Springboot全局异常处理

2021-02-16 MarsHu springboot springboot

---

• 如何统一捕获异常
• 异常分类Error、CheckedException与RunTimeException
• 同时监听Exception和HTTPException
• 定义统一的异常返回信息类
• 定义异常信息的配置文件
• 根据目录结构,自动添加请求的前缀

如何统一捕获异常

package com.zhqx.missyou.core;

import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;

import javax.servlet.http.HttpServletRequest;

@ControllerAdvice
public class GlobalExceptionAdvice {

    @ExceptionHandler(value = Exception.class)
    public void handleException(HttpServletRequest request, Exception e) {
        //处理逻辑
    }
}

异常分类Error、CheckedException与RunTimeException

Error:错误,通常是系统级别的。Exception:异常

CheckedException:必须进行处理的异常,编译阶段不处理就会报错—通常是我们可以处理的异常

RuntimeException:运行时异常—通常是我们不可以处理的异常

同时监听Exception和HTTPException

自定义HttpException;

package com.zhqx.missyou.exception.http;

public class HttpException extends RuntimeException {
    protected Integer code;
    protected Integer httpStatusCode = 500;
	//省略get和set方法...
}

定义2个属于HttpException的子类异常

package com.zhqx.missyou.exception.http;

public class NotFoundException extends HttpException {
    public NotFoundException(int code) {
        this.code = code;
        this.httpStatusCode = 404;
    }
}	

package com.zhqx.missyou.exception.http;

public class ForbiddenException extends HttpException {
    public ForbiddenException(int code) {
        this.code = code;
        this.httpStatusCode = 403;
    }
}

修改异常处理类

package com.zhqx.missyou.core;

import com.zhqx.missyou.exception.http.HttpException;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;

import javax.servlet.http.HttpServletRequest;

@ControllerAdvice
public class GlobalExceptionAdvice {

	//主要用来处理未知异常
    @ExceptionHandler(value = Exception.class)
    public void handleException(HttpServletRequest request, Exception e) {
        //处理逻辑
    }
	//主要用来处理已知异常
    //当业务代码中抛出属于httpException的异常时,只会执行handleHttpException
    @ExceptionHandler(HttpException.class)
    public void handleHttpException(HttpServletRequest request, HttpException e) {
        //处理httpException逻辑
    }
}

定义统一的异常返回信息类

定义统一异常返回信息类UnifyResponse

package com.zhqx.missyou.core;

public class UnifyResponse {
    private int code;
    private String message;
    private String request;

    public UnifyResponse(int code, String message, String request) {
        this.code = code;
        this.message = message;
        this.request = request;
    }

    //省略get、set方法
	//这里必须要有get方法,否则返回信息时,拿不到相关字段的值,会报错
}

修改异常处理类

import com.zhqx.missyou.exception.http.HttpException;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;

import javax.servlet.http.HttpServletRequest;

@ControllerAdvice
public class GlobalExceptionAdvice {

    @ExceptionHandler(value = Exception.class)
    @ResponseBody
    public UnifyResponse handleException(HttpServletRequest request, Exception e) {
        UnifyResponse message = new UnifyResponse(9999, "服务器异常", "url");
        return message;
    }

    //当业务代码中抛出属于httpException的异常时,只会执行handleHttpException
    @ExceptionHandler(HttpException.class)
    public void handleHttpException(HttpServletRequest request, HttpException e) {
        //处理httpException逻辑
    }
}

进行如上修改后,我们在控制器中抛出Exception时,就会得到正常的json格式的返回信息。

{
    "code": 9999,
    "message": "服务器异常",
    "request": "url"
}

但是这个时候,我们发现Status还是200,这是不符合常理的。因为我们系统已经出错了。使用@ResponseStatus注解来控制请求状态码。

import com.zhqx.missyou.exception.http.HttpException;
import org.springframework.http.HttpStatus;
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;

@ControllerAdvice
public class GlobalExceptionAdvice {

    @ExceptionHandler(value = Exception.class)
    @ResponseBody
    @ResponseStatus(code = HttpStatus.INTERNAL_SERVER_ERROR)
    public UnifyResponse handleException(HttpServletRequest request, Exception e) {
        String requestUrl = request.getRequestURI();
        String method = request.getMethod();
		//打印异常信息
		System.out.println(e);
        UnifyResponse message = new UnifyResponse(9999, "服务器异常", method + " " +requestUrl);
        return message;
    }

    //当业务代码中抛出属于httpException的异常时,只会执行handleHttpException
    @ExceptionHandler(HttpException.class)
    public void handleHttpException(HttpServletRequest request, HttpException e) {
        //处理httpException逻辑
    }
}

使用@ResponseStatus注解没有办法灵活的自定义状态码。当我们需要在控制器中抛出自定义的HttpException时,我们通常会自定义一个code值。

假设控制器中抛出的异常如下：

import com.zhqx.missyou.exception.http.ForbiddenException;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/v1/banner")
public class BannerController {

    @GetMapping("/test")
    public String test() throws Exception {
        throw new ForbiddenException(10001);
    }
}

这个时候,我们修改统一异常处理,针对自定义的HttpException做出修改。

@ControllerAdvice
public class GlobalExceptionAdvice {

    @ExceptionHandler(value = Exception.class)
    @ResponseBody
    @ResponseStatus(code = HttpStatus.INTERNAL_SERVER_ERROR)
    public UnifyResponse handleException(HttpServletRequest request, Exception e) {
        String requestUrl = request.getRequestURI();
        String method = request.getMethod();
		//打印异常信息
		System.out.println(e);
        UnifyResponse message = new UnifyResponse(9999, "服务器异常", method + " " +requestUrl);
        return message;
    }

    //当业务代码中抛出属于httpException的异常时,只会执行handleHttpException
    @ExceptionHandler(HttpException.class)
    public ResponseEntity<UnifyResponse> handleHttpException(HttpServletRequest request, HttpException e) {
        //处理httpException逻辑
        String requestUrl = request.getRequestURI();
        String method = request.getMethod();
        UnifyResponse message = new UnifyResponse(e.getCode(), "xxx", method + " " +requestUrl);
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_JSON);
        HttpStatus status = HttpStatus.resolve(e.getHttpStatusCode());
        ResponseEntity<UnifyResponse> responseEntity = new ResponseEntity<>(message, headers, status);
        return responseEntity;
    }
}

定义异常信息的配置文件

在上面的过程中,我们没有针对10001这个code码返回具体的错误信息。在很多时候我们会采取硬编码的方式,来返回错误信息。实际上,为了方便管理 错误信息。我们也可以将所有错误信息保存在配置文件中。

定义错误信息配置文件。文件位置resources/config/exception-code.properties.

zhqx.codes[10000]="通用异常"
zhqx.codes[10001]="通用参数异常"

定义错误信息配置类,与配置文件对应

package com.zhqx.missyou.core.configuration;

import java.util.HashMap;
import java.util.Map;

//对应配置文件中的前缀
@ConfigurationProperties(prefix = "zhqx")
//读取对应的配置文件
@PropertySource("classpath:config/exception-code.properties")
//交由容器管理
@Component
public class ExceptionCodeConfiguration {
	//这里需要codes与配置文件中的一致
    private Map<Integer, String> codes = new HashMap<>();

    public Map<Integer, String> getCodes() {
        return codes;
    }

    public void setCodes(Map<Integer, String> codes) {
        this.codes = codes;
    }

    public String getMessage(int code) {
        String message = codes.get(code);
        return message;
    }
}

修改统一异常处理类：

package com.zhqx.missyou.core;

import com.zhqx.missyou.core.configuration.ExceptionCodeConfiguration;
import com.zhqx.missyou.exception.http.HttpException;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
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;

@ControllerAdvice
public class GlobalExceptionAdvice {
    
	//关联异常信息配置类
    @Autowired
    private ExceptionCodeConfiguration exceptionCodeConfiguration;

    @ExceptionHandler(value = Exception.class)
    @ResponseBody
    @ResponseStatus(code = HttpStatus.INTERNAL_SERVER_ERROR)
    public UnifyResponse handleException(HttpServletRequest request, Exception e) {
        String requestUrl = request.getRequestURI();
        String method = request.getMethod();
		//打印异常信息
		System.out.println(e);
        UnifyResponse message = new UnifyResponse(9999, "服务器异常", method + " " +requestUrl);
        return message;
    }

    //当业务代码中抛出属于httpException的异常时,只会执行handleHttpException
    @ExceptionHandler(HttpException.class)
    public ResponseEntity<UnifyResponse> handleHttpException(HttpServletRequest request, HttpException e) {
        //处理httpException逻辑
        String requestUrl = request.getRequestURI();
        String method = request.getMethod();
		//读取对应code值的message信息 
        UnifyResponse message = new UnifyResponse(e.getCode(), exceptionCodeConfiguration.getMessage(e.getCode()), method + " " +requestUrl);
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_JSON);
        HttpStatus status = HttpStatus.resolve(e.getHttpStatusCode());
        ResponseEntity<UnifyResponse> responseEntity = new ResponseEntity<>(message, headers, status);
        return responseEntity;
    }
}

这个时候,我们重新访问,我们得到返回结果

{
    "code": 10001,
    "message": "\"通用参数异常\"",
    "request": "GET /v1/banner/test"
}

这里会有2个问题,一个是返回信息出现乱码,第二个是,返回的信息加上了引号 ““。

乱码需要修改File

Settings

Editor

File Encodings配置项的properties file的编码为UTF-8,并勾选后面的native-to-ascii选项

引号问题需要将原来配置文件中的引号去掉

zhqx.codes[10000]=通用异常
zhqx.codes[10001]=通用参数异常

再次访问后得到正常信息

{
    "code": 10001,
    "message": "通用参数异常",
    "request": "GET /v1/banner/test"
}

根据目录结构,自动添加请求的前缀

当前我们控制器的路径结构是com.zhqx.missyou.api.v1,如下

package com.zhqx.missyou.api.v1;

import com.zhqx.missyou.exception.http.ForbiddenException;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/v1/banner")
public class BannerController {

    @GetMapping("/test")
    public String test() throws Exception {
        throw new ForbiddenException(10001);
    }
}

当我们在v1目录下有很多个控制器的时候,我们如何避免在每个控制器上都手动书写/v1这样的前缀呢。

Springboot默认情况下是通过RequestMappingInfo来统一处理@RequestMapping注解的请求。

所以我们需要自定义一个RequestMappingInfo,实现添加请求前缀

package com.zhqx.missyou.core.hack;

import org.springframework.web.servlet.mvc.method.RequestMappingInfo;
import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping;

import java.lang.reflect.Method;

public class AutoPrefixUrlMapping extends RequestMappingHandlerMapping {

    @Override
    protected RequestMappingInfo getMappingForMethod(Method method, Class<?> handlerType) {
        RequestMappingInfo requestMappingInfo = super.getMappingForMethod(method, handlerType);
        if(requestMappingInfo != null) {

        }
        return requestMappingInfo;
    }

    private String getPrefix(Class<?> handlerType) {
        String packageName = handlerType.getPackage().getName();
        return packageName;
    }
}

RequestMappingInfo自定义之后,我们还需要将他注册到整个容器中,我们需要定义一个配置类,让Springboot处理请求时,会调用我们自定义请求处理类

package com.zhqx.missyou.core.configuration;

import com.zhqx.missyou.core.hack.AutoPrefixUrlMapping;
import org.springframework.boot.autoconfigure.web.servlet.WebMvcRegistrations;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping;

@Component
public class AutoPrefixConfiguration implements WebMvcRegistrations {
    @Override
    public RequestMappingHandlerMapping getRequestMappingHandlerMapping() {
        return new AutoPrefixUrlMapping();
    }
}

在配置文件application.properties中定义当前所有控制器所处的根目录

demo.condition=demo1
zhqx.api-package = com.zhqx.missyou.api

修改自定义的RequestMappingInfo实现类

package com.zhqx.missyou.core.hack;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.servlet.mvc.method.RequestMappingInfo;
import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping;

import java.lang.reflect.Method;

public class AutoPrefixUrlMapping extends RequestMappingHandlerMapping {

    //读取配置文件中自定义的控制器所处根路径
    @Value("${zhqx.api-package}")
    private String apiPackagePath;

    @Override
    protected RequestMappingInfo getMappingForMethod(Method method, Class<?> handlerType) {
        RequestMappingInfo requestMappingInfo = super.getMappingForMethod(method, handlerType);
        if(requestMappingInfo != null) {
            String prefix = this.getPrefix(handlerType);
            return RequestMappingInfo.paths(prefix).build().combine(requestMappingInfo);
        }
        return requestMappingInfo;
    }

    private String getPrefix(Class<?> handlerType) {
        String packageName = handlerType.getPackage().getName();
        String dotPath = packageName.replaceAll(this.apiPackagePath, "");
        return dotPath.replace(".", "/");
    }
}

这个时候我们修改控制器的请求

package com.zhqx.missyou.api.v1;

import com.zhqx.missyou.exception.http.ForbiddenException;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/banner")
public class BannerController {

    @GetMapping("/test")
    public String test() throws Exception {
        throw new ForbiddenException(10001);
    }
}

我们仍然可以通过http://localhost:8080/v1/banner/test来访问请求。

当我们的控制器位于com.zhqx.missyou.api.v1.other包下时

package com.zhqx.missyou.api.v1.other;

import com.zhqx.missyou.exception.http.ForbiddenException;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/banner")
public class BannerController {

    @GetMapping("/test")
    public String test() throws Exception {
        throw new ForbiddenException(10001);
    }
}

我们可以通过http://localhost:8080/v1/other/banner/test来访问请求。

原文链接: https://marshucheng1.github.io/2021/02/16/springboot-qiyue-2/

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