mybatis 增删改查

mapper:

<mapper namespace="com.uban.mybatis.dao.EmployeeMapper">
<!-- 
namespace:名称空间;指定为接口的全类名
id：唯一标识
resultType：返回值类型
#{id}：从传递过来的参数中取出id值

public Employee getEmpById(Integer id);
 -->
	<select id="getEmpById" resultType="com.uban.mybatis.bean.Employee">
		select*from employee where id = #{id}
	</select>
	
	<insert id="addEmp" parameterType="com.uban.mybatis.bean.Employee">
		insert into employee(name,gender,email)
		values(#{name},#{gender},#{email})
	</insert>
	
	<update id="updateEmp">
		update employee set name=#{name},gender=#{gender},email=#{email}
		where id = #{id}
	</update>
	
	<delete id="deleteEmp">
		delete from employee where id = #{id}
	</delete>
</mapper>

接口：

        public Employee getEmpById(Integer id); 
	
	public void addEmp(Employee employee);
	
	public boolean updateEmp(Employee employee);
	
	public long deleteEmp(Integer id);

根据返回值判断：

boolean：成功则返回true,失败返回false

long：返回操作了多少条数据

                /*Employee employee2=new Employee(2,"b","bb","bbb");
		
		mapper.addEmp(employee2);*/
		
		/*Employee employee2=new Employee(1,"a","aa","aaa");
		mapper.updateEmp(employee2);*/
		
		long a=mapper.deleteEmp(2); 
		System.out.println(a);
		opensession.commit();

切记要commit() ，否则该次操作无效

<insert id="addEmp" parameterType="com.uban.mybatis.bean.Employee"
		useGeneratedKeys="true" keyProperty="id">
		insert into employee(name,gender,email)
		values(#{name},#{gender},#{email})
	</insert>

可以获取insert自增主键的值