IDEA中用maven连接数据库的教程

<?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>org.example</groupId>
  <artifactId>Connection_mysql</artifactId>
  <version>1.0-SNAPSHOT</version>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>

  <dependencies>
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>5.1.37</version>
    </dependency>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.12</version>
      <scope>test</scope>
    </dependency>
  </dependencies>

</project>

package cn.she.domain;

public class Province {
  private int id;
  private String name;

  public int getId() {
    return id;
  }

  public void setId(int id) {
    this.id = id;
  }

  public String getName() {
    return name;
  }

  public void setName(String name) {
    this.name = name;
  }
}

package cn.she.dao;

import cn.she.domain.Province;

import java.util.List;

public interface ProvinceDao {
  public List<Province> findAll() throws Exception;
}

package cn.she.dao.impl;

import cn.she.dao.ProvinceDao;
import cn.she.domain.Province;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;

public class ProvinceDaoImpl implements ProvinceDao {
  @Override
  public List<Province> findAll() throws Exception{

    /**
     * 从数据库中取数，须有四个属性
     * 数据库驱动，连接数据库的地址，数据库用户名称，数据库密码
     */

    List<Province> list = new ArrayList<>();
    Connection conn = null;
    PreparedStatement pst = null;
    ResultSet rs = null;

    try{
      //1、注册驱动
      Class.forName("com.mysql.jdbc.Driver");
      //2、获取连接对象
      conn = DriverManager.getConnection("jdbc:mysql://localhost/test?useUnicode=true&characterEncoding=UTF-8","root","root");
      //3、获取执行数据的对象
      pst= conn.prepareCall("select * from province");
      //4、执行sql，获得结果集对象
      rs = pst.executeQuery();
      //5、把结果集转为java的List集合
      while(rs.next()){
        Province p = new Province();
        p.setId(rs.getInt("id"));
        p.setName(rs.getString("name"));
        list.add(p);
      }

    }catch(Exception e){
      e.printStackTrace();
    }finally{
      conn.close();
      pst.close();
      rs.close();
    }
    
    return list;
  }
}

package cn.she.test;

import cn.she.dao.ProvinceDao;
import cn.she.dao.impl.ProvinceDaoImpl;
import cn.she.domain.Province;
import org.junit.Test;
import java.util.List;

public class ProvinceTest {
  @Test
  public void find() throws Exception {
    ProvinceDao dao = new ProvinceDaoImpl();
    List<Province> list = dao.findAll();
    for(Province p : list){
      System.out.println(p.getId()+" : "+p.getName());
    }
  }

}