mybatis的sql映射文件—增删改查

前提：需要的包log4j.jar,mybatis-3.4.1.jar,mysql-connector-java-5.1.37-bin.jar

1.基本类

员工类

package com.hand.mybatis.bean;

public class Employee {
    
    private Integer eId;
    private String eName;
    private Integer gender;
    private String email;
    private Department dept;
    public Employee() {
        super();
    }
    public Employee(Integer eId,String eName, Integer gender, String email) {
        super();
        this.eId=eId;
        this.eName = eName;
        this.gender = gender;
        this.email = email;
    }
    public Integer geteId() {
        return eId;
    }
    public void seteId(Integer eId) {
        this.eId = eId;
    }
   
    public String getEName() {
        return eName;
    }
    public void setEname(String ename) {
        this.eName = ename;
    }
    public Integer getGender() {
        return gender;
    }
    public void setGender(Integer gender) {
        this.gender = gender;
    }
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = email;
    }
    
    
    
    public Department getDept() {
        return dept;
    }

public void setDept(Department dept) {
        this.dept = dept;
    }
    @Override
    public String toString() {
        return "Employee [eId=" + eId + ", ename=" + eName + ", gender=" + gender + ", email=" + email + "]";
    }

}

部门类

package com.hand.mybatis.bean;
import java.util.List;

public class Department {
    private Integer id;
    private String departName;
    private List<Employee> empList;
    
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getDepartName() {
        return departName;
    }
    public void setDepartName(String departName) {
        this.departName = departName;
    }
    
    public List<Employee> getEmpList() {
        return empList;
    }
    public void setEmpList(List<Employee> empList) {
        this.empList = empList;
    }
   
    @Override
    public String toString() {
        return "Department [id=" + id + ", departName=" + departName + "]";
    }
   
}

EmployeeMapper.java 接口

package com.hand.mybatis.dao;
import java.util.List;
import java.util.Map;

import org.apache.ibatis.annotations.MapKey;
import org.apache.ibatis.annotations.Param;
import com.hand.mybatis.bean.Employee;

public interface EmployeeMapper {
    
    Employee selectEmployee(Integer eid);
    
    int addEmp(Employee employee);
    
    Boolean updateEmp(Employee employee);
    
    int deleteEmpById(Integer id);
    
    //传入多个参数的情况
    //Employee getEmp(@Param("id") Integer id,@Param("ename") String ename);
    
    //传入多个参数的情况(map)
    Employee getEmp(Map<String, Object> map);
    
    //集合List
    List<Employee> getEmpByeNameLike(String ename);
    
    //返回一条记录的map;key就是列名，值是对应的值
    Map<String, Object> getEmpByIdReturnMap(Integer id);
    
    //多条记录封装一个map:Map<Integer,Employee>:键是这条记录的主键，值是记录封装后的javaBean
    //告诉mybatis封装这个map的时候使用哪个属性作为map的key
    /*@MapKey("eId")
     Map<Integer, Employee> getEmpByLastNameLikeReturnMap(String ename);*/
    @MapKey("eName")
    Map<String, Employee> getEmpByLastNameLikeReturnMap(String ename);
   
}

EmployeeMapper.xml映射文件

<?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.hand.mybatis.dao.EmployeeMapper">

<!-- mapper接口 public interface EmployeeMapper {} -->
 <!--  查找
  Employee selectEmployee(Integer eid); -->
 <select id="selectEmployee" resultType="com.hand.mybatis.bean.Employee">
   SELECT * FROM emp WHERE eid=#{eid}
 </select>
 
 <!--添加  
 int addEmp(Employee employee);-->
 <insert id="addEmp" useGeneratedKeys="true" keyProperty="eId">  //使用 useGeneratedKeys="true" keyProperty="eId" 调用接口时，可以获得主键eid
    insert into emp(ename,gender,email)
    VALUES(#{eName},#{gender},#{email})
 </insert>
 
 <!-- 更新
  Boolean updateEmp(Employee employee); -->  //返回值类型Boolen int void long 都行
 <update id="updateEmp">
   UPDATE emp SET ename=#{eName},gender=#{gender},email=#{email}
   WHERE eid=#{eId}
 </update>
 
 <!--删除
  int deleteEmpById(Integer id); -->
 <delete id="deleteEmpById">
    DELETE FROM emp WHERE eid=#{eid}
 </delete>
 
 <!--   
     //传入多个参数的情况
    //Employee getEmp(@Param("id") Integer id,@Param("ename") String ename); //使用@Param()注解
    
    //传入多个参数的情况(map)  
    Employee getEmp(Map<String, Object> map); --> //调用接口时，需要给map赋值

<select id="getEmp" resultType="com.hand.mybatis.bean.Employee">
  SELECT * FROM emp WHERE eid=#{id} AND ename=#{ename}
 </select>

  如：

    Map<String, Object> map=new HashMap<>(); 

    map.put("id", 101);

map.put("ename", "张三");
    Employee employee=employeeMapper.getEmp(map);
    System.out.println(employee);

<!-- //集合List
  List<Employee> getEmpByeNameLike(String ename); -->
 <select id="getEmpByeNameLike" resultType="com.hand.mybatis.bean.Employee">
  SELECT * FROM emp WHERE ename like #{ename}
 </select>
 
 <!--  //返回一条记录的map;key就是列名，值是对应的值
 Map<String, Object> getEmpByIdReturnMap(Integer id); -->
 <select id="getEmpByIdReturnMap" resultType="map">
 SELECT * FROM emp WHERE eid=#{id}
 </select>

调用 Map<String, Object> getEmpByIdReturnMap(Integer id)接口：

Map<String, Object> map= employeeMapper.getEmpByIdReturnMap(101);
    System.out.println(map);

结果：

    {eid=101, ename=张三, gender=0, email=2714763867@qq.com, did=1}

<!-- //多条记录封装一个map:Map<Integer,Employee>:键是这条记录的主键，值是记录封装后的javaBean
    //告诉mybatis封装这个map的时候使用哪个属性作为map的key
    /*@MapKey("eId")
     Map<Integer, Employee> getEmpByLastNameLikeReturnMap(String ename);*/
    @MapKey("eName")
    Map<String, Employee> getEmpByLastNameLikeReturnMap(String ename); -->
 <select id="getEmpByLastNameLikeReturnMap" resultType="com.hand.mybatis.bean.Employee">
 SELECT * FROM emp WHERE ename like #{ename}
 </select>
调用：

Map<Integer, Employee> map=employeeMapper.getEmpByLastNameLikeReturnMap("%张%");
  System.out.println(map);

结果 {101=Employee [eId=101, ename=张三, gender=0, email=2714763867@qq.com], 102=Employee [eId=102, ename=张丽, gender=0,       email=163826386@qq.com], 103=Employee [eId=103, ename=杨张, gender=1, email=21901826380863@163.com]}

</mapper>

代码：https://github.com/shuaishuaihand/mybatis.git