以下是
Java 7中java.lang.reflect.Method.equals(Object obj)的实现:
/**
* Compares this {@code Method} against the specified object. Returns
* true if the objects are the same. Two {@code Methods} are the same if
* they were declared by the same class and have the same name
* and formal parameter types and return type.
*/
public boolean equals(Object obj) {
if (obj != null && obj instanceof Method) {
Method other = (Method)obj;
if ((getDeclaringClass() == other.getDeclaringClass())
&& (getName() == other.getName())) {
if (!returnType.equals(other.getReturnType()))
return false;
/* Avoid unnecessary cloning */
Class<?>[] params1 = parameterTypes;
Class<?>[] params2 = other.parameterTypes;
if (params1.length == params2.length) {
for (int i = 0; i < params1.length; i++) {
if (params1[i] != params2[i])
return false;
}
return true;
}
}
}
return false;
}
这里最有趣的部分是比较方法名称:getName()== other.getName().那些返回java.lang.String,因此一个自然的问题是它是否有效通过引用(==)进行比较.虽然这个代码显然是有效的,但是它是否可以成为面向反射的框架中的错误源.你怎么看?
解决方法
当你直接看到Method类的name属性时,有一件事情是有趣的.
// This is guaranteed to be interned by the VM in the 1.4 // reflection implementation private String name;
所以通过interning String你可以直接比较参考.
更多在String.intern()
