Question

线程“ main”中的异常com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException：无法创建与数据库服务器的连接。尝试重新连接3次。放弃。

public class MyClass {

    public static void main(String[] args) throws Exception {



         String url= "jdbc:mysql://localhost:3306/first/?useUnicode=yes&autoReconnect=true&useSSL=false";
         String uname="root";
         String pass="****";

         Class.forName("com.mysql.jdbc.Driver");
         Connection con= DriverManager.getConnection(url,uname,pass);

         Statement st= con.createStatement();
         ResultSet rs=st.executeQuery("select name from sample_t where rollno=1");

         rs.next();
         String name1=rs.getString("name");
         System.out.println(name1);

         st.close();
         con.close();
    }

}

Answer 1

请检查您的MySQL Server是否正在运行。

Answer 2

检查您的MySQL连接是否正常，然后尝试如下更改网址：

String url= "jdbc:mysql://localhost/first/?useUnicode=yes&autoReconnect=true&useSSL=false";

Answer 3

您可以尝试这种方法

    try 
    {
        Class.forName("com.mysql.jdbc.Driver");     
        String url="jdbc:mysql://localhost:3306/first";
        String user="root";
        String pass="****";
        con=DriverManager.getConnection(url,user,pass);

        String query="select name from sample_t where rollno=?";
        pstmt=con.prepareStatement(query);

        System.out.println("Enter user id : ");
        pstmt.setInt(1, sc.nextInt());
        rs=pstmt.executeQuery();

        //Process the result
        if(rs.next())
        {
            System.out.println("Roll No. : " +rs.getInt(1));
        }

        //closing connections
        sc.close();
        pstmt.close();
        rs.close();
        con.close();

    }   

    catch (Exception e) 
    {`
        e.printStackTrace();
    }

将Java代码连接到mysql时遇到问题

3 个答案: