📄 selectdbdemo.java
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import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import com.mysql.jdbc.ResultSet;
import com.mysql.jdbc.Statement;
public class SelectDBDemo
{
public static void main(String[] args)
{
try
{ //加载MySQL数据库驱动
Class.forName("org.gjt.mm.mysql.Driver");
}
catch (java.lang.ClassNotFoundException e)
{
System.out.print("Class not found exception occur. Message is:");
System.out.print(e.getMessage());
}
//连接数据库,并在数据库中查找是否存在用户名为username,对应密码为password的用户
try
{
Statement stmt;
ResultSet rs;
//声明并初始化数据库连接地址
String url = "jdbc:mysql://localhost:3306/test";
//声明并初始化数据库登陆用户名及密码
String user = "root";
String passwordOfDB = "root";
Connection conn = null;
//连接数据库并验证数据
try
{
conn = DriverManager.getConnection(url, user, passwordOfDB);
}
catch (Exception ex)
{
ex.printStackTrace();
}
//使用SQL语句操作数据库,在数据库表中查找是否有符合的记录
stmt = (Statement) conn.createStatement();
rs = (ResultSet) stmt.executeQuery("select * from userinfo");
//获取每条记录中的数据信息,并显示出来
while (rs.next()) //当存在下一条记录时再次循环
{
//获取一条记录的所有列的数据信息
int id = rs.getInt(1);
String name = rs.getString(2);
String password = rs.getString(3);
int age = rs.getInt(4);
String gender = rs.getString(5);
String email = rs.getString(6);
//显示记录信息
System.out.println("id:"+id);
System.out.println("username:"+name);
System.out.println("password:"+password);
System.out.println("age:"+age);
System.out.println("gender:"+gender);
System.out.println("email:"+email+"\n");
}
rs.close(); //关闭ResultSet对象
stmt.close(); //关闭Statement对象
conn.close(); //关闭Connection连接对象
}
catch (SQLException e)
{
System.out.print("SQL Exception occur. Message is:");
System.out.print(e.getMessage());
}
}
}
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