where set trim sql if foreach 实现xml方式的动态sql

1.student-mapping.xml

<?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="dyna">
<!-- create table STUDENT (
ID NUMBER not null,
NAME VARCHAR2(20),
SEX NUMBER(2),
HOBBY VARCHAR2(200),
AGE NUMBER )
-->

<!-- sql用于定义共享的sql 其他select中通过include引用该sql -->
<sql id="queryColumn">
name,sex,age
</sql>
<select id="queryStudnetABCDEFG">
select
<!-- include 应用 -->
<include refid="queryColumn"></include>
from book
</select>

<!-- trim

suffixOverrides
prefixOverrides 要覆盖的字符串
suffix
prefix 替换的字符串
-->
<insert id="addStudent" parameterType="map" >
insert into student(
<!-- trim 前缀替换用法 -->
<trim prefixOverrides="," prefix="">
,id
<if test="name!=null and name!=null" >
,name
</if>
<if test="sex!=null and sex!=null" >
,sex
</if>
<if test="hobby!=null and hobby!=null" >
,hobby
</if>
<if test="age!=null and age!=null" >
,age
</if>
</trim>
)
values(
#{id},
<!-- trim 后缀替换用法 -->
<trim suffixOverrides="," suffix="">
<if test="name!=null and name!=''" >
#{name},
</if>
<if test="sex!=null and sex!=''" >
#{sex},
</if>
<if test="hobby!=null and hobby!=''" >
#{hobby},
</if>
<if test="age!=null and age!=''" >
#{age},
</if>

</trim>
)
<!-- selectKey主键生成 -->
<selectKey keyProperty="id"
order="BEFORE"
resultType="string"
>
select max(id)+1 from student
</selectKey>
</insert>

<!-- where -->
<select id="queryStudent" parameterType="map" resultType="map">
select * from student
<!-- where 默认代替第一的 and 为 where-->
<where>
<if test="id!=null and id!=''" >
and id=#{id}
</if>
<if test="name!=null and name!=''" >
and name=#{name}
</if>
<if test="sex!=null and sex!=''" >
and sex=#{sex}
</if>
<if test="hobby!=null and hobby!=''" >
and hobby=#{hobby}
</if>
<if test="age!=null and age!=''" >
and age=#{age}
</if>
</where>
</select>

<!-- set -->
<update id="updateStudent" parameterType="map"  >
update student
<!-- set 默认会去掉最后一个   逗号（,）  -->
<set>
<if test="name!=null and name!=''" >
name=#{name},
</if>
<if test="sex!=null and sex!=''" >
sex=#{sex},
</if>
<if test="hobby!=null and hobby!=''" >
hobby=#{hobby},
</if>
<if test="age!=null and age!=''" >
age=#{age},
</if>
</set>
where id=#{id}
</update>

<!-- foreach -->
<select id="queryStudentByHobby" parameterType="map" resultType="map">
<!-- open  循环开始前的字符串
close 循环结束的字符串
collection 循环的参数(该参数是一个集合或数组)
index 循环的索引
item  循环所使用的变量
separator 除了最后一次循环外 所要拼接的字符串（分隔符）
-->
<foreach  open="select * from student where hobby in("
close=")"
collection="hobbys"
index="i"
item="hobby"
separator=","
>
#{hobby}
</foreach>
</select>

</mapper>

private static SqlSession sqlSession;
@Before
public void getSqlSession() throws IOException{
if (sqlSession==null) {
final String mybatisConf = "mybatis-conf.xml";
InputStream in = Resources.getResourceAsStream(mybatisConf);
SqlSessionFactory ssf= new SqlSessionFactoryBuilder() .build(in);
sqlSession=ssf.openSession();
}
}
@After
public void closeSqlSession(){
sqlSession.commit();
sqlSession.close();
}
@Test
public void testDynaSqlWhere(){
String statement="dyna.queryStudent";
Map map= new HashMap();
map.put("id", "1");
map.put("name", "oracle");
List result=sqlSession.selectList(statement, map);
System.out.println("--->  " +result);
}
@Test
public void testDynaSqlSet(){
String statement="dyna.updateStudent";
Map map= new HashMap();
map.put("id", "1");
map.put("name", "11122");
map.put("age", "30");
sqlSession.update(statement, map);

}
@Test
public void testDynaSqlForEach(){
String statement="dyna.queryStudentByHobby";
Map map= new HashMap();
String[] hobbys={"playgame","readbook","listenCD"};
map.put("hobbys",hobbys );
List result=sqlSession.selectList(statement, map);
System.out.println("--->  " +result);

}
@Test
public void testDynaSqlTrim(){
String statement="dyna.addStudent";
Map map= new HashMap();
map.put("hobby","playgame");
sqlSession.insert(statement, map);
}