Question

java中的catch块是否可以简单地重新执行主代码块？

我有一个程序，每5分钟迭代一次并查看纯文本文件。如果有更改，它会执行try代码块，包括将文件转换为html并将其转换为网站。它运行完美，除了随机IO中断等。有没有办法简单地告诉它，如果它遇到所述异常，只需继续将所有内容抛出窗口并从主代码块再次开始？或者，是否有一种简单的方法可以让它作为一种服务运行，因为同样的问题不会停止执行？

import java.io.*;
import java.util.*;
import org.apache.commons.net.ftp.FTP;
import org.apache.commons.net.ftp.FTPClient;
import java.sql.Timestamp;

public class PrintOutConvosFtp4
{
public static void main(String[] args) throws IOException, InterruptedException
    {
    boolean infiniteLoop = true;
    long currentLoopModified = 0;
    long lastLoopModified = 0;

    while (infiniteLoop)
    {
    currentLoopModified = new File("C:/Documents and Settings/Cuckoo/Desktop/Syss-convos.LOG").lastModified();
    if (currentLoopModified > lastLoopModified)
    {

    //Read in the conversation log
BufferedReader reader = new BufferedReader(new FileReader("C:/Documents and Settings/Cuckoo/Desktop/Syss-convos.LOG"));
FileWriter output = new FileWriter("C:/Documents and Settings/Cuckoo/Desktop/Conversations.html");
List<String> lines = new ArrayList<String>();
String line = null;
while ((line = reader.readLine()) != null)
    //Remove some unnecessary clutter from the log
 {
 if (!(line.contains("just hung up!!!") || line.contains("just left the Realm.")
        || line.contains("Hurry, I've many esoteric secrets to divulge, and welcome to BaDbOy's realm.")
        || line.contains("For custom MegaMud paths and additional information, check out the website:")
        || line.contains("Syss gossips: Discuss new ideas/issues & see the most up to date information on Facebook!")
        || line.contains("Syss gossips: http://www.facebook.com/groups/EsotericEdits/")
        || line.contains("Syss gossips: MME Dats, Megamud path files and quest walkthroughs are available at my site")
        || line.contains("Syss gossips: www.esoteric-edits.fhero.net")
        || line.contains("telepaths: @")
        || line.contains("I'm a bot.  Try telepathing me with @commands.")
        || line.contains("Syss gossips: Remember, you can telepath me @commands for useful things like adding lives.")
        || line.contains("Syss gossips: Bring a friend, help keep mud alive!")
        || line.contains("You say \"http://esoteric-edits.fhero.net/\"")
        || line.contains("For a list of available commands, you can telepath me with @commands.")))
 {
 //Make the dates american style
     String day = line.substring(0,2);
     String month = line.substring(3,5);
lines.add(month + "/" + day + line.substring(5));
}


 }
//initialize the output file with HTML header
output.write("<html>");
output.write(System.getProperty("line.separator") + "\t<head>");
output.write(System.getProperty("line.separator") + "\t\t<link type=\"text/css\" rel=\"stylesheet\" href=\"stylesheet.css\"/>");
output.write(System.getProperty("line.separator") + "\t\t<title>Esoteric Edits BBS - Conversation Log</title>");
output.write(System.getProperty("line.separator") + "\t</head>");
output.write(System.getProperty("line.separator") + "\t<body>"+ System.getProperty("line.separator") + System.getProperty("line.separator"));
output.write(System.getProperty("line.separator") + "<div id='cssmenu'>");
output.write(System.getProperty("line.separator") + "\t\t<center><img src=\"logo_10_2.png\">");
output.write(System.getProperty("line.separator") + "<ul>");
output.write(System.getProperty("line.separator") + "\t<li> <a href='index.html'><span>Home</span></a></li>");
output.write(System.getProperty("line.separator") + "\t<li> <a href='downloads.html'><span>Downloads</span></a></li>");
output.write(System.getProperty("line.separator") + "\t<li> <a href='Quests.html'><span>Quest Walkthroughs</span></a></li>");
output.write(System.getProperty("line.separator") + "\t<li> <a href='https://www.facebook.com/groups/EsotericEdits/'><span>Facebook</span></a></li>");
output.write(System.getProperty("line.separator") + "\t<li> <a href='captures.html'><span>Captures</span></a></li>");
output.write(System.getProperty("line.separator") + "\t<li class='last'> <a href='FAQs.html'><span>FAQs</span></a></li>");
output.write(System.getProperty("line.separator") + "</ul></center>");
output.write(System.getProperty("line.separator") + "</div><div id='mainpage'>");
output.write(System.getProperty("line.separator") + "<center><img src=\"divider.png\"></center>");

//write out a new file with HTML coloration
for (ListIterator<String> iter = lines.listIterator(); iter.hasNext(); ) 
{
    String currentline = iter.next();
    output.write("<b>"); //make everything bold
    if (currentline.contains("gangpaths: "))
{
output.write(System.getProperty("line.separator") + "<font color=\"#808000\">" + currentline + "<br></font>");
}
    else if (currentline.contains("gossips: ") || currentline.contains("auctions: "))
{
output.write(System.getProperty("line.separator") + "<font color=\"#FF00FF\">" + currentline + "<br></font>");
}
else if (currentline.contains("Broadcast from "))
{
output.write(System.getProperty("line.separator") + "<font color=\"yellow\">" + currentline + "<br></font>");
}
else if (currentline.contains("says \"") || currentline.contains("greets you.") || currentline.contains("bows deeply.")
             || currentline.contains("breaks into a wide grin.") || currentline.contains("You say \"") 
             || currentline.contains("nods affirmatively.") || currentline.contains("grin slyly"))
{
output.write(System.getProperty("line.separator") + "<font color=\"green\">" + currentline + "<br></font>");
}
else
{
output.write(System.getProperty("line.separator") + currentline + "<br>");
}
}
//finalize the HTML footer
output.write(System.getProperty("line.separator") + "</b>");
output.write(System.getProperty("line.separator") + "</div>");
output.write(System.getProperty("line.separator") + "</body>");
output.write(System.getProperty("line.separator") + "\t</html>");
output.close(); //file is finalized locally



//define variables for FTP process
String server = "servername";
int port = 21;
String user = "fake";
String pass = "password";

//begin FTP process to web server
FTPClient ftpClient = new FTPClient();
FileInputStream fis = null;
try {

    File localFile = new File("C:/Documents and Settings/Cuckoo/Desktop/Conversations.html");
    ftpClient.connect(server, port);
    ftpClient.login(user, pass);
    ftpClient.setFileType(FTP.BINARY_FILE_TYPE);
    fis = new FileInputStream(localFile);
    String remoteFile = "/public_html/Conversations.html";
    ftpClient.storeFile(remoteFile, fis);
    java.util.Date currentDate = new java.util.Date();
    Timestamp ftpTimestamp = new Timestamp(currentDate.getTime());
    //Create writer file to log iterations of the loop as successful or skipped.
    Writer writer = new BufferedWriter(new FileWriter("C:/Documents and Settings/Cuckoo/Desktop/Convo-Upload.log", true));
    writer.append("Successfully uploaded file as of " + ftpTimestamp.toString() + System.getProperty("line.separator"));
    writer.close(); 
    ftpClient.logout();
} catch (IOException e) {
    //turn the stack trace into a string and output to the log file
    StackTraceElement[] stack = e.getStackTrace();
    String theTrace = "";
    for(StackTraceElement IOstackline : stack)
    {
       theTrace += IOstackline.toString();
    }
    Writer writer = new BufferedWriter(new FileWriter("C:/Documents and Settings/Cuckoo/Desktop/Convo-Upload.log", true));
    writer.append(theTrace + System.getProperty("line.separator"));
    writer.close(); 
} finally {
    try {
        if (fis != null) {
            fis.close();
        }
        ftpClient.disconnect();
    } catch (IOException e) {
        //turn the stack trace into a string and output to the log file
        StackTraceElement[] stack = e.getStackTrace();
        String theTrace = "";
        for(StackTraceElement IOstackline : stack)
        {
           theTrace += IOstackline.toString();
        }
        Writer writer = new BufferedWriter(new FileWriter("C:/Documents and Settings/Cuckoo/Desktop/Convo-Upload.log", true));
        writer.append(theTrace + System.getProperty("line.separator"));
        writer.close();
        e.printStackTrace();
        }
    }


lastLoopModified = currentLoopModified; //set the timestamp for the lastmodified on the file being read in

}
    else
    {
        java.util.Date currDate = new java.util.Date();
        Timestamp currTimestamp = new Timestamp(currDate.getTime());
        //Create writer file to log iterations of the loop as successful or skipped.
        Writer writer = new BufferedWriter(new FileWriter("C:/Documents and Settings/Cuckoo/Desktop/Convo-Upload.log", true));
        writer.append("Did not detect any new content in file.  Did not upload as of " + currTimestamp.toString() + System.getProperty("line.separator"));
        writer.close(); 
    }
    Thread.sleep(300000); //5 minutes
}

}
}

Answer 1

更新：

只是抓住所有异常，然后就可以了

例如：

  public static void main(String[] args) throws Exception {
    while (true) {
      try {
        doAll();
      } catch (Exception e) {
        e.printStackTrace();
      }
      Thread.sleep(5000);
    }
  }

  public static void doAll() {
    doA();
    doB();
    doC();
  }

  public static void doA() {
    System.out.println("Do A");
  }

  public static void doB() {
    System.out.println("Do B");
  }

  public static void doC() {
    System.out.println("Do C");
    throw new RuntimeException();
  }

Answer 2

未经测试的代码：

  public void run() {
    while(true) {
      initialize();
      try {
        doCommunication();
      } catch (WhateverException e){
        logIt(e);
      }
    }
  }

这个想法是留在while循环中，每次出现异常时重新运行初始化。

java中的catch块是否可以简单地重新执行主代码块？

2 个答案:

更新：