mybatis动态sql

package com.cbh.dao;

import java.util.List;
import com.cbh.beans.Student;

public interface IStudent {
List<Student>selectStudentsByCondition(String name,int age,int score);
List<Student>selectStudentsByConditionif(Student student);
List<Student>selectStudentsByConditionwhere(Student student);
}

<?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.cbh.dao.IStudent">
<select id="selectStudentsByConditionif" resultType="Student">
select id,name,age,score
from student1
where 1=1
<if test="name !=null and name !=''">
and name like '%' #{name} '%'
</if>
<if test="age>0">
and age> #{age}
</if>
</select>
<select id="selectStudentsByConditionwhere" resultType="Student">
select id,name,age,score
from student1
<where>
<if test="name !=null and name !=''">
name like '%' #{name} '%'
</if>
<if test="age>0">
and age> #{age}
</if>
<if test="score>0">
and score>#{score}
</if>
</where>
</select>
<!--
#{}中可以放入的内容
1.参数对象的属性
2.随意的内容，此时#｛｝是个占位符
3.参数为map时的key
4.参数为map时，若key所对应的value为对象，则可以将该对象的属性放入
5.参数的索引号（本次就是参数的索引号）
-->

</mapper>

package com.cbh.test;

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

import org.apache.ibatis.session.SqlSession;
import org.junit.Before;
import org.junit.Test;

import com.cbh.Utils.MybatisUtils;
import com.cbh.beans.Student;
import com.cbh.dao.IStudent;

public class mytest {
private IStudent dao;
@Before
public void before() {
SqlSession sqlSession=	MybatisUtils.getSqlSession();
dao =sqlSession.getMapper(IStudent.class) ;
}

@After
public void after(){
if(sqlsession!=null）｛
sqlsession.close();
｝

｝
@Testpublic void test8(){
//Student stu=new Student("大",23,0);
Student stu=new Student("",0,0);
List<Student> student=dao.selectStudentsByConditionif(stu );
for (Student student2 : student) {
System.out.println(student2);
}
}
@Testpublic void test9(){
Student stu=new Student("",0,100);
List<Student> student=dao.selectStudentsByConditionwhere(stu);
for (Student student2 : student) {
System.out.println(student2);
}
}
}