[Java] 相對路徑，絕對路徑

public class testPath {

 public static void main(String[] args) {

  System.out.println(System.getProperty("java.class.path"));//Java 類別路徑
  
  
  System.out.println(System.getProperty("user.dir"));//用戶的當前工作目錄
  //System.getProperty("user.dir") + "/filename" ，較安全的相對路徑
  
  String basePathR = new File("").getPath();
  System.out.println("getPath:"+basePathR);
  
  String basePathA = new File("").getAbsolutePath();
  System.out.println("getAbsolutePath:"+basePathA);

  try {
   String basePathC = new File("").getCanonicalPath();
   System.out.println("getCanonicalPath:"+basePathC);
   
  } catch (IOException e1) {
   // TODO Auto-generated catch block
   e1.printStackTrace();
  }
  System.out.println("=releative path=============");
  
  FileWriter writer = null;
  try {
   File file = new File("releative.txt");
   writer = new FileWriter(file);
   writer.write("test re");
   displayPath(file);
  } catch (IOException e) {
   System.out.println("releative:" + e.getMessage());
  } finally {
   try {
    if (writer != null)
     writer.close();
   } catch (IOException e) {
   }
  }

  System.out.println("=absolute path=============");
  
  try {
   File file = new File("/candelete/absolute.txt");
   
   writer = new FileWriter(file);
   writer.write("test ab");
   displayPath(file);
  } catch (IOException e) {
   System.out.println("absolute:" + e.getMessage());
  } finally {
   try {
    if (writer != null)
     writer.close();
   } catch (IOException e) {
   }
  }

 }

 public static void displayPath(File testFile) {

  System.out.println("path : " + testFile.getPath());

  System.out.println("absolute path : " + testFile.getAbsolutePath());

  try {

   System.out.println("canonical path : "
     + testFile.getCanonicalPath());

  } catch (Exception e) {

   e.printStackTrace();

  }

 }

}

輸出結果:

C:\Users\Melody\workspace_web\testJava\bin
C:\Users\Melody\workspace_web\testJava
getPath:
getAbsolutePath:C:\Users\Melody\workspace_web\testJava
getCanonicalPath:C:\Users\Melody\workspace_web\testJava
=releative path=============
path : releative.txt
absolute path : C:\Users\Melody\workspace_web\testJava\releative.txt
canonical path : C:\Users\Melody\workspace_web\testJava\releative.txt
=absolute path=============
path : \candelete\absolute.txt
absolute path : C:\candelete\absolute.txt
canonical path : C:\candelete\absolute.txt