mybatis-动态sql1

在多条件查询的情况下必须用到动态sql

沿用之前的项目

1.在dao中添加多添件查询方法

package com.java1234.mappers;

import java.util.List;
import java.util.Map;

import com.java1234.model.Student;

public interface StudentMapper {

public List<Student> searchStudents(Map<String,Object> map);

public List<Student> searchStudents2(Map<String,Object> map);
}

2.在mapper中添加动态sql

<?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.java1234.mappers.StudentMapper">

<resultMap type="Student" id="StudentResult">
<id property="id" column="id"/>
<result property="name" column="name"/>
<result property="age" column="age"/>
</resultMap>

<select id="searchStudents" parameterType="Map" resultMap="StudentResult">
select * from t_student
where gradeId=#{gradeId}
<if test="name!=null">
and name like #{name}
</if>
<if test="age!=nulll">
and age=#{age}
</if>
</select>

<select id="searchStudents2" parameterType="Map" resultMap="StudentResult">
select * from t_student
<choose>
<when test="searchBy=='gradeId'">
where gradeId=#{gradeId}
</when>
<when test="searchBy=='name'">
where name like #{name}
</when>
<otherwise>
where age=#{age}
</otherwise>
</choose>

</select>
</mapper>

3.在测试方法中测试案例：

package com.java1234.service;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.ibatis.session.SqlSession;
import org.apache.log4j.Logger;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import com.java1234.mappers.StudentMapper;
import com.java1234.model.Student;
import com.java1234.util.SqlSessionFactoryUtil;

public class StudentTest {

private static Logger logger=Logger.getLogger(StudentTest.class);
private SqlSession sqlSession=null;
private StudentMapper studentMapper=null;

/**
* 测试方法前调用
* @throws Exception
*/
@Before
public void setUp() throws Exception {
sqlSession=SqlSessionFactoryUtil.openSession();
studentMapper=sqlSession.getMapper(StudentMapper.class);
}

/**
* 测试方法后调用
* @throws Exception
*/
@After
public void tearDown() throws Exception {
sqlSession.close();
}

@Test
public void testSearchStudents() {
logger.info("添加学生(带条件)");
Map<String,Object> map=new HashMap<String,Object>();
map.put("gradeId", 2);
// map.put("name", "%李%");
// map.put("age", 11);
List<Student> studentList=studentMapper.searchStudents(map);
for(Student student:studentList){
System.out.println(student);
}
}

@Test
public void testSearchStudents2() {
logger.info("添加学生(带条件)");
Map<String,Object> map=new HashMap<String,Object>();
map.put("searchBy", "age");
map.put("gradeId", 2);
map.put("name", "%李%");
map.put("age", 11);
List<Student> studentList=studentMapper.searchStudents2(map);
for(Student student:studentList){
System.out.println(student);
}
}

}