一是从linux中编译后源码中提取该隐藏类所在的jar包，然后导入项目中调用；

二是从编译前的源码中提取相应的java类，将其包含在项目中使用；

从性能的角度将，我不提倡使用反射，据网上测试结果说，简单方法使用反射调用其性能损耗太大，但复杂方法或项目中使用性能损耗比例小一些，但还是会有损耗，所以希望大家在用之前多多斟酌得失吧~

转载：

之前在写2.2的退出程序的时候，发现一些API是被隐藏的，App不能直接使用，在讨论的时候知道利用反射可以实现。今天就做了个反射的测试用例。做为引子！

为了实用，概念性的东西，直接上代码了：

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Arrays;

//: ShowMethod.java
//Using Java 1.1 reflection to show all the
//methods of a class, even if the methods are
//defined in the base class

public class ShowMethod {
static final String usage =
"usage: \n" +
"ShowMethods qualified.class.name\n" +
"To show all methods in class or: \n" +
"ShowMethods qualified.class.name word\n" +
"To search for methods involving 'word'";

public static void main(String[] args) {
System.out.println(Arrays.deepToString(args));
if(args.length < 1) {
System.out.println(usage);
System.exit(0);
}
try {
Class c = Class.forName(args[0]);

Class[] parameterTypes = new Class[1];
parameterTypes[0] = char[].class;
try {
Method tt = c.getMethod("valueOf", parameterTypes);
char[] pp = {'a','b','c','d'};
try {
String back = (String)tt.invoke(c.newInstance(), pp);
System.out.println("反射调用方法valueOf(char[])返回String: "+back);
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InvocationTargetException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InstantiationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

} catch (SecurityException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (NoSuchMethodException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

Method[] m = c.getMethods();
Constructor[] ctor = c.getConstructors();
if(args.length == 1) {
for (int i = 0; i < m.length; i++)
System.out.println(m.toString());
for (int i = 0; i < ctor.length; i++)
System.out.println(ctor.toString());
}
else {
for (int i = 0; i < m.length; i++)
if(m.toString()
.indexOf(args[1])!= -1)
System.out.println(m.toString());
for (int i = 0; i < ctor.length; i++)
if(ctor.toString()
.indexOf(args[1])!= -1)
System.out.println(ctor.toString());
}
} catch (ClassNotFoundException e) {
System.out.println("No such class: " + e);
}

}

}

例子的执行需要注意下：