检查Java反射调用的正确方法？

Question

我昨晚发布了一个关于Java Reflection的问题,并且今天早上发现了编译器警告.

C:\javasandbox\reflection>javac ReflectionTest.java
Note: ReflectionTest.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.

C:\javasandbox\reflection>javac -Xlint:unchecked ReflectionTest.java
ReflectionTest.java:17: warning: [unchecked] unchecked call to
getDeclaredMethod(java.lang.String,java.lang.Class<?>...) as a member of the raw
type java.lang.Class

        myMethod = myTarget.getDeclaredMethod("getValue");
                                             ^
ReflectionTest.java:22: warning: [unchecked] unchecked call to
getDeclaredMethod(java.lang.String,java.lang.Class<?>...) as a member of the raw
type java.lang.Class

        myMethod = myTarget.getDeclaredMethod("setValue", params);
                                             ^
2 warnings

是否有"正确"的方法来检查这些返回的方法？(即有没有正确的方法来摆脱这些警告？)

源代码:

import java.lang.reflect.*;

class Target {
    String value;

    public Target() { this.value = new String("."); }
    public void setValue(String value) { this.value = value; }
    public String getValue() { return this.value; }
}

class ReflectionTest {
    public static void main(String args[]) {
        try {
            Class myTarget = Class.forName("Target");

            Method myMethod;
            myMethod = myTarget.getDeclaredMethod("getValue");
            System.out.println("Method Name: " + myMethod.toString());

            Class params[] = new Class[1];
            params[0] = String.class;
            myMethod = myTarget.getDeclaredMethod("setValue", params);
            System.out.println("Method Name: " + myMethod.toString());

        } catch (Exception e) {
            System.out.println("ERROR");
        }
    }
}

Answer 1

更改

Class myTarget = Class.forName("Target");

至

Class<?> myTarget = Class.forName("Target");

这基本上意味着,"我知道它是通用的,但我对类型论证一无所知." 它们在语义上是等价的,但编译器可以区分它们.有关更多信息,请参阅相关的Java Generics FAQ条目("无界通配符实例和原始类型之间有什么区别？").