Question

我收到以下错误消息，我似乎无法弄清楚问题。非常感谢任何帮助。错误消息显示为： -

BaseStaInstance.java:68：找不到符号

symbol：构造函数StringTokenizer（java.lang.Object，java.lang.String）

location：class java.util.StringTokenizer st = new StringTokenizer（buf，“，”）;

在这里，BaseStaInstance是我的主要公共课。

实现此StringTokenizer的类如下： -

类ServerConnect扩展了线程{

Socket skt;
int iProcessId, iInProcessId;
int iOwnTimeStamp, iInTimeStamp;
ServerConnect scnt = null;

ObjectOutputStream myOutput;
ObjectInputStream myInput;

ServerConnect(){}
ServerConnect(Socket connection, int iProcessNo) {
    this.skt = connection;
    this.iProcessId = iProcessNo;
}

public void run() {
    try {

        //initialize the object "scnt" using the parameterized constructor
        ServerConnect scnt = new ServerConnect(skt, iProcessId);
        myInput = new ObjectInputStream(skt.getInputStream());

        while(true) {
            try{
                iOwnTimeStamp = Global.iTimeStamp;

                Object buf = myInput.readObject();

                //if we got input, print it out and write a message back to the remote client...
                if(buf != null){
                    scnt.replyChoice(buf);
                }
            }catch(ClassNotFoundException e) {
                e.printStackTrace();
            }
        }
    } catch(IOException e) {
        e.printStackTrace();
    }
}

void replyChoice(Object buf){       
    try{
        String sDeferReply = "";
        myOutput = new ObjectOutputStream(skt.getOutputStream());

        //the place where the basestation reads the request from the other basestation
        System.out.println("Server read:[ "+buf+" ]");

        //extract out the process id and the timestamp from the incoming request
        buf = buf.toString();

        ***StringTokenizer st = new StringTokenizer(buf,",");***

        //skip the word request
        st.nextToken();
        iInProcessId = Integer.parseInt(st.nextToken());
        iInTimeStamp = Integer.parseInt(st.nextToken());

        //check request is made
        //there is a possibility of entering the else loop only on the very first iteration
        //the control flows into the if loop even if one request has been made
        if(iOwnTimeStamp != 0){
            //if the incoming request has a larger timestamp (logical clock value, process id) than the current process, we defer the reply
            if(iOwnTimeStamp < iInTimeStamp || iProcessId < iInProcessId){
                sDeferReply="iInTimeStamp"+","+"iInProcessId";
                Global.v.addElement(new String(sDeferReply));
            }
            //incoming request has a smaller timestamp than the basestation request itself
            else{
                myOutput.writeObject("Reply");
                myOutput.flush();
            }
        }
        //if the current process is in the critical section then we defer replies
        else if(Global.iCriticalSection==1){
            sDeferReply="iInTimeStamp"+","+"iInProcessId";
            Global.v.addElement(new String(sDeferReply));
        }
        //start of execution of the thread, there is a possibility that the basestation hasn't issued a request
        else{
            myOutput.writeObject("Reply");
            myOutput.flush();   
        }
    }catch(IOException e){
        e.printStackTrace();
    }
}

}

实现StringTokenizer函数的部分有***围绕它。

提前感谢任何可能帮助我的人。

Answer 1

尝试

StringTokenizer st = new StringTokenizer((String) buf,",");

您收到该错误的原因是因为buf，在此时引用String，仍然是Object类型。

作为补充提示，您真的应该努力尝试理解编译器提供的错误消息。请看以下内容：

cannot find symbol constructor StringTokenizer(java.lang.Object,java.lang.String)
location: class java.util.StringTokenizer st = new StringTokenizer(buf,",");

编译器错误消息并不总是有意义，但是这是最好的。它告诉你：

找到了正确的类型java.util.StringTokenizer，因此它不是import或名称模糊问题等。
它告诉您无法找到具有给定签名的特定方法。实际上，使用API快速检查确认StringTokenizer没有带(java.lang.Object, java.lang.String)的构造函数。
它告诉你程序中的代码行试图调用这个不存在的方法。 确实是，你的第一个参数的类型是java.lang.Object，第二个参数的类型是java.lang.String !!!

这就是我能够快速查明源代码中的问题并建议快速修复的方法。

能够处理编译器提供的错误消息是您必须开发的必备技能，所以我希望这对您来说是一种教育体验。

使用StringTokenizer时出现问题

1 个答案: