mybatis--day01动态查询、动态更新、动态删除、动态插入
动态查询
<mapper namespace="studentNamespace">
<resultMap type="cn.itcast.javaee.mybatis.app11.Student" id="studentMap">
<id property="id" column="students_id"/>
<result property="name" column="students_name"/>
<result property="sal" column="students_sal"/>
resultMap>
//传入的是map对象，会自动取map中相同名的值
<select id="findAll" parameterType="map" resultMap="studentMap">
select * from students
<where>
<if test="pid!=null">
and students_id = #{pid}
if>
<if test="pname!=null">
and students_name = #{pname}
if>
<if test="psal!=null">
and students_sal = #{psal}
if>
where>
select>
mapper>
//测试
/**
* 持久层
* @author AdminTC
*/
public class StudentDao {
/**
* 有条件的查询所有学生
*/
public List findAll(Integer id,String name,Double sal) throws Exception{
SqlSession sqlSession = null;
try{
sqlSession = MybatisUtil.getSqlSession();
Map map = new LinkedHashMap();
map.put("pid",id);
map.put("pname",name);
map.put("psal",sal);
return sqlSession.selectList("studentNamespace.findAll",map);
}catch(Exception e){
e.printStackTrace();
throw e;
}finally{
MybatisUtil.closeSqlSession();
}
}
public static void main(String[] args) throws Exception{
StudentDao dao = new StudentDao();
List studentList = dao.findAll(5,"哈哈",7000D);
for(Student s : studentList){
System.out.println(s.getId()+":"+s.getName()+":"+s.getSal());
}
}
} 动态更新
<mapper namespace="studentNamespace">
<resultMap type="cn.itcast.javaee.mybatis.app12.Student" id="studentMap">
<id property="id" column="students_id"/>
<result property="name" column="students_name"/>
<result property="sal" column="students_sal"/>
resultMap>
<update id="dynaUpdate" parameterType="map">
update students
<set>
<if test="pname!=null">
students_name = #{pname},
if>
<if test="psal!=null">
students_sal = #{psal},
if>
set>
where students_id = #{pid}
update>
mapper> /**
* 有条件更新学生
*/
public void dynaUpdate(Integer id,String name,Double sal) throws Exception{
SqlSession sqlSession = null;
try{
sqlSession = MybatisUtil.getSqlSession();
Map map = new HashMap();
map.put("pid",id);
map.put("pname",name);
map.put("psal",sal);
sqlSession.update("studentNamespace.dynaUpdate",map);
sqlSession.commit();
}catch(Exception e){
e.printStackTrace();
sqlSession.rollback();
throw e;
}finally{
MybatisUtil.closeSqlSession();
}
}
public static void main(String[] args) throws Exception{
StudentDao dao = new StudentDao();
//关注SQL的变化
//dao.dynaUpdate(1,null,9000D);//update students set sal=? where id=?
//dao.dynaUpdate(1,"笨笨",null);//update students set name=? where id=?
dao.dynaUpdate(1,"笨笨",10000D);//update students set name=? and sal=? where id=?
} 动态删除
<mapper namespace="studentNamespace">
<resultMap type="cn.itcast.javaee.mybatis.app13.Student" id="studentMap">
<id property="id" column="students_id"/>
<result property="name" column="students_name"/>
<result property="sal" column="students_sal"/>
resultMap>
<delete id="dynaDeleteArray">
delete from students where students_id in
<foreach collection="array" open="(" close=")" separator="," item="ids">
#{ids}
foreach>
delete>
<delete id="dynaDeleteList">
delete from students where students_id in
<foreach collection="list" open="(" close=")" separator="," item="ids">
#{ids}
foreach>
delete>
mapper>/**
* 持久层
* @author AdminTC
*/
public class StudentDao {
/**
* 根据ID批量删除学生(数组版本)
*/
public void dynaDeleteArray(int... ids) throws Exception{
SqlSession sqlSession = null;
try{
sqlSession = MybatisUtil.getSqlSession();
sqlSession.delete("studentNamespace.dynaDeleteArray",ids);
sqlSession.commit();
}catch(Exception e){
e.printStackTrace();
sqlSession.rollback();
throw e;
}finally{
MybatisUtil.closeSqlSession();
}
}
/**
* 根据ID批量删除学生(集合版本)
*/
public void dynaDeleteList(List ids) throws Exception{
SqlSession sqlSession = null;
try{
sqlSession = MybatisUtil.getSqlSession();
sqlSession.delete("studentNamespace.dynaDeleteList",ids);
sqlSession.commit();
}catch(Exception e){
e.printStackTrace();
sqlSession.rollback();
throw e;
}finally{
MybatisUtil.closeSqlSession();
}
}
//测试
public static void main(String[] args) throws Exception{
StudentDao dao = new StudentDao();
//dao.dynaDeleteArray(new int[]{1,3,5,7,77});
//dao.dynaDeleteArray(1,3,5,7,77);
//dao.dynaDeleteArray(2,4,444);
List ids = new ArrayList();
ids.add(6);
ids.add(8);
ids.add(9);
dao.dynaDeleteList(ids);
}
}
动态插入
<mapper namespace="studentNamespace">
<resultMap type="cn.itcast.javaee.mybatis.app14.Student" id="studentMap">
<id property="id" column="students_id"/>
<result property="name" column="students_name"/>
<result property="sal" column="students_sal"/>
resultMap>
<sql id="key">
<trim suffixOverrides=",">
<if test="id!=null">
students_id,
if>
<if test="name!=null">
students_name,
if>
<if test="sal!=null">
students_sal,
if>
trim>
sql>
<sql id="value">
<trim suffixOverrides=",">
<if test="id!=null">
#{id},
if>
<if test="name!=null">
#{name},
if>
<if test="sal!=null">
#{sal},
if>
trim>
sql>
<insert id="dynaInsert" parameterType="cn.itcast.javaee.mybatis.app14.Student">
insert into students(<include refid="key"/>) values(<include refid="value"/>)
insert>
mapper>
/**
* 持久层
* @author AdminTC
*/
public class StudentDao {
/**
* 插入学生
*/
public void dynaInsert(Student student) throws Exception{
SqlSession sqlSession = null;
try{
sqlSession = MybatisUtil.getSqlSession();
sqlSession.insert("studentNamespace.dynaInsert",student);
sqlSession.commit();
}catch(Exception e){
e.printStackTrace();
sqlSession.rollback();
throw e;
}finally{
MybatisUtil.closeSqlSession();
}
}
public static void main(String[] args) throws Exception{
StudentDao dao = new StudentDao();
//dao.dynaInsert(new Student(1,"哈哈",7000D));//insert into 表名(*,*,*) values(?,?,?)
//dao.dynaInsert(new Student(2,"哈哈",null));//insert into 表名(*,*) values(?,?)
//dao.dynaInsert(new Student(3,null,7000D));//insert into 表名(*,*) values(?,?)
dao.dynaInsert(new Student(4,null,null));//insert into 表名(*) values(?)
}
}