异常

ExceptionEnum

/**
 自定义异常枚举类
 */
public enum ExceptionEnum {
    Exception404("页面没找到错误", 404),
    Exception500("后端错误", 500),
    Exception501("除数不能为0, 语法错误", 501)
    ;

    private String errorMsg;
    private Integer errorCode;

    ExceptionEnum(String errorMsg, Integer errorCode) {
        this.errorMsg = errorMsg;
        this.errorCode = errorCode;
    }

    public Integer getErrorCode() {
        return errorCode;
    }

    public String getErrorMsg() {
        return errorMsg;
    }
}

MyException

/**
 自定义异常类
 */
public class MyException extends Exception {

    private String errorMsg;
    private Integer errorCode;

    public MyException() {
    }
    public MyException(String errorMsg, Integer errorCode) {
        this.errorMsg = errorMsg;
        this.errorCode = errorCode;
    }

    public String getErrorMsg() {
        return errorMsg;
    }

    public void setErrorMsg(String errorMsg) {
        this.errorMsg = errorMsg;
    }

    public Integer getErrorCode() {
        return errorCode;
    }

    public void setErrorCode(Integer errorCode) {
        this.errorCode = errorCode;
    }
}

Exception

// Throwable  子类: Exception
// Exception  子类: RuntimeException

public class ExceptionDemo
    public static void main(String[] args) {

        try {
            med2();
        } catch (ArithmeticException e) {
           System.out.println(e.getMessage());
        }

        try {
            med3();
        } catch (ArithmeticException e) {
            System.out.println(e.getMessage());
        }

        try {
            med4();
        } catch (Exception e) {

            System.out.println("e.getMessage()=" + e.getMessage());
            System.out.println(" e.getCause()=" + e.getCause());
            StackTraceElement[] stackTrace = e.getStackTrace();
            if (stackTrace == null || stackTrace.length == 0) {
                return;
            }
            Stream.of(stackTrace).forEach(ee -> System.out.println(" e.getStackTrace()=" + ee));

        }

        // 自定义异常
        try {
            med5();
        } catch (MyException e) {
            System.out.println(e.getErrorCode() + "---" + e.getErrorMsg());
        }
    }

public static void med2() {
        throw new ArithmeticException("我自己抛出一个异常");
    }

    public static void med3() {
        int i = 1 / 0;
    }

    public static void med4() throws Exception {
        try {
            int i = 1 / 0;
        } catch (ArithmeticException e) {
            throw new Exception("我自己抛出一个Exception异常信息", e);
        }
    }

    public static void med5() throws MyException {
        try {
            int i = 1 / 0;
        } catch (Exception e) {
            throw new MyException(ExceptionEnum.Exception501.getErrorMsg()
                    , ExceptionEnum.Exception501.getErrorCode());
        }
    }
}