java - 抛出多个自定义异常时如何处理

Question

从单个方法中根据条件抛出两个不同的自定义异常。创建自定义异常时，传递两件事，一件事是错误消息，另一件事是字符串形式的错误代码。但我无法根据错误代码获取错误。调用 processErrorCodes() 方法时出现错误。谁能帮我解决这个问题。

// BackgroundException is a custom EXCEPTION 
public class BackgroundException extends Exception {

        private static final long serialVersionUID = 4664456874499611218L;

        private String errorCode="Unknown_Exception";

        public BackgroundException(String message, String errorCode){
            super(message);
            this.errorCode=errorCode;
        }

        public String getErrorCode(){
            return this.errorCode;
        }    
}

// Similarly I have InvalidException custom exception

public class MyExceptionTest {

public void methodTest(){
    String policyId =null;
    String policyNotification = null;
    String policyStatus = null;
    try {
        if(policyNotification !=null) {

            if(policyStatus!=null) {

                if(policyId!=null) {    

                }
                else{
                    throw new InvalidException("Policy ID Is Null","POLICY_ID");
                }

            }else{
                throw new BackgroundException("Policy Status Is Null","POLICY_STATUS");
            }
        }
        else{
            throw new BackgroundException("Policy Notification Is Null","POLICY_NOTIFICATION");
        }
    } catch (BackgroundException | InvalidException e  ) {
        // TODO Auto-generated catch block
        try {
            processErrorCodes(e);
        } catch (MyExcep e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }
        e.getMessage();
    }

}
private static void processErrorCodes(Exception e) throws BackgroundException,InvalidException {
    switch(e.getErrorCode()){
    case "POLICY_NOTIFICATION":
       System.out.println(e.getMessage());
        throw e;
    case "POLICY_ID":
        System.out.println(e.getMessage());
        throw e;
    case "POLICY_STATUS":
        System.out.println(e.getMessage());
        throw e;
    default:
        System.out.println("Unknown exception occured, lets log it for further debugging."+e.getMessage());
        e.printStackTrace();
    }
}
 public static void main(String[] args) {
     MyExceptionTest mt = new MyExceptionTest(); 
     mt.methodTest();
}
}

I just want to handle those exceptions based on the error code.

Answer 1

您需要一个通用的父类(super class)来处理所有自定义异常，例如 MessageCodeException ，延伸Exception并接受这个父类(super class)类型作为 processErrorCodes 内的参数方法

public abstract class MessageCodeException extends Exception {
    public abstract String getCode();

    // you can have a same abstract method for message
}

public class BackgroundException extends MessageCodeException {
    // ...
}

public class InvalidException extends MessageCodeException {
    // ...
}

//and now the process method will look like

private static void processErrorCodes(Exception e) throws ... {
    // ...
}

很明显，对于当前的实现，您无法访问 code字段，因为Exception类接口(interface)不提供类似的东西

<小时/>

顺便说一句，创建异常驱动的业务验证逻辑似乎是一个非常糟糕的主意。创建某种 ValidationResult 不是更好吗？包含错误/警告/成功列表的对象并在最后处理此类验证结果？ Exception的目的存在并不是为了控制应用程序流程，而是为了强制用户为紧急情况提供一些支持(或者用 RuntimeException 处理某种意外情况)