Mybatis框架学习（1）——单表增删改查

1.创建名为mybatis-001-hello的Maven项目，项目结构如下



2.在pom.xml中加载所需的jar包的依赖坐标

<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.yc</groupId>
<artifactId>mybatis</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>

<name>mybatis-001-hello</name>
<url>http://maven.apache.org</url>

<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<junit.version>4.12</junit.version>
<mybatis.version>3.4.1</mybatis.version>
<oracle.version>12.1.0.1</oracle.version>
<log4j.version>2.6.2</log4j.version>
</properties>

<dependencies>
<!-- 单元测试包 -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>${junit.version}</version>
<scope>test</scope>
</dependency>

<!-- mybatis框架包 -->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>${mybatis.version}</version>
</dependency>
<!-- oracle数据库驱动包 -->
<dependency>
<groupId>com.hynnet</groupId>
<artifactId>oracle-driver-ojdbc6</artifactId>
<version>${oracle.version}</version>
<exclusions>
<exclusion>
<artifactId>slf4j-api</artifactId>
<groupId>org.slf4j</groupId>
</exclusion>
</exclusions>
</dependency>
<!-- log4j日志框架jar包 -->
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>${log4j.version}</version>
</dependency>
</dependencies>
</project>

3.mybatis.xml代码如下

<?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" />
<!-- 配置数据源 -->
<dataSource type="POOLED">
<property name="driver"value="oracle.jdbc.driver.OracleDriver"/>
<property name="url" value="jdbc:oracle:thin:@localhost:1521:yc" />
<property name="username" value="mybatis26" />
<property name="password" value="a" />
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="mapper/UserMapper.xml"/>
</mappers>
</configuration>

配置日志文件log4j2.xml,代码如下

<?xml version="1.0" encoding="UTF-8"?>
<Configuration>
<Appenders>
<Console name="STDOUT" target="SYSTEM_OUT">
<PatternLayout pattern="%d %-5p %C{1} (%F:%L) - %m%n"/>
</Console>
</Appenders>
<Loggers>
<Logger name="com.yc.mybatis" level="debug"/>
<Logger name="org.apache.ibatis.logging.jdbc" level="debug"/>
<Root level="error">
<AppenderRef ref="STDOUT"/>
</Root>
</Loggers>
</Configuration>

创建实体类User.java,代码如下

package com.yc.mybatis.entity;

public class User {
private Integer id;
private String uname;
private String upwd;
public User() {
}
public User(String uname, String upwd) {
this.uname = uname;
this.upwd = upwd;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getUname() {
return uname;
}
public void setUname(String uname) {
this.uname = uname;
}
public String getUpwd() {
return upwd;
}
public void setUpwd(String upwd) {
this.upwd = upwd;
}
@Override
public String toString() {
return "\nUser [id=" + id + ", uname=" + uname + ", upwd=" + upwd + "]";
}
}

创建映射接口UserMapper.java,代码如下

package com.yc.mybatis.mapper;

import java.util.List;

import com.yc.mybatis.entity.User;

public interface UserMapper {

public User getUserById(Integer id);

public int insertUser(User user);

public int updateUser(User user);

public int deleteUser(int id);

public List<User> getAllUsers();

}

创建工具类MyBatisUtil.java,代码如下

package com.yc.mybatis.util;

import java.io.IOException;
import java.io.InputStream;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.apache.logging.log4j.LogManager;

public class MyBatisUtil {
private  static SqlSessionFactory factory;

static{
InputStream in=null;
try {
//加载类路径下的mybatis框架的配置文件
in=Resources.getResourceAsStream("mybatis.xml");
LogManager.getLogger().debug("加载类路径下的mybatis框架的配置文件成功...");
} catch (IOException e) {
LogManager.getLogger().error("加载类路径下的mybatis框架的配置文件失败！！！");
}
//根据加载上来的mybatis配置文件信息，构建SqlSessionFactory的对象
factory=new SqlSessionFactoryBuilder().build(in);
LogManager.getLogger().debug("根据加载上来的mybatis配置文件信息，构建SqlSessionFactory的对象成功....");
}

//取到数据库会话对象
public static SqlSession getSession(){
SqlSession session=null;
if (factory !=null) {
session= factory.openSession();
LogManager.getLogger().debug("使用SqlSessionFactory的对象，生产出SqlSession对象成功....");
}
return session;
}

//取到数据库会话对象
public static SqlSession getAutoCommitSession(){
SqlSession session=null;
if (factory !=null) {
session= factory.openSession(true);
LogManager.getLogger().debug("使用SqlSessionFactory的对象，生产出SqlSession对象成功....");
}
return session;
}
}

创建映射文件UserMapper.xml,代码如下

<?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">
<!-- 命名空间与对应映射接口的全类名一致 -->
<mapper namespace="com.yc.mybatis.mapper.UserMapper">
<!-- id与方法名一致 -->
<select id="getUserById"  parameterType="int"  resultType="com.yc.mybatis.entity.User">
select * from users where id=#{id}
</select>

<insert id="insertUser" parameterType="com.yc.mybatis.entity.User">
insert into users values(seq_users.nextval, #{uname}, #{upwd})
</insert>

<update id="updateUser" parameterType="com.yc.mybatis.entity.User">
update users set uname=#{uname}, upwd=#{upwd} where id=#{id}
</update>

<delete id="deleteUser" parameterType="int">
delete from users where id=#{id}
</delete>

<!-- resultType:返回一个对象是指对象类型，返回多个对象是指集合的泛型类型 -->
<select id="getAllUsers" resultType="com.yc.mybatis.entity.User">
select * from users
</select>
</mapper>

创建测试类MybatisTest.java,代码如下

package com.yc.mybatis;

import static org.junit.Assert.*;

import java.sql.Connection;
import java.util.List;

import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import com.yc.mybatis.entity.User;
import com.yc.mybatis.mapper.UserMapper;
import com.yc.mybatis.util.MyBatisUtil;

public class MybatisTest {

@Test
public void testConn() {
SqlSession session=MyBatisUtil.getSession();
//通过SqlSession对象，获得数据库连接
Connection con=session.getConnection();
assertNotNull(con);
}
@Test
public void testSelect(){
SqlSession session=MyBatisUtil.getSession();
UserMapper userMapper=session.getMapper(UserMapper.class);
User user=userMapper.getUserById(10003);
System.out.println(user);
assertNotNull(user);
}
@Test
public void testInsert(){
//SqlSession session=MyBatisUtil.getSession();
SqlSession session=MyBatisUtil.getAutoCommitSession();
UserMapper userMapper=session.getMapper(UserMapper.class);
User user=new User("小红","abc123");
int result=userMapper.insertUser(user);
//session.commit();
assertEquals(1, result);
}

@Test
public void testUpdate(){
//SqlSession session=MyBatisUtil.getSession();
SqlSession session=MyBatisUtil.getAutoCommitSession();
UserMapper userMapper=session.getMapper(UserMapper.class);
User user=new User("小白","abc1234");
user.setId(10013);
int result=userMapper.updateUser(user);
//session.commit();
assertEquals(1, result);
}

@Test
public void testDelete(){
//SqlSession session=MyBatisUtil.getSession();
SqlSession session=MyBatisUtil.getAutoCommitSession();
UserMapper userMapper=session.getMapper(UserMapper.class);
int result=userMapper.deleteUser(10013);
//session.commit();
assertEquals(1, result);
}

@Test
public void testReadAll(){
SqlSession session=MyBatisUtil.getAutoCommitSession();
UserMapper userMapper=session.getMapper(UserMapper.class);
List<User>users=userMapper.getAllUsers();
System.out.println(users);
assertNotNull(users);
}
}