MyBatis中的动态SQL
MyBatis中的动态SQL
-
- 参考代码：
-
- EmpMapper:
- EmpMapper.xml:
- demo6:
- demo7:
- demo8:
- 知识点：
-
- 3.1 if:
- 3.2 where:
- 3.3 trim, set:
- 3.4 foreach:
- 3.5 choose(when,otherwise):
- 3.6 返回自动增长的主键
- 3.7 sql标签定义通用sql片段
- 案例演练：（员工）
-
- 1.条件查询：if where trim
- 代码整体布局：
- 代码如下：
-
- EmpMapper:
- EmpMapper.xml:
- demo5:
- 结果展示：
-
- testTest1():
- testTest11():
- testTest2():
- 2.修改：set
- 代码整体布局：
- 代码如下：
-
- EmpMapper:
- EmpMapper.xml:
- demo6:
- 结果展示：
-
- testUpdate1():
- testUpdate2():
- 3.循环拼接和批量插入：foreach
-
- 思路：
- 代码整体布局：
- 代码如下：
-
- EmpMapper:
- EmpMapper.xml:
- Demo7:
- 结果展示：
-
- testTestByIds():
- testInsertBatch():
- 4.choose 返回自动增长的主键
- 结果展示：
- 代码整体布局：
- 代码如下：
-
- EmpMapper:
- EmpMapper.xml:
- Demo8:
- 5.sql标签定义通用sql片段 sql
- 结果展示：
- 代码整体布局：
- 代码如下：
-
- EmpMapper:
- EmpMapper.xml:
- Demo9:
注意：这里是在《一对一关系实现员工—＞部门的查询》的基础进行编写代码
《一对一关系实现员工—＞部门的查询》
参考代码：
EmpMapper:
package com.yzh7.mapper;
import com.yzh7.entity.Emp;
import org.apache.ibatis.annotations.Param;
import java.util.List;
import java.util.Map;
public interface EmpMapper {
//查询所有员工，并且每个员工关联一个部门对象
List listAll();
//条件查询1
List list1(@Param("empName") String name,
@Param("phone") String phone);
//条件查询2
List list2(Map map);
//条件查询3
List list3(Map map);
//条件查询4
List list4(Map map);
//根据编号查询数据
List listByIds(List ids);
//分支条件查询
List listByChoose(Emp emp);
//针对所有字段进行修改
int update1(Emp emp);
//根据传入的数据是否为空，不为空的才修改
int update2(Emp emp);
//批量插入
int insertBatch(List empList);
//插入并接收返回的自增值
int insertAndGetAutoVal(Emp emp);
}
EmpMapper.xml:
emp_id,emp_name,sex,phone
select e.emp_id ,e.emp_name ,e.sex,e.phone,
d.dept_id,d.dept_name,d.description
from t_emp e
join t_dept d
on e.dept_id = d.dept_id
insert into t_emp
(emp_name,sex,phone)
values
(#{empName},#{sex},#{phone})
insert into t_emp
(emp_name,sex,phone)
VALUES
(#{e.empName},#{e.sex},#{e.phone})
update t_emp
emp_name = #{empName},
sex = #{sex},
phone = #{phone},
dept_id = #{dept.deptId},
where emp_id = #{empId}
demo6:
package com.yzh7.test;
import com.yzh7.entity.Dept;
import com.yzh7.entity.Emp;
import com.yzh7.mapper.EmpMapper;
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.junit.After;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;
import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class Demo6 {
//条件查询
@Test
public void test(){
EmpMapper empMapper = session.getMapper(EmpMapper.class);
//构建要修改的员工对象
Emp emp = new Emp();
emp.setEmpId(1);
emp.setEmpName("张三丰");
Dept dept = new Dept();
dept.setDeptId(2);
emp.setDept(dept);
int count = empMapper.update1(emp);
System.out.println("修改的记录数:"+count);
}
@Test
public void test2(){
EmpMapper empMapper = session.getMapper(EmpMapper.class);
//构建要修改的员工对象
Emp emp = new Emp();
emp.setEmpId(2);
emp.setEmpName("李四西");
Dept dept = new Dept();
dept.setDeptId(3);
emp.setDept(dept);
//根据数据本身是否为空，进行修改
int count = empMapper.update2(emp);
System.out.println("修改的记录数:"+count);
}
//会话工厂
private static SqlSessionFactory factory;
//会话
private SqlSession session;
@BeforeClass
public static void befCls() throws IOException {
InputStream is = Resources.getResourceAsStream("mybatis-config.xml");
factory = new SqlSessionFactoryBuilder().build(is);
}
@Before
public void bf(){
session = factory.openSession();
}
@After
public void af(){
//提交事务
session.commit();
//关闭会话
session.close();
}
}
demo7:
package com.yzh7.test;
import com.yzh7.entity.Dept;
import com.yzh7.entity.Emp;
import com.yzh7.mapper.EmpMapper;
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.junit.After;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
public class Demo7 {
//条件查询
@Test
public void test(){
EmpMapper empMapper = session.getMapper(EmpMapper.class);
List ids = new ArrayList<>();
ids.add(1);
ids.add(3);
ids.add(4);
List empList = empMapper.listByIds(ids);
System.out.println(empList);
}
@Test
public void test2(){
EmpMapper empMapper = session.getMapper(EmpMapper.class);
Emp e1 = new Emp();
e1.setEmpName("aa1");
e1.setSex("男");
e1.setPhone("1212");
Emp e2 = new Emp();
e2.setEmpName("aa2");
e2.setSex("男");
e2.setPhone("1212");
Emp e3 = new Emp();
e3.setEmpName("aa2");
e3.setSex("男");
e3.setPhone("1212");
List empList = new ArrayList<>();
empList.add(e1);
empList.add(e2);
empList.add(e3);
int count = empMapper.insertBatch(empList);
System.out.println("记录数:"+count);
}
//条件查询
@Test
public void test3(){
Emp emp = new Emp();
//emp.setEmpName("张三丰");
//emp.setSex("男");
EmpMapper empMapper = session.getMapper(EmpMapper.class);
List empList = empMapper.listByChoose(emp);
System.out.println(empList);
}
//条件查询
@Test
public void test4(){
Emp emp = new Emp();
emp.setEmpName("武松");
emp.setSex("男");
emp.setPhone("12312");
EmpMapper empMapper = session.getMapper(EmpMapper.class);
int count = empMapper.insertAndGetAutoVal(emp);
System.out.println("插入的记录数:"+count);
System.out.println("插入之后，返回的自增值:"+emp);
}
//会话工厂
private static SqlSessionFactory factory;
//会话
private SqlSession session;
@BeforeClass
public static void befCls() throws IOException {
InputStream is = Resources.getResourceAsStream("mybatis-config.xml");
factory = new SqlSessionFactoryBuilder().build(is);
}
@Before
public void bf(){
session = factory.openSession();
}
@After
public void af(){
//提交事务
session.commit();
//关闭会话
session.close();
}
}
demo8:
package com.yzh7.test;
import com.yzh7.entity.Emp;
import com.yzh7.mapper.EmpMapper;
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.junit.After;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class Demo8 {
//条件查询
@Test
public void test(){
EmpMapper empMapper = session.getMapper(EmpMapper.class);
Map map = new HashMap();
map.put("empName","李");
List empList = empMapper.list4(map);
System.out.println(empList);
}
//会话工厂
private static SqlSessionFactory factory;
//会话
private SqlSession session;
@BeforeClass
public static void befCls() throws IOException {
InputStream is = Resources.getResourceAsStream("mybatis-config.xml");
factory = new SqlSessionFactoryBuilder().build(is);
}
@Before
public void bf(){
session = factory.openSession();
}
@After
public void af(){
//提交事务
session.commit();
//关闭会话
session.close();
}
}
知识点：
3.1 if:
3.2 where:
3.3 trim, set:
3.4 foreach:
3.5 choose(when,otherwise):
3.6 返回自动增长的主键
3.7 sql标签定义通用sql片段
案例演练：（员工）
（仅展示主要添加代码，其他的mybatis配置等与上篇保持一致）
1.条件查询：if where trim
代码整体布局：
代码如下：
EmpMapper:
package com.yzh7.mapper;
import com.yzh7.entity.Emp;
import org.apache.ibatis.annotations.Param;
import java.util.List;
import java.util.Map;
public interface EmpMapper {
//查询所有员工，并且每个员工关联一个部门对象
List listAll();
//条件查询1(多参查询)
List test1(@Param("empName") String empName,
@Param("phone") String phone);
List test11(@Param("empName") String empName,
@Param("phone") String phone);
//条件查询2（对象查询）
List test2(Map map);
}
EmpMapper.xml:
demo5:
package com.yzh7.test;
import com.yzh7.entity.Emp;
import com.yzh7.mapper.EmpMapper;
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.junit.After;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;
import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class Demo5 {
//条件查询
@Test
public void testTest1(){
EmpMapper empMapper=session.getMapper(EmpMapper.class);
//List empList=empMapper.test1(null,null);
List empList=empMapper.test1("张","123");
System.out.println(empList);
}
@Test
public void testTest11(){
EmpMapper empMapper=session.getMapper(EmpMapper.class);
//List empList=empMapper.test1(null,null);
List empList=empMapper.test11("张","123");
System.out.println(empList);
}
@Test
public void test2(){
Map map = new HashMap();
map.put("startId",1);
map.put("endId",3);
map.put("empName","四");
EmpMapper empMapper = session.getMapper(EmpMapper.class);
List empList = empMapper.test2(map);
System.out.println(empList);
}
private static SqlSessionFactory factory; //静态
private SqlSession session;
@BeforeClass
public static void befCla() throws IOException {
String resource = "mybatis_config.xml"; //mybatis_config.xml
InputStream inputStream = Resources.getResourceAsStream(resource);
factory = new SqlSessionFactoryBuilder().build(inputStream);
}
@Before
public void bf(){
session=factory.openSession();
}
@After
public void af(){
session.commit();
session.close();
}
}
结果展示：
testTest1():
testTest11():
testTest2():
2.修改：set
代码整体布局：
代码如下：
EmpMapper:
package com.yzh7.mapper;
import com.yzh7.entity.Emp;
import org.apache.ibatis.annotations.Param;
import java.util.List;
import java.util.Map;
public interface EmpMapper {
//查询所有员工，并且每个员工关联一个部门对象
List listAll();
//条件查询1(多参查询)
List test1(@Param("empName") String empName,
@Param("phone") String phone);
List test11(@Param("empName") String empName,
@Param("phone") String phone);
//条件查询2（对象查询）
List test2(Map map);
//针对所有字段进行修改
int update1(Emp emp);
//根据传入的数据是否为空，不为空的才修改
int update2(Emp emp);
}
EmpMapper.xml:
update t_emp
set emp_name=#{empName},
sex=#{sex},
phone=#{phone},
dept_id=#{dept.deptId}
where emp_id=#{empId}
update t_emp
emp_name=#{empName},
sex=#{sex},
phone=#{phone},
dept_id=#{dept.deptId},
where emp_id=#{empId}
demo6:
package com.yzh7.test;
import com.yzh7.entity.Dept;
import com.yzh7.entity.Emp;
import com.yzh7.mapper.EmpMapper;
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.junit.After;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;
import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Map;
public class Demo6 {
@Test
public void testUpdate1(){
EmpMapper empMapper=session.getMapper(EmpMapper.class);
//int update1(Emp emp); //构建要修改的员工对象
Emp emp=new Emp();
emp.setEmpId(1);
emp.setEmpName("张三疯"); //如果表中的列不赋值，将会赋空值
Dept dept=new Dept();
dept.setDeptId(2);
emp.setDept(dept); //注意
int count=empMapper.update1(emp);
System.out.println("修改的记录数："+count);
}
@Test
public void testUpdate2(){
EmpMapper empMapper=session.getMapper(EmpMapper.class);
//int update1(Emp emp); //构建要修改的员工对象
Emp emp=new Emp();
emp.setEmpId(2);
emp.setEmpName("李四皮"); //如果表中的列不赋值，将会赋空值
Dept dept=new Dept();
dept.setDeptId(3);
emp.setDept(dept); //注意
int count=empMapper.update2(emp);
System.out.println("修改的记录数："+count);
}
private static SqlSessionFactory factory; //静态
private SqlSession session;
@BeforeClass
public static void befCla() throws IOException {
String resource = "mybatis_config.xml"; //mybatis_config.xml
InputStream inputStream = Resources.getResourceAsStream(resource);
factory = new SqlSessionFactoryBuilder().build(inputStream);
}
@Before
public void bf(){
session=factory.openSession();
}
@After
public void af(){
session.commit();
session.close();
}
}
结果展示：
testUpdate1():
比较生硬霸道的修改方式：
修改后的数据表：
testUpdate2():
使用set、if标签之后：
修改后的数据表：
3.循环拼接和批量插入：foreach
思路：
代码整体布局：
代码如下：
EmpMapper:
package com.yzh7.mapper;
import com.yzh7.entity.Emp;
import org.apache.ibatis.annotations.Param;
import java.util.List;
import java.util.Map;
public interface EmpMapper {
//查询所有员工，并且每个员工关联一个部门对象
List listAll();
//条件查询1(多参查询)
List test1(@Param("empName") String empName,
@Param("phone") String phone);
List test11(@Param("empName") String empName,
@Param("phone") String phone);
//条件查询2（对象查询）
List test2(Map map);
//针对所有字段进行修改
int update1(Emp emp);
//根据传入的数据是否为空，不为空的才修改
int update2(Emp emp);
//根据编号查询数据
List testByIds(List ids);
//批量插入
int insertBatch(List empList);
}
EmpMapper.xml:
update t_emp
set emp_name=#{empName},
sex=#{sex},
phone=#{phone},
dept_id=#{dept.deptId}
where emp_id=#{empId}
update t_emp
emp_name=#{empName},
sex=#{sex},
phone=#{phone},
dept_id=#{dept.deptId},
where emp_id=#{empId}
insert into t_emp
(emp_name,sex,phone)
values
(#{e.empName},#{e.sex},#{e.phone})
Demo7:
package com.yzh7.test;
import com.yzh7.entity.Emp;
import com.yzh7.mapper.EmpMapper;
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.junit.After;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
public class Demo7 {
@Test
public void testTestByIds(){
EmpMapper empMapper=session.getMapper(EmpMapper.class);
List ids=new ArrayList<>();
ids.add(1);
ids.add(3);
ids.add(4);
List empList=empMapper.testByIds(ids);
System.out.println(empList);
}
@Test
public void testInsertBatch(){
EmpMapper empMapper=session.getMapper(EmpMapper.class);
Emp emp1=new Emp();
emp1.setEmpName("aaa");
emp1.setSex("男");
emp1.setPhone("1234561");
Emp emp2=new Emp();
emp2.setEmpName("bbb");
emp2.setSex("女");
emp2.setPhone("1234562");
Emp emp3=new Emp();
emp3.setEmpName("ccc");
emp3.setSex("男");
emp3.setPhone("1234563");
List empList=new ArrayList<>();
empList.add(emp1);
empList.add(emp2);
empList.add(emp3);
int count =empMapper.insertBatch(empList);
System.out.println("批量插入的记录数；"+count);
}
private static SqlSessionFactory factory; //静态
private SqlSession session;
@BeforeClass
public static void befCla() throws IOException {
String resource = "mybatis_config.xml"; //mybatis_config.xml
InputStream inputStream = Resources.getResourceAsStream(resource);
factory = new SqlSessionFactoryBuilder().build(inputStream);
}
@Before
public void bf(){
session=factory.openSession();
}
@After
public void af(){
session.commit();
session.close();
}
}
结果展示：
testTestByIds():
testInsertBatch():
批量插入之后，数据表如下：
4.choose 返回自动增长的主键
结果展示：
代码整体布局：
代码如下：
EmpMapper:
package com.yzh7.mapper;
import com.yzh7.entity.Emp;
import org.apache.ibatis.annotations.Param;
import java.util.List;
import java.util.Map;
public interface EmpMapper {
//查询所有员工，并且每个员工关联一个部门对象
List listAll();
//条件查询1(多参查询)
List test1(@Param("empName") String empName,
@Param("phone") String phone);
List test11(@Param("empName") String empName,
@Param("phone") String phone);
//条件查询2（对象查询）
List test2(Map map);
//针对所有字段进行修改
int update1(Emp emp);
//根据传入的数据是否为空，不为空的才修改
int update2(Emp emp);
//根据编号查询数据
List testByIds(List ids);
//批量插入
int insertBatch(List empList);
//分支条件查询
List testByChoose(Emp emp);
//插入并接受返回的自增值
int insertAndGetAutoVal(Emp emp);
}
EmpMapper.xml:
update t_emp
set emp_name=#{empName},
sex=#{sex},
phone=#{phone},
dept_id=#{dept.deptId}
where emp_id=#{empId}
update t_emp
emp_name=#{empName},
sex=#{sex},
phone=#{phone},
dept_id=#{dept.deptId},
where emp_id=#{empId}
insert into t_emp
(emp_name,sex,phone)
values
(#{e.empName},#{e.sex},#{e.phone})
insert into t_emp
(emp_name,sex,phone)
values
(#{empName},#{sex},#{phone})
Demo8:
package com.yzh7.test;
import com.yzh7.entity.Emp;
import com.yzh7.mapper.EmpMapper;
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.junit.After;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
public class Demo8 {
// List testByChoose(Emp emp);
@Test
public void testTestByChoose(){
EmpMapper empMapper=session.getMapper(EmpMapper.class);
Emp emp=new Emp();
emp.setEmpName("王五");
emp.setSex("女");
List empList=empMapper.testByChoose(emp);
System.out.println(empList);
}
@Test
public void testInsertAndGetAutoVal(){
EmpMapper empMapper=session.getMapper(EmpMapper.class);
Emp emp=new Emp();
emp.setEmpName("王十一");
emp.setSex("男");
emp.setPhone("1234561");
int count=empMapper.insertAndGetAutoVal(emp);
System.out.println("记录数："+count);
System.out.println("插入之后，返回的子增值："+emp);
}
private static SqlSessionFactory factory;
private SqlSession session;
@BeforeClass
public static void befCla() throws IOException {
String resource="mybatis_config.xml";
InputStream inputStream= Resources.getResourceAsStream(resource);
factory=new SqlSessionFactoryBuilder().build(inputStream);
}
@Before
public void bf(){
session=factory.openSession();
}
@After
public void af(){
session.commit();
session.close();
}
}
5.sql标签定义通用sql片段 sql
结果展示：
代码整体布局：
代码如下：
EmpMapper:
package com.yzh7.mapper;
import com.yzh7.entity.Emp;
import org.apache.ibatis.annotations.Param;
import java.util.List;
import java.util.Map;
public interface EmpMapper {
//查询所有员工，并且每个员工关联一个部门对象
List listAll();
//条件查询1(多参查询)
List test1(@Param("empName") String empName,
@Param("phone") String phone);
List test11(@Param("empName") String empName,
@Param("phone") String phone);
//条件查询2（对象查询）
List test2(Map map);
//针对所有字段进行修改
int update1(Emp emp);
//根据传入的数据是否为空，不为空的才修改
int update2(Emp emp);
//根据编号查询数据
List testByIds(List ids);
//批量插入
int insertBatch(List empList);
//分支条件查询
List testByChoose(Emp emp);
//插入并接受返回的自增值
int insertAndGetAutoVal(Emp emp);
//条件查询3
Emp test3(Integer empId);
//条件查询4
List test4(Map map);
}
EmpMapper.xml:
update t_emp
set emp_name=#{empName},
sex=#{sex},
phone=#{phone},
dept_id=#{dept.deptId}
where emp_id=#{empId}
update t_emp
emp_name=#{empName},
sex=#{sex},
phone=#{phone},
dept_id=#{dept.deptId},
where emp_id=#{empId}
insert into t_emp
(emp_name,sex,phone)
values
(#{e.empName},#{e.sex},#{e.phone})
insert into t_emp
(emp_name,sex,phone)
values
(#{empName},#{sex},#{phone})
emp_id,emp_name,sex,phone
select e.emp_id ,e.emp_name ,e.sex,e.phone,
d.dept_id,d.dept_name,d.description
from t_emp e
join t_dept d
on e.dept_id = d.dept_id
Demo9:
package com.yzh7.test;
import com.yzh7.entity.Emp;
import com.yzh7.mapper.EmpMapper;
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.junit.After;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;
import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class Demo9 {
@Test
public void testTest3(){
EmpMapper empMapper=session.getMapper(EmpMapper.class);
System.out.println(empMapper.test3(1));
}
@Test
public void testTest4(){
EmpMapper empMapper=session.getMapper(EmpMapper.class);
Map map=new HashMap();
map.put("empName","李");
List empList=empMapper.test4(map);
System.out.println(empList);
}
private static SqlSessionFactory factory;
private SqlSession session;
@BeforeClass
public static void befCla() throws IOException {
String resource="mybatis_config.xml";
InputStream inputStream= Resources.getResourceAsStream(resource);
factory=new SqlSessionFactoryBuilder().build(inputStream);
}
@Before
public void bf(){
session=factory.openSession();
}
@After
public void af(){
session.commit();
session.close();
}
}