Mybatis框架的CRUD操作

1.1 添加

1.1.1 准备环境

1.1.1.1 创建项目、添加依赖、

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>javaee</groupId>
    <artifactId>mybatis_CRUDTest</artifactId>
    <version>1.0-SNAPSHOT</version>

    <!--添加依赖-->
    <dependencies>
        <!--mybatis-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.4</version>
        </dependency>

        <!--junit-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <!--mysql驱动-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.40</version>
        </dependency>

        <!--日志文件-->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
    </dependencies>
</project>

• 将log4j.properties日志文件复制到resources下

# Set root category priority to INFO and its only appender to CONSOLE.
#log4j.rootCategory=INFO, CONSOLE            debug   info   warn error fatal
log4j.rootCategory=debug, CONSOLE, LOGFILE

# Set the enterprise logger category to FATAL and its only appender to CONSOLE.
log4j.logger.org.apache.axis.enterprise=FATAL, CONSOLE

# CONSOLE is set to be a ConsoleAppender using a PatternLayout.
log4j.appender.CONSOLE=org.apache.log4j.ConsoleAppender
log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout
log4j.appender.CONSOLE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n

# LOGFILE is set to be a File appender using a PatternLayout.
log4j.appender.LOGFILE=org.apache.log4j.FileAppender
log4j.appender.LOGFILE.File=d:\axis.log
log4j.appender.LOGFILE.Append=true
log4j.appender.LOGFILE.layout=org.apache.log4j.PatternLayout
log4j.appender.LOGFILE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n

 1.1.1.2 SqlMapConfig.xml主配置

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <!--1. 数据库环境配置-->
    <environments default="mysql">
        <environment id="mysql">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="pooled">
                <property name="driver" value="com.mysql.jdbc.Driver"></property>
                <property name="url" value="jdbc:mysql://localhost:3306/mybatis?characterEncoding=utf8"></property>
                <property name="username" value="root"></property>
                <property name="password" value="root"></property>
            </dataSource>
        </environment>
    </environments>

    <!--2. 加载映射文件-->
</configuration>

1.1.1.3  entity实体类

package com.sunny.entity;

import java.io.Serializable;
import java.util.Date;

public class User implements Serializable {
    private int id;
    private String username;
    private Date birthday;
    private String sex;
    private String address;

    public User() {
    }

    public User(int id, String username, Date birthday, String sex, String address) {
        this.id = id;
        this.username = username;
        this.birthday = birthday;
        this.sex = sex;
        this.address = address;
    }

    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 + '\'' +
                '}';
    }
}

1.1.1.4 dao接口

package com.sunny.dao;

import com.sunny.entity.User;

public interface IUserDao {
    /**
     * 添加
     * @param user
     */
    void save(User user);

}

 1.1.1.5 接口映射

• 创建映射文件IUserDao.xml

• 文件内容 

<?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">
<!--namespace名称空间，用于定义是哪个类的映射文件，这里需要写所映射接口的类全名-->
<mapper namespace="com.sunny.dao.IUserDao">
    <!--
        insert:执行的是插入操作
        id:接口中的方法名字
        parameterType:设置接口方法参数类型
        #{对象的属性名}，是一种表达式，可以获取参数类型对象的数据数据，要求表达式里面的属性名与对象属性名必须完全一致
                        OGNL表达式。
    -->
    <insert id="save" parameterType="com.sunny.entity.User">
        INSERT INTO USER (username, birthday, sex, address) VALUES
        (#{username},#{birthday},#{sex},#{address})
    </insert>
</mapper>

1.1.1.6 加载配置文件

 1.1.1.7 测试（推荐使用手动事务控制）

import com.sunny.dao.IUserDao;
import com.sunny.entity.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.text.ParseException;
import java.text.SimpleDateFormat;

public class UserDaoTest {

    InputStream in = null;

    SqlSession sqlSession = null;

    @Before
    public void before() throws IOException {
        //1.获取文件输入流
        in = Resources.getResourceAsStream("SqlMapConfig.xml");
        //2.创建SqlSession工厂构造器
        SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
        //3.根据SqlSession工厂构造器创建SqlSession工厂
        SqlSessionFactory sqlSessionFactory = sqlSessionFactoryBuilder.build(in);
        //4.根据SqlSession工厂创建SqlSession
        sqlSession = sqlSessionFactory.openSession();
    }

    /**
     * 添加
     */
    @Test
    public void add() throws ParseException {
        //创建接口代理对象
        IUserDao userDao = sqlSession.getMapper(IUserDao.class);
        User user = new User();
        user.setUsername("Luck");
        user.setBirthday(new SimpleDateFormat("yyyy-MM-dd").parse("1996-07-07"));
        user.setSex("男");
        user.setAddress("江西");
        //插入数据
        userDao.save(user);
    }


    @After
    public void after() throws IOException {
        //手动提交事务
        sqlSession.commit();
        //关闭资源
        sqlSession.close();
        in.close();
    }
}

• 事务自动提交（不推荐）：
•  创建SqlSession
   openSession(false) 默认值，表示事务手动提交，必须要提交事务
   相当于：connection.setAutoCommit(false),
   openSession(true)  表示事务自动提交, 此时就不用写 session.commit();
   SqlSession session = factory.openSession(true);
   

---

2.1  保存后获取主键值

• 测试：没有获取到主键值

import com.sunny.dao.IUserDao;
import com.sunny.entity.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.text.ParseException;
import java.text.SimpleDateFormat;

public class UserDaoTest {

    InputStream in = null;

    SqlSession sqlSession = null;

    @Before
    public void before() throws IOException {
        //1.获取文件输入流
        in = Resources.getResourceAsStream("SqlMapConfig.xml");
        //2.创建SqlSession工厂构造器
        SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
        //3.根据SqlSession工厂构造器创建SqlSession工厂
        SqlSessionFactory sqlSessionFactory = sqlSessionFactoryBuilder.build(in);
        //4.根据SqlSession工厂创建SqlSession
        sqlSession = sqlSessionFactory.openSession();
    }

    /**
     * 添加
     */
    @Test
    public void add() throws ParseException {
        //创建接口代理对象
        IUserDao userDao = sqlSession.getMapper(IUserDao.class);
        User user = new User();
        user.setUsername("Luck");
        user.setBirthday(new SimpleDateFormat("yyyy-MM-dd").parse("1996-07-07"));
        user.setSex("男");
        user.setAddress("江西");
        //保存
        System.out.println("保存前："+user);
        userDao.save(user);
        System.out.println("保存后："+user);
    }


    @After
    public void after() throws IOException {
        //手动提交事务
        sqlSession.commit();
        //关闭资源
        sqlSession.close();
        in.close();
    }
}

• 方式一：常用

 1.数据库查询自增长的值

 2.dao接口

package com.sunny.dao;

import com.sunny.entity.User;

public interface IUserDao {
    /**
     * 添加
     * @param user
     */
    void save(User user);

    /**
     * 添加后获取自增长值
     */
    void save2(User user);
}

3.dao接口映射（方式一、方式二）

<!--
        insert:执行的是插入操作
        id:接口中的方法名字
        parameterType:设置接口方法参数类型

        #{对象的属性名}，是一种表达式，可以获取参数类型对象的数据数据，要求表达式里面的属性名与对象属性名必须完全一致
                        OGNL表达式。

         selectKey:获取主键自增长值的最后封装到对象中（方式一，推荐，可以根据不同数据库类型设置）
         resultType：主键类型，int
         keyColumn:主键在数据库表中的字段名
         keyProperty：主键在对象中的属性名
         order：
            after,自增长主键插入数据之后获取主键值，适合支持具有自增长字段数据库，适合mysql
            before，自增长主键插入数据之前获取主键值,适合oracle，因为oracle没有自增长列，是通过序列解决的

    -->

<?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">
<!--namespace名称空间，用于定义是哪个类的映射文件，这里需要写所映射接口的类全名-->
<mapper namespace="com.sunny.dao.IUserDao">
    <!--
        insert:执行的是插入操作
        id:接口中的方法名字
        parameterType:设置接口方法参数类型
        #{对象的属性名}，是一种表达式，可以获取参数类型对象的数据数据，要求表达式里面的属性名与对象属性名必须完全一致
                        OGNL表达式。
    -->
    <!--增加（方式一）：获取插入数据的主键-->
    <insert id="save" parameterType="com.sunny.entity.User">
        <selectKey resultType="int" keyColumn="id" keyProperty="id" order="AFTER">
            SELECT LAST_INSERT_ID();
        </selectKey>
        INSERT INTO USER (username, birthday, sex, address) VALUES
        (#{username},#{birthday},#{sex},#{address})
    </insert>

    <!--增加（方式二）：获取自增长主键值（不推荐）
        设置标签属性useGeneratedKeys="true"，获取支持自增长字段数据库的主键值
    -->
   <insert id="save2" parameterType="com.sunny.entity.User" useGeneratedKeys="true" keyProperty="id" keyColumn="id">
       INSERT INTO VALUES(username, birthday, sex, address)VALUES
       (#{username},#{birthday},#{sex},#{address})
   </insert>


</mapper>

4.测试

import com.sunny.dao.IUserDao;
import com.sunny.entity.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.text.ParseException;
import java.text.SimpleDateFormat;

public class UserDaoTest {

    InputStream in = null;

    SqlSession sqlSession = null;

    @Before
    public void before() throws IOException {
        //1.获取文件输入流
        in = Resources.getResourceAsStream("SqlMapConfig.xml");
        //2.创建SqlSession工厂构造器
        SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
        //3.根据SqlSession工厂构造器创建SqlSession工厂
        SqlSessionFactory sqlSessionFactory = sqlSessionFactoryBuilder.build(in);
        //4.根据SqlSession工厂创建SqlSession
        sqlSession = sqlSessionFactory.openSession();
    }

    /**
     * 增加：获取插入数据的主键(方式一)
     */
    @Test
    public void add() throws ParseException {
        //创建接口代理对象
        IUserDao userDao = sqlSession.getMapper(IUserDao.class);
        User user = new User();
        user.setUsername("Tom");
        user.setBirthday(new SimpleDateFormat("yyyy-MM-dd").parse("1996-07-07"));
        user.setSex("女");
        user.setAddress("浙江");
        //保存
        System.out.println("保存前："+user);
        userDao.save(user);
        System.out.println("保存后："+user);
    }

    /**
     * 增加：获取插入数据的主键(方式二)
     */
    @Test
    public void add2() throws ParseException {
        //创建接口代理对象
        IUserDao userDao = sqlSession.getMapper(IUserDao.class);
        User user = new User();
        user.setUsername("Nancy");
        user.setBirthday(new SimpleDateFormat("yyyy-MM-dd").parse("1996-07-07"));
        user.setSex("男");
        user.setAddress("北京");
        //保存
        System.out.println("保存前："+user);
        userDao.save(user);
        System.out.println("保存后："+user);
    }


    @After
    public void after() throws IOException {
        //手动提交事务
        sqlSession.commit();
        //关闭资源
        sqlSession.close();
        in.close();
    }
}

---

 3.1 修改

1.    IUserDao.java接口

package com.sunny.dao;

import com.sunny.entity.User;

public interface IUserDao {

    /**
     * 修改
     */
    int update(User user);
}

 2.  IUserDao.xml接口映射

  <!--
    修改操作映射配置
        update,代表修改操作
        id，接口方法名字
        parameterType，参数类型
        没有设置返回类型，默认返回影响的行数
    -->

  <!--修改-->
    <update id="update" parameterType="com.sunny.entity.User">
        UPDATE USER SET username=#{username},birthday=#{birthday},
        sex=#{sex},address=#{address} where id=#{id}
    </update>

 3.测试

import com.sunny.dao.IUserDao;
import com.sunny.entity.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.text.ParseException;
import java.text.SimpleDateFormat;

public class UserDaoTest {

    InputStream in = null;

    SqlSession sqlSession = null;

    @Before
    public void before() throws IOException {
        //1.获取文件输入流
        in = Resources.getResourceAsStream("SqlMapConfig.xml");
        //2.创建SqlSession工厂构造器
        SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
        //3.根据SqlSession工厂构造器创建SqlSession工厂
        SqlSessionFactory sqlSessionFactory = sqlSessionFactoryBuilder.build(in);
        //4.根据SqlSession工厂创建SqlSession
        sqlSession = sqlSessionFactory.openSession();
    }

    /**
     * 修改操作
     */
    @Test
    public void update() throws ParseException {
        //创建接口代理对象
        IUserDao userDao = sqlSession.getMapper(IUserDao.class);
        User user = new User();
        user.setId(51);
        user.setUsername("C罗002");
        user.setSex("男");
        user.setAddress("广东");
        user.setBirthday(new SimpleDateFormat("yyyy-MM-dd").parse("2018-01-01"));
        System.out.println("影响的行数："+userDao.update(user));
    }

    @After
    public void after() throws IOException {
        //手动提交事务
        sqlSession.commit();
        //关闭资源
        sqlSession.close();
        in.close();
    }
}

---

4.1 删除

1.dao接口

package com.sunny.dao;

import com.sunny.entity.User;

public interface IUserDao {

    /**
     * 删除
     */
    int delete(int id);
}

2. 接口映射

 <!--删除
        这里参数只有1个基本数据类型，#{id}的名字随便写
    -->
    <delete id="delete" parameterType="int">
        DELETE from USER WHERE id=#{userId}
    </delete>

3.测试

import com.sunny.dao.IUserDao;
import com.sunny.entity.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.text.ParseException;
import java.text.SimpleDateFormat;

public class UserDaoTest {

    InputStream in = null;

    SqlSession sqlSession = null;

    @Before
    public void before() throws IOException {
        //1.获取文件输入流
        in = Resources.getResourceAsStream("SqlMapConfig.xml");
        //2.创建SqlSession工厂构造器
        SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
        //3.根据SqlSession工厂构造器创建SqlSession工厂
        SqlSessionFactory sqlSessionFactory = sqlSessionFactoryBuilder.build(in);
        //4.根据SqlSession工厂创建SqlSession
        sqlSession = sqlSessionFactory.openSession();
    }

    /**
     * 删除操作
     */
    @Test
    public void delete(){
        //创建接口代理对象
        IUserDao userDao = sqlSession.getMapper(IUserDao.class);
        userDao.delete(48);
    }

    @After
    public void after() throws IOException {
        //手动提交事务
        sqlSession.commit();
        //关闭资源
        sqlSession.close();
        in.close();
    }
}

---

5.1 主键查询

  <!--根据主键查找User对象
         parameterType="int" 参数类型写法，类型写法不区分大小写
                int
                _int
                integer
                Integer
                java.lang.Integer

                int_,不可以
    -->

 1. dao接口

package com.sunny.dao;

import com.sunny.entity.User;

public interface IUserDao {

    /**
     * 根据主键查询对象
     */
    User findById(int id);
}

2. 接口映射

<!--根据主键查询-->
    <select id="findById" resultType="com.sunny.entity.User" parameterType="int">
        SELECT * from USER WHERE id=#{id}
    </select>

3.测试

import com.sunny.dao.IUserDao;
import com.sunny.entity.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.text.ParseException;
import java.text.SimpleDateFormat;

public class UserDaoTest {

    InputStream in = null;

    SqlSession sqlSession = null;

    @Before
    public void before() throws IOException {
        //1.获取文件输入流
        in = Resources.getResourceAsStream("SqlMapConfig.xml");
        //2.创建SqlSession工厂构造器
        SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
        //3.根据SqlSession工厂构造器创建SqlSession工厂
        SqlSessionFactory sqlSessionFactory = sqlSessionFactoryBuilder.build(in);
        //4.根据SqlSession工厂创建SqlSession
        sqlSession = sqlSessionFactory.openSession();
    }

    /**
     * 根据主键查询实体类对象
     * */
    @Test
    public void findById() {
        //创建接口代理对象
        IUserDao userDao = sqlSession.getMapper(IUserDao.class);
        System.out.println(userDao.findById(50));
    }



    @After
    public void after() throws IOException {
        //手动提交事务
        sqlSession.commit();
        //关闭资源
        sqlSession.close();
        in.close();
    }
}

---

6.1 模糊查询

1. dao接口

package com.sunny.dao;

import com.sunny.entity.User;

import java.util.List;

public interface IUserDao {
    /**
     * 模糊查询，根据用户名查找用户列表
     */
    List<User> findByName(String username);
}

2. 接口映射

<!--模糊查询，根据用户名查找用户列表-->
    <select id="findByName" resultType="com.sunny.entity.User" parameterType="String">
         select * from user where username like #{name}
    </select>

3. 测试

import com.sunny.dao.IUserDao;
import com.sunny.entity.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.text.ParseException;
import java.text.SimpleDateFormat;

public class UserDaoTest {

    InputStream in = null;

    SqlSession sqlSession = null;

    @Before
    public void before() throws IOException {
        //1.获取文件输入流
        in = Resources.getResourceAsStream("SqlMapConfig.xml");
        //2.创建SqlSession工厂构造器
        SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
        //3.根据SqlSession工厂构造器创建SqlSession工厂
        SqlSessionFactory sqlSessionFactory = sqlSessionFactoryBuilder.build(in);
        //4.根据SqlSession工厂创建SqlSession
        sqlSession = sqlSessionFactory.openSession();
    }

    /**
     * 模糊查询，根据用户名查找用户列表
     */
    @Test
    public void findByName(){
        //创建接口代理对象
        IUserDao userDao = sqlSession.getMapper(IUserDao.class);
        System.out.println(userDao.findByName("%梅%"));
    }



    @After
    public void after() throws IOException {
        //手动提交事务
        sqlSession.commit();
        //关闭资源
        sqlSession.close();
        in.close();
    }
}

---

6.2 拼接字符串方式进行模糊查询（强烈不建议使用，SQL注入，采用拼接字符串）

1. dao接口

package com.sunny.dao;

import com.sunny.entity.User;

import java.util.List;

public interface IUserDao {

    /**
     * 模糊查询，根据用户名查找用户列表
     */
    List<User> findByName2(String name);
}

2. 接口映射

    <!--
        拼接字符串的方式进行模糊查询
        '%${value}%',里面的内容必须为value，不能写别的名称
    -->
    <select id="findByName2" resultType="com.sunny.entity.User" parameterType="String">
        SELECT * FROM USER WHERE username like '%${value}%'
    </select>

3. 测试

import com.sunny.dao.IUserDao;
import com.sunny.entity.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.text.ParseException;
import java.text.SimpleDateFormat;

public class UserDaoTest {

    InputStream in = null;

    SqlSession sqlSession = null;

    @Before
    public void before() throws IOException {
        //1.获取文件输入流
        in = Resources.getResourceAsStream("SqlMapConfig.xml");
        //2.创建SqlSession工厂构造器
        SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
        //3.根据SqlSession工厂构造器创建SqlSession工厂
        SqlSessionFactory sqlSessionFactory = sqlSessionFactoryBuilder.build(in);
        //4.根据SqlSession工厂创建SqlSession
        sqlSession = sqlSessionFactory.openSession();
    }

    /**
     *模糊查询，根据用户名查找用户列表（强烈不建议，SQL注入，采用拼接字符串）
     */
    @Test
    public void findByName2(){
        //创建接口代理对象
        IUserDao userDao = sqlSession.getMapper(IUserDao.class);
        //模糊查询（底层原理是拼接字符串方式）
        //System.out.println(userDao.findByName2("张"));//select * from user where username like '%张%'
        System.out.println(userDao.findByName2("' or 1=1 -- "));
    }


    @After
    public void after() throws IOException {
        //手动提交事务
        sqlSession.commit();
        //关闭资源
        sqlSession.close();
        in.close();
    }
}