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：
package com.xm.mapper;
import java.util.List;
import com.xm.pojo.Student;
public interface StudentMapper {
/**
* 根据name查询
* @param name
* @return
*/
public Student getByName(String name);
}
StudentMapper.java
2.实现mapper映射：
<?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.xm.mapper.StudentMapper">
<!-- 根据name查询 -->
<select id="getByName" resultType="student">
select * from student where name=#{name}
</select>
</mapper>
StudentMapper.xml
3.定义测试用例：
package com.xm;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
import com.xm.mapper.StudentMapper;
import com.xm.pojo.Student;
@RunWith(SpringRunner.class)
@SpringBootTest
public class StudentTest {
@Autowired
private StudentMapper studentMapper;
@Test
public void selectStudent() {
Student student = studentMapper.getByName("郭小明");
System.out.println(student);
}
}
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#
实现mapper映射：
<?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.xm.mapper.StudentMapper">
<!-- 根据name查询 -->
<select id="getByName" resultType="student">
<!-- select * from student where name=#{name} -->
select * from student where name=#{names}
</select>
</mapper>
StudentMapper.xml
二、多个参数
1.根据参数名查询
（1）定义mapper接口：
package com.xm.mapper;
import java.util.List;
import com.xm.pojo.Student;
public interface StudentMapper {
/**
* 根据用户名和id同时查询
* @param id
* @param name
* @return
*/
public Student getStudentByIdAndName(Integer id,String name);
}
StudentMapper.java
（2）实现mapper映射：
<?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.xm.mapper.StudentMapper">
<!-- 根据用户名和id同时查询 -->
<select id="getStudentByIdAndName" resultType="student">
select * from student where name=#{name} and id=#{id}
</select>
</mapper>
StudentMapper.xml
（3）定义测试用例：
package com.xm;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
import com.xm.mapper.StudentMapper;
import com.xm.pojo.Student;
@RunWith(SpringRunner.class)
@SpringBootTest
public class StudentTest {
@Autowired
private StudentMapper studentMapper;
@Test
public void selectStudent() {
/*Student student = studentMapper.getByName("郭小明");*/
Student student = studentMapper.getStudentByIdAndName(1, "郭小明");
System.out.println(student);
}
}
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：
<?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.xm.mapper.StudentMapper">
<!-- 根据用户名和id同时查询 -->
<select id="getStudentByIdAndName" resultType="student">
<!-- select * from student where name=#{name} and id=#{id} -->
select * from student where name=#{param2} and id=#{param1}
</select>
</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：
package com.xm.mapper;
import java.util.List;
import org.apache.ibatis.annotations.Param;
import com.xm.pojo.Student;
public interface StudentMapper {
/**
* 根据用户名和id同时查询
* @param id
* @param name
* @return
*/
public Student getStudentByIdAndName(@Param("id")Integer id,@Param("name")String name);
}
StudentMapper.java
（2）实现mapper映射：
<?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.xm.mapper.StudentMapper">
<!-- 根据用户名和id同时查询 -->
<select id="getStudentByIdAndName" resultType="student">
select * from student where name=#{name} and id=#{id}
<!-- select * from student where name=#{param2} and id=#{param1} -->
</select>
</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：
package com.xm.mapper;
import java.util.List;
import org.apache.ibatis.annotations.Param;
import com.xm.pojo.Student;
public interface StudentMapper {
/**
* 根据用户名和id同时查询
* @param id
* @param name
* @return
*/
public Student getStudentByIdAndName(Student student);
}
StudentMapper.java
（2）定义测试用例：
package com.xm;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
import com.xm.mapper.StudentMapper;
import com.xm.pojo.Student;
@RunWith(SpringRunner.class)
@SpringBootTest
public class StudentTest {
@Autowired
private StudentMapper studentMapper;
@Test
public void selectStudent() {
/*Student student = studentMapper.getByName("郭小明");*/
/*Student student = studentMapper.getStudentByIdAndName(1, "郭小明");*/
Student student = new Student();
student.setName("郭小明");
student.setId(1);
Student student2 = studentMapper.getStudentByIdAndName(student);
System.out.println(student2);
}
}
StudentMapper.java
（3）测试结果：
2018-07-02