mybatis入门程序

jar包

log4j.properties

# 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

mybatis.xml

<?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>
    <!--mybatis的运行环境
        mybatis与Spring整合后就不需要了
    -->
    <environments default="sqlServer">
        <environment id="sqlServer">
           <!-- 事务-->
            <transactionManager type="JDBC"></transactionManager>
            <!--数据库连接池-->
            <dataSource type="POOLED">
                <property name="driver" value="com.microsoft.sqlserver.jdbc.SQLServerDriver"></property>
                <property name="url" value="jdbc:sqlserver://localhost:1433;database=ssm"></property>
                <property name="username" value="sa"></property>
                <property name="password" value="123456"></property>
            </dataSource>
        </environment>
    </environments>

    <mappers>
        <mapper resource="UsersMapper.xml"></mapper>
    </mappers>
</configuration>

Users.java

public class Users {
    private String username;
    private Date birthday;
    private String sex;
    private String address;

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }
}

Users.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">
<!--
    namespace;命名空间
    作用：分割sql
    -->
<mapper namespace="UserMapper">
    <!--根据姓名查询用户信息-->
    <!--
        id用于标识映射文件中的sql，其实是statement的id
        parameterType:参数类型
        resultType:输出结果类型，单条结果的类型
        #{}:占位符。如果为简单类型，则可以通过#{value}来取值，也可以通过#{任意名字}来取值
    -->
    <select id="selectById" parameterType="int" resultType="com.me.pojo.Users">
        select * from users where id=#{id}
    </select>

    <!--${}字符串拼接，不能防止sql注入-->
    <select id="selectByUserName" parameterType="String" resultType="com.me.pojo.Users">
        /*传参为‘李%’*/
        select * from users where username like #{value}
        /*传参为‘李’*/
        /*select * from users where username like '${value}%'*/
    </select>
</mapper>

UsersTest.java

package com.me.test;

import com.me.pojo.Users;
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.Before;
import org.junit.Test;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

public class UsersTest {
    private SqlSessionFactory sqlSessionFactory;
    @Before
    public void init() throws IOException {
        //获取全局配置文件
        InputStream in= Resources.getResourceAsStream("mybatis.xml");
        //获取SqlSessionFactory
        sqlSessionFactory=new SqlSessionFactoryBuilder().build(in);
    }

    @Test
    public void test() throws IOException {


        //获取sqlSession
        SqlSession sqlSession=sqlSessionFactory.openSession();
        //执行sql
        Users user=sqlSession.selectOne("UsersMapper.selectById",1);
        System.err.println(user.getUsername());
        sqlSession.close();
    }

    @Test
    public void test2(){
        SqlSession sqlSession=sqlSessionFactory.openSession();
        List<Users> usersList=sqlSession.selectList("UsersMapper.selectByUserName","李%");
        /*List<Users> usersList=sqlSession.selectList("UsersMapper.selectByUserName","李");*/
        System.err.println(usersList);
        /*System.out.println(usersList.get(0).getUsername());
        System.out.println(usersList.get(1).getUsername());*/
    }
}