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初学Spring真是伤不起呀，连一个Mybatis的配置都整了一天才弄出来，太不容易了，所以这里一定要把它记录下来，防止自已到时候又忘记了，虽然前后经历了好长时间，但好在磕磕碰碰的弄出来了，也算给自已一点小安慰吧。 其实Mybatis的配置网上的资料真的不要太多，百度一下会找到好多，也许就是因为太多了，加上好多的文章都差不多，有时候想找点有用的东西还真不是那么容易的事。而且，由于Mybatis版本的原因，找到的内容好多已经过时了，所以中间经历的过程就不细说了，都是泪呀，当然可能也是因为我初学，菜鸟的原因吧，哎。 网上大部分能找到的 Mybatis的配置很多都是基于XML配置这种，那种也不是我想要的，我的整个Spring MVC工程也是用的Java config，就是没有在web.xml或者其它的配置文件去配置Bean这种，所以，我的Mybatis也想用Java代码的方式，这个就有一点不一样了，所以在配置中遇到了一些问题。 Mybatis相关网站像Maven、Spring MVC的配置过程这里就不说了，这不是本文的重点，所以Mybatis的配置是在Spring框架配置好的基础上进行的。 目录结构在配置之前，先看下整个项目的目录结构 pom.xml的配置需要在这个文件里面增加Mybatis、Mybatis-spring、MySql的一些依赖 <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <maven.compiler.source>1.7</maven.compiler.source> <maven.compiler.target>1.7</maven.compiler.target> <spring.version>4.3.18.RELEASE</spring.version> <spring.jdbc.version>5.2.0.RELEASE</spring.jdbc.version> <mysql.connector.version>5.1.21</mysql.connector.version> <servlet.version>3.0.1</servlet.version> <jsp.version>2.2.1-b03</jsp.version> <jstl.version>1.2</jstl.version> <redis.version>2.0.3.RELEASE</redis.version> <jedis.version>2.9.0</jedis.version> <mybatis.version>3.5.4</mybatis.version> <mybatis.spring.version>2.0.4</mybatis.spring.version> </properties>
<dependencies> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.11</version> <scope>test</scope> </dependency>
<dependency> <groupId>javax.servlet.jsp.jstl</groupId> <artifactId>jstl-api</artifactId> <version>1.2</version> </dependency>
<!-- Servlet API 3.0 --> <dependency> <groupId>javax.servlet</groupId> <artifactId>javax.servlet-api</artifactId> <version>${servlet.version}</version> </dependency>
<dependency> <groupId>javax.servlet.jsp</groupId> <artifactId>jsp-api</artifactId> <version>${jsp.version}</version> <scope>provided</scope> </dependency> <dependency> <groupId>javax.servlet</groupId> <artifactId>jstl</artifactId> <version>${jstl.version}</version> </dependency>
<dependency> <groupId>org.springframework</groupId> <artifactId>spring-core</artifactId> <version>${spring.version}</version> </dependency>
<dependency> <groupId>org.springframework</groupId> <artifactId>spring-beans</artifactId> <version>${spring.version}</version> </dependency>
<dependency> <groupId>org.springframework</groupId> <artifactId>spring-test</artifactId> <version>${spring.version}</version> <scope>test</scope> </dependency>
<dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>${spring.version}</version> </dependency>
<dependency> <groupId>org.springframework</groupId> <artifactId>spring-web</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc</artifactId> <version>${spring.version}</version> </dependency>
<dependency> <groupId>org.thymeleaf</groupId> <artifactId>thymeleaf-spring4</artifactId> <version>3.0.11.RELEASE</version> </dependency>
<dependency> <groupId>org.springframework</groupId> <artifactId>spring-jdbc</artifactId> <version>${spring.jdbc.version}</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>${mysql.connector.version}</version> </dependency>
<dependency> <groupId>org.springframework.data</groupId> <artifactId>spring-data-redis</artifactId> <version>${redis.version}</version> </dependency> <dependency> <groupId>redis.clients</groupId> <artifactId>jedis</artifactId> <version>${jedis.version}</version> </dependency>
<dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.12</version> <scope>test</scope> </dependency>
<dependency> <groupId>org.springframework</groupId> <artifactId>spring-test</artifactId> <version>${spring.version}</version> <scope>test</scope> </dependency>
<dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis</artifactId> <version>${mybatis.version}</version> </dependency>
<dependency> <groupId>com.alibaba</groupId> <artifactId>druid</artifactId> <version>1.0.16</version> </dependency>
<dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis-spring</artifactId> <version>${mybatis.spring.version}</version> </dependency> </dependencies> 再添加一个Mybatis的Bean配置，文件在 config/MyBatisConfig.java package com.smartrui.common.config;
import com.alibaba.druid.pool.DruidDataSource; import org.mybatis.spring.SqlSessionFactoryBean; import org.mybatis.spring.annotation.MapperScan; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.beans.factory.annotation.Value; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.context.annotation.PropertySource; import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import javax.sql.DataSource; import java.sql.SQLException;
@Configuration @PropertySource("classpath:config/application.properties") @MapperScan(basePackages = {"com.smartrui.dao"}) public class MyBatisConfig {
@Value("${spring.datasource.url}") private String dbUrl;
@Value("${spring.datasource.username}") private String username;
@Value("${spring.datasource.password}") private String password;
@Value("${spring.datasource.driverClassName}") private String driverClassName;
@Value("${spring.datasource.initialSize}") private int initialSize;
@Value("${spring.datasource.minIdle}") private int minIdle;
@Value("${spring.datasource.maxActive}") private int maxActive;
@Value("${spring.datasource.maxWait}") private int maxWait;
@Value("${spring.datasource.timeBetweenEvictionRunsMillis}") private int timeBetweenEvictionRunsMillis;
@Value("${spring.datasource.minEvictableIdleTimeMillis}") private int minEvictableIdleTimeMillis;
@Value("${spring.datasource.validationQuery}") private String validationQuery;
@Value("${spring.datasource.testWhileIdle}") private boolean testWhileIdle;
@Value("${spring.datasource.testOnBorrow}") private boolean testOnBorrow;
@Value("${spring.datasource.testOnReturn}") private boolean testOnReturn;
@Value("${spring.datasource.poolPreparedStatements}") private boolean poolPreparedStatements;
@Value("${spring.datasource.maxPoolPreparedStatementPerConnectionSize}") private int maxPoolPreparedStatementPerConnectionSize;
@Value("${spring.datasource.filters}") private String filters;
@Value("{spring.datasource.connectionProperties}") private String connectionProperties;
@Value("${mybatis.type.alias.package}") private String mybatisTypeAliasPackage;
@Bean //声明其为Bean实例 public DataSource dataSource(){ DruidDataSource datasource = new DruidDataSource();
datasource.setUrl(this.dbUrl); datasource.setUsername(username); datasource.setPassword(password); datasource.setDriverClassName(driverClassName); datasource.setInitialSize(initialSize); datasource.setMinIdle(minIdle); datasource.setMaxActive(maxActive); datasource.setMaxWait(maxWait); datasource.setTimeBetweenEvictionRunsMillis(timeBetweenEvictionRunsMillis); datasource.setMinEvictableIdleTimeMillis(minEvictableIdleTimeMillis); datasource.setValidationQuery(validationQuery); datasource.setTestWhileIdle(testWhileIdle); datasource.setTestOnBorrow(testOnBorrow); datasource.setTestOnReturn(testOnReturn); datasource.setPoolPreparedStatements(poolPreparedStatements); datasource.setMaxPoolPreparedStatementPerConnectionSize(maxPoolPreparedStatementPerConnectionSize); try { datasource.setFilters(filters); } catch (SQLException e) { } datasource.setConnectionProperties(connectionProperties);
return datasource; }
@Bean @Autowired public SqlSessionFactoryBean sqlSessionFactoryBean(DataSource dataSource) throws Exception {
SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
sqlSessionFactoryBean.setDataSource(dataSource);
sqlSessionFactoryBean.setTypeAliasesPackage(mybatisTypeAliasPackage);
//指定mapper路径地址 PathMatchingResourcePatternResolver classPathResource = new PathMatchingResourcePatternResolver(); sqlSessionFactoryBean.setMapperLocations(classPathResource.getResources("classpath*:config/mappers/*.xml"));
org.apache.ibatis.session.Configuration configuration = new org.apache.ibatis.session.Configuration() ;
sqlSessionFactoryBean.setConfiguration(configuration);
return sqlSessionFactoryBean; }
}
上面的 SqlSessionFactoryBean方法，主要有数据库的配置
sqlSessionFactoryBean.setDataSource(dataSource);和 mapper xml的路径配置 sqlSessionFactoryBean.setMapperLocations, 那个dataSource可以配置数据源像Mysql、Oracle和其它的连接池配置等。
文件加好后，需要在WebConfig.java这个文件中保证能扫描到,用 ComponentScan或Import的方式弄进去
@Configuration @EnableWebMvc @ComponentScan(basePackages = {"com.smartrui.dao","com.smartrui.service","com.smartrui.controller"}) @Import({DataBaseConfig.class,MyBatisConfig.class}) public class WebAppConfig extends WebMvcConfigurerAdapter { /** * 静态资源过滤 */ @Override public void addResourceHandlers( ResourceHandlerRegistry registry) { super.addResourceHandlers(registry); registry.addResourceHandler("/img/**").addResourceLocations("/img/"); registry.addResourceHandler("/css/**").addResourceLocations("/css/"); registry.addResourceHandler("/js/**").addResourceLocations("/js/"); } .... 注入SqlSessionFactory 新的MyBatis的sessionFactory加载有些不太一样，需要指定下，我开始一直报SqlSessionFactory不存在，后面搜索了下，我在dao下建立一个公共的commonDAO，加上如下内容就可以了, 注意有 @Autowired这个
package com.smartrui.dao;
import org.apache.ibatis.session.SqlSessionFactory; import org.mybatis.spring.support.SqlSessionDaoSupport; import org.springframework.beans.factory.annotation.Autowired;
public class CommonDAO extends SqlSessionDaoSupport {
@Autowired public void setSqlSessionFactory(SqlSessionFactory sqlSessionFactory) { super.setSqlSessionFactory(sqlSessionFactory); } } 好了，增加上面的几个文件后，Mybatis应该就算是配置好了，没弄好之前感觉好难，其实做好后，你会发现就是那么几个配置就行了，接下来，来一个简单的测试。
在service下面写一个简单的查询 package com.smartrui.service; import org.apache.ibatis.annotations.Param; public interface PersonService { String getUserName(@Param("id") Integer id); }
写一个service的实现
package com.smartrui.service.impl;
import com.smartrui.dao.PersonDAO; import com.smartrui.dao.UserDAO; import com.smartrui.model.User; import com.smartrui.service.PersonService; import com.smartrui.service.UserService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service;
@Service("PersonService") public class PersonServiceImpl implements PersonService {
@Autowired private PersonDAO personDAO ;
@Override public String getUserName(Integer id) { return personDAO.getUserName(id); }
} dao层加上接口 package com.smartrui.dao;
import org.apache.ibatis.annotations.Param; import org.apache.ibatis.annotations.Select; import org.springframework.stereotype.Repository;
@Repository public interface PersonDAO {
// @Select("SELECT user_name FROM tb_user WHERE id = #{id}") String getUserName(@Param("id") Integer id); }
在 config/mapper/PersonMapper.xml里面加上xml的配置
<?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.smartrui.dao.PersonDAO"> <select id="getUserName" resultType="String"> SELECT user_name FROM tb_user WHERE id = #{id} </select> </mapper>
上面有几个注意的地方
dao层里面的方式如 getUserName要和PersonMapper.xml里面具体查询里的 id值一样。 PersonMapper.xml的namespace的值，就是dao层那个包的路径。 上面的写完后，在Controller层增加一个service的调用就行了
@RequestMapping("/getbyid") public String getById(){
String name; try { name = personService.getUserName(11); }catch(Exception e){ e.printStackTrace(); name = "N/A"; } System.out.println("name:" + name); return "user"; } 通过上面的配置就能把Mybatis搭建起来了，至于更深层原理性的东西，这个我暂时没有时间去深究了，待后续框架用熟一些了再说吧，当前的目标就是能先用起来。
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