6、SpringBoot+Mybatis整合------参数传递

开发工具：STS

代码下载链接：https://github.com/theIndoorTrain/SpringBoot_Mybatis/tree/7892801d804d2060774f3720f82e776ff318e3ba

前言：

在调用mybatis的查询条件时，之前，遇到需要验证多个参数的查询时，往往需要把所有参数都绑定到一个实体中去，然后调用获取。

现在，我们来详细描述mybatis传递参数的细节。

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一、单个参数：

1.定义mapper接口：

 1 package com.xm.mapper;
 2 
 3 import java.util.List;
 4 
 5 import com.xm.pojo.Student;
 6 
 7 public interface StudentMapper {
 8 
 9 
10     /**
11      * 根据name查询
12      * @param name
13      * @return
14      */
15     public Student getByName(String name);
16     
17 }

StudentMapper.java

2.实现mapper映射：

 1 <?xml version="1.0" encoding="UTF-8" ?>
 2 <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
 3 <mapper namespace="com.xm.mapper.StudentMapper">
 4 
 5     
 6     
 7     <!-- 根据name查询 -->
 8     <select id="getByName" resultType="student">
 9     select * from student where name=#{name}
10     </select>
11 </mapper>

StudentMapper.xml

3.定义测试用例：

 1 package com.xm;
 2 
 3 import org.junit.Test;
 4 import org.junit.runner.RunWith;
 5 import org.springframework.beans.factory.annotation.Autowired;
 6 import org.springframework.boot.test.context.SpringBootTest;
 7 import org.springframework.test.context.junit4.SpringRunner;
 8 
 9 import com.xm.mapper.StudentMapper;
10 import com.xm.pojo.Student;
11 
12 @RunWith(SpringRunner.class)
13 @SpringBootTest
14 public class StudentTest {
15     @Autowired
16     private StudentMapper studentMapper;
17     
18     @Test
19     public void selectStudent() {
20         
21         Student student = studentMapper.getByName("郭小明");
22         System.out.println(student);
23         
24     }
25     
26 
27 }

StudentTest.java

4.测试结果：

(1)数据库查询结果：

（2）测试结果输出：

 注意在mapper映射中，单个参数类型，也可以不写 parameterType=""，参数名可以随意写，比如#{names}

实现mapper映射：

 1 <?xml version="1.0" encoding="UTF-8" ?>
 2 <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
 3 <mapper namespace="com.xm.mapper.StudentMapper">
 4 
 5     
 6     
 7     <!-- 根据name查询 -->
 8     <select id="getByName" resultType="student">
 9     <!-- select * from student where name=#{name} -->
10     select * from student where name=#{names}
11     </select>
12 </mapper>

StudentMapper.xml

二、多个参数

1.根据参数名查询

（1）定义mapper接口：

 1 package com.xm.mapper;
 2 
 3 import java.util.List;
 4 
 5 import com.xm.pojo.Student;
 6 
 7 public interface StudentMapper {
 8 
 9     
10     /**
11      * 根据用户名和id同时查询
12      * @param id
13      * @param name
14      * @return
15      */
16     public Student getStudentByIdAndName(Integer id,String name);
17     
18 }

StudentMapper.java

（2）实现mapper映射：

 1 <?xml version="1.0" encoding="UTF-8" ?>
 2 <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
 3 <mapper namespace="com.xm.mapper.StudentMapper">
 4 
 5     
 6     <!-- 根据用户名和id同时查询 -->
 7     <select id="getStudentByIdAndName" resultType="student">
 8     select * from student where name=#{name} and id=#{id} 
 9     </select>
10 </mapper>

StudentMapper.xml

（3）定义测试用例：

 1 package com.xm;
 2 
 3 import org.junit.Test;
 4 import org.junit.runner.RunWith;
 5 import org.springframework.beans.factory.annotation.Autowired;
 6 import org.springframework.boot.test.context.SpringBootTest;
 7 import org.springframework.test.context.junit4.SpringRunner;
 8 
 9 import com.xm.mapper.StudentMapper;
10 import com.xm.pojo.Student;
11 
12 @RunWith(SpringRunner.class)
13 @SpringBootTest
14 public class StudentTest {
15     @Autowired
16     private StudentMapper studentMapper;
17     
18     
19     @Test
20     public void selectStudent() {
21         
22         /*Student student = studentMapper.getByName("郭小明");*/
23         Student student = studentMapper.getStudentByIdAndName(1, "郭小明");
24         System.out.println(student);
25         
26     }
27     
28 
29 }

StudentTest.java

（4）测试结果：

说明：这种简单的根据参数名传参是失败的

2.根据参数key值获取，获取规则为param1，param2，param3.........：

（1）实现mapper映射：

 1 <?xml version="1.0" encoding="UTF-8" ?>
 2 <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
 3 <mapper namespace="com.xm.mapper.StudentMapper">
 4 
 5 
 6     <!-- 根据用户名和id同时查询 -->
 7     <select id="getStudentByIdAndName" resultType="student">
 8     <!-- select * from student where name=#{name} and id=#{id}  -->
 9     select * from student where name=#{param2} and id=#{param1} 
10     </select>
11 </mapper>

StudentMapper.xml

（2）测试结果：

说明：针对这种情况，如果参数较多的情况下，获取准确的参数名更好一些

3.绑定参数名

（1）定义mapper接口：

 1 package com.xm.mapper;
 2 
 3 import java.util.List;
 4 
 5 import org.apache.ibatis.annotations.Param;
 6 
 7 import com.xm.pojo.Student;
 8 
 9 public interface StudentMapper {
10 
11     
12     
13     /**
14      * 根据用户名和id同时查询
15      * @param id
16      * @param name
17      * @return
18      */
19     public Student getStudentByIdAndName(@Param("id")Integer id,@Param("name")String name);
20     
21 }

StudentMapper.java

 

（2）实现mapper映射：

 1 <?xml version="1.0" encoding="UTF-8" ?>
 2 <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
 3 <mapper namespace="com.xm.mapper.StudentMapper">
 4 
 5 
 6     <!-- 根据用户名和id同时查询 -->
 7     <select id="getStudentByIdAndName" resultType="student">
 8     select * from student where name=#{name} and id=#{id} 
 9     <!-- select * from student where name=#{param2} and id=#{param1}  -->
10     </select>
11 </mapper>

StudentMapper.xml

（3）测试结果：

说明：针对参数较多，且参数都属于同一个pojo类的时候，可以把参数先封装入实体，再获取

4.封装实体参数：

（1）定义mapper接口：

 1 package com.xm.mapper;
 2 
 3 import java.util.List;
 4 
 5 import org.apache.ibatis.annotations.Param;
 6 
 7 import com.xm.pojo.Student;
 8 
 9 public interface StudentMapper {
10 
11     
12     
13     /**
14      * 根据用户名和id同时查询
15      * @param id
16      * @param name
17      * @return
18      */
19     public Student getStudentByIdAndName(Student student);
20     
21 }

StudentMapper.java

 

（2）定义测试用例：

 1 package com.xm;
 2 
 3 import org.junit.Test;
 4 import org.junit.runner.RunWith;
 5 import org.springframework.beans.factory.annotation.Autowired;
 6 import org.springframework.boot.test.context.SpringBootTest;
 7 import org.springframework.test.context.junit4.SpringRunner;
 8 
 9 import com.xm.mapper.StudentMapper;
10 import com.xm.pojo.Student;
11 
12 @RunWith(SpringRunner.class)
13 @SpringBootTest
14 public class StudentTest {
15     @Autowired
16     private StudentMapper studentMapper;
17     
18     @Test
19     public void selectStudent() {
20         
21         /*Student student = studentMapper.getByName("郭小明");*/
22         /*Student student = studentMapper.getStudentByIdAndName(1, "郭小明");*/
23         Student student = new Student();
24         student.setName("郭小明");
25         student.setId(1);
26         Student student2 = studentMapper.getStudentByIdAndName(student);
27         System.out.println(student2);
28         
29     }
30     
31 
32 }

StudentMapper.java

 

（3）测试结果：

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