SSM(Spring MVC+Spring+Mybatis)框架学习（一）：Mybatis框架学习
基于idea+mysql+mybatis
源码下载链接：https://pan.baidu.com/s/16fTVYRWrWdkkpbBjuD3GTw
提取码：x1to
- Mybatis框架学习
- 1.Mybatis完成CRUD
- 2.Mybatis的动态SQL/dd>
- 3.Mybatis的多表查询
- 4.Mybatis的注解开发
1.Mybatis完成CRUD
1.mysql中创建user表
2.项目目录结构：
3.创建domain中实体类User 以及dao接口中IUser
package edu.hue.jk.domian;
import java.io.Serializable;
import java.util.Date;
import java.util.List;
public class User implements Serializable {
private Integer id;
private String username;
private Date birthday;
private String sex;
private String address;
private List<Account> accounts;
private List<Role> roles;
public List<Role> getRoles() {
return roles;
}
public void setRoles(List<Role> roles) {
this.roles = roles;
}
public List<Account> getAccounts() {
return accounts;
}
public void setAccounts(List<Account> accounts) {
this.accounts = accounts;
}
public Integer getId() {
return id;
}
public void setId(Integer 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 + '\'' +
'}';
}
}
package edu.hue.jk.dao;
import edu.hue.jk.domian.QueryVo;
import edu.hue.jk.domian.User;
import java.util.Collection;
import java.util.List;
public interface IUserDao {
//查询所有
//@Select("select * from user")
List<User> findAll();
//保存
//@Insert("insert into user(username,birthday,sex,address) value(#{username},#{birthday},#{sex},#{address})")
void saveUser(User user);
//更新
void updateUser(User user);
//删除
void deleteUser(Integer id);
//根据id查询信息
User findById(Integer id);
//根据name查询信息(模糊查询)
List<User> findByName(String name);
//第二种模糊查询
List<User> findByName2(String name);
//根据聚合函数查询行数count()
Integer findTotalLine();
//根据QueryVo进行模糊查询
List<User> findByVo(QueryVo vo);
/*--------------------下面是动态SQL查询--------------------------------------------*/
//动态Sql,根据传参不同(有可能没有username、有可能有。。。)，返回值也不同
List<User> findByCondition(User user);
//根据一个范围id(41,42,43,44,45)查询信息
List<User> findInIds(QueryVo vo);
//测试抽取重复的sql语句后的查询所有
List<User> findAll2();
//测试一对多查询
List<User> findAccountUser();
//测试用户角色多对多查询
List<User> findUserToRole();
}
创建SqlMapConfig.xml配置文件
<configuration>
<typeAliases>
<package name="edu.hue.jk.domian">package>
typeAliases>
<environments default="mysql">
<environment id="mysql">
<transactionManager type="JDBC">transactionManager>
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/mybatis"/>
<property name="username" value="root"/>
<property name="password" value="root"/>
dataSource>
environment>
environments>
<mappers>
<mapper resource="edu/hue/jk/dao/IUserDao.xml"/>
<mapper resource="edu/hue/jk/dao/IAccountDao.xml"/>
<mapper resource="edu/hue/jk/dao/IRoleDao.xml"/>
mappers>
configuration>
创建mapper映射 IUserDao.xml文件
<mapper namespace="edu.hue.jk.dao.IUserDao">
<select id="findAll" resultType="User">
select * from user
select>
<insert id="saveUser" parameterType="User">
<selectKey keyProperty="id" keyColumn="id" resultType="Integer" order="AFTER">
select last_insert_id()
selectKey>
insert into user(username,birthday,sex,address) values(#{username},#{birthday},#{sex},#{address})
insert>
<update id="updateUser" parameterType="User">
update user set username=#{username},birthday=#{birthday},sex=#{sex},address=#{address} where id=#{id}
update>
<delete id="deleteUser" parameterType="java.lang.Integer">
delete from user where id=#{id}
delete>
<select id="findById" resultType="User" parameterType="java.lang.Integer">
select * from user where id=#{id}
select>
<select id="findByName" resultType="User" parameterType="java.lang.String">
select * from user where username like #{username}
select>
<select id="findByName2" resultType="User" parameterType="java.lang.String">
select * from user where username like '%${value}%'
select>
<select id="findTotalLine" resultType="java.lang.Integer" >
select count(id) from user
select>
<select id="findByVo" parameterType="QueryVo" resultType="User" >
select * from user where username like #{user.username}
select>
<select id="findByCondition" parameterType="User" resultType="User" >
select * from user
<where>
<if test="username!=null">
and username = #{username}
if>
<if test="sex != null">
and sex = #{sex}
if>
where>
select>
<select id="findInIds" parameterType="QueryVo" resultType="User" >
select * from user
<where>
<if test="ids!=null and ids.size>0">
<foreach collection="ids" open="and id in (" close=")" item="id" separator=",">
#{id}
foreach>
if>
where>
select>
<sql id="defaultUser">
select * from user
sql>
<select id="findAll2" resultType="edu.hue.jk.domian.User">
<include refid="defaultUser">include>
select>
<resultMap id="userAccountMap" type="user">
<id property="id" column="id">id>
<result property="username" column="username">result>
<result property="birthday" column="birthday">result>
<result property="sex" column="sex">result>
<result property="address" column="address">result>
<collection property="accounts" ofType="Account">
<id property="id" column="aid">id>
<result property="uid" column="uid">result>
<result property="money" column="money">result>
collection>
resultMap>
<select id="findAccountUser" resultMap="userAccountMap">
select * from user u left outer join account a on u.id=a.uid
select>
<resultMap id="UserRoleMap" type="user">
<id property="id" column="id">id>
<result property="username" column="username">result>
<result property="birthday" column="birthday">result>
<result property="sex" column="sex">result>
<result property="address" column="address">result>
<collection property="roles" ofType="role">
<id property="id" column="rid">id>
<result property="role_name" column="role_name">result>
<result property="role_desc" column="role_desc">result>
collection>
resultMap>
<select id="findUserToRole" resultMap="UserRoleMap">
select u.*,r.id as rid ,r.role_name,r.role_desc from user u
left outer join user_role ur on u.id = ur.uid
left outer join role r on r.id= ur.rid
select>
mapper>
测试CRUD
package edu.hue.jk.test;
import edu.hue.jk.dao.IUserDao;
import edu.hue.jk.domian.QueryVo;
import edu.hue.jk.domian.User;
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.After;
import org.junit.Before;
import org.junit.Test;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
public class UserTest {
private InputStream in;
private static SqlSession session;
private IUserDao UserDao;
@Before
public void init() throws Exception{
//1.获取SqlMapConfig的流对象
in = Resources.getResourceAsStream("SqlMapConfig.xml");
//2.利用构建者模式创建SqlSessionFactory工厂
SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
//3.利用工厂创建SqlSession对象
SqlSessionFactory factory = builder.build(in);
//4.用SqlSession对象创建Session对象
session = factory.openSession();
//5.创建Dao接口的代理对象
UserDao = session.getMapper(IUserDao.class);
}
@After
public void destroy() throws Exception{
//7.释放资源
if(session !=null) {
session.close();
}
in.close();
}
@Test //测试查询所有
public void findAll(){
//6.执行方法
List<User> users = UserDao.findAll();
for (User user : users){
System.out.println(user);
}
}
@Test //测试保存
public void saveUser(){
User user = new User();
user.setUsername("王大姐");
user.setBirthday(new Date());
user.setSex("女");
user.setAddress("爱情公寓");
//6.执行方法
System.out.println("保存前："+user);
UserDao.saveUser(user);
System.out.println("保存后："+user);
session.commit();
}
@Test //测试更新
public void updateUser(){
User user = new User();
user.setId(51);
user.setUsername("王二姐");
user.setBirthday(new Date());
user.setSex("女");
user.setAddress("爱森公寓");
//6.执行方法
UserDao.updateUser(user);
session.commit();
}
@Test //测试删除
public void deleteUser(){
//6.执行方法
UserDao.deleteUser(46);
}
@Test //测试根据id查信息
public void findById(){
//6.执行方法
User user= UserDao.findById(51);
System.out.println(user);
}
@Test //测试根据name查信息、模糊查询
public void findByName(){
//6.执行方法
List<User> users = UserDao.findByName("%二%");
for (User user : users){
System.out.println(user);
}
}
@Test //测试第二种模糊查询
public void findByName2(){
//6.执行方法
List<User> users = UserDao.findByName2("二");
for (User user : users){
System.out.println(user);
}
}
@Test //测试查询行数总和 根据聚合函数count()
public void findTotalLine(){
//6.执行方法
Integer totalLine = UserDao.findTotalLine();
System.out.println(totalLine);
}
@Test //QuertVo进行模糊查询
public void findByVo(){
//6.执行方法
User user =new User();
QueryVo vo =new QueryVo();
user.setUsername("%王%");
vo.setUser(user);
List<User> users= UserDao.findByVo(vo);
for (User u : users){
System.out.println(u);
}
}
//------------测试动态SQL--------------
@Test //根据传参不同动态查询
public void findByCondition(){
//6.执行方法
User user1 =new User();
User user2 =new User();
User user3 =new User();
user2.setUsername("田二妞");
user3.setSex("女");
user3.setUsername("小二王");
//测试不传入参数
List<User> users1= UserDao.findByCondition(user1);
for (User u : users1){
System.out.println(u);
}
//username不为空
List<User> users2= UserDao.findByCondition(user2);
for (User u : users2){
System.out.println(u);
}
//username和sex都不为空
List<User> users3= UserDao.findByCondition(user3);
for (User u : users3){
System.out.println(u);
}
}
@Test //QuertVo进行模糊查询
public void findInIds(){
//6.执行方法
QueryVo vo =new QueryVo();
List<Integer> list = new ArrayList<Integer>();
list.add(41);
list.add(42);
list.add(45);
list.add(50);
list.add(51);
vo.setIds(list);
List<User> users= UserDao.findInIds(vo);
for (User u : users){
System.out.println(u);
}
}
@Test //测试抽取重复sql后的查询所有
public void findAll2(){
//6.执行方法
List<User> users = UserDao.findAll2();
for (User user : users){
System.out.println(user);
}
}
@Test //测试一对多查询
public void findAccountUser(){
//6.执行方法
List<User> users = UserDao.findAccountUser();
for (User user : users){
System.out.println(user);
System.out.println(user.getAccounts());
}
}
@Test //测试多对多
public void findUserToRole(){
//6.执行方法
List<User> users = UserDao.findUserToRole();
for (User user : users){
System.out.println(user);
System.out.println(user.getRoles());
}
}
}
2.Mybatis的动态SQL
也是在IUserDao.xml文件中书写
<select id="findByCondition" parameterType="User" resultType="User" >
select * from user
<where>
<if test="username!=null">
and username = #{username}
if>
<if test="sex != null">
and sex = #{sex}
if>
where>
select>
<select id="findInIds" parameterType="QueryVo" resultType="User" >
select * from user
<where>
<if test="ids!=null and ids.size>0">
<foreach collection="ids" open="and id in (" close=")" item="id" separator=",">
#{id}
foreach>
if>
where>
3.Mybatis的多表查询
再mysql中创建accout表，以及domain中的对应实体类account ，并且再account中加入：private User user；以及get set方法，与user关系上。
account实体类
package edu.hue.jk.domian;
import java.io.Serializable;
public class Account implements Serializable {
private Integer id;
private Integer uid;
private Double money;
private User user;
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public Integer getUid() {
return uid;
}
public void setUid(Integer uid) {
this.uid = uid;
}
public Double getMoney() {
return money;
}
public void setMoney(Double money) {
this.money = money;
}
@Override
public String toString() {
return "Account{" +
"id=" + id +
", uid=" + uid +
", money=" + money +
'}';
}
}
创建IAccountDao接口以及IAccountDao.xml
<mapper namespace="edu.hue.jk.dao.IAccountDao">
<sql id="defaultAccount">
select * from account
sql>
<resultMap id="accountUserMap" type="account">
<id property="id" column="aid">id>
<result property="uid" column="uid">result>
<result property="money" column="money">result>
<association property="user" column="id" javaType="user">
<id property="id" column="id">id>
<result property="username" column="username">result>
<result property="birthday" column="birthday">result>
<result property="sex" column="sex">result>
<result property="address" column="address">result>
association>
resultMap>
<select id="findAll" resultMap="accountUserMap">
select a.*,u.* from user u,account a where u.id = a.uid
select>
<select id="findAllAccount" resultType="AccountUser">
select a.*,u.username,u.address from user u,account a where u.id = a.uid
select>
mapper>
package edu.hue.jk.dao;
import edu.hue.jk.domian.Account;
import edu.hue.jk.domian.AccountUser;
import java.util.List;
public interface IAccountDao {
//查询所有账户
List<Account> findAll();
//查询所有账户且所属user信息的username和address
List<AccountUser> findAllAccount();
}
测试一对一
package edu.hue.jk.test;
import edu.hue.jk.dao.IAccountDao;
import edu.hue.jk.dao.IUserDao;
import edu.hue.jk.domian.Account;
import edu.hue.jk.domian.AccountUser;
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.After;
import org.junit.Before;
import org.junit.Test;
import java.io.InputStream;
import java.util.List;
public class AccountTest {
private InputStream in;
private static SqlSession session;
private IAccountDao AccountDao;
@Before
public void init() throws Exception{
//1.获取SqlMapConfig的流对象
in = Resources.getResourceAsStream("SqlMapConfig.xml");
//2.利用构建者模式创建SqlSessionFactory工厂
SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
//3.利用工厂创建SqlSession对象
SqlSessionFactory factory = builder.build(in);
//4.用SqlSession对象创建Session对象
session = factory.openSession();
//5.创建Dao接口的代理对象
AccountDao = session.getMapper(IAccountDao.class);
}
@After
public void destroy() throws Exception{
//7.释放资源
if(session !=null) {
session.close();
}
in.close();
}
@Test //测试一对一查询
public void findAll(){
//6.执行方法
List<Account> accounts = AccountDao.findAll();
for (Account account : accounts){
System.out.println(account);
System.out.println(account.getUser());
}
}
@Test //测试查询所有
public void findAllAccount(){
//6.执行方法
List<AccountUser> accounts = AccountDao.findAllAccount();
for (AccountUser account : accounts){
System.out.println(account);
}
}
}
User对应Account为一对多：
创建AccountUser对应实体类
package edu.hue.jk.domian;
public class AccountUser extends Account{
private String username;
private String address;
@Override
public String toString() {
return super.toString()+"AccountUser{" +
"username='" + username + '\'' +
", address='" + address + '\'' +
'}';
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
}
一对多方法
List findAccountUser();
再IUserDao.xml实现一堆多查询
<resultMap id="userAccountMap" type="user">
<id property="id" column="id">id>
<result property="username" column="username">result>
<result property="birthday" column="birthday">result>
<result property="sex" column="sex">result>
<result property="address" column="address">result>
<collection property="accounts" ofType="Account">
<id property="id" column="aid">id>
<result property="uid" column="uid">result>
<result property="money" column="money">result>
collection>
resultMap>
<select id="findAccountUser" resultMap="userAccountMap">
select * from user u left outer join account a on u.id=a.uid
select>
测试一对多：
@Test //测试一对多查询
public void findAccountUser(){
//6.执行方法
List<User> users = UserDao.findAccountUser();
for (User user : users){
System.out.println(user);
System.out.println(user.getAccounts());
}
}