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java.lang.reflect.InvocationTargetException

程序员文章站 2024-01-10 15:33:22
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在通过反射执行方法的时,如Method.invoke(),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,这个异常会被包装成InvocationTargetException重新抛出.

比如方法抛出了org.springframework.jdbc.BadSqlGrammarException,则Method.invoke方法抛出的是InvocationTargetException,而不是 BadSqlGrammarException,必须要提取它的TargetException重新抛出才行.

org.apache.commons.lang.StringUtils
org.springframework.context.ApplicationContext
java.lang.reflect.Method
java.lang.Throwable

public Object invokeMethod(String subscriber,String params) {
	String managerName =  StringUtils.substringBefore(subscriber.trim(),".");;
	String methodName = StringUtils.substringAfter(subscriber.trim(),".");
	Object manager = applicationContext.getBean(managerName);
	Object obj = null;
	String message = "";
	try {
		Method method = manager.getClass().getMethod(methodName, new Class[]{String.class});
		obj = method.invoke(manager,new Object[]{params});
	} 
	catch (IllegalArgumentException e) {
		throw new BusinessException(e.getMessage());
	} catch (SecurityException e) {
		throw new BusinessException(e.getMessage());
	} catch (IllegalAccessException e) {
		throw new BusinessException(e.getMessage());
	} catch (InvocationTargetException e) {
		Throwable targetEx = ((InvocationTargetException) e)
				.getTargetException();
		if (targetEx != null){
			message = targetEx.getMessage();
		}else{
			message = e.getMessage();
		}
		throw new BusinessException(message);//e.getCause()
	} catch (NoSuchMethodException e) {
		throw new BusinessException(e.getMessage());
	}catch (Exception e) {
		throw new BusinessException(e.getMessage());
	}
	return obj;
}

package com.test.reflect;  
  
public class Reflect {  
    public void run(int j) throws BusinessException {  
        BOL b = new BOL();  
        b.run(i);  
    }  
}
class BOL {  
    public void run(int j) throws BusinessException {  
        if (j < 0) {  
            throw new BusinessException("参数不能小于零!");  
        } 
    }  
} 
class BusinessException extends Exception {  
    private static final long serialVersionUID = 1L;  
  
    private String message;  
  
    public BusinessException(String message) {  
        this.message = message;  
    }  
  
    public String getMessage() {  
        return message;  
    }  
} 

TEST:

package com.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.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) {
			
            Throwable t = e.getTargetException();// 获取目标异常  
            t.printStackTrace();  //重新抛出
        } catch (InstantiationException e) {  
            e.printStackTrace();  
        }  
    }  
} 

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