集册 Java实例教程 返回与给定方法相对应的描述符。

返回与给定方法相对应的描述符。

欢马劈雪     最近更新时间:2020-01-02 10:19:05

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返回与给定方法相对应的描述符。

//package com.nowjava;


import java.lang.reflect.Method;

/*
 from N o  w  J a v a . c o m - 时  代  Java 
*/

public class Main {

    /**

     * Returns the descriptor corresponding to the given method.

     * @param m a {@link Method Method} object.

     * @return the descriptor of the given method.

     * (All credit to ObjectWeb ASM)

     * @author Eric Bruneton  

     * @author Chris Nokleberg

     */

    public static String getMethodDescriptor(final Method m) {

        Class<?>[] parameters = m.getParameterTypes();

        StringBuffer buf = new StringBuffer();

        buf.append('(');

        for (int i = 0; i < parameters.length; ++i) {

            getDescriptor(buf, parameters[i]);

        }

        buf.append(')');

        getDescriptor(buf, m.getReturnType());

        return buf.toString();

    }


    /**

     * Appends the descriptor of the given class to the given string buffer.

     * @param buf the string buffer to which the descriptor must be appended.

     * @param c the class whose descriptor must be computed.

     * (All credit to ObjectWeb ASM)

     * @author Eric Bruneton  

     * @author Chris Nokleberg

     */

    private static void getDescriptor(final StringBuffer buf,/** 来自 时代Java公众号 - N o w J a  v a . c o m**/

            final Class<?> c) {

        Class<?> d = c;

        while (true) {

            if (d.isPrimitive()) {

                char car;

                if (d == Integer.TYPE) {

                    car = 'I';

                } else if (d == Void.TYPE) {

                    car = 'V';

                } else if (d == Boolean.TYPE) {

                    car = 'Z';

                } else if (d == Byte.TYPE) {

                    car = 'B';

                } else if (d == Character.TYPE) {

                    car = 'C';

                } else if (d == Short.TYPE) {

                    car = 'S';

                } else if (d == Double.TYPE) {

                    car = 'D';

                } else if (d == Float.TYPE) {

                    car = 'F';

                } else /* if (d == Long.TYPE) */{

                    car = 'J';

                }

                buf.append(car);

                return;

            } else if (d.isArray()) {

                buf.append('[');

                d = d.getComponentT
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