eclipse下的文件路径问题

public class PropertiesGetting {
 
 private Properties properties;
 
 /*
  *  A constructor is built.
  */
 public PropertiesGetting(String fileName)throws Exception{
  properties = new Properties();
  System.out.println();
  InputStream inputstream=new FileInputStream(fileName);
  properties.load(inputstream);
 }
 
 /*
  * A method for getting a value by a specified key
  * is implemented.
  */
 public String getValue(String key)throws Exception{
  String result;
  result=properties.getProperty(key);
  if (result==null){
     throw new Exception("Getting properties from a property file failure!The key can not be found");
  }
  return result; 
 }
}

 

 

 

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;

/*
 * This class provides a general method to get the
 * value of a key from a specified properites file.
 */
public class PropertiesGetting {
 
 private Properties properties;
 
 /*
  *  A constructor is built.
  */
 public PropertiesGetting(String fileName)throws Exception{
  properties = new Properties();

  //InputStream inputstream=new FileInputStream(fileName);
  InputStream inputstream = this.getClass().getResourceAsStream("/"+fileName);
  properties.load(inputstream);
  inputstream.close();
 }
 
 /*
  * A method for getting a value by a specified key
  * is implemented.
  */
 public String getValue(String key)throws Exception{
  String result;
  result=properties.getProperty(key);
  if (result==null){
     throw new Exception("Getting properties from a property file failure!The key can not be found");
  }
  return result; 
 }
 
 public Properties getProperties(){
  return properties;
 }
}

 

这两个类，如果都只是放在eclipse/workspace/project/src的一个包下面，只要把要读取的文件放到src下就没有问题。

 

但是， 为了日后便于操作，我把这个类文件封装成了一个jar包，作为我的utility。这两个类唯一的区别在于：

 InputStream inputstream=new FileInputStream(fileName);
 InputStream inputstream = this.getClass().getResourceAsStream("/"+fileName);

 

打成jar包后，前一种在不同的环境下得到的文件的当前路径不同，比如在ecliipse环境下，如果是java项目则在项目根目录下；如果是j2ee项目则在eclipse目录下（很奇怪！）；如果是制作成war包，则应该放到“tomcat”根目录下，并不是tomcat的webapp/projec 下。所以变数很多！

 

后者相对来说比较固定，就在eclipse的project/src目录下。打成war包应该也不会变（需要测试！）。。。

考虑到项目需要打包，只能把配置文件放到项目根目录下。用如下方法。

 

  //The following method requires the file is in the root directory of project.
  String projectAbsolutePath = System.getProperty( "user.dir");
  
  if (System.getProperty("os.name").contains("Windows")) {
   fileName = projectAbsolutePath+"\\"+fileName;
  }else {
   fileName = projectAbsolutePath+"/"+fileName;
  }
  InputStream inputstream = new FileInputStream(fileName);