java - 新文件未在 renameTo() 上被调用

Question

我使用以下代码在 linux 上编辑文件 OIMV2Migration.sh。

    String oldFileName = "OIMV2Migration.sh";//file to be edited
    String tmpFileName = "tmp_try.dat"; //new file containing changes
    BufferedReader br = null;
    BufferedWriter bw = null;
                  try {
                     br = new BufferedReader(new FileReader(oldFileName));
                     bw = new BufferedWriter(new FileWriter(tmpFileName));
                     String line;
                     while ((line = br.readLine()) != null) {
                        if (line.contains("SURBHI")) {
                           line = line.replace("SURBHI MITTAL" , "SURBHI GUPTA");}
                        bw.write(line+"\n");
                     }
                  } catch (Exception e) {
                     return;
                  } finally {
                     try {
                        if(br != null)
                           br.close();
                     } catch (IOException e) {
                        //
                     }
                     try {
                        if(bw != null)
                           bw.close();
                     } catch (IOException e) {
                        //
                     }}

                 //delete the old file
                  File oldFile = new File(oldFileName);;
                  oldFile.delete();
                 //rename the new file to old file        
                  File newFile = new File(tmpFileName);
                  System.out.println(newFile.getAbsolutePath());
                  Boolean success = newFile.renameTo(oldFile);
                  System.out.println(newFile.getAbsolutePath());

此处，文件已正确更新，但 newFile 的绝对路径始终指向“tmp_try.dat”，无论是在执行 renameTo() 之前还是执行 renameTo() 之后。

我从堆栈溢出链接了解到文件实例的绝对路径不会改变，它保持不变。但我的问题是我的系统中有另一个文件 idmlcm.sh，它在内部调用 OIMV2Migration.sh。但是执行此方法后，idmlcm.sh 无法调用 OIMV2Migration.sh，就好像找不到该文件一样。尽管该文件仅存在于正确的目录中。

Answer 1

根据 JAVA Documentation

renameTo 的行为:

Many aspects of the behavior of this method are inherently platform-dependent: The rename operation might not be able to move a file from one filesystem to another, it might not be atomic, and it might not succeed if a file with the destination abstract pathname already exists. The return value should always be checked to make sure that the rename operation was successful.

在你的例子中，首先你要删除 oldFile 然后将 tmpFile 重命名为 oldFileName，这实际上是完美的，但是当你调用newFile.getAbsolutePath() 将打印 tmpFile 的路径，因为 Object newFile 仍然只引用旧路径。您需要重新创建 File Object 才能访问重命名的 File。