Question

我有一个String，它位于一个单独的类中，我想在另一个String中引用它。

public static void filedemo(String[] args) {
    FileDemo.readLibDir("C:/test/lib");
}

public static void readLibDir(String directoryname) {
    File dir = null;
    String[] paths;
    try {
        dir = new File(directoryname);
        paths = dir.list(new FilenameFilter() {
            public boolean accept(File directory, String name) {
                // return only files that end .jar extension
                return name.toLowerCase().endsWith(".jar");
            }
        });
        // enhanced for loop used to iterate through the array
        for (String path : paths) {
            // check to see if jar filename exist  
            boolean found = FileNameStorage.exists(path);
            if (found) {
                // didn't find
                FileNameStorage.delete(path);
            } else {
                System.out.print(path+" was not found.\n ");
            }
        }
    } catch (Exception e) {
        // if any error occurs
        e.printStackTrace();
    }
}

public class HtmlDataTable {
    String lines = "<tr>  <td>" + jarfilename + "</td>  <td>"
                        + paths + " </td> <td>" + jarfilename

Answer 1

您的paths变量是方法的本地变量。因此，无法从任何其他类（或甚至同一类中的任何其他方法）访问它。看看Variable Scope，或谷歌了解它。

如果您想从其他课程访问paths，最简单的选择是将其设为实例变量并公开。

Answer 2

如评论中所述，变量paths应定义为类成员（当前在静态方法中定义为局部变量）。
只有这样才能使外部调用者可以使用它

一种方法如下：

public class FileDemo {
  private final File dir;

  // constructor
  public FileDemo (String directoryname) {
    dir = new File(directoryname);
  }

  public String[] getPaths() {
    return dir.list(new FilenameFilter() {
       public boolean accept(File directory, String name) {
         // return only files that end .jar extension
         return name.toLowerCase().endsWith(".jar");
       }
    });
  }
  :

  public static void main(String[] args) {
    FileDemo demo = new FileDemo("C:/test/lib");
    String[] paths = demo.getPaths();
    :  // now it is available 
  }
}

如何在String行中引用String路径？

2 个答案: