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。
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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