Mybatis增删改查(非接口，接口两种方式)

MybatisCRUD

• CRUD简称
• 1.非接口实现
• • 1.1创建mapper.xml映射文件
  • 1.2编写sql语句
  • 1.3配置mybatis核心配置文件
• 2. 接口实现
• 3. mybatisUtil工具类（减少重复代码编写）

CRUD简称

CRUD:增加(Create)、检索(Retrieve)、更新(Update)和删除(Delete)

1.非接口实现

1.1创建mapper.xml映射文件

namespace：名称空间，填写对应mapper.xml全限名

<?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.zwh.mapper.EmployeeMapper">
</mapper>

1.2编写sql语句

1.2.1 新增数据

mapper.xml:
parameterType：输入类型

<insert id="insertEmployee" parameterType="com.zwh.pojo.Employee">
	insert into employee
(name,gender,birthday,mobile,email,position,note) values(#{name},#{gender},#{birthday},#{mobile},#{email},#{position},#{note})
</insert>

test测试文件:

    @Test
	public void insertEmployee() throws IOException {
		/* 读取配置文件 */
		InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");
		/* 根据配置文件构建SqlSessionFactory会话工厂 */
		SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
		/* 通过SqlSessionFactory创建SqlSession */
		SqlSession sqlSession = sqlSessionFactory.openSession();
		Employee employee=new Employee();
		employee.setName("李四");
		employee.setGender(1);
		employee.setBirthday(new Date());
		employee.setMobile("1365445855");
		employee.setEmail("[e-mail]");
		employee.setPosition("工程师");
		employee.setNote("新增");
		/* SqlSession执行映射文件中自定义的SQL，并返回映射结果 */
		try {			
			int insert =
 sqlSession.insert("com.zwh.mapper.EmployeeMapper.insertEmployee", employee);
			System.out.println("添加成功："+insert+"行发生更改");
			/* 提交事务 */
			sqlSession.commit();
		} finally {		
			sqlSession.close();
		}		
	}

1.2.2 删除数据

mapper.xml：

<delete id="deleteEmployee" parameterType="Integer">
	delete from employee where empid=#{empid}
</delete>

test测试文件：

    @Test
	public void deleteEmployee() throws IOException {
		/* 读取配置文件 */
		InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");
		/* 根据配置文件构建SqlSessionFactory会话工厂*/
		SqlSessionFactory sqlSessionFactory =
 new SqlSessionFactoryBuilder().build(inputStream);
		/* 通过SqlSessionFactory创建SqlSession */
		SqlSession sqlSession = sqlSessionFactory.openSession();
		/* SqlSession执行映射文件中自定义的SQL，并返回映射结果 */
		try {			
			int insert =
 sqlSession.delete("com.zwh.mapper.EmployeeMapper.deleteEmployee", 6);
			System.out.println("删除成功："+insert+"行发生更改");
			/* 提交事务 */
			sqlSession.commit();
		} finally {		
			sqlSession.close();
		}		
	}

1.2.3 更改数据

mapper.xml:

<update id="updateEmployee" parameterType="com.zwh.pojo.Employee">
	update employee set name=#{name} where empid=#{empId}
</update>

test测试文件：

@Test
	public void updateEmployee() throws IOException {
		/* 读取配置文件 */
		InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");
		/* 根据配置文件构建SqlSessionFactory会话工厂*/
		SqlSessionFactory sqlSessionFactory =
 new SqlSessionFactoryBuilder().build(inputStream);
		/* 通过SqlSessionFactory创建SqlSession */
		SqlSession sqlSession = sqlSessionFactory.openSession();
		Employee employee=new Employee();
		employee.setEmpId(2);
		employee.setName("王五");
		/* SqlSession执行映射文件中自定义的SQL，并返回映射结果 */
		try {			
			int insert =
 sqlSession.update("com.zwh.mapper.EmployeeMapper.updateEmployee", employee);
			System.out.println("修改成功："+insert+"行发生更改");
			/* 提交事务 */
			sqlSession.commit();
		} finally {		
			sqlSession.close();
		}		
	}

1.2.4 查询数据

mapper.xml:
resultType：查询结果集返回类型

<select id="selectEmployee" parameterType="Integer" resultType="employee">
	select * from employee where empid=#{empId}
</select>

test测试文件：
sqlSession.selectOne()：查询单个
sqlSession.selectList()：查询多个

	@Test
	public void selectEmployee() throws IOException {
		/* 读取配置文件 */
		InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");
		/* 根据配置文件构建SqlSessionFactory会话工厂 */
		SqlSessionFactory sqlSessionFactory =
 new SqlSessionFactoryBuilder().build(inputStream);
		/* 通过SqlSessionFactory创建SqlSession */
		SqlSession sqlSession = sqlSessionFactory.openSession();
		/* SqlSession执行映射文件中自定义的SQL，并返回映射结果 */
		try {
			Employee employee = 
sqlSession.selectOne("com.zwh.mapper.EmployeeMapper.selectEmployee", 1);
			System.out.println(employee);
		} finally {
			/*关闭SqlSession*/
			sqlSession.close();
		}
	}

1.3配置mybatis核心配置文件

<?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>
    <!-- 类型别名，用来减少类完全限定名的冗余 -->
	<typeAliases>
       <!-- 指定类 -->
        <typeAlias alias="employee" type="com.zwh.pojo.Employee"/>
        <!-- 指定包 -->
		<package name="com.zwh.pojo"/>
	</typeAliases>
	<!-- 配置环境，指定默认的环境 id -->
	<environments default="mysql">
	<!-- 配置 environment 元素定义的环境 id -->
		<environment id="mysql">
		<!-- 事务管理器的配置，使用JDBC事务管理器 -->
			<transactionManager type="JDBC"></transactionManager>
			<!-- 数据源的配置，使用数据库连接池 -->
			<dataSource type="POOLED">
				<property name="driver" value="com.mysql.jdbc.Driver" />
				<property name="url"
					value="jdbc:mysql://127.0.0.1:3306/mybatisdb?characterEncoding=utf-8" />
				<property name="username" value="root" />
				<property name="password" value="123456" />
			</dataSource>
		</environment>
	</environments>
	<!-- 配置映射文件mapper.xml的位置 -->
	<mappers>
		<mapper resource="com/zwh/mapper/EmployeeMapper.xml" />
	</mappers>
</configuration>

2. 接口实现

2.1 创建接口

public interface EmployeeDao {
	public Employee selectEmployee(int empid);
}

2.2 创建mapper映射文件

namespace名称空间,填写对应接口全限定名
由于非接口方式的sql块代码和接口方式的sql块代码是一样的，下面写的是查询方法，其他三种增删改就省略了。

<?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.zwh.dao.EmployeeDao">

<select id="selectEmployee" parameterType="Integer" resultType="employee">
	select * from employee where empid=#{empid}
</select>
</mapper>

2.3 配置mybatis核心配置文件

mybatis核心配置文件中添加EmployeeDaoMapper.xml映射文件地址

	<mappers>
		<mapper resource="com/zwh/dao/mapper/EmployeeDaoMapper.xml" />
	</mappers>

2.4 test测试

	@Test
	public void selectEmployee() {
		SqlSession sqlSession = MybatisUtils.getSession();
		EmployeeDao mapper = sqlSession.getMapper(EmployeeDao.class);
		Employee  employee = mapper.selectEmployee(1);
		sqlSession.close();
	}

3. mybatisUtil工具类（减少重复代码编写）

public class MybatisUtils {
	private static SqlSessionFactory sqlSessionFactory=null;
	static {
		try {
			InputStream inputStream = 
Resources.getResourceAsStream("mybatis-config.xml");
			sqlSessionFactory= new SqlSessionFactoryBuilder().build(inputStream);
		}catch(IOException e) {
			e.printStackTrace();
		}
	}
	
	public static SqlSession getSession() {
		return sqlSessionFactory.openSession();
	}

本文地址：https://blog.csdn.net/ZhaZha__Hui/article/details/108970810