[Java知识库]spring 的全局异常的实现

非保姆教程

整体思路：
1、通过@ControllerAdvice和@ExceptionHandler注解实现全局异常
2、按照规范实现和填充其他细节

首先全局捕捉异常

package **

import lombok.extern.slf4j.Slf4j;
import org.apache.poi.EncryptedDocumentException;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.dao.DuplicateKeyException;
import org.springframework.http.HttpStatus;
import org.springframework.http.converter.HttpMessageNotReadableException;
import org.springframework.validation.BindException;
import org.springframework.validation.BindingResult;
import org.springframework.validation.FieldError;
import org.springframework.web.HttpMediaTypeNotSupportedException;
import org.springframework.web.HttpRequestMethodNotSupportedException;
import org.springframework.web.bind.MethodArgumentNotValidException;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.ResponseStatus;

import javax.servlet.http.HttpServletRequest;
import javax.validation.ConstraintViolation;
import javax.validation.ConstraintViolationException;
import java.nio.file.AccessDeniedException;

@Slf4j
@ControllerAdvice
@ResponseBody
@Qualifier("globalExceptionAdvice")
public class GlobalExceptionAdvice {

 	@ResponseStatus(HttpStatus.METHOD_NOT_ALLOWED)
    @ExceptionHandler(MyException.class)
    public MyResponse MyException(MyException e) {
		//log.error("参数解析失败 {}:{}", e.getStackTrace()[0].getClassName(), e.getStackTrace()[0].getMethodName(), e);
        return MyResponse.error("异常文字提醒", HttpStatus.BAD_REQUEST.value());
    }
	//基于此，可以实现各种各样的 自定义异常
	//亦或者是 “想要做的事情”，这里的代码块是会捕捉到异常，并不一定要返回哦
}

自定义异常实现
我们可以借鉴已经实现的异常，来使自定义的异常更加规范

package com.**

import com.**.commons.enums.IErrorCode;

public class MyException extends RuntimeException {
    private int code;
    private String message;

    public MyException(IErrorCode code) {
        this.code = code.getCode();
        this.message = code.getDesc();
    }

    public MyException(IErrorCode code, String message) {
        this.code = code.getCode();
        this.message = message;
    }

    public MyException(final int code, final String message) {
        this.code = code;
        this.message = message;
    }

    public int getCode() {
        return this.code;
    }

    public String getMessage() {
        return this.message;
    }

    public void setCode(final int code) {
        this.code = code;
    }

    public void setMessage(final String message) {
        this.message = message;
    }

    public boolean equals(final Object o) {
        if (o == this) {
            return true;
        } else if (!(o instanceof MyException)) {
            return false;
        } else {
            MyException other = (MyException)o;
            if (!other.canEqual(this)) {
                return false;
            } else if (this.getCode() != other.getCode()) {
                return false;
            } else {
                Object this$message = this.getMessage();
                Object other$message = other.getMessage();
                if (this$message == null) {
                    if (other$message != null) {
                        return false;
                    }
                } else if (!this$message.equals(other$message)) {
                    return false;
                }

                return true;
            }
        }
    }

    protected boolean canEqual(final Object other) {
        return other instanceof MyException;
    }

    public int hashCode() {
        int PRIME = true;
        int result = 1;
        int result = result * 59 + this.getCode();
        Object $message = this.getMessage();
        result = result * 59 + ($message == null ? 43 : $message.hashCode());
        return result;
    }

    public String toString() {
        return "MyException(code=" + this.getCode() + ", message=" + this.getMessage() + ")";
    }
}

以下是spring-web定义的一些异常可以参考

response实现

package **

import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;
import java.io.Serializable;

@ApiModel
public class MyResponse<T> implements Serializable {
// 你可以定义各种各样你需要的信息用来响应
   
   @ApiModelProperty(
        value = "返回状态码，10000代表成功",
        example = "10000"
    )
    private int bizcode;
    
    @ApiModelProperty(
        value = "返回消息，当状态码为非10000，该字段为异常信息",
        example = ""
    )
    private String bizmsg;
    
    @ApiModelProperty(
        value = "返回的数据",
        example = ""
    )
    private T data;
    
    private String sign;
    private long timestamp;
    private String postToken;

//你可以实现各种各样的构造方法
    public MyResponse(String bizmsg, T data, int bizcode) {
        this(bizcode, bizmsg, data, (String)null);
    }

    public MyResponse(int bizcode, String bizmsg, T data, String postToken) {
        this.bizcode = MyEnumCode.SUCCESS.getStatus();
        this.bizmsg = "操作成功";
        this.timestamp = System.currentTimeMillis();
        this.bizcode = bizcode;
        this.bizmsg = bizmsg;
        this.data = data;
        this.postToken = postToken;
        this.timestamp = System.currentTimeMillis();
    }
    public MyResponse(T data) {
        this("", data, CommonErrorCode.SUCCESS.getStatus());
    }

    public MyResponse() {
        this("", (Object)null, CommonErrorCode.SUCCESS.getStatus());
    }

 //省略各种 getter 和 setter 方法

    public static MyResponse ok() {
        return new MyResponse();
    }

    public static <T> MyResponse ok(T data) {
        return new MyResponse(data);
    }

    public static <T> MyResponse<T> ok(String msg, T data) {
        return new MyResponse(msg, data, CommonErrorCode.SUCCESS.getStatus());
    }

    public static MyResponse error() {
        return new MyResponse("操作失败", (Object)null, CommonErrorCode.ERROR.getStatus());
    }

    public static MyResponse error(String msg) {
        return new MyResponse(msg, (Object)null, CommonErrorCode.ERROR.getStatus());
    }

    public static MyResponse error(String msg, int bizcode) {
        return new MyResponse(msg, (Object)null, bizcode);
    }
    
//同理你可以定义各种各样的 方法以及他们的重载方法

}

关于响应状态，jdk8中有一个枚举类来定义
包package org.springframework.http下的HttpStatus

    CONTINUE(100, "Continue"),
    SWITCHING_PROTOCOLS(101, "Switching Protocols"),
    PROCESSING(102, "Processing"),
    CHECKPOINT(103, "Checkpoint"),
    OK(200, "OK"),
    CREATED(201, "Created"),
    ACCEPTED(202, "Accepted"),
    NON_AUTHORITATIVE_INFORMATION(203, "Non-Authoritative Information"),
    NO_CONTENT(204, "No Content"),
    RESET_CONTENT(205, "Reset Content"),
    PARTIAL_CONTENT(206, "Partial Content"),
    MULTI_STATUS(207, "Multi-Status"),
    ALREADY_REPORTED(208, "Already Reported"),
    IM_USED(226, "IM Used"),
    MULTIPLE_CHOICES(300, "Multiple Choices"),
    MOVED_PERMANENTLY(301, "Moved Permanently"),
    FOUND(302, "Found"),
    /** @deprecated */
    @Deprecated
    MOVED_TEMPORARILY(302, "Moved Temporarily"),
    SEE_OTHER(303, "See Other"),
    NOT_MODIFIED(304, "Not Modified"),
    /** @deprecated */
    @Deprecated
    USE_PROXY(305, "Use Proxy"),
    TEMPORARY_REDIRECT(307, "Temporary Redirect"),
    PERMANENT_REDIRECT(308, "Permanent Redirect"),
    BAD_REQUEST(400, "Bad Request"),
    UNAUTHORIZED(401, "Unauthorized"),
    PAYMENT_REQUIRED(402, "Payment Required"),
    FORBIDDEN(403, "Forbidden"),
    NOT_FOUND(404, "Not Found"),
    METHOD_NOT_ALLOWED(405, "Method Not Allowed"),
    NOT_ACCEPTABLE(406, "Not Acceptable"),
    PROXY_AUTHENTICATION_REQUIRED(407, "Proxy Authentication Required"),
    REQUEST_TIMEOUT(408, "Request Timeout"),
    CONFLICT(409, "Conflict"),
    GONE(410, "Gone"),
    LENGTH_REQUIRED(411, "Length Required"),
    PRECONDITION_FAILED(412, "Precondition Failed"),
    PAYLOAD_TOO_LARGE(413, "Payload Too Large"),
    /** @deprecated */
    @Deprecated
    REQUEST_ENTITY_TOO_LARGE(413, "Request Entity Too Large"),
    URI_TOO_LONG(414, "URI Too Long"),
    /** @deprecated */
    @Deprecated
    REQUEST_URI_TOO_LONG(414, "Request-URI Too Long"),
    UNSUPPORTED_MEDIA_TYPE(415, "Unsupported Media Type"),
    REQUESTED_RANGE_NOT_SATISFIABLE(416, "Requested range not satisfiable"),
    EXPECTATION_FAILED(417, "Expectation Failed"),
    I_AM_A_TEAPOT(418, "I'm a teapot"),
    /** @deprecated */
    @Deprecated
    INSUFFICIENT_SPACE_ON_RESOURCE(419, "Insufficient Space On Resource"),
    /** @deprecated */
    @Deprecated
    METHOD_FAILURE(420, "Method Failure"),
    /** @deprecated */
    @Deprecated
    DESTINATION_LOCKED(421, "Destination Locked"),
    UNPROCESSABLE_ENTITY(422, "Unprocessable Entity"),
    LOCKED(423, "Locked"),
    FAILED_DEPENDENCY(424, "Failed Dependency"),
    TOO_EARLY(425, "Too Early"),
    UPGRADE_REQUIRED(426, "Upgrade Required"),
    PRECONDITION_REQUIRED(428, "Precondition Required"),
    TOO_MANY_REQUESTS(429, "Too Many Requests"),
    REQUEST_HEADER_FIELDS_TOO_LARGE(431, "Request Header Fields Too Large"),
    UNAVAILABLE_FOR_LEGAL_REASONS(451, "Unavailable For Legal Reasons"),
    INTERNAL_SERVER_ERROR(500, "Internal Server Error"),
    NOT_IMPLEMENTED(501, "Not Implemented"),
    BAD_GATEWAY(502, "Bad Gateway"),
    SERVICE_UNAVAILABLE(503, "Service Unavailable"),
    GATEWAY_TIMEOUT(504, "Gateway Timeout"),
    HTTP_VERSION_NOT_SUPPORTED(505, "HTTP Version not supported"),
    VARIANT_ALSO_NEGOTIATES(506, "Variant Also Negotiates"),
    INSUFFICIENT_STORAGE(507, "Insufficient Storage"),
    LOOP_DETECTED(508, "Loop Detected"),
    BANDWIDTH_LIMIT_EXCEEDED(509, "Bandwidth Limit Exceeded"),
    NOT_EXTENDED(510, "Not Extended"),
    NETWORK_AUTHENTICATION_REQUIRED(511, "Network Authentication Required");

基于此，我们可以仿照jdk中的一些设计模式来设计一套更加完美的全局异常。