javabean：
我要评论package com.me.model;
import java.io.serializable;
import java.util.date;
import java.util.list;
public class user implements serializable {
/**
*
*/
private static final long serialversionuid = 1l;
private int id;
private string username;
private date birthday;
private string sex;
private string address;
//一對一 放入對象
private morder morder;
//一對多 放入對象集合
private list<home> homelist;
public list<home> gethomelist() {
return homelist;
}
public void sethomelist(list<home> homelist) {
this.homelist = homelist;
}
public morder getmorder() {
return morder;
}
public void setmorder(morder morder) {
this.morder = morder;
}
public static long getserialversionuid() {
return serialversionuid;
}
public int getid() {
return id;
}
public void setid(int id) {
this.id = id;
}
public string getusername() {
return username;
}
public void setusername(string username) {
this.username = username;
}
public date getbirthday() {
return birthday;
}
public void setbirthday(date birthday) {
this.birthday = birthday;
}
public string getsex() {
return sex;
}
public void setsex(string sex) {
this.sex = sex;
}
public string getaddress() {
return address;
}
public void setaddress(string address) {
this.address = address;
}
@override
public string tostring() {
return "user [id=" + id + ", username=" + username + ", birthday="
+ birthday + ", sex=" + sex + ", address=" + address
+ ", morder=" + morder + ", homelist=" + homelist + "]";
}
}
package com.me.model;
public class morder {
private int orderid;
private string ordername;
private string ordermessage;
public int getorderid() {
return orderid;
}
public void setorderid(int orderid) {
this.orderid = orderid;
}
public string getordername() {
return ordername;
}
public void setordername(string ordername) {
this.ordername = ordername;
}
public string getordermessage() {
return ordermessage;
}
public void setordermessage(string ordermessage) {
this.ordermessage = ordermessage;
}
}
package com.me.model;
public class home {
private int homeid;
private string homename;
public int gethomeid() {
return homeid;
}
public void sethomeid(int homeid) {
this.homeid = homeid;
}
public string gethomename() {
return homename;
}
public void sethomename(string homename) {
this.homename = homename;
}
}
mapper.xml 代码
<!-- collection ：collection属性的值有三个分别是list、array、map三种， 分别对应的参数类型为：list、数组、map集合，我在上面传的参数为数组，所以值为array
item ： 表示在迭代过程中每一个元素的别名 index ：表示在迭代过程中每次迭代到的位置（下标） open ：前缀 close ：后缀 separator
：分隔符，表示迭代时每个元素之间以什么分隔 -->
<delete id="deletesome">
delete from user where id in
<foreach collection="list" item="id" index="index" open="("
close=")" separator=",">
#{id}
</foreach>
</delete>
<!-- 关联查询 -->
<!-- 關聯查詢 1對1 -->
<select id="selectgl" resultmap="userrsultmap">
select * from user u,morder m
where u.oid=m.order_id
</select>
<resultmap type="com.me.model.user" id="userrsultmap">
<id property="id" column="id" />
<result column="username" property="username" />
<result column="birthday" property="birthday" />
<result column="sex" property="sex" />
<result column="address" property="address" />
<association property="morder" javatype="com.me.model.morder">
<id column="order_id" property="orderid" />
<result column="order_name" property="ordername" />
<result column="order_message" property="ordermessage" />
</association>
</resultmap>
<!-- 關聯查詢 1對多 -->
<select id="selectgl2" resultmap="userrsultmap2">
select * from user u,home h where u.hid=h.home_id;
</select>
<resultmap type="com.me.model.user" id="userrsultmap2">
<id property="id" column="id" />
<result column="username" property="username" />
<result column="birthday" property="birthday" />
<result column="sex" property="sex" />
<result column="address" property="address" />
<collection property="homelist" oftype="com.me.model.home">
<id property="homeid" column="home_id" />
<result property="homename" column="home_name" />
</collection>
</resultmap>
图文解释：
测试：
//關聯查詢 1 to 多
@test
public void selectgl2(){
try {
inputstream = resources.getresourceasstream(resource);
// 创建会话工厂，传入mybatis的配置文件信息
sqlsessionfactory sqlsessionfactory = new sqlsessionfactorybuilder()
.build(inputstream);
// 通过工厂得到sqlsession
sqlsession = sqlsessionfactory.opensession();
list<user> list = sqlsession.selectlist("test.selectgl2");
for (user u : list) {
system.err.println(u.gethomelist().get(0).gethomename());
}
} catch (ioexception e) {
e.printstacktrace();
} finally {
// 释放资源
sqlsession.close();
}
}
结果：
22:47:17.005 [main] debug org.apache.ibatis.logging.logfactory - logging initialized using 'class org.apache.ibatis.logging.slf4j.slf4jimpl' adapter.
22:47:17.140 [main] debug o.a.i.d.pooled.pooleddatasource - pooleddatasource forcefully closed/removed all connections.
22:47:17.140 [main] debug o.a.i.d.pooled.pooleddatasource - pooleddatasource forcefully closed/removed all connections.
22:47:17.140 [main] debug o.a.i.d.pooled.pooleddatasource - pooleddatasource forcefully closed/removed all connections.
22:47:17.140 [main] debug o.a.i.d.pooled.pooleddatasource - pooleddatasource forcefully closed/removed all connections.
22:47:17.215 [main] debug o.a.i.t.jdbc.jdbctransaction - opening jdbc connection
22:47:17.420 [main] debug o.a.i.d.pooled.pooleddatasource - created connection 518522822.
22:47:17.420 [main] debug o.a.i.t.jdbc.jdbctransaction - setting autocommit to false on jdbc connection [com.mysql.jdbc.jdbc4connection@1ee807c6]
22:47:17.421 [main] debug test.selectgl2 - ==> preparing: select * from user u,home h where u.hid=h.home_id;
22:47:17.444 [main] debug test.selectgl2 - ==> parameters:
22:47:17.461 [main] debug test.selectgl2 - <== total: 4
sasadasd
22:47:17.462 [main] debug o.a.i.t.jdbc.jdbctransaction - resetting autocommit to true on jdbc connection [com.mysql.jdbc.jdbc4connection@1ee807c6]
22:47:17.462 [main] debug o.a.i.t.jdbc.jdbctransaction - closing jdbc connection [com.mysql.jdbc.jdbc4connection@1ee807c6]
22:47:17.463 [main] debug o.a.i.d.pooled.pooleddatasource - returned connection 518522822 to pool.
更多可以参考：https://www.cnblogs.com/xdp-gacl/p/4264440.html
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