATE TABLE `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `create_date` date DEFAULT NULL,
  `create_time` datetime DEFAULT NULL,
  PRIMARY KEY (`id`)
)

实体类

package com.carry.dto;
import java.io.Serializable;

import java.time.LocalDate;

import java.time.LocalDateTime;
import javax.persistence.GeneratedValue;

import javax.persistence.GenerationType;

import javax.persistence.Id;
import com.fasterxml.jackson.annotation.JsonFormat;
public class User implements Serializable{
</span><span style="color: #0000ff;">private</span> <span style="color: #0000ff;">static</span> <span style="color: #0000ff;">final</span> <span style="color: #0000ff;">long</span> serialVersionUID = -108907189034815108L<span style="color: #000000;">;

@Id
@GeneratedValue(strategy </span>=<span style="color: #000000;"> GenerationType.IDENTITY)
</span><span style="color: #0000ff;">private</span><span style="color: #000000;"> Long id;
@JsonFormat(pattern </span>= "yyyy-MM-dd"<span style="color: #000000;">)
</span><span style="color: #0000ff;">private</span><span style="color: #000000;"> LocalDate createDate;
@JsonFormat(pattern </span>= "yyyy-MM-dd HH:mm:ss"<span style="color: #000000;">)
</span><span style="color: #0000ff;">private</span><span style="color: #000000;"> LocalDateTime createTime;

</span><span style="color: #0000ff;">public</span><span style="color: #000000;"> Long getId() {
    </span><span style="color: #0000ff;">return</span><span style="color: #000000;"> id;
}

</span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> setId(Long id) {
    </span><span style="color: #0000ff;">this</span>.id =<span style="color: #000000;"> id;
}

</span><span style="color: #0000ff;">public</span><span style="color: #000000;"> LocalDate getCreateDate() {
    </span><span style="color: #0000ff;">return</span><span style="color: #000000;"> createDate;
}

</span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> setCreateDate(LocalDate createDate) {
    </span><span style="color: #0000ff;">this</span>.createDate =<span style="color: #000000;"> createDate;
}

</span><span style="color: #0000ff;">public</span><span style="color: #000000;"> LocalDateTime getCreateTime() {
    </span><span style="color: #0000ff;">return</span><span style="color: #000000;"> createTime;
}

</span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> setCreateTime(LocalDateTime createTime) {
    </span><span style="color: #0000ff;">this</span>.createTime =<span style="color: #000000;"> createTime;
}

}

Mapper类

package com.carry.mapper;
import com.carry.dto.User;
import tk.mybatis.mapper.common.Mapper;
public interface UserMapper extends Mapper<User> {
}

启动类

package com.carry;
import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;
import tk.mybatis.spring.annotation.MapperScan;
@SpringBootApplication

@MapperScan(basePackages = "com.carry.mapper")

public class SpringBootDateMysqlApplication {

public static void main(String[] args) {
        SpringApplication.run(SpringBootDateMysqlApplication.class, args);
    }
}

测试

package com.carry;
import java.time.LocalDate;

import java.time.LocalDateTime;
import org.junit.Test;

import org.junit.runner.RunWith;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.boot.test.context.SpringBootTest;

import org.springframework.test.context.junit4.SpringRunner;
import com.carry.dto.User;

import com.carry.mapper.UserMapper;

import com.fasterxml.jackson.core.JsonProcessingException;

import com.fasterxml.jackson.databind.ObjectMapper;
@RunWith(SpringRunner.class)

@SpringBootTest

public class SpringBootDateMysqlApplicationTests {
@Autowired
</span><span style="color: #0000ff;">private</span><span style="color: #000000;"> UserMapper mapper;

@Autowired
</span><span style="color: #0000ff;">private</span><span style="color: #000000;"> ObjectMapper objectMapper;

@Test
</span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> insert() {
    User user </span>= <span style="color: #0000ff;">new</span><span style="color: #000000;"> User();
    user.setCreateDate(LocalDate.now());
    user.setCreateTime(LocalDateTime.now());
    mapper.insertSelective(user);
}

@Test
</span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> query() {
    mapper.selectAll().stream().forEach(e </span>-&gt;<span style="color: #000000;"> {
        </span><span style="color: #0000ff;">try</span><span style="color: #000000;"> {
            System.out.println(objectMapper.writeValueAsString(e));
        } </span><span style="color: #0000ff;">catch</span><span style="color: #000000;"> (JsonProcessingException ex) {
            ex.printStackTrace();
        }
    });
}

}

先后执行测试方法 insert 和 query，无错误说明测试通过

SpringBootDateMysql

原文地址：https://blog.csdn.net/kingboyworld/article/details/75808108