示例代码如下。它将目标文件和目录从一个位置复制到另一个位置。通过网络复制文件时处理 IO 异常的最佳实践是什么？
我使用了 printStackTrace() 但感觉这只是一个更好的解决方案的占位符。记录是答案吗？除了记录之外是否应该采取另一个步骤来实际“处理”错误？
感谢您的反馈。
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
/**
This is a test program to copy a directory(s) & file(s) from one location to another.
*/
public class CopyTest{
public static void main(String[] args) {
//Declarations
String sourcePath = "I:\\MB\\PO";
String destPath = "C:\\testPO\\";
System.out.println("Source path: " + sourcePath);
System.out.println("Destination path: " + destPath);
File source = new File(sourcePath);
File dest = new File(destPath);
//Process
//Call to method copyUsingStream
long start = System.nanoTime(); //start recording how much time the copy takes.
copyUsingStream(source, dest); //method to copy the directory/files.
System.out.println("Time taken to copy the file: "+(System.nanoTime() -start) + " nanoseconds");
} //end main method
/**
The copyUsingStream method is a recursive method to copy folders and files from one location to another.
*/
private static void copyUsingStream(File source, File dest) {
if (!source.isDirectory()){
// If source is a file -> copy it to the new folder
InputStream inStream = null;
OutputStream outStream = null;
try {
inStream = new FileInputStream(source);
outStream = new FileOutputStream(dest);
byte[] buffer = new byte[1024];
int length;
while ((length = inStream.read(buffer)) > 0) {
outStream.write(buffer, 0, length);
}
} catch(IOException ioe) {
ioe.printStackTrace();
} finally {
try{
inStream.close();
outStream.close();
System.out.println("File copied from " + source + " to " + dest + "successfully");
} catch(IOException ioe2) {
ioe2.printStackTrace();
}
}
} else {
//If a directory -> create the directory inside the new destination
//List all contents
if (!dest.exists()) {
dest.mkdir();
System.out.println("Directory copied from " + source + " to " + dest + "successfully");
}
String folder_contents[] = source.list();
for (String file : folder_contents) {
File srcFile = new File(source, file);
File destFile = new File(dest, file);
copyUsingStream(srcFile, destFile);
}
}
} //end method copyUsingStream
} //end class CopyTest
没有捕获的方法:
private static void copyUsingStream(File source, File dest) throws IOException {
if (!source.isDirectory()){
// If source is a file -> copy it to the new folder
InputStream inStream = null;
OutputStream outStream = null;
try {
inStream = new FileInputStream(source);
outStream = new FileOutputStream(dest);
byte[] buffer = new byte[1024];
int length;
while ((length = inStream.read(buffer)) > 0) {
outStream.write(buffer, 0, length);
}
} finally {
inStream.close();
outStream.close();
System.out.println("File copied from " + source + " to " + dest + "successfully");
}
} else {
//If a directory -> create the directory inside the new destination
//List all contents
if (!dest.exists()) {
dest.mkdir();
System.out.println("Directory copied from " + source + " to " + dest + "successfully");
}
String folder_contents[] = source.list();
for (String file : folder_contents) {
File srcFile = new File(source, file);
File destFile = new File(dest, file);
copyUsingStream(srcFile, destFile);
}
}
} //end method copyUsingStream
最佳答案
这很大程度上取决于您的应用程序。
无论如何都会继续运行的应用程序(例如网络服务器、守护进程和批处理处理器)通常会将此类错误与时间戳、线程 ID 和可能的其他有用信息一起记录在文件中。
我对两个日志文件的组合有非常好的经验。
myapp.log仅接收重要消息，通常是警告和错误。该文件适用于普通用户和系统运算符(operator)。debug.log适用于开发人员。它提供错误发生前的调试消息，但只要一切正常，就不会显示任何消息。为了实现这一点，需要一个内存缓冲区。
如果您对该缓冲区感兴趣，可以查看 http://stefanfrings.de/bfUtilities/index.html 。该网站是德语的，但库及其文档是英语的。
在桌面 GUI 应用程序上，当错误中止请求的操作时，最好在弹出窗口中显示简短的错误消息，并在可扩展框中隐藏详细信息(堆栈跟踪)。不要忘记清楚地告诉用户什么操作失败了。异常本身对于开发人员来说可能足够清楚，但普通用户期望技术性较低的文本。例如:“从服务 Weather.com 加载天气信息失败:连接失败”，后面是堆栈跟踪。
对于立即停止的控制台应用程序，我更喜欢直接在屏幕上查看由 printStackTrace() 编写的堆栈跟踪。
关于java - 处理目录和文件时处理 IO 异常的最佳实践？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/60120526/