java中的庫查找路徑

Question

每當有人部署應用程序時，這個問題就是一個問題：在部署項目後，java在哪裏查找庫（jar和dll）？

最好的問候， 斯特凡

Answer 1

在其classpath。

在應用程序服務器上，通常設置了很多路徑。通常，您可以檢查啓動日誌或登錄以下屬性的值，以確定其尋找：

System.getProperty("java.class.path") 

Answer 2

http://en.wikipedia.org/wiki/Classpath_%28Java%29

**虛擬機搜索和加載類的順序如下：

bootstrap classes: the classes that are fundamental to the Java Platform (comprising the public classes of the Java Class Library, and the private classes that are necessary for this library to be functional). 
extension classes: packages that are in the extension directory of the JRE or JDK, jre/lib/ext/ 
user-defined packages and libraries 

**

Answer 3

它看起來幾個不同的地方，如其他答案建議。您可以使用System.getProperty("java.library.path")或System.getProperty("java.class.path")來查看實際路徑。

下面的代碼我也發現很有用。您可以使用它在運行時添加搜索到的庫路徑的路徑。

 

    /** 
    * Allows you to add a path to the library path during runtime 
    * @param dllLocation The path you would like to add 
    * @return True if the operation completed successfully, false otherwise 
    */ 
    public boolean addDllLocationToPath(final String dllLocation) 
    { 
     //our return value 
     boolean retVal = false; 
     try 
     { 
      System.setProperty("java.library.path", System.getProperty("java.library.path") + ";" + dllLocation); 
      //get the sys path field 
      Field fieldSysPath = ClassLoader.class.getDeclaredField("sys_paths"); 
      fieldSysPath.setAccessible(true); 
      fieldSysPath.set(null, null); 
      retVal = true; 
     } 
     catch (Exception e) 
     { 
      System.err.println("Could not modify path"); 
     } 
     return retVal; 
    }