这一篇,代码折腾的时间较长,完成之后都是一些小细节,主要有三:
1、引入的依赖错误;
2、启动配置错误;
3、xml文件的mapper命名空间错误。
一、完整的pom.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>
- <groupId>com.example</groupId>
- <artifactId>spring-boot-sample-mybatis</artifactId>
- <version>0.0.1-SNAPSHOT</version>
- <packaging>jar</packaging>
- <name>spring-boot-sample-mybatis</name>
- <description>Demo project for Spring Boot</description>
- <parent>
- <groupId>org.springframework.boot</groupId>
- <artifactId>spring-boot-starter-parent</artifactId>
- <version>1.3.5.RELEASE</version>
- <relativePath/> <!-- lookup parent from repository -->
- </parent>
- <properties>
- <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
- <java.version>1.8</java.version>
- </properties>
- <dependencies>
- <dependency>
- <groupId>org.springframework.boot</groupId>
- <artifactId>spring-boot-starter-web</artifactId>
- </dependency>
- <dependency>
- <groupId>org.springframework.boot</groupId>
- <artifactId>spring-boot-starter-test</artifactId>
- <scope>test</scope>
- </dependency>
- <!-- mysql连接 -->
- <dependency>
- <groupId>mysql</groupId>
- <artifactId>mysql-connector-java</artifactId>
- <scope>runtime</scope>
- </dependency>
- <!-- mybatis -->
- <dependency>
- <groupId>org.mybatis.spring.boot</groupId>
- <artifactId>mybatis-spring-boot-starter</artifactId>
- <version>1.1.1</version>
- </dependency>
- </dependencies>
- <build>
- <plugins>
- <plugin>
- <groupId>org.springframework.boot</groupId>
- <artifactId>spring-boot-maven-plugin</artifactId>
- </plugin>
- </plugins>
- </build>
- </project>
二、启动文件 Application.java
- package com.example;
- import org.apache.ibatis.session.SqlSessionFactory;
- import org.apache.tomcat.jdbc.pool.DataSource;
- import org.mybatis.spring.SqlSessionFactoryBean;
- import org.mybatis.spring.annotation.MapperScan;
- import org.slf4j.Logger;
- import org.slf4j.LoggerFactory;
- import org.springframework.boot.SpringApplication;
- import org.springframework.boot.autoconfigure.SpringBootApplication;
- import org.springframework.boot.context.properties.ConfigurationProperties;
- import org.springframework.context.annotation.Bean;
- import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
- import org.springframework.jdbc.datasource.DataSourceTransactionManager;
- import org.springframework.transaction.PlatformTransactionManager;
- @SpringBootApplication
- @MapperScan("com.example.mapper")
- public class Application {
- protected static Logger logger=LoggerFactory.getLogger(Application.class);
- @Bean
- @ConfigurationProperties(prefix="spring.datasource")
- public DataSource dataSource() {
- return new org.apache.tomcat.jdbc.pool.DataSource();
- }
- @Bean
- public SqlSessionFactory sqlSessionFactoryBean() throws Exception {
- SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
- sqlSessionFactoryBean.setDataSource(dataSource());
- PathMatchingResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
- sqlSessionFactoryBean.setMapperLocations(resolver.getResources("classpath:/mybatis/*.xml"));
- return sqlSessionFactoryBean.getObject();
- }
- @Bean
- public PlatformTransactionManager transactionManager() {
- return new DataSourceTransactionManager(dataSource());
- }
- public static void main(String[] args) {
- SpringApplication.run(Application.class, args);
- logger.info("SpringBoot Start Success");
- }
- }
1、在类上声明MapperScan,这是mybatis-spring-boot-starter在1.1.1引入的类Mapper,从而在mapper接口上不需要任何声明
2、配置dataSource、SqlSessionFactory、PlatformTransactionManager,其实默认的都已经配好,这里主要是为了标明Mapper的xml文件存在位置
3、src/main/resources下的文件,在打包之后,都在工程的根目录。
这个只需要更改两个地方:
1、MapperScan之后的"com.example.mapper",改成Mapper接口文件所在的包名
2、sqlSessionFactoryBean方法中"classpath:/mybatis/*.xml",改成Mapper的xml文件存在位置
三、启动配置文件 application.properties
- spring.datasource.url=jdbc:mysql://192.168.56.201:3306/bootsample?useUnicode=true&characterEncoding=UTF-8
- spring.datasource.username=root
- spring.datasource.password=123456
- spring.datasource.driver-class-name=com.mysql.jdbc.Driver
- spring.datasource.max-active=10
- spring.datasource.max-idle=5
- spring.datasource.min-idle=0
四、Mapper的XML文件
- <?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">
- <!-- namespace必须指向Dao接口 -->
- <mapper namespace="com.example.mapper.HotelDtoMapper">
- <resultMap id="ListHotelDto" type="com.example.dto.HotelDto" >
- <result column="cityName" property="cityName" />
- <result column="hotelName" property="hotelName" />
- <result column="address" property="address" />
- <result column="zip" property="zip" />
- <result column="state" property="state" />
- <result column="country" property="country" />
- </resultMap>
- <!-- 根据ID查询数据 -->
- <select id="findByCountry" parameterType="String" resultMap="ListHotelDto">
- select
- c.name as cityName,
- h.name as hotelName,
- h.address,
- h.zip,
- c.state,
- c.country
- from city c
- join hotel h on c.id=h.city
- where c.country = #{country}
- </select>
- </mapper>
1、mapper的命名空间(namespace),一定是所对应的接口的包名+类名
2、parameterType和resultMap,与实际匹配
五、接口文件
- package com.example.mapper;
- import java.util.List;
- import com.example.dto.HotelDto;
- public interface HotelDtoMapper {
- public List<HotelDto> findByCountry(String country);
- }
1、类上没有任何的声明
2、方法的名称、输入参数书,与xml定义的一直
六、文件结构
七、其它说明
使用mybatis的主要目的,就是解决复杂sql。在数据库工具中拼写好sql,拷贝进xml文件;验证sql,仅需要把sql拷贝到数据库工具进行分析即可,简单高效。
源代码:http://download.csdn.net/detail/lxhjh/9560276