反射用的Field类的set(Object obj ,Object value)方法里面隐含有类型转换？

MikeDDT009 2017-06-30 12:42:56

RT，才开始还没有发觉，但是在实际写的时候，写到这一步突然发现第二个设置值的参数类型是Object类型。这样就产生了一个疑惑：
假如我的对象的某属性类型是BBB类，然后这样设置值就会说BBB prop = Object obj ----这里只是比较形象的说明，并不是什么语法问题。
那么这样就会明显类型不匹配，所以就想是不是此方法内部其实是有个强制类型转换，本来打算瞅瞅源码，结果发现此方法里面的方法没源码，只有字节码文件，所以看不到具体实现。于是问问

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自由自在_Yu 2017-07-03

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eclipse插件 http://download.csdn.net/detail/lijun7788/9689312 单独打开jar包工具： jd-gui

MikeDDT009 2017-06-30

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引用 1 楼 yuxiangaaaaa 的回复:

 public void set(Object obj, Object value)
	throws IllegalArgumentException, IllegalAccessException
    {
        getFieldAccessor(obj).set(obj, value);
    }

private FieldAccessor getFieldAccessor(Object obj)
        throws IllegalAccessException
    {
        doSecurityCheck(obj);
        boolean ov = override;
        FieldAccessor a = (ov)? overrideFieldAccessor : fieldAccessor;
        return (a != null)? a : acquireFieldAccessor(ov);
    }

private FieldAccessor acquireFieldAccessor(boolean overrideFinalCheck) {
        // First check to see if one has been created yet, and take it
        // if so
        FieldAccessor tmp = null;
        if (root != null) tmp = root.getFieldAccessor(overrideFinalCheck);
        if (tmp != null) {
            if (overrideFinalCheck)
                overrideFieldAccessor = tmp;
            else
                fieldAccessor = tmp;
        } else {
            // Otherwise fabricate one and propagate it up to the root
            tmp = reflectionFactory.newFieldAccessor(this, overrideFinalCheck);
            setFieldAccessor(tmp, overrideFinalCheck);
        }
        return tmp;
    }

你要的源码

你是哪查看的呢？表示用eclipse大部分的使用ctrl+鼠标左键都可以查看，而有些只有字节码

自由自在_Yu 2017-06-30

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 public void set(Object obj, Object value)
	throws IllegalArgumentException, IllegalAccessException
    {
        getFieldAccessor(obj).set(obj, value);
    }

private FieldAccessor getFieldAccessor(Object obj)
        throws IllegalAccessException
    {
        doSecurityCheck(obj);
        boolean ov = override;
        FieldAccessor a = (ov)? overrideFieldAccessor : fieldAccessor;
        return (a != null)? a : acquireFieldAccessor(ov);
    }

private FieldAccessor acquireFieldAccessor(boolean overrideFinalCheck) {
        // First check to see if one has been created yet, and take it
        // if so
        FieldAccessor tmp = null;
        if (root != null) tmp = root.getFieldAccessor(overrideFinalCheck);
        if (tmp != null) {
            if (overrideFinalCheck)
                overrideFieldAccessor = tmp;
            else
                fieldAccessor = tmp;
        } else {
            // Otherwise fabricate one and propagate it up to the root
            tmp = reflectionFactory.newFieldAccessor(this, overrideFinalCheck);
            setFieldAccessor(tmp, overrideFinalCheck);
        }
        return tmp;
    }

你要的源码

MikeDDT009 2017-06-30