mybatis集成spring操作数据库（注解方式）

这里以增删改查user table为例

1 首先导入相关的jar包文件，如下：

导入的包：commons- dbcp,commons-logging,commons-pool,mybatis-3.0.5,mybatis-spring,mysql-connector-java,spring,spring-aop,spring-beans,spring-context,spring-core,spring-expression,spring-tx

2 然后确定pojo对象，User.java

public class User implements Serializable {

private String username;

private String password;

public String getUsername() {

return username;

}

public void setUsername(String username) {

this.username = username;

}

public String getPassword() {

return password;

}

public void setPassword(String password) {

this.password = password;

}

}

 

3 用接口形式调用映射文件UserMapper.java

public interface UserMapper {

User getUser(String username);

User getUserList();

@Select("select * from User where username=#{username}")

User getUserAnnotation(String username);

}

 

4 书写操作数据库的sql语句，UserMapper.xml

<?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.cienet.bjk.persistence.UserMapper">

<cache />

<select id="getUser" parameterType="string" resultType="User">

SELECT

* from user where  username = #{username}

</select>

<select id="getUserList" resultType="list">

SELECT

* from user

</select>

</mapper>

代码解释：namespace为映射的interface文件的位置，这个必须和上面的UserMapper.xml文件放在同一个目录下，且名称要一样，不然会出现找不到文件的错误。

select标签中的id表示与UserMapper.java中的方法对应。

parameterType表示传入参数的类型，resultType表示返回结果的类型#{}表示传入参数。

5 业务逻辑层代码

@Service

public class UserService {

@Autowired

private UserMapper userMapper;

public User getUser(String username){

return userMapper.getUser(username);

}

public User getUserAnnotation(String username){

return userMapper.getUser(username);

}

@SuppressWarnings("unchecked")

public List<User> getUserList() {

return (List<User>) userMapper.getUserList();

}

}

6 然后在spring配置以注解方式运行，这样的好处是不用为每个pojo写对应的xml映射文件。

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xmlns:context="http://www.springframework.org/schema/context"

xmlns:aop="http://www.springframework.org/schema/aop"

xmlns:tx="http://www.springframework.org/schema/tx"

xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd">
<bean

class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">

<property name="locations">

<value>classpath:com/cienet/bjk/config/jdbc.proper
4000
ties</value>

</property>

</bean>

<bean id="dataSource" destroy-method="close"

class="org.apache.commons.dbcp.BasicDataSource">

<property name="driverClassName"

value="${jdbc.driverClassName}" />

<property name="url" value="${jdbc.url}" />

<property name="username" value="${jdbc.username}" />

<property name="password" value="${jdbc.password}" />

</bean>

<bean id="sqlSessionFactory">

<property name="dataSource" ref="dataSource" />

<property name="typeAliasesPackage" value="com.cienet.bjk.model" />

</bean>

<bean id="transactionManager">

<property name="dataSource" ref="dataSource" />

</bean>

<!-- scan for mappers and let them be autowired -->

<bean>

<property name="basePackage" value="com.cienet.bjk.persistence" />

</bean>

<context:component-scan base-package="com.cienet.bjk.service" />

<context:annotation-config />

<tx:annotation-driven />

</beans>

 

7 最后，写测试代码进行验证是否运行成功。

@Test

public void testUsert1(){

ctx = new ClassPathXmlApplicationContext(

"com/cienet/bjk/config/beans.xml");

UserService user = (UserService) ctx.getBean("userService");

System.out.print(user.getUser("123").getPassword());

//System.out.print(user.getUserList().get(0).getPassword());

System.out.println(user.getUserAnnotation("123").getPassword());//invoke the annotation

UserMapper um = sqlSession.getMapper(UserMapper.class);

System.out.println(um.getUserAnnotation("123").getPassword());

}

运行成功最后。其中System.out.println(user.getUserAnnotation("123").getPassword());//invoke the annotation

表示用注解的方式访问访问数据库，这种形式允许直接把sql语句写在java文件中，不过，不推荐这种方式，因为java文件会过于臃肿，不好维护。