技術標籤：linuxjavajar載入so

java載入so在一些情況下是必須的，

如何生成so，以及在Java中呼叫So ，請見https://blog.csdn.net/dmw412724/article/details/81477546

最常見的問題是，so的載入System.load();必須是全路徑的so，不能使用相對路徑

打包程式最好都放在一個jar裡面，如何從Jar裡面載入so呢？

可以參考這個例子

https://github.com/mkowsiak/jnicookbook/tree/master/recipes/recipeNo031

把so從jar中取出來，放到臨時目錄中，然後再載入

private String extractLibrary() {
    try {
      // Create temporary file
      File file = File.createTempFile("libHelloWorld", ".so");

      // In case it worked, we can extract lib
      if (file.exists()) {
        // First of all, let's show where do we plan to extract it
        System.out.println("Temporary file: " + file.getAbsoluteFile().toPath());

        // Now, we can get the lib file from JAR and put it inside temporary location
        InputStream link = (getClass().getResourceAsStream("/lib/libHelloWorld.so"));

        // We want to overwrite existing file. This is why we are using
        //
        // java.nio.file.StandardCopyOption.REPLACE_EXISTING
        Files.copy(
            link,
            file.getAbsoluteFile().toPath(),
            java.nio.file.StandardCopyOption.REPLACE_EXISTING);
        return file.getAbsoluteFile().toPath().toString();
      }
      // In case something goes wrong, we will simply return null
      return null;

    } catch (IOException e) {
      // The same goes for exception - we are passing null back
      e.printStackTrace();
      return null;
    }
  }
 

public class HelloWorld {

  // Location of native code will be passed from the
  // outside. In this case, Main class makes sure
  // to extract native code from JAR file
  String libFileLocation = null;

  /* This is the native method we want to call */
  public native void displayMessage();

  // In constructor we pass only location of the lib
  // file
  public HelloWorld(String lib) {
    this.libFileLocation = lib;
  }

  // This method will load native code
  // and call native method declared above
  public void callNativeMethod() {
    System.load(libFileLocation);
    displayMessage();
  }
 

參考

https://stackoverflow.com/questions/46609450/encapsulating-a-jni-library-inside-a-jar-file