【目录】
1 一对一
2 一对多
在项目开始之前准备好数据库。
数据库database：
创建User表
插入一些数据
创建country表
插入一些数据
1 一对一
关系图
项目目录
相关代码：
主配置文件SqlMapConfig.xml：
User.java：
package com.test.bean;
import java.util.Date;
public class User {
/**
* CREATE TABLE `user` (
`u_id` INT(11) NOT NULL AUTO_INCREMENT COMMENT '用户id',
`u_username` VARCHAR(64) NOT NULL COMMENT '用户名',
`u_password` VARCHAR(64) NOT NULL COMMENT '用户密码',
`u_sex` VARCHAR(16) DEFAULT NULL COMMENT '用户性别',
`u_createTime` DATETIME DEFAULT NULL COMMENT '用户创建时间',
`u_cid` INT(11) NOT NULL COMMENT '用户国家id',
*/
private Integer u_id;
private String u_username;
private String u_password;
private String u_sex;
private Date u_createTime;
private Integer u_cid;
public Integer getU_id() {
return u_id;
}
public void setU_id(Integer u_id) {
this.u_id = u_id;
}
public String getU_username() {
return u_username;
}
public void setU_username(String u_username) {
this.u_username = u_username;
}
public String getU_password() {
return u_password;
}
public void setU_password(String u_password) {
this.u_password = u_password;
}
public String getU_sex() {
return u_sex;
}
public void setU_sex(String u_sex) {
this.u_sex = u_sex;
}
public Date getU_createTime() {
return u_createTime;
}
public void setU_createTime(Date u_createTime) {
this.u_createTime = u_createTime;
}
public Integer getU_cid() {
return u_cid;
}
public void setU_cid(Integer u_cid) {
this.u_cid = u_cid;
}
@Override
public String toString() {
return "User [u_id=" + u_id + ", u_username=" + u_username + ", u_password=" + u_password + ", u_sex=" + u_sex
+ ", u_createTime=" + u_createTime + ", u_cid=" + u_cid + "]";
}
}
Country.java：
package com.test.bean;
public class Country {
// `c_id` INT(11) NOT NULL AUTO_INCREMENT COMMENT '国家id',
// `c_countryname` VARCHAR(128) NOT NULL COMMENT '国家名称',
// `c_capital` VARCHAR(128) DEFAULT NULL COMMENT '国家首都名称',
private Integer id;
private String c_countryname;
private String c_capital;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getC_countryname() {
return c_countryname;
}
public void setC_countryname(String c_countryname) {
this.c_countryname = c_countryname;
}
public String getC_capital() {
return c_capital;
}
public void setC_capital(String c_capital) {
this.c_capital = c_capital;
}
@Override
public String toString() {
return "Country [id=" + id + ", c_countryname=" + c_countryname + ", c_capital=" + c_capital + "]";
}
}
User包装类UserVo.java：
package com.test.bean;
public class UserVo extends User {
//包装类
private Country country;
public Country getCountry() {
return country;
}
public void setCountry(Country country) {
this.country = country;
}
@Override
public String toString() {
return "UserVo [country=" + country + ", getU_id()=" + getU_id() + ", getU_username()=" + getU_username()
+ ", getU_sex()=" + getU_sex() + "]";
}
}
动态代理接口UserMapper.java：
package com.test.mapper;
import java.util.List;
import com.test.bean.UserVo;
public interface UserMapper {
//查询所有用户包装类
public List selectAllUserVo();
}
映射文件UserMapper.xml：
测试类MapperTest.java：
package com.test.test;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;
import com.test.bean.UserVo;
import com.test.mapper.UserMapper;
public class MapperTest {
@Test
public void Test_selectAllUserVo() throws IOException {
String resource = "sqlMapConfig.xml";
//读取配置文件
InputStream in = Resources.getResourceAsStream(resource );
//创建sqlSessionfactory
SqlSessionFactory ssf = new SqlSessionFactoryBuilder().build(in);
//生产一个sqlSession
SqlSession session = ssf.openSession();
UserMapper mapper = session.getMapper(UserMapper.class);
List list = mapper.selectAllUserVo();
for (UserVo userVo : list) {
System.out.println(userVo);
}
}
}
进行测试。
测试结果
2 一对多
关系图
项目目录
主配置文件SqlMapConfig.xml：
Country.java：
package com.test.bean;
public class Country {
// `c_id` INT(11) NOT NULL AUTO_INCREMENT COMMENT '国家id',
// `c_countryname` VARCHAR(128) NOT NULL COMMENT '国家名称',
// `c_capital` VARCHAR(128) DEFAULT NULL COMMENT '国家首都名称',
private Integer id;
private String c_countryname;
private String c_capital;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getC_countryname() {
return c_countryname;
}
public void setC_countryname(String c_countryname) {
this.c_countryname = c_countryname;
}
public String getC_capital() {
return c_capital;
}
public void setC_capital(String c_capital) {
this.c_capital = c_capital;
}
@Override
public String toString() {
return "Country [id=" + id + ", c_countryname=" + c_countryname + ", c_capital=" + c_capital + "]";
}
}
User.java：
package com.test.bean;
import java.util.Date;
public class User {
/**
* CREATE TABLE `user` (
`u_id` INT(11) NOT NULL AUTO_INCREMENT COMMENT '用户id',
`u_username` VARCHAR(64) NOT NULL COMMENT '用户名',
`u_password` VARCHAR(64) NOT NULL COMMENT '用户密码',
`u_sex` VARCHAR(16) DEFAULT NULL COMMENT '用户性别',
`u_createTime` DATETIME DEFAULT NULL COMMENT '用户创建时间',
`u_cid` INT(11) NOT NULL COMMENT '用户国家id',
*/
private Integer u_id;
private String u_username;
private String u_password;
private String u_sex;
private Date u_createTime;
private Integer u_cid;
public Integer getU_id() {
return u_id;
}
public void setU_id(Integer u_id) {
this.u_id = u_id;
}
public String getU_username() {
return u_username;
}
public void setU_username(String u_username) {
this.u_username = u_username;
}
public String getU_password() {
return u_password;
}
public void setU_password(String u_password) {
this.u_password = u_password;
}
public String getU_sex() {
return u_sex;
}
public void setU_sex(String u_sex) {
this.u_sex = u_sex;
}
public Date getU_createTime() {
return u_createTime;
}
public void setU_createTime(Date u_createTime) {
this.u_createTime = u_createTime;
}
public Integer getU_cid() {
return u_cid;
}
public void setU_cid(Integer u_cid) {
this.u_cid = u_cid;
}
@Override
public String toString() {
return "User [u_id=" + u_id + ", u_username=" + u_username + ", u_password=" + u_password + ", u_sex=" + u_sex
+ ", u_createTime=" + u_createTime + ", u_cid=" + u_cid + "]";
}
}
Country包装类CountryVo.java：
package com.test.bean;
import java.util.List;
public class CountryVo extends Country {
//需要维护一个User集合
private List userList;
public List getUserList() {
return userList;
}
public void setUserList(List userList) {
this.userList = userList;
}
@Override
public String toString() {
//return "CountryVo [userList=" + userList + ", toString()=" + super.toString() + "]";
return super.toString() + " userList = " + userList;
}
}
动态代理接口CountryMapper.java：
package com.test.mapper;
import java.util.List;
import com.test.bean.CountryVo;
public interface CountryMapper {
//查询所有CountryVo
List selectAllCountryVo();
}
映射文件CountryMapper.xml：
测试类MapperTest.java：
package com.test.test;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;
import com.test.bean.CountryVo;
import com.test.mapper.CountryMapper;
public class MapperTest {
@Test
public void Test_selectAllCountryVo() throws IOException {
String resource = "sqlMapConfig.xml";
//读取配置文件
InputStream in = Resources.getResourceAsStream(resource );
//创建sqlSessionfactory
SqlSessionFactory ssf = new SqlSessionFactoryBuilder().build(in);
//生产一个sqlSession
SqlSession session = ssf.openSession();
CountryMapper mapper = session.getMapper(CountryMapper.class);
List list = mapper.selectAllCountryVo();
for (CountryVo countryVo : list) {
System.out.println(countryVo);
}
}
}
进行测试。
测试结果