Question

请在此处找到我的代码：

基本上，位于aa.aa.a.aaa的数据库连接失败，我继续收到以下错误：

    The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
SQLState: 08S01
VendorError: 0
SQLException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
SQLState: 08S01
VendorError: 0
SQLException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
SQLState: 08S01
VendorError: 0
SQLException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
SQLState: 08S01
VendorError: 0
SQLException: Communications link failure

有没有办法，我可以退出Catch块，以便错误在一次让用户知道后停止打印，好的错误已经发生，然后从bb.bb.b开始转移到下一个IP地址。 bbb等等..

我的代码如下，

import javafx.concurrent.Task;
import javafx.event.ActionEvent;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.ResultSet;
import static com.Ostermiller.util.StringHelper.escapeSQL;
import static java.lang.Math.abs;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;

public class ResultsReader extends Task<Integer> {
    private static int NumberOfResultsThreads = 10;
    private static int NumberOfResultsContactsToProcessPerThread = 1000;
    private static int NumberOfRecordsToInsertAtATime = 100;

    private int CurrModValue;
    private static String IP[];

    @Override
    protected Integer call() throws Exception {
        int iterations = 0;
        int i = 0;
        // boolean done = false;
        Statement SelectResultsStmt = null;
        Statement UpdateResultsStmt = null;
        Statement InsertRemoteResultsStmt = null;
        Statement InsertRemoteResultsErrorLogStmt = null;
        ResultSet SelectResultsRS = null;
        Connection connRemote = null;
        Connection connRemoteforCatch = null;

        while (i <= 5) {
            try {
                Connection[] MainConnection = new Connection[5];
                String[] RemoteIPAddress = new String[5];

                RemoteIPAddress[0] = "aa.aa.a.aaa";
                RemoteIPAddress[1] = "bb.bb.b.bbb";
                RemoteIPAddress[2] = "cc.cc.c.ccc";
                RemoteIPAddress[3] = "dd.dd.d.ddd";
                RemoteIPAddress[4] = "ee.ee.e.eee";
                RemoteIPAddress[5] = "ff.ff.f.fff";
                RemoteIPAddress[6] = "gg.gg.g.ggg";

                MainConnection[0] = DriverManager.getConnection("jdbc:mysql://" + RemoteIPAddress[0] + ":3306/test", RemoteUser, RemotePass);
                MainConnection[1] = DriverManager.getConnection("jdbc:mysql://" + RemoteIPAddress[1] + ":3306/test", RemoteUser, RemotePass);
                MainConnection[2] = DriverManager.getConnection("jdbc:mysql://" + RemoteIPAddress[2] + ":3306/test", RemoteUser, RemotePass);
                MainConnection[3] = DriverManager.getConnection("jdbc:mysql://" + RemoteIPAddress[3] + ":3306/test", RemoteUser, RemotePass);
                MainConnection[4] = DriverManager.getConnection("jdbc:mysql://" + RemoteIPAddress[4] + ":3306/test", RemoteUser, RemotePass);
                MainConnection[5] = DriverManager.getConnection("jdbc:mysql://" + RemoteIPAddress[5] + ":3306/test", RemoteUser, RemotePass);
                MainConnection[6] = DriverManager.getConnection("jdbc:mysql://" + RemoteIPAddress[6] + ":3306/test", RemoteUser, RemotePass);

                Connection connRemote = DriverManager.getConnection("jdbc:mysql://xx.xx.x.xxx:3306/test", MainUser, MainPass);
                String QueryString = " SELECT "+ " // my table fields here+ " + " FROM "+ " RemoteIPtable "+ " ;

                SelectResultsStmt = MainConnection[i].createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
                SelectResultsRS = SelectResultsStmt.executeQuery(QueryString);
                                                    int CurrentBillingAmount = 0;
                                                    int CurrentRowCount = 0;
                                                    String QueryStringInsertFromRemote = "";

                while (SelectResultsRS.next() ) {
                    CurrentRowCount++;

                    QueryStringInsertFromRemote = " INSERT INTO mytabletest "
                        + " ( " + " + " + " + "" + " ) " 
                        + " VALUES " 
                        + " ( " + " NULL, " + " " + " ) ";

                    InsertRemoteResultsStmt = connRemote.createStatement();
                    InsertRemoteResultsStmt.executeUpdate(QueryStringInsertFromRemote);
                    // reset string to empty
                    QueryStringInsertFromRemote = "";
                    SelectResultsRS.updateRow();
                }

                System.out.println("IP Just Completed is:" + RemoteIPAddress[i]);
                i++;

                System.out.println("Value of i is :" + i);
            } 
            catch (SQLException ex) {

                System.out.println("SQLException: " + ex.getMessage());
                System.out.println("SQLState: " + ex.getSQLState());
                System.out.println("VendorError: " + ex.getErrorCode());
            } 
        } // END Of WHILE 
    } 
    return iterations;
}

我在SOF的某个地方读过，有人建议在catch块结束后使用continue语句，但这对我不起作用。

Answer 1

是..这样做..

...
boolean flag = false;
while (i <= 5) {
...
try{ ... }
catch (SQLException ex) {
    if(!flag){
       System.out.println("SQLException: " + ex.getMessage());
       System.out.println("SQLState: " + ex.getSQLState());
       System.out.println("VendorError: " + ex.getErrorCode());
       flag = true; 

    }
    i++;
}
...

Answer 2

boolean flag = false; //declare boolean variable

while (i <= 5) {
 //Your code

  try { ... 

  }  catch (SQLException ex) {

    if(flag){
     continue;
    }

    System.out.println("SQLException: " + ex.getMessage());
    System.out.println("SQLState: " + ex.getSQLState());
    System.out.println("VendorError: " + ex.getErrorCode());
    flag = true;
    i++;
}

强行退出拦截块

2 个答案: