使用反射在字段上调用方法 [英] Using Reflection to call a method on a field

问题描述

好的，已经为此工作了太久，无法让它发挥作用.我有一个线程类型列表，它们可以是不同的类，即 WriteFileData(extends Thread).我想循环遍历该列表并调用以将字节数组添加到队列中.我目前在 Broker 类中有这个

Okay been working on this too long and can't get it to work. I have a list of Thread types that can be different classes i.e. WriteFileData(extends Thread). I want to for loop through that list and do a call to add to queue a byte array. I currently have this in a Broker class

// consumers is filled with different Thread types all having a queue
// variable of type LinkedBlockingQueue
ArrayList<Thread> consumers = new ArrayList<Thread>();

synchronized void insert(final byte[] send) throws InterruptedException {
    for (final Thread c : consumers) {
        if (c instanceof WriteFileData) {
            ((WriteFileData)c).queue.add(send);
        } 
        ...other class threads...
}

但我想做的更多是

synchronized void insert(final byte[] send) throws InterruptedException {
    for (final Thread c : consumers) {
       Class<?> cls = Class.forName(c.getClass().getName());
       Field field = cls.getDeclaredField("queue");
       Class<?> cf = Class.forName(field.getType().getName());
       Class[] params = new Class[]{Object.class};

       Method meth = cf.getMethod("offer", params);

       meth.invoke(cf, send);  // errors at this line....

修复了方法未找到错误"但现在似乎无法调用方法，因为我向它发送了一个数组，而它的方法只需要一个对象.

.... 唉，它在 meth.invoke 出错了.不知道如何做到这一点，因为这是很多层次的深度，我想在队列上使用 add 方法，但那是类抽象的另一层.

.... alas it errors out at meth.invoke. Not sure how to do this as this is many levels deep, I wanted to use the add method on queue but that is one more layer of class abstraction.

这是 WriteFileData 有什么...

Here is what WriteFileData has...

public class WriteFileData extends Thread {
    LinkedBlockingQueue<byte[]> queue = new LinkedBlockingQueue<byte[]>();

...
}

推荐答案

这是我根据 @Erik 的一些建议所做的.

Here is what I did with some advice from @Erik.

这是添加了方法 add(byte[] send) ...

Here is WriteFileData with added method add(byte[] send) ...

public class WriteFileData extends Thread {
    private LinkedBlockingQueue<byte[]> queue = new LinkedBlockingQueue<byte[]>();

    public void add(byte[] send) {
        queue.add(send);
    }

...
}

现在我的 Broker 类方法如下所示:

And now my Broker class method looks like this:

public synchronized void insert(final byte[] send) {
    for (final Thread c : consumers) {
    try {
        Class<?> cls = Class.forName(c.getClass().getName());
        Method meth = cls.getMethod("add", new Class[]{byte[].class});
        meth.invoke(c, send);

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