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告别代码中遍地的 try-catch，使用 spring 全局统一异常处理

前言

今天要给大家介绍的是如何告别业务代码中大量的try-catch，让你专注于业务代码而不用考虑异常处理。

大家是不是在业务代码里面经常看到这种代码：

/**
 * 坏的案例
 *
 * @return
 */
@RequestMapping(value = "/base-case")
public ActionResult baseCase() {
    try {
        // 业务处理
        // ...
    } catch (BusinessException e) {log.info("业务发生异常", e);
        return ActionResult.fail(e.getCode(), e.getMessage());
    } catch (Exception e) {
        log.info("业务发生异常", e);
        return ActionResult.fail(CommonExceptionEnum.SYSTEM_ERROR.getCode(), e.getMessage());
    }
    return ActionResult.isSuccess();
}

在每个类里都写上这些代码，不仅仅看起来丑陋，后续维护也非常麻烦，万一要改个异常或者日志，要改一万个地方。

今天我要手把手教大家使用使用统一拦截器来告别这种丑陋的代码。

最佳实践

基本思路使用spring提供的ExceptionHandler注解来统一拦截异常，并返回给前端。

直接上案例

案例地址： https://github.com/zhuangjiaju/easytools/blob/main/easytools-web/easytools-web-web/src/main/java/com/github/zhuangjiaju/easytools/web/web/contoller/exception/ExceptionWebController.java

这里需要配合 "统一 Reuslt 对象去封装返回值" 一起使用,可以打开 https://github.com/zhuangjiaju/easytools 找到案例

业务代码中直接抛出异常即可

 /**
 * demo/异常模板
 *
 * @author Jiaju Zhuang
 */
@Slf4j
@RestController
@RequiredArgsConstructor
@RequestMapping("/api/web/result")
public class ExceptionWebController {

    /**
     * 测试业务异常
     *
     * @return
     */
    @GetMapping("business-exception")
    public ActionResult businessException() {
        // 直接抛出异常，不用返回ActionResult
        throw BusinessException.of("业务异常");
    }

    /**
     * 测试系统异常
     *
     * @return
     */
    @GetMapping("system-exception")
    public ActionResult systemException() {
        // 直接抛出异常，不用返回ActionResult
        throw SystemException.of("系统异常");
    }

}

返回的结果：

{
    "success": false,
    "errorCode": "BUSINESS_ERROR",
    "errorMessage": "业务异常",
    "traceId": null
}

{
  "success": false,
  "errorCode": "SYSTEM_ERROR",
  "errorMessage": "系统开小差啦，请尝试刷新页面或者联系管理员",
  "traceId": null
}

输出的异常日志：

2024-07-04T20:54:40.903+08:00  INFO 17360 --- [nio-8080-exec-1] c.g.z.e.w.c.h.ControllerExceptionHandler : 发生业务异常/api/web/result/business-exception:ActionResult(success=false, errorCode=BUSINESS_ERROR, errorMessage=业务异常, traceId=null)

com.github.zhuangjiaju.easytools.tools.base.excption.BusinessException: 业务异常
	at com.github.zhuangjiaju.easytools.tools.base.excption.BusinessException.of(BusinessException.java:47)
	at com.github.zhuangjiaju.easytools.web.web.contoller.exception.ExceptionWebController.businessException(ExceptionWebController.java:30)
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
	at java.base/java.lang.reflect.Method.invoke(Method.java:580)
	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:255)
	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:188)
	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:118)
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:926)
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:831)
	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1089)
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:979)
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1014)
	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:903)
	at jakarta.servlet.http.HttpServlet.service(HttpServlet.java:564)
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:885)
	at jakarta.servlet.http.HttpServlet.service(HttpServlet.java:658)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:195)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:164)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140)
	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:164)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140)
	at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:164)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140)
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:164)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:167)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:90)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:482)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:115)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:93)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:344)
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:389)
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:63)
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:904)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1741)
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52)
	at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1190)
	at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:63)
	at java.base/java.lang.Thread.run(Thread.java:1583)

2024-07-04T20:54:47.361+08:00 ERROR 17360 --- [nio-8080-exec-2] c.g.z.e.w.c.h.ControllerExceptionHandler : 发生业务异常/api/web/result/system-exception:ActionResult(success=false, errorCode=SYSTEM_ERROR, errorMessage=系统开小差啦，请尝试刷新页面或者联系管理员, traceId=null)

com.github.zhuangjiaju.easytools.tools.base.excption.SystemException: 系统异常
	at com.github.zhuangjiaju.easytools.tools.base.excption.SystemException.of(SystemException.java:47)
	at com.github.zhuangjiaju.easytools.web.web.contoller.exception.ExceptionWebController.systemException(ExceptionWebController.java:40)
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
	at java.base/java.lang.reflect.Method.invoke(Method.java:580)
	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:255)
	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:188)
	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:118)
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:926)
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:831)
	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1089)
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:979)
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1014)
	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:903)
	at jakarta.servlet.http.HttpServlet.service(HttpServlet.java:564)
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:885)
	at jakarta.servlet.http.HttpServlet.service(HttpServlet.java:658)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:195)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:164)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140)
	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:164)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140)
	at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:164)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140)
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:164)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:167)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:90)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:482)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:115)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:93)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:344)
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:389)
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:63)
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:904)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1741)
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52)
	at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1190)
	at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:63)
	at java.base/java.lang.Thread.run(Thread.java:1583)

使用 ExceptionHandler 拦截业务中抛出异常

所有的异常转换 由ExceptionConvertorUtils 统一转换成输出 ActionResult 对象，并返回给前端

/**
 * 拦截Controller异常
 *
 * @author Jiaju Zhuang
 */
@ControllerAdvice
@Slf4j
public class ControllerExceptionHandler {

    /**
     * 业务异常
     * 这里整合了spring常见的异常
     *
     * @param request   request
     * @param exception exception
     * @return return
     */
    @ExceptionHandler({MethodArgumentNotValidException.class, BindException.class, IllegalArgumentException.class,
        MissingServletRequestParameterException.class, MethodArgumentTypeMismatchException.class,
        BusinessException.class, MaxUploadSizeExceededException.class, ClientAbortException.class,
        HttpRequestMethodNotSupportedException.class, HttpMediaTypeNotAcceptableException.class,
        MultipartException.class, MissingRequestHeaderException.class, HttpMediaTypeNotSupportedException.class,
        ConstraintViolationException.class, HttpMessageNotReadableException.class})
    @ResponseStatus(value = HttpStatus.OK)
    @ResponseBody
    public ActionResult handleBusinessException(HttpServletRequest request, Exception exception) {
        ActionResult result = ExceptionConvertorUtils.convert(exception);
        log.info("发生业务异常{}:{}", request.getRequestURI(), result, exception);
        return result;
    }

    /**
     * 系统异常
     *
     * @param request   request
     * @param exception exception
     * @return return
     */
    @ExceptionHandler({SystemException.class})
    @ResponseStatus(value = HttpStatus.OK)
    @ResponseBody
    public ActionResult handleSystemException(HttpServletRequest request, Exception exception) {
        ActionResult result = ExceptionConvertorUtils.convert(exception);
        log.error("发生业务异常{}:{}", request.getRequestURI(), result, exception);
        return result;
    }

    /**
     * 未知异常 需要人工介入查看日志
     *
     * @param request   request
     * @param exception exception
     * @return return
     */
    @ExceptionHandler(Exception.class)
    @ResponseStatus(value = HttpStatus.OK)
    @ResponseBody
    public ActionResult handledException(HttpServletRequest request, Exception exception) {
        ActionResult result = ExceptionConvertorUtils.convert(exception);
        log.error("发生未知异常{}:{}:{},请求参数:{}", request.getRequestURI(),
            ExceptionConvertorUtils.buildHeaderString(request), result,
            JSON.toJSONString(request.getParameterMap()), exception);
        return result;
    }

}

ExceptionConvertorUtils 根据不同的异常来转换异常信息

自己可以在 EXCEPTION_CONVERTOR_MAP 中加入更多的自定义异常，可以无限扩展

/**
 * 转换异常工具类
 *
 * @author Jiaju Zhuang
 */
public class ExceptionConvertorUtils {

    /**
     * 所有的异常处理转换器
     */
    public static final Map<Class<?>, ExceptionConvertor> EXCEPTION_CONVERTOR_MAP = Maps.newHashMap();

    static {
        EXCEPTION_CONVERTOR_MAP.put(MethodArgumentNotValidException.class,
            new MethodArgumentNotValidExceptionConvertor());
        EXCEPTION_CONVERTOR_MAP.put(BindException.class, new BindExceptionConvertor());
        EXCEPTION_CONVERTOR_MAP.put(BusinessException.class, new BusinessExceptionConvertor());
        EXCEPTION_CONVERTOR_MAP.put(MissingServletRequestParameterException.class, new ParamExceptionConvertor());
        EXCEPTION_CONVERTOR_MAP.put(IllegalArgumentException.class, new ParamExceptionConvertor());
        EXCEPTION_CONVERTOR_MAP.put(MethodArgumentTypeMismatchException.class,
            new MethodArgumentTypeMismatchExceptionConvertor());
        EXCEPTION_CONVERTOR_MAP.put(MaxUploadSizeExceededException.class,
            new MaxUploadSizeExceededExceptionConvertor());
        EXCEPTION_CONVERTOR_MAP.put(HttpRequestMethodNotSupportedException.class, new BusinessExceptionConvertor());
        EXCEPTION_CONVERTOR_MAP.put(ConstraintViolationException.class, new ConstraintViolationExceptionConvertor());
        EXCEPTION_CONVERTOR_MAP.put(HttpMessageNotReadableException.class,
            new ParamExceptionConvertor());
    }

    /**
     * 默认转换器
     */
    public static ExceptionConvertor DEFAULT_EXCEPTION_CONVERTOR = new DefaultExceptionConvertor();

    /**
     * 提取ConstraintViolationException中的错误消息
     *
     * @param e
     * @return
     */
    public static String buildMessage(ConstraintViolationException e) {
        if (e == null || CollectionUtils.isEmpty(e.getConstraintViolations())) {
            return null;
        }
        int index = 1;
        StringBuilder msg = new StringBuilder();
        msg.append("请检查以下信息：");
        for (ConstraintViolation<?> constraintViolation : e.getConstraintViolations()) {
            msg.append(index++);
            // 得到错误消息
            msg.append(SymbolConstant.DOT);
            msg.append(" 字段(");
            msg.append(constraintViolation.getPropertyPath());
            msg.append(")传入的值为：\"");
            msg.append(constraintViolation.getInvalidValue());
            msg.append("\"，校验失败,原因是：");
            msg.append(constraintViolation.getMessage());
            msg.append(SymbolConstant.SEMICOLON);
        }
        return msg.toString();
    }

    /**
     * 提取BindingResult中的错误消息
     *
     * @param result
     * @return
     */
    public static String buildMessage(BindingResult result) {
        List<ObjectError> errors = result.getAllErrors();
        if (CollectionUtils.isEmpty(errors)) {
            return null;
        }

        int index = 1;
        StringBuilder msg = new StringBuilder();
        msg.append("请检查以下信息：");
        for (ObjectError e : errors) {
            msg.append(index++);
            // 得到错误消息
            msg.append(SymbolConstant.DOT);
            msg.append(" ");
            msg.append("字段(");
            msg.append(e.getObjectName());
            if (e instanceof FieldError) {
                FieldError fieldError = (FieldError)e;
                msg.append(SymbolConstant.DOT);
                msg.append(fieldError.getField());
            }
            msg.append(")");
            if (e instanceof FieldError) {
                FieldError fieldError = (FieldError)e;
                msg.append("传入的值为：\"");
                msg.append(fieldError.getRejectedValue());
                msg.append("\",");
            }
            msg.append("校验失败,原因是：");
            msg.append(e.getDefaultMessage());
            msg.append(SymbolConstant.SEMICOLON);
        }
        return msg.toString();
    }

    /**
     * 拼接头的日志信息
     *
     * @param request
     * @return
     */
    public static String buildHeaderString(HttpServletRequest request) {
        StringBuilder stringBuilder = new StringBuilder();
        Enumeration<String> headerNames = request.getHeaderNames();
        while (headerNames.hasMoreElements()) {
            String headName = headerNames.nextElement();
            stringBuilder.append(headName);
            stringBuilder.append(SymbolConstant.COLON);
            stringBuilder.append(request.getHeader(headName));
            stringBuilder.append(SymbolConstant.COMMA);
        }
        return stringBuilder.toString();
    }

    /**
     * 转换结果
     *
     * @param exception
     * @return
     */
    public static ActionResult convert(Throwable exception) {
        ExceptionConvertor exceptionConvertor = EXCEPTION_CONVERTOR_MAP.get(exception.getClass());
        if (exceptionConvertor == null) {
            exceptionConvertor = DEFAULT_EXCEPTION_CONVERTOR;
        }
        return exceptionConvertor.convert(exception);
    }

}

拿一个 ParamExceptionConvertor 参数异常举例

/**
 * 参数异常 目前包括
 * ConstraintViolationException
 * MissingServletRequestParameterException
 * IllegalArgumentException
 * HttpMessageNotReadableException
 *
 * @author Jiaju Zhuang
 */
public class ParamExceptionConvertor implements ExceptionConvertor<Throwable> {

    @Override
    public ActionResult convert(Throwable exception) {
        return ActionResult.fail(CommonExceptionEnum.INVALID_PARAMETER, exception.getMessage());
    }
}

总结

这样子我们就完成了全局异常处理，再也不用担心整个项目的 try-catch 代码了。

写在最后

给大家推荐一个非常完整的Java项目搭建的最佳实践,也是本文的源码出处，由大厂程序员&EasyExcel作者维护，地址：https://github.com/zhuangjiaju/easytools