java.lang.NumberFormatException：对于输入字符串：“5

Question

When I run this Java code:

public void run(){
    String stringPacketData=null;
    try {
        stringPacketData = new String(clientPacketData,"UTF-8");
    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
        System.exit(1);
    }       
    String[] splitString=stringPacketData.split("@");
    this.clientID = Integer.parseInt(splitString[0]);
    String op="";

    op=splitString[1];
    if(op.equalsIgnoreCase("popola_cache")){
        popolamentoCache(Integer.parseInt(splitString[2]));
    }
    else{
        System.exit(0);
    }
} 

Where stringPacketData has a format: idClient@operationType@dimCache, it will throw this excpetion:

Exception in thread "Thread-2" java.lang.NumberFormatException: For input string: "5"
at java.lang.NumberFormatException.forInputString(Unknown Source)
at java.lang.Integer.parseInt(Unknown Source)
at java.lang.Integer.parseInt(Unknown Source)
at UDPSocketBased.WorkerUDP.run(WorkerUDP.java:53)

WorkerUDP.java:53 statement corresponds to: popolamentoCache(Integer.parseInt(splitString[2]));

I can't understand why my input string "5" is not in the correct format.

Answer 1

首先，您需要在尝试解析之前修剪字符串

this.clientID = Integer.parseInt(splitString[0].trim());

Answer 2

I resolve it in this way:

popolamentoCache(Integer.parseInt(String.valueOf(splitString[2].charAt(0))));

The problem was that I received a DatagramPacket called "pkt":

byte[] buffer=new byte[65508];
DatagramPacket pkt = new DatagramPacket(buffer, buffer.length);

So, when I get my packet data with:

clientPacketData=pkt.getData();

it considers a payload length of 65508 byte, in the same way stringPacketData length.

Thanks!

Answer 3

Try put one delimiter character, the same that you use to split the string at the beginning of yours text file. This way you avoid the situation when first character throws the exception because that's not a integer.