如何从当前运行的jar中复制文件

Question

我有一个.jar,它有两个依赖的.dll文件.我想知道是否有任何方法可以将这些文件从.jar中复制到运行时的用户临时文件夹中.这是我当前的代码(编辑为只有一个.dll加载以减少问题大小):

public String tempDir = System.getProperty("java.io.tmpdir");
public String workingDir = dllInstall.class.getProtectionDomain().getCodeSource().getLocation().getPath();

public boolean installDLL() throws UnsupportedEncodingException {

try {
             String decodedPath = URLDecoder.decode(workingDir, "UTF-8");
             InputStream fileInStream = null;
             OutputStream fileOutStream = null;

             File fileIn = new File(decodedPath + "\\loadAtRuntime.dll");
             File fileOut = new File(tempDir + "loadAtRuntime.dll");

             fileInStream = new FileInputStream(fileIn);
             fileOutStream = new FileOutputStream(fileOut);

             byte[] bufferJNI = new byte[8192000013370000];
             int lengthFileIn;

             while ((lengthFileIn = fileInStream.read(bufferJNI)) > 0) {
                fileOutStream.write(bufferJNI, 0, lengthFileIn);
             }

            //close all steams
        } catch (IOException e) {
      e.printStackTrace();
             return false;
        } catch (UnsupportedEncodingException e) {
             System.out.println(e);
              return false;
        }

我的主要问题是在运行时将.dll文件从jar中取出.从.jar中检索路径的任何方法都会有所帮助.

提前致谢.

Answer 1

由于您的dll在jar文件中是可靠的,因此您可以尝试使用ClassLoader#getResourceAsStream将它们作为资源进行处理,并将它们作为二进制文件写入硬盘上的任何位置.

以下是一些示例代码:

InputStream ddlStream = <SomeClassInsideTheSameJar>.class
    .getClassLoader().getResourceAsStream("some/pack/age/somelib.dll");

try (FileOutputStream fos = new FileOutputStream("somelib.dll");){
    byte[] buf = new byte[2048];
    int r;
    while(-1 != (r = ddlStream.read(buf))) {
        fos.write(buf, 0, r);
    }
}

上面的代码将提取包中的dll some.pack.age到当前工作目录.