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());
		}
	}
}