2013-04-23 94 views
0

如何给args [0]中的源文件和args [1]中的目标文件?我在同一个包中创建了一个source.txt和一个target.txt,并在运行配置中放入了“./source.txt”和“./target.txt”作为参数。但它会抛出“./source.txt”不可读取的异常。Paths.get(args [0])不起作用

Exception in thread "main" java.lang.IllegalArgumnetException: ./source.txt 

什么是worng?

import java.io.IOException; 
import java.nio.file.Files; 
import java.nio.file.Path; 
import java.nio.file.Paths; 
import java.nio.file.StandardCopyOption; 
import de.sb.javase.TypeMetadata; 


/** 
    * Demonstrates copying a file using a single thread. 
*/ 
public final class FileCopyLinear { 

/** 
* Copies a file. The first argument is expected to be a qualified source file name, 
* the second a qualified target file name. 
* @param args the VM arguments 
* @throws IOException if there's an I/O related problem 
*/ 
public static void main(final String[] args) throws IOException { 
    final Path sourcePath = Paths.get(args[0]); 
    if (!Files.isReadable(sourcePath)) throw new IllegalArgumentException(sourcePath.toString()); 

    final Path sinkPath = Paths.get(args[1]); 
    if (sinkPath.getParent() != null && !Files.isDirectory(sinkPath.getParent())) throw new IllegalArgumentException(sinkPath.toString()); 

    Files.copy(sourcePath, sinkPath, StandardCopyOption.REPLACE_EXISTING); 

    System.out.println("done."); 
} 
} 
+1

“./source.txt” 不readdable?我希望实现者不会犯这种拼写错误。总是复制粘贴原始堆栈跟踪 – 2013-04-23 10:01:58

+1

什么是“异常”的详细信息(类型,消息,合理详细的堆栈跟踪)? – 2013-04-23 10:02:37

+0

是不是args [0]你正在擅长的.java文件?还是仅仅在C++中? – 2013-04-23 10:03:38

回答

4

相对文件路径不是相对于包的任何类的。它们与当前目录相关,该目录是执行java命令以启动程序的目录。

所以,如果你在目录/home/user1477955并键入

/home/user1477955 > java com.foo.bar.FileCopyLinear source.txt target.txt 

它将搜索文件/home/user1477955/source.txt/home/user1477955/target.txt

+0

你是完全正确的,非常感谢你的快速反应 – user1477955 2013-04-23 10:17:41

0

你可以试试这个:

try { 
     File file = new File(args[0]); 
     BufferedReader in = new BufferedReader(new FileReader(file)); 
     //rest of your code 
     in.close(); 
    } catch (IOException e) { 
     System.out.println("File Read Error: " + e.getMessage()); 
    } 
+1

如果路径错误或文件不可读,这将无济于事。 – NilsH 2013-04-23 10:05:54