Mybatis注解方法操作数据库

Java中使用Mybatis操作数据库主要有两种方法：注解和xml配置，注解相对比较简单和方便，两种方式的效果一致。本文以注解的方式说明用Mybatis访问数据库的方法

一、创建数据表(MySql)

-- ----------------------------
-- Table structure for admininfo
-- ----------------------------
DROP TABLE IF EXISTS `admininfo`;
CREATE TABLE `admininfo` (
  `ID` int(11) NOT NULL AUTO_INCREMENT,
  `AdminName` varchar(20) NOT NULL,
  PRIMARY KEY (`ID`)
) ENGINE=InnoDB AUTO_INCREMENT=25 DEFAULT CHARSET=latin1;

二、创建mybatis的配置文件：mybatisConf.xml，由于使用maven进行管理，所以放在java-->resources文件夹下，其它位置也可以，只有最终在 argetclassesmybatisConf.xml生成文件即可

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC" />
            <!-- 配置数据库连接信息 -->
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver" />
                <property name="url" value="jdbc:mysql://127.0.0.1/test" />
                <property name="username" value="root" />
                <property name="password" value="root" />
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <!-- 注册映射接口，该接口文件包含了数据访问方法和SQL -->
        <mapper class="dal.dataaccess.IAdminInfoMapper" />
    </mappers>
</configuration>

三、创建IAdminInfoMapper文件（本文中包名为dal.dataaccess)

该接口的功能主要是提供对AdminInfo表的数据操作

package dal.dataaccess;
 
import java.util.List;
import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;
import dal.beans.AdminInfo;
import dal.beans.AdminRightInfo;
 
public interface IAdminInfoMapper {
     
    //使用@Select注解指明getById方法要执行的SQL
    @Select("select * from admininfo where id=#{id}")
    public AdminInfo getById(int id);
     
    //使用@Select注解指明getAll方法要执行的SQL
    @Select("select * from admininfo")
    public List<AdminInfo> getAll();
     
    //使用@Insert注解指明add方法要执行的SQL
    @Insert("insert into admininfo(adminName) values(#{adminName})")
    public int add(AdminInfo user);
     
    //使用@Update注解指明update方法要执行的SQL
    @Update("update admininfo set adminName=#{adminName} where id=#{id}")
    public int update(AdminInfo user);
     
    //使用@Delete注解指明deleteById方法要执行的SQL
    @Delete("delete from admininfo where id=#{id}")
    public int deleteById(int id);
}

四、定义操作数据库的公共方法

package framework.utils;
 
import java.io.InputStream;
 
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
 
public class MyBatisUtil {
    /**
     * 获取SqlSessionFactory
     * 
     * @return SqlSessionFactory
     */
    public static SqlSessionFactory getSqlSessionFactory() {
        String resource = "mybatisConf.xml";
        InputStream is = MyBatisUtil.class.getClassLoader().getResourceAsStream(resource);
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(is);
        return factory;
    }
 
    /**
     * 获取SqlSession
     * 
     * @return SqlSession
     */
    public static SqlSession getSqlSession() {
        return getSqlSessionFactory().openSession();
    }
 
    /**
     * 获取SqlSession
     * 
     * @param isAutoCommit
     *            true 表示创建的SqlSession对象在执行完SQL之后会自动提交事务 false
     *            表示创建的SqlSession对象在执行完SQL之后不会自动提交事务，这时就需要我们手动调用sqlSession.
     *            commit()提交事务
     * @return SqlSession
     */
    public static SqlSession getSqlSession(boolean isAutoCommit) {
        return getSqlSessionFactory().openSession(isAutoCommit);
    }
}

五、对adminInfo表进行增删改查

package test;
 
import java.util.List;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;
import dal.beans.*;
import framework.utils.MyBatisUtil;
import dal.dataaccess.*;
 
public class MybatisAnnotationTest {
 
    // http://www.cnblogs.com/xdp-gacl/p/4261895.html
    @Test
    public void Select() {
        SqlSession sqlSession = MyBatisUtil.getSqlSession();
        // 得到AdminInfoMapper接口的实现类对象，IAdminInfoMapper接口的实现类对象由sqlSession.getMapper(IAdminInfoMapper.class)动态构建出来
        IAdminInfoMapper mapper = sqlSession.getMapper(IAdminInfoMapper.class);
        // 执行查询操作，将查询结果自动封装成User返回
        AdminInfo bean = mapper.getById(13);
        // 使用SqlSession执行完SQL之后需要关闭SqlSession
        sqlSession.close();
        System.out.println(bean.getId());
        System.out.println(bean.getAdminName());
    }
 
    @Test
    public void SelectAll() {
        SqlSession sqlSession = MyBatisUtil.getSqlSession();
        IAdminInfoMapper mapper = sqlSession.getMapper(IAdminInfoMapper.class);
        List<AdminInfo> bean = mapper.getAll();
        sqlSession.close();
 
        System.out.println(bean.size());
    }
 
    @Test
    public void Insert() {
        SqlSession sqlSession = MyBatisUtil.getSqlSession();
        IAdminInfoMapper mapper = sqlSession.getMapper(IAdminInfoMapper.class);
 
        AdminInfo bean = new AdminInfo();
        bean.setAdminName("Admin" + System.currentTimeMillis());
 
        int result = mapper.add(bean);
        sqlSession.commit();
        sqlSession.close();
 
        System.out.println(result);
    }
 
    @Test
    public void Update() {
        SqlSession sqlSession = MyBatisUtil.getSqlSession();
        IAdminInfoMapper mapper = sqlSession.getMapper(IAdminInfoMapper.class);
 
        AdminInfo bean = new AdminInfo();
        bean.setId(12);
        bean.setAdminName("Admin" + System.currentTimeMillis());
 
        int result = mapper.update(bean);
        sqlSession.commit();
        sqlSession.close();
 
        System.out.println(result);
    }
 
    @Test
    public void Delete() {
 
        SqlSession sqlSession = MyBatisUtil.getSqlSession();
        IAdminInfoMapper mapper = sqlSession.getMapper(IAdminInfoMapper.class);
 
        int result = mapper.deleteById(12);
        sqlSession.commit();
        sqlSession.close();
 
        System.out.println(result);
    }
}

六、由于使用了maven进行依赖管理，pom.xml还需要添加

<dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.38</version>
    </dependency>
    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis</artifactId>
        <version>3.3.0</version>
    </dependency>

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