系列博文:  

    JavaWeb_(Mybatis框架)JDBC操作数据库和Mybatis框架操作数据库区别_一    传送门

    JavaWeb_(Mybatis框架)使用Mybatis对表进行增、删、改、查操作_二        传送门

    JavaWeb_(Mybatis框架)Mapper动态代理开发_三                 传送门

    JavaWeb_(Mybatis框架)主配置文件介绍_四                     传送门

    JavaWeb_(Mybatis框架)输入和输出参数_五                   传送门

    JavaWeb_(Mybatis框架)关联查询_六传送门                   传送门

    JavaWeb_(Mybatis框架)动态sql_七传送门                   传送门

  原有基础上,创建HelloMyBatis.java、HelloMyBatis2.java、HelloMyBatis3.java、HelloMyBatis4.java、HelloMyBatis5.java分别为

    a)通过ID去查询一个用户

package com.Gary.test;

import java.io.IOException;
import java.io.InputStream; 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.jupiter.api.Test; import com.Gary.bean.User; public class HelloMyBatis { @Test
//入门程序,通过ID,查询用户
public void Test1() throws IOException {
//读取配置文件
String resource = "sqlMapConfig.xml"; InputStream in = Resources.getResourceAsStream(resource); //需要sqlSessionFactoryBuilder
SqlSessionFactoryBuilder ssfb = new SqlSessionFactoryBuilder(); //创建sqlSessionFactory
SqlSessionFactory ssf = ssfb.build(in); //生产一个sqlSession
SqlSession session = ssf.openSession(); //操作数据库
//参数1:要操作的sql语句 参数2:sql语句的参数
User user = session.selectOne("UserMapper.selectUserById", 1);
System.err.println(user); } }

HelloMyBatis.java

    b)通过用户名模糊查找匹配的用户列表

package com.Gary.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.jupiter.api.Test; import com.Gary.bean.User; public class HelloMyBatis2 { @Test
//入门程序,通过ID,查询用户
public void Test1() throws IOException {
//读取配置文件
String resource = "sqlMapConfig.xml"; InputStream in = Resources.getResourceAsStream(resource); //需要sqlSessionFactoryBuilder
SqlSessionFactoryBuilder ssfb = new SqlSessionFactoryBuilder(); //创建sqlSessionFactory
SqlSessionFactory ssf = ssfb.build(in); //生产一个sqlSession
SqlSession session = ssf.openSession(); //操作数据库
//参数1:要操作的sql语句 参数2:sql语句的参数
List<User> list = session.selectList("UserMapper.selectUserByName", "王"); for(User u : list) {
System.out.println(u);
} } }

HelloMyBatis2.java

    c)完成添加用户

package com.Gary.test;

import java.io.IOException;
import java.io.InputStream;
import java.util.Date;
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.jupiter.api.Test; import com.Gary.bean.User; public class HelloMyBatis3 { @Test
//入门程序,通过ID,查询用户
public void Test1() throws IOException {
//读取配置文件
String resource = "sqlMapConfig.xml"; InputStream in = Resources.getResourceAsStream(resource); //需要sqlSessionFactoryBuilder
SqlSessionFactoryBuilder ssfb = new SqlSessionFactoryBuilder(); //创建sqlSessionFactory
SqlSessionFactory ssf = ssfb.build(in); //生产一个sqlSession
SqlSession session = ssf.openSession(); //操作数据库
//参数1:要操作的sql语句 参数2:sql语句的参数
User user = new User(); user.setU_username("Gary");
user.setU_password("494949");
user.setU_sex("1");
user.setU_createTime(new Date());
user.setU_cid(1); session.insert("UserMapper.insertUser", user);
//提交事务
session.commit(); } }

HelloMyBatis3.java

    d)修改用户

package com.Gary.test;

import java.io.IOException;
import java.io.InputStream;
import java.util.Date;
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.jupiter.api.Test; import com.Gary.bean.User; public class HelloMyBatis4 { @Test
//入门程序,通过ID,查询用户
public void Test1() throws IOException {
//读取配置文件
String resource = "sqlMapConfig.xml"; InputStream in = Resources.getResourceAsStream(resource); //需要sqlSessionFactoryBuilder
SqlSessionFactoryBuilder ssfb = new SqlSessionFactoryBuilder(); //创建sqlSessionFactory
SqlSessionFactory ssf = ssfb.build(in); //生产一个sqlSession
SqlSession session = ssf.openSession(); //操作数据库
//参数1:要操作的sql语句 参数2:sql语句的参数
User user = new User();
user.setU_id(13);
user.setU_username("修改后Gary"); session.insert("UserMapper.updateUser", user);
//提交事务
session.commit(); } }

HelloMyBatis4.java

    e)根据id删除用户

package com.Gary.test;

import java.io.IOException;
import java.io.InputStream;
import java.util.Date;
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.jupiter.api.Test; import com.Gary.bean.User; public class HelloMyBatis5 { @Test
//入门程序,通过ID,查询用户
public void Test1() throws IOException {
//读取配置文件
String resource = "sqlMapConfig.xml"; InputStream in = Resources.getResourceAsStream(resource); //需要sqlSessionFactoryBuilder
SqlSessionFactoryBuilder ssfb = new SqlSessionFactoryBuilder(); //创建sqlSessionFactory
SqlSessionFactory ssf = ssfb.build(in); //生产一个sqlSession
SqlSession session = ssf.openSession(); //操作数据库
//参数1:要操作的sql语句 参数2:sql语句的参数 session.delete("UserMapper.deleteUserById", 13);
//提交事务
session.commit(); } }

HelloMyBatis5.java

<?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="UserMapper"> <select id="selectUserById" parameterType="Integer" resultType="com.Gary.bean.User">
select * from user where u_id = #{id}
</select> <!-- #{}占位符 尽量使用#{}来解决问题 -->
<!-- ${}字符串拼接 容易sql注入 (or 1 = 1) --> <!-- ${value}中间的字符串一定需要使用value -->
<select id="selectUserByName" parameterType="String" resultType="com.Gary.bean.User">
<!-- select * from user where u_username like '%${value}%' -->
select * from user where u_username like "%"#{name}"%"
</select> <!-- 添加用户 参数为全包名 -->
<insert id="insertUser" parameterType="com.Gary.bean.User">
insert into user values(null,#{u_username},#{u_password},#{u_sex},#{u_createTime},#{u_cid})
</insert> <!-- 根据id修改username字段的语句 -->
<update id="updateUser" parameterType="com.Gary.bean.User">
update user set u_username = #{u_username} where u_id = #{u_id}
</update> <!-- 根据id删除用户 -->
<delete id="deleteUserById" parameterType="Integer">
delete from user where u_id = #{id}
</delete> </mapper>

UserMapper.xml

  

实现过程

  添加log4j.properties用于测试时打印执行数据库的语句

# Global logging configuration
log4j.rootLogger=DEBUG, stdout
# Console output...
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n

log4j.properties

  获取sqlSession

package com.Gary.test;

import java.io.IOException;
import java.io.InputStream; 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.jupiter.api.Test; public class HelloMyBatis { @Test
//入门程序,通过ID,查询用户
public void Test1() throws IOException {
//读取配置文件
String resource = "sqlMapConfig.xml"; InputStream in = Resources.getResourceAsStream(resource); //需要sqlSessionFactoryBuilder
SqlSessionFactoryBuilder ssfb = new SqlSessionFactoryBuilder(); //创建sqlSessionFactory
SqlSessionFactory ssf = ssfb.build(in); //生产一个sqlSession
SqlSession session = ssf.openSession(); //操作数据库
//参数1:要操作的sql语句 参数2:sql语句的参数
//session.select(statement, parameter); } }

HelloMyBatis.java

  接下来的操作在UserMapper中书写sql语句并完成查询

一、通过ID去查找一个用户

 <mapper namespace="UserMapper">
<select id="selectUserById" parameterType="Integer" resultType="com.Gary.bean.User">
select * from user where u_id = #{id}
</select>
</mapper>
<?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="UserMapper">
<select id="selectUserById" parameterType="Integer" resultType="com.Gary.bean.User">
select * from user where u_id = #{id}
</select>
</mapper>

UserMapper.xml

  

  通过ID去查询一个用户

  //参数1:要操作的sql语句   参数2:sql语句的参数
  User user = session.selectOne("UserMapper.selectUserById", 1);

  

package com.Gary.test;

import java.io.IOException;
import java.io.InputStream; 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.jupiter.api.Test; import com.Gary.bean.User; public class HelloMyBatis { @Test
//入门程序,通过ID,查询用户
public void Test1() throws IOException {
//读取配置文件
String resource = "sqlMapConfig.xml"; InputStream in = Resources.getResourceAsStream(resource); //需要sqlSessionFactoryBuilder
SqlSessionFactoryBuilder ssfb = new SqlSessionFactoryBuilder(); //创建sqlSessionFactory
SqlSessionFactory ssf = ssfb.build(in); //生产一个sqlSession
SqlSession session = ssf.openSession(); //操作数据库
//参数1:要操作的sql语句 参数2:sql语句的参数
User user = session.selectOne("UserMapper.selectUserById", 1);
System.err.println(user); } }

HelloMyBatis.java

二、通过用户名模糊查询用户列表

  查找数据库中名字带有王字的数据

     <!-- ${value}中间的字符串一定需要使用value -->
<select id="selectUserByName" parameterType="String" resultType="com.Gary.bean.User">
select * from user where u_username like '%${value}%'
</select>
<?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="UserMapper"> <select id="selectUserById" parameterType="Integer" resultType="com.Gary.bean.User">
select * from user where u_id = #{id}
</select> <!-- ${value}中间的字符串一定需要使用value -->
<select id="selectUserByName" parameterType="String" resultType="com.Gary.bean.User">
select * from user where u_username like '%${value}%'
</select> </mapper>

UserMapper.xml

  

  通过字符串去进行模糊查询

  //操作数据库
  //参数1:要操作的sql语句 参数2:sql语句的参数
  List<User> list = session.selectList("UserMapper.selectUserByName", "王");

  

package com.Gary.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.jupiter.api.Test; import com.Gary.bean.User; public class HelloMyBatis2 { @Test
//入门程序,通过ID,查询用户
public void Test1() throws IOException {
//读取配置文件
String resource = "sqlMapConfig.xml"; InputStream in = Resources.getResourceAsStream(resource); //需要sqlSessionFactoryBuilder
SqlSessionFactoryBuilder ssfb = new SqlSessionFactoryBuilder(); //创建sqlSessionFactory
SqlSessionFactory ssf = ssfb.build(in); //生产一个sqlSession
SqlSession session = ssf.openSession(); //操作数据库
//参数1:要操作的sql语句 参数2:sql语句的参数
List<User> list = session.selectList("UserMapper.selectUserByName", "王"); for(User u : list) {
System.out.println(u);
} } }

HelloMyBatis2.java

  注意:

    #{}占位符 尽量使用#{}来解决问题  使用占位符#{}中间的字符串一定要为value

    ${}字符串拼接   容易sql注入 (or 1 = 1)  

     <!-- ${value}中间的字符串一定需要使用value -->
<select id="selectUserByName" parameterType="String" resultType="com.Gary.bean.User">
<!-- select * from user where u_username like '%${value}%' -->
select * from user where u_username like "%"#{name}"%"
</select>

  

package com.Gary.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.jupiter.api.Test; import com.Gary.bean.User; public class HelloMyBatis2 { @Test
//入门程序,通过ID,查询用户
public void Test1() throws IOException {
//读取配置文件
String resource = "sqlMapConfig.xml"; InputStream in = Resources.getResourceAsStream(resource); //需要sqlSessionFactoryBuilder
SqlSessionFactoryBuilder ssfb = new SqlSessionFactoryBuilder(); //创建sqlSessionFactory
SqlSessionFactory ssf = ssfb.build(in); //生产一个sqlSession
SqlSession session = ssf.openSession(); //操作数据库
//参数1:要操作的sql语句 参数2:sql语句的参数
List<User> list = session.selectList("UserMapper.selectUserByName", "王"); for(User u : list) {
System.out.println(u);
} } }

HelloMyBatis2.java

<?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="UserMapper"> <select id="selectUserById" parameterType="Integer" resultType="com.Gary.bean.User">
select * from user where u_id = #{id}
</select> <!-- #{}占位符 尽量使用#{}来解决问题 -->
<!-- ${}字符串拼接 容易sql注入 (or 1 = 1) --> <!-- ${value}中间的字符串一定需要使用value -->
<select id="selectUserByName" parameterType="String" resultType="com.Gary.bean.User">
<!-- select * from user where u_username like '%${value}%' -->
select * from user where u_username like "%"#{name}"%"
</select> </mapper>

UserMapper.xml

三、添加用户

  在UserMapper.xml中编写插入User对象

  <!-- 添加用户 参数为全包名 -->
  <insert id="insertUser" parameterType="com.Gary.bean.User">
    insert into user values(null,#{u_username},#{u_password},#{u_sex},#{u_createTime},#{u_cid})
  </insert>
<?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="UserMapper"> <select id="selectUserById" parameterType="Integer" resultType="com.Gary.bean.User">
select * from user where u_id = #{id}
</select> <!-- #{}占位符 尽量使用#{}来解决问题 -->
<!-- ${}字符串拼接 容易sql注入 (or 1 = 1) --> <!-- ${value}中间的字符串一定需要使用value -->
<select id="selectUserByName" parameterType="String" resultType="com.Gary.bean.User">
<!-- select * from user where u_username like '%${value}%' -->
select * from user where u_username like "%"#{name}"%"
</select> <!-- 添加用户 参数为全包名 -->
<insert id="insertUser" parameterType="com.Gary.bean.User">
insert into user values(null,#{u_username},#{u_password},#{u_sex},#{u_createTime},#{u_cid})
</insert> </mapper>

UserMapper.xml

  使用了session.insert()后别忘记提交事务!

  

package com.Gary.test;

import java.io.IOException;
import java.io.InputStream;
import java.util.Date;
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.jupiter.api.Test; import com.Gary.bean.User; public class HelloMyBatis3 { @Test
//入门程序,通过ID,查询用户
public void Test1() throws IOException {
//读取配置文件
String resource = "sqlMapConfig.xml"; InputStream in = Resources.getResourceAsStream(resource); //需要sqlSessionFactoryBuilder
SqlSessionFactoryBuilder ssfb = new SqlSessionFactoryBuilder(); //创建sqlSessionFactory
SqlSessionFactory ssf = ssfb.build(in); //生产一个sqlSession
SqlSession session = ssf.openSession(); //操作数据库
//参数1:要操作的sql语句 参数2:sql语句的参数
User user = new User(); user.setU_username("Gary");
user.setU_password("494949");
user.setU_sex("1");
user.setU_createTime(new Date());
user.setU_cid(1); session.insert("UserMapper.insertUser", user);
//提交事务
session.commit(); } }

HelloMyBatis3.java

  

四、修改用户

  修改id为13的Gary的username字段

  在UserMapper.xml中编写修改User对象字段username

  <!-- 根据id修改username字段的语句 -->
  <update id="updateUser" parameterType="com.Gary.bean.User">
    update user set u_username = #{u_username} where u_id = #{u_id}
  </update>
<?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="UserMapper"> <select id="selectUserById" parameterType="Integer" resultType="com.Gary.bean.User">
select * from user where u_id = #{id}
</select> <!-- #{}占位符 尽量使用#{}来解决问题 -->
<!-- ${}字符串拼接 容易sql注入 (or 1 = 1) --> <!-- ${value}中间的字符串一定需要使用value -->
<select id="selectUserByName" parameterType="String" resultType="com.Gary.bean.User">
<!-- select * from user where u_username like '%${value}%' -->
select * from user where u_username like "%"#{name}"%"
</select> <!-- 添加用户 参数为全包名 -->
<insert id="insertUser" parameterType="com.Gary.bean.User">
insert into user values(null,#{u_username},#{u_password},#{u_sex},#{u_createTime},#{u_cid})
</insert> <!-- 根据id修改username字段的语句 -->
<update id="updateUser" parameterType="com.Gary.bean.User">
update user set u_username = #{u_username} where u_id = #{u_id}
</update> </mapper>

UserMapper.xml

  将id为13的用户,名字修改成"修改后Gary"

  

package com.Gary.test;

import java.io.IOException;
import java.io.InputStream;
import java.util.Date;
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.jupiter.api.Test; import com.Gary.bean.User; public class HelloMyBatis4 { @Test
//入门程序,通过ID,查询用户
public void Test1() throws IOException {
//读取配置文件
String resource = "sqlMapConfig.xml"; InputStream in = Resources.getResourceAsStream(resource); //需要sqlSessionFactoryBuilder
SqlSessionFactoryBuilder ssfb = new SqlSessionFactoryBuilder(); //创建sqlSessionFactory
SqlSessionFactory ssf = ssfb.build(in); //生产一个sqlSession
SqlSession session = ssf.openSession(); //操作数据库
//参数1:要操作的sql语句 参数2:sql语句的参数
User user = new User();
user.setU_id(13);
user.setU_username("修改后Gary"); session.insert("UserMapper.updateUser", user);
//提交事务
session.commit(); } }

HelloMybatis4.java

  

五、根据id删除用户

  删除id为13的Gary用户

  在UserMapper.xml中编写根据id删除用户

     <!-- 根据id删除用户 -->
<delete id="deleteUserById" parameterType="Integer">
delete from user where u_id = #{id}
</delete>
<?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="UserMapper"> <select id="selectUserById" parameterType="Integer" resultType="com.Gary.bean.User">
select * from user where u_id = #{id}
</select> <!-- #{}占位符 尽量使用#{}来解决问题 -->
<!-- ${}字符串拼接 容易sql注入 (or 1 = 1) --> <!-- ${value}中间的字符串一定需要使用value -->
<select id="selectUserByName" parameterType="String" resultType="com.Gary.bean.User">
<!-- select * from user where u_username like '%${value}%' -->
select * from user where u_username like "%"#{name}"%"
</select> <!-- 添加用户 参数为全包名 -->
<insert id="insertUser" parameterType="com.Gary.bean.User">
insert into user values(null,#{u_username},#{u_password},#{u_sex},#{u_createTime},#{u_cid})
</insert> <!-- 根据id修改username字段的语句 -->
<update id="updateUser" parameterType="com.Gary.bean.User">
update user set u_username = #{u_username} where u_id = #{u_id}
</update> <!-- 根据id删除用户 -->
<delete id="deleteUserById" parameterType="Integer">
delete from user where u_id = #{id}
</delete> </mapper>

UserMapper.xml

  删除id为13的user对象

  

<?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="UserMapper"> <select id="selectUserById" parameterType="Integer" resultType="com.Gary.bean.User">
select * from user where u_id = #{id}
</select> <!-- #{}占位符 尽量使用#{}来解决问题 -->
<!-- ${}字符串拼接 容易sql注入 (or 1 = 1) --> <!-- ${value}中间的字符串一定需要使用value -->
<select id="selectUserByName" parameterType="String" resultType="com.Gary.bean.User">
<!-- select * from user where u_username like '%${value}%' -->
select * from user where u_username like "%"#{name}"%"
</select> <!-- 添加用户 参数为全包名 -->
<insert id="insertUser" parameterType="com.Gary.bean.User">
insert into user values(null,#{u_username},#{u_password},#{u_sex},#{u_createTime},#{u_cid})
</insert> <!-- 根据id修改username字段的语句 -->
<update id="updateUser" parameterType="com.Gary.bean.User">
update user set u_username = #{u_username} where u_id = #{u_id}
</update> <!-- 根据id删除用户 -->
<delete id="deleteUserById" parameterType="Integer">
delete from user where u_id = #{id}
</delete> </mapper>

HelloMyBatis5.java

  

 六、使用MyBatis开发简易Dao层

  实现根据用户id查询用户测试方法

  

  

package com.Gary.dao;

import com.Gary.bean.User;

public interface UserDao {

    //根据id查询用户
public User getUserById(Integer id); }

UserDao.java

package com.Gary.dao;

import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory; import com.Gary.bean.User; public class UserDaoImpl implements UserDao{ //sqlSession工厂
private SqlSessionFactory ssf; //通过构造器给ssf赋值
public UserDaoImpl(SqlSessionFactory ssf) {
super();
this.ssf = ssf;
} @Override
public User getUserById(Integer id) {
//生产一个sqlSession
SqlSession session = ssf.openSession(); //操作数据库
//参数1:要操作的sql语句 参数2:sql语句的参数
return session.selectOne("UserMapper.selectUserById", id); }
}

UserDaoImpl.java

package com.Gary.dao;

import java.io.IOException;
import java.io.InputStream; import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test; import com.Gary.bean.User; //取代Service层
public class UserDaoTest { //sqlSession工厂
private static SqlSessionFactory ssf; //利用静态代码块获取sqlSessionFactory
static {
//读取配置文件
String resource = "sqlMapConfig.xml";
InputStream in;
try {
in = Resources.getResourceAsStream(resource);
//需要sqlSessionFactoryBuilder
SqlSessionFactoryBuilder ssfb = new SqlSessionFactoryBuilder();
//创建sqlSessionFactory
ssf = ssfb.build(in);
in.close();
} catch (IOException e) { e.printStackTrace();
} } @Test
public void DaoTest() {
UserDao dao = new UserDaoImpl(ssf);
//查询id为1的兑对象
User user = dao.getUserById(1);
System.out.println(user);
} }

UserDaoTest.java

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