methodspy.java

来自「java tutorial.sun公司官方出品。java入门书籍。最新版」· Java 代码 · 共 76 行

/*
 * Copyright (c) 1995 - 2008 Sun Microsystems, Inc.  All rights reserved.
 *
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 * modification, are permitted provided that the following conditions
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 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
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 *     documentation and/or other materials provided with the distribution.
 *
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 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */ 

import java.lang.reflect.Method;
import java.lang.reflect.Type;
import static java.lang.System.out;

public class MethodSpy {
    private static final String  fmt = "%24s: %s%n";

    // for the morbidly curious
    <E extends RuntimeException> void genericThrow() throws E {}

    public static void main(String... args) {
	try {
	    Class<?> c = Class.forName(args[0]);
	    Method[] allMethods = c.getDeclaredMethods();
	    for (Method m : allMethods) {
		if (!m.getName().equals(args[1])) {
		    continue;
		}
		out.format("%s%n", m.toGenericString());

		out.format(fmt, "ReturnType", m.getReturnType());
		out.format(fmt, "GenericReturnType", m.getGenericReturnType());

		Class<?>[] pType  = m.getParameterTypes();
		Type[] gpType = m.getGenericParameterTypes();
		for (int i = 0; i < pType.length; i++) {
		    out.format(fmt,"ParameterType", pType[i]);
		    out.format(fmt,"GenericParameterType", gpType[i]);
		}

		Class<?>[] xType  = m.getExceptionTypes();
		Type[] gxType = m.getGenericExceptionTypes();
		for (int i = 0; i < xType.length; i++) {
		    out.format(fmt,"ExceptionType", xType[i]);
		    out.format(fmt,"GenericExceptionType", gxType[i]);
		}
	    }

        // production code should handle these exceptions more gracefully
	} catch (ClassNotFoundException x) {
	    x.printStackTrace();
	}
    }
}