springboot整合mybatis中的问题及出现的一些问题小结
时间：2020-10-10 11:46:30 | 栏目：JAVA代码 | 点击：次
1.springboot整合mybatis mapper注入时显示could not autowire,如果强行写(value = false ),可能会报NullPointException异常
解决方案:
dao层加注解@Component(value = "首字母小写的接口名如UserMapper->userMapper")
dao层还可以加注解@Mapper
2.The server time zone value 'Öйú±ê׼ʱ¼ä' is unrecognized or represents more than one time zone问题
3.java.lang.IllegalArgumentException: DefaultSerializer requires a Serializable payload but received an object of type[xxx]
解决:实体对象类没有序列化,需要implements Serializable
PS：下面看下springboot整合mybatis出现的一些问题
springboot整合mybatis非常非常的简单，简直简单到发指。但是也有一些坑，这里我会详细的指出会遇到什么问题，并且这些配置的作用
整合mybatis，无疑需要mapper文件，实体类，dao层，数据库连接池。。。。。也就没了。
先放配置application.yml
spring: datasource: type: com.alibaba.druid.pool.DruidDataSource driver-class-name: com.mysql.jdbc.Driver filters: stat maxActive: 20 initialSize: 1 maxWait: 60000 minIdle: 1 timeBetweenEvictionRunsMillis: 60000 minEvictableIdleTimeMillis: 300000 validationQuery: select 'x' testWhileIdle: true testOnBorrow: false testOnReturn: false poolPreparedStatements: true maxOpenPreparedStatements: 20 name: test url: jdbc:mysql://localhost:3306/mama-bike?useUnicode=true&characterEncoding=UTF-8&zeroDateTimeBehavior=convertToNull username: root password: root mybatis: #告诉spring你的mapper的位置。 mapper-locations: classpath:com/coder520/mamabike/**/**.xml #告诉spring你的实体类的位置 type-aliases-package: classpath:com.coder520.mamabike.**.entity logging: config: classpath:logback.xml
dao层接口 //就简单的写一个方法
public interface UserMapper {
int insert(User record);
}
mapper
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.coder520.mamabike.user.dao.UserMapper" >
<resultMap id="BaseResultMap" type="com.coder520.mamabike.user.entity.User" >
<id column="id" property="id" jdbcType="BIGINT" />
<result column="nickname" property="nickname" jdbcType="VARCHAR" />
<result column="enable_flag" property="enableFlag" jdbcType="TINYINT" />
<result column="verify_flag" property="verifyFlag" jdbcType="TINYINT" />
<result column="head_img" property="headImg" jdbcType="VARCHAR" />
<result column="mobile" property="mobile" jdbcType="VARCHAR" />
</resultMap>
<sql id="Base_Column_List" >
id, nickname, enable_flag, verify_flag, head_img, mobile
</sql>
<insert id="insert" parameterType="com.coder520.mamabike.user.entity.User" >
insert into user (id, nickname, enable_flag,
verify_flag, head_img, mobile
)
values (#{id,jdbcType=BIGINT}, #{nickname,jdbcType=VARCHAR}, #{enableFlag,jdbcType=TINYINT},
#{verifyFlag,jdbcType=TINYINT}, #{headImg,jdbcType=VARCHAR}, #{mobile,jdbcType=VARCHAR}
)
</insert>
</mapper>
main方法
@SpringBootApplication
@ComponentScan(basePackages={"com.coder520.mamabike"})
@MapperScan(basePackages="com.demo.user.mapper")
public class MamaBikeApplication {
public static void main(String[] args) {
SpringApplication.run(MamaBikeApplication.class, args);
}
}
需要注意的是，dao层接口spring怎么会知道呢？这里就需要@MapperScan(basePackages="com.demo.user.mapper") 这个注解来指定mapper接口的位置。用@ComponentScan(basePackages={"com.coder520.mamabike"})这个注解来让spring扫描我们指定包下的注解。
如果我们不用@MapperScan这个注解的话，也可以在接口类的上方加上@Mapper这个注解也可以。
总结