import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.Iterator;
import java.util.Vector;
public class FreeDynamicDll {
static {
// 首先確保這些dll文件存在
System.load("c:/test/Decode.dll");
}
/**
* 卸載已經裝載的dll
*
* @param dllName
* 庫名，如Decode.dll
*/
private synchronized void freeDll(String dllName) {
try {
ClassLoader classLoader = this.getClass().getClassLoader();
Field field = ClassLoader.class.getDeclaredField("nativeLibraries");
field.setAccessible(true);
Vector<Object> libs = (Vector<Object>) field.get(classLoader);
Iterator<Object> it = libs.iterator();
Object o;
while (it.hasNext()) {
o = it.next();
Field[] fs = o.getClass().getDeclaredFields();
boolean hasInit = false;
for (int k = 0; k < fs.length; k++) {
if (fs[k].getName().equals("name")) {
fs[k].setAccessible(true);
String dllPath = fs[k].get(o).toString();
if (dllPath.endsWith(dllName)) {
hasInit = true;
}
}
}
if (hasInit) {
Method finalize = o.getClass().getDeclaredMethod(
"finalize", new Class[0]);
finalize.setAccessible(true);
finalize.invoke(o, new Object[0]);
it.remove();
libs.remove(o);
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
public static void main(String args[]) {
FreeDynamicDll t = new FreeDynamicDll();
t.freeDll("Decode.dll");
}
}
</script>