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1.2.1 新增数据1.2.2 删除数据1.2.3 更改数据1.2.4 查询数据 1.3配置mybatis核心配置文件 2. 接口实现2.1 创建接口2.2 创建mapper映射文件2.3 配置mybatis核心配置文件2.4 test测试 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("123456@qq.com"); 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(); }