基本java代码出错

Question

这是一些基本的java代码：

package javaapplication32;

import java.io.*;

public class JavaApplication32 {
    public static void main(String[] args)throws Exception {
        try{
            out = new DataOutputStream(new BufferedOutputStream(new FileOutputStream("dec.dat")));
            in = new DataInputStream(new BufferedInputStream(new FileInputStream("enc.dat")));

            String enc=in.readUTF();
            System.out.println(enc);
        }catch(EOFException e){
        }
    }   
}

我收到错误，它找不到符号'in'或'out'

Answer 1

你应该先申报它们。

public static void main(String[] args)throws Exception {
    DataOutputStream out = null; 
    DataInputStream in = null;
    try{
        out = new DataOutputStream(new BufferedOutputStream(new FileOutputStream("dec.dat")));
        in = new DataInputStream(new BufferedInputStream(new FileInputStream("enc.dat")));

        String enc=in.readUTF();
        System.out.println(enc);
    }catch(EOFException e){
    }
}   

Answer 2

为了定义变量，您必须为它们提供类型，例如：

OutpustStream out = new DataOutputStream(new BufferedOutputStream(new FileOutputStream("dec.dat")));
InputStream in = new DataInputStream(new BufferedInputStream(new FileInputStream("enc.dat")));

Answer 3

您还没有真正宣布任何作为in或out 。

DataInputStream in =

DataOutputStream out =

Answer 4

这应该工作。

package javaapplication32;
import java.io.*;

public class JavaApplication32 {
    public static void main(String[] args)throws Exception {
        try {
            DataOutputStream out = new DataOutputStream(new BufferedOutputStream(new FileOutputStream("dec.dat")));
            DataInputStream in = new DataInputStream(new BufferedInputStream(new FileInputStream("enc.dat")));

            String enc=in.readUTF();
            System.out.println(enc);
        } catch(EOFException e) {
        }
    }   
}

Answer 5

你需要首先申报进出！

DataInputStream in =

DataOutputStream out =

例如

out = new DataOutputStream(new BufferedOutputStream(new FileOutputStream("dec.dat")));
    in = new DataInputStream(new BufferedInputStream(new FileInputStream("enc.dat")));

Answer 6

在Java中，字符串的预初始化是强制性的。 只有这样你才能在程序中使用它们。 最简单的方法是：

String in="";
String out="";

你应该没事......