Java异常处理之InvocationTargetException（反射异常）

InvocationTargetException异常由Method.invoke(obj, args...)方法抛出。当被调用的方法的内部抛出了异常而没有被捕获时，将由此异常接收！！！

示例：

package com.zzj.test.reflect;

public class Reflect {
    public void run(int i) throws ZeroException {
        B b = new B();
        b.run(i);
    }
}

class B {
    public void run(int i) throws ZeroException {
        if (i < 0) {
            throw new ZeroException("参数不能小于零！");
        }
        System.out.println("参数：" + i);

    }
}

class ZeroException extends Exception {
    private static final long serialVersionUID = 1L;

    private String detailMessage;

    public ZeroException(String detailMessage) {
        this.detailMessage = detailMessage;
    }

    public String getMessage() {
        return detailMessage;
    }
}

测试：

package com.zzj.test.reflect;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

public class Test {
    public static void main(String[] args) {
        try {
            Class<?> clazz = Class.forName("com.zzj.test.reflect.Reflect");
            Method method = clazz.getMethod("run", int.class);
            method.invoke(clazz.newInstance(), -1);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SecurityException e) {
            e.printStackTrace();
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            System.out.println("此处接收被调用方法内部未被捕获的异常");
            e.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
        }
    }
}

输出：

此处接收被调用方法内部未被捕获的异常
java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at com.zzj.test.reflect.Test.main(Test.java:11)
Caused by: com.zzj.test.reflect.ZeroException: 参数不能小于零！
    at com.zzj.test.reflect.B.run(Reflect.java:13)
    at com.zzj.test.reflect.Reflect.run(Reflect.java:6)
    ... 5 more

也可以直接打印目标异常：

package com.zzj.test.reflect;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

public class Test {
    public static void main(String[] args) {
        try {
            Class<?> clazz = Class.forName("com.zzj.test.reflect.Reflect");
            Method method = clazz.getMethod("run", int.class);
            method.invoke(clazz.newInstance(), -1);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SecurityException e) {
            e.printStackTrace();
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            System.out.println("此处接收被调用方法内部未被捕获的异常");
            Throwable t = e.getTargetException();// 获取目标异常
            t.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
        }
    }
}

输出：

此处接收被调用方法内部未被捕获的异常
com.zzj.test.reflect.ZeroException: 参数不能小于零！
    at com.zzj.test.reflect.B.run(Reflect.java:13)
    at com.zzj.test.reflect.Reflect.run(Reflect.java:6)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at com.zzj.test.reflect.Test.main(Test.java:11)

人一定要靠自己