java - 捕获标志错误: could not find or load main class Espresso

Question

这个问题已经有答案了:

What does "Could not find or load main class" mean? (63 个回答)

已关闭 4 年前。

您好，我正在捕获标志事件，当前问题出在 Java 中，但我没有任何使用 Java 的经验。当我尝试运行该文件时，我收到“无法找到或加载主类 Espresso”。我在这里看过其他帖子，我尝试过 java -cp . Espresso但没有任何运气。我确实跑了javac Espresso.java在运行之前编译它 java Espresso 。任何帮助将不胜感激，这里的代码是:

package com.hackinglab.ctf;
import java.io.PrintStream;

public class Espresso { public Espresso() {} private static String key = "Stringab";
  private static String cipher = "'>xgx47#)~Fp?8k4%IHsC9_a";

  public static void main(String[] paramArrayOfString) {
    if (paramArrayOfString.length != 1) {
      System.out.println("You must enter the flag.");
      System.exit(-1);
    }
    String str = paramArrayOfString[0];
    System.out.println(str);
    StringBuffer localStringBuffer = new StringBuffer();
    for (int i = 0; i < cipher.length(); i++) {
      localStringBuffer.append((char)(key.charAt(i % key.length()) - cipher.charAt(i) + 55));
    }
    if (localStringBuffer.toString().equals(str)) {
      System.out.println("Flag correct, well done!");
    } else {
      System.out.println("Dude, that's wrong!");
    }
  }
}

Answer 1

确保您的文件夹结构与包名称相同

../com/hackinglab/ctf/Espresso.java

然后你可以像这样构建并运行它

javac com/hackinglab/ctf/Espresso.java
java com/hackinglab/ctf/Espresso

或从源文件中删除行package com.hackinglab.ctf;