空指针异常问题 把jdk编译时报的错误,和你的程序帖出来吧有很多原因可以造成空指针错误 解决方案 » 免费领取超大流量手机卡,每月29元包185G流量+100分钟通话, 中国电信官方发货 大概程序出错在implements Runnable,我删除它后就没有问题了(但它是程序的必须模块)。如果加上后就说空指针错误,真的不明白啊!请指教啊:public class ServerCenter implements Runnable{ ServerSocket serverSocket; Thread serverThread; public ServerCenter() { try { serverSocket = new ServerSocket(5001); serverThread=new Thread(this); System.out.println("ServerCenter: server is started..."); serverThread.start(); } catch(IOException e) { fail(e,"Could not start Server"); } } public static void fail(Exception e,String str) { System.err.println(str + " . " + e); } public void run() { try { while(true) { Socket postOffice = serverSocket.accept(); DataProcessingCenter con = new DataProcessingCenter(postOffice); } } catch(IOException e) { fail(e,"Not Listening"); } } public static void main(String args[]) { new ServerCenter(); }}class DataProcessingCenter extends Thread{ protected Socket postOffice; protected ObjectInputStream acceptLetterMiss; protected ObjectOutputStream sendLetterMan; String response; String findID; String findID1; String findID2; String findID3; String findFName; String findLName; liulan ll; baozhuang bzh; yunhuo yh; shippingrate sr; Recipient reci; Orders orders; public DataProcessingCenter(Socket postOffice) { try { acceptLetterMiss = new ObjectInputStream(postOffice.getInputStream()); sendLetterMan =new ObjectOutputStream(postOffice.getOutputStream()); } catch(IOException e) { try { postOffice.close(); } catch(IOException e1) { ServerCenter.fail(e1,"Unable to set up stream"); return; } } this.start(); } public void run() { try { while(true) { response = (String)acceptLetterMiss.readObject(); responseMiss(); } } catch(ClassNotFoundException e1) { ServerCenter.fail(e1,"" ); } catch(IOException e2) { ServerCenter.fail(e2,"" ); } finally { try { System.out.println("Socket closed"); postOffice.close(); } catch(IOException e) { ServerCenter.fail(e,""); } } } 二维数组如何删除事特定行的数据 JAVA的package问题? 请问下在网上报名考SCJP的网址 jar运行的怪问题 为何执行update语句去更新ACCESS时,程序没错,却更新不了 表达式相加问题 推荐一个用Java写的类似于SpreadSheet的开源的表格控件啊? 一个关于在线程中计算时间的问题! 高分请教:怎样能让JList控件自动把当前选中的项目显示出来? 求助! 在servlet里怎么连接oracle数据库 applet程序问题(线上等待,谢谢!)
public class ServerCenter implements Runnable
{
ServerSocket serverSocket;
Thread serverThread;
public ServerCenter()
{
try
{
serverSocket = new ServerSocket(5001);
serverThread=new Thread(this);
System.out.println("ServerCenter: server is started...");
serverThread.start();
}
catch(IOException e)
{
fail(e,"Could not start Server");
}
}
public static void fail(Exception e,String str)
{
System.err.println(str + " . " + e);
}
public void run()
{
try
{
while(true)
{
Socket postOffice = serverSocket.accept();
DataProcessingCenter con = new DataProcessingCenter(postOffice);
}
}
catch(IOException e)
{
fail(e,"Not Listening");
}
}
public static void main(String args[])
{
new ServerCenter();
}
}
class DataProcessingCenter extends Thread
{
protected Socket postOffice;
protected ObjectInputStream acceptLetterMiss;
protected ObjectOutputStream sendLetterMan;
String response;
String findID;
String findID1;
String findID2;
String findID3;
String findFName;
String findLName;
liulan ll;
baozhuang bzh;
yunhuo yh;
shippingrate sr;
Recipient reci;
Orders orders;
public DataProcessingCenter(Socket postOffice)
{
try
{
acceptLetterMiss = new ObjectInputStream(postOffice.getInputStream());
sendLetterMan =new ObjectOutputStream(postOffice.getOutputStream());
}
catch(IOException e)
{
try
{
postOffice.close();
}
catch(IOException e1)
{
ServerCenter.fail(e1,"Unable to set up stream");
return;
}
}
this.start();
}
public void run()
{
try
{
while(true)
{
response = (String)acceptLetterMiss.readObject();
responseMiss();
}
}
catch(ClassNotFoundException e1)
{
ServerCenter.fail(e1,"" );
}
catch(IOException e2)
{
ServerCenter.fail(e2,"" );
}
finally
{
try
{
System.out.println("Socket closed");
postOffice.close();
}
catch(IOException e)
{
ServerCenter.fail(e,"");
}
}
}