每日总结2023-05-14

今天运用mybaits来进行mysql操作：

连接数据库信息：

<?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>
    <!--别名-->
    <typeAliases>
        <package name="user"/>
    </typeAliases>

    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <!--mysql 连接信息-->
                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
                <property name="url"
                          value="数据库连接名"/>
                <property name="username" value="用户名"/>
                <property name="password" value="密码"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <package name="mapper"/>
    </mappers>
</configuration>

bean类

package bean;

public class User {
    private String username;
    private String password;

    public String getUsername() {
        return username;
    }

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

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    @Override
    public String toString() {
        return "User{" +
                "username='" + username + '\'' +
                ", password='" + password + '\'' +
                '}';
    }

    public User(String username, String password) {
        this.username = username;
        this.password = password;
    }
}

持久层：

package mapper;

import bean.User;
import org.apache.ibatis.annotations.Select;

import java.util.List;

public interface UserMapper {
    @Select("select * from tb_user")
    List<User> selectAll();
    @Select("select * from tb_user where username=#{username}")
    List<User> selectByName(String username);
}

服务层：

package res;

import bean.User;
import mapper.UserMapper;
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 java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

public class UserRes {
    public static List<User> findAll() throws IOException {
        List<User> list = new ArrayList<>();
        String resource = "mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

        SqlSession sqlSession = sqlSessionFactory.openSession();
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        list = userMapper.selectAll();
        sqlSession.close();
        return  list;
    }

    public static List<User> selectByName(String name) throws IOException {
        List<User> list = null;
        String resource = "mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

        SqlSession sqlSession = sqlSessionFactory.openSession();
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        list = userMapper.selectByName(name);
        sqlSession.close();
        return list;
    }
}