这是我的输出:
/channel #blarg123
chanswitch: #blarg123
hello
----->PRIVMSG #blarg123 :hello
----->Logging: -->:phyrrus92 :hai ]
Error open
Exception in thread "main" java.lang.NullPointerException
at irc_channel_obj.writemsg(irc_channel.java:66)
at irc_channel.sendmsg(irc_channel.java:24)
at irc.irc_log(irc.java:28)
at irc.main(irc.java:91)
我不明白为什么它抛出这个异常，因为所有的代码似乎都是正确的并且文件存在(./#blarg123)
代码如下:
File: irc.java
import java.net.*;
import java.io.*;
class irc
{
static Socket server;
static BufferedReader in;
static BufferedReader stdin;
static PrintWriter out;
static String channel;
static irc_channel chanlist;
public static void irc_log(String line)
{
System.out.println("----->Logging: " + line);
String[] splitted = line.split(" ");
String channel = "", sendline = "";
if (splitted[0].indexOf("!") != -1)
splitted[0] = splitted[0].substring(0, splitted[0].indexOf("!"));
for (int i = 0; i < splitted.length; i++)
{
sendline += splitted[i];
if (splitted[i].indexOf("#") != -1)
{
channel = splitted[i];
}
}
chanlist.sendmsg(channel, sendline);
}
public static void main(String args[])
{
String user_line;
channel = "none";
chanlist = new irc_channel();
try
{
server = new Socket(args[0], 6667);
in = new BufferedReader( new InputStreamReader(server.getInputStream()) );
stdin = new BufferedReader( new InputStreamReader(System.in) );
out = new PrintWriter(server.getOutputStream());
}
catch (UnknownHostException e) {}
catch (IOException e) {}
irc_in input = new irc_in(server, out, stdin);
Thread t = new Thread(input);
t.start();
while (true)
{
try {
user_line = in.readLine();
String[] splitted = user_line.split(" ");
if (splitted[0].equals("PING"))
{
out.print("PONG " + splitted[1] + "\r\n");
out.flush();
continue;
}
boolean chan_filtered = false;
if (splitted[0].indexOf("!") != -1)
{
splitted[0] = "" + splitted[0].substring(0, splitted[0].indexOf("!"));
}
for (int i = 1; i < splitted.length && !chan_filtered; i++)
{
if (splitted[i].equals(channel))
{
chan_filtered = true;
user_line = "\u001B[0;32m-->" + splitted[0] + " ";
for (int x = 3; x < splitted.length; x++) //x=i
{
user_line += splitted[x] + " ";
}
user_line += "\u001B[0m]";
}
else if (splitted[i].indexOf("#") != -1)
{
chan_filtered = true;
user_line = "\u001B[0;31m-->" + splitted[0] + " ";
for (int x = 2; x < splitted.length; x++) //x=i
{
user_line += splitted[x] + " ";
}
user_line += "\u001B[0m]";
}
}
if (!channel.equals("none"))
{
irc_log(user_line);
//chanlist.displayall(channel);
}
//else
{
System.out.println(user_line);
System.out.flush();
}
//Thread.sleep(2000);
} catch (IOException e) {}
}
}
}
class irc_in implements Runnable
{
static Socket server;
static PrintWriter out;
static BufferedReader stdin;
irc_in(Socket a, PrintWriter b, BufferedReader c)
{
server = a;
out = b;
stdin = c;
}
public void run()
{
String user_line;
while (true)
{
try
{
//Thread.sleep(1000);
user_line = stdin.readLine();
String[] splitted=user_line.split(" ");
if (splitted[0].equals("/channel") || splitted[0].equals("/JOIN"))
{
user_line = "";
splitted[0] = splitted[0].substring(1, splitted[0].length());
for (int i = 0; i < splitted.length; i++)
user_line += splitted[i] + " ";
irc.channel = splitted[1];
System.out.println("chanswitch: " + irc.channel);
if (splitted[0].equals("channel"))
continue;
}
else if (splitted[0].equals("/setname") && splitted.length >= 2)
{
String user_name = "";
for (int i = 0; i < splitted.length; i++)
user_name += splitted[i];
out.print("NICK " + splitted[1] + "\r\n");
out.print("USER " + splitted[1] + " * 8 : " + user_name + "\r\n");
out.flush();
}
else if (!splitted[0].startsWith("/"))
{
int startpos = 0;
String send_channel = irc.channel;
if (splitted[0].startsWith("#"))
{
send_channel = splitted[0];
startpos = 1;
}
user_line = "PRIVMSG " + send_channel + " :";
for (int i = startpos; i < splitted.length; i++)
user_line += splitted[i] + " ";
System.out.println("----->" + user_line);
}
else
user_line = user_line.substring(1, user_line.length());
out.print(user_line + "\r\n");
out.flush();
}
catch (IOException e) {}
}
}
}
还有一个文件
File: irc_channel.java
import java.io.*;
import java.util.*;
public class irc_channel
{
public static ArrayList<irc_channel_obj> list;
irc_channel()
{
list = new ArrayList<irc_channel_obj>();
}
public void sendmsg(String channel, String line)
{
for (int i = 0; i < list.size(); i++)
{
if (list.get(i).name.equals(channel))
{
list.get(i).writemsg(line);
return;
}
}
irc_channel_obj newchan = new irc_channel_obj(channel);
newchan.writemsg(line);
list.add(newchan);
}
public void displayall(String channel)
{
for (int i = 0; i < list.size(); i++)
{
if (list.get(i).name.equals(channel))
{
list.get(i).displayall();
return;
}
}
System.out.println("No messages for channel " + channel);
}
}
class irc_channel_obj
{
public static String name;
static PrintWriter out;
static BufferedReader in;
irc_channel_obj(String chan)
{
name = chan;
try
{
out = new PrintWriter(name);
out.println("Channel: " + name);
out.flush();
}
catch (FileNotFoundException e)
{
System.out.println("Error open");
return;
}
}
public void writemsg(String line)
{
out.println(line);
out.flush();
}
public void displayall()
{
String line = "";
try
{
in = new BufferedReader( new FileReader(name) );
while ((line = in.readLine()) != null)
{
System.out.println(line);
}
}
catch (FileNotFoundException e) { return; }
catch (IOException e) { return; }
}
}
任何帮助都会很棒。
最佳答案
输出的相关部分:
Error open
Exception in thread "main" java.lang.NullPointerException
at irc_channel_obj.writemsg(irc_channel.java:66)
Error open 意味着您的 irc_channel_obj 构造函数抛出了一个 FileNotFoundException。这就是 out 保持 null 的原因。
稍后，在 writemsg(String line) 中调用
out.println(line);
out 仍然是 null --> NullPointerException。
关于Java 没有正确写入文件，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/18232496/