springboot 错误处理

在 java web开发过程中，难免会有一些系统异常或人为产生一些异常。在 RESTful springboot 项目中如何优雅的处理？

分析：在RESTful 风格的springboot 项目中，返回的都是 body 对象，所以定义一个结果基类，其中包含 status,message,data(请求方法的返回结果),是比较合适的。

如果定义多个异常类进行处理，会比较麻烦。比如StudentNotExistsException、StudentExistsException。。。等，并且不能指定错误码，不方便前端根据错误码进行处理。

说明：一般的spring mvc模型处理流程如下

一般controller层 -> Service层 -> Dao层。

1.controller层，接受请求，进行分页，DTO对象封装操作。

2.service层，执行逻辑，控制并发，事务。

3.Dao层，与数据库交互。

使用一个学生表的处理进行说明：

1、定义常见的错误枚举 StudentExceptionEnum

public enum StudentExceptionEnum {
    STUDENT_NOT_EXIST(,"学生不存在，请确认后再查"),
    STUDENT_EXIST(,"学生已存在");

    private Integer status;
    private String comment;

    StudentExceptionEnum(Integer status, String comment) {
        this.status = status;
        this.comment = comment;
    }

    public Integer getStatus() {
        return status;
    }

    public void setStatus(Integer status) {
        this.status = status;
    }

    public String getComment() {
        return comment;
    }

    public void setComment(String comment) {
        this.comment = comment;
    }
}

2 定义一个基本的处理结果类 RequestResult

@Data
public class RequestResult {
    private String message;
    private Integer status;
    private Object data;

    public RequestResult(String message, Integer status, Object data) {
        this.message = message;
        this.status = status;
        this.data = data;
    }

    public RequestResult(String message, Integer status) {
        this.message = message;
        this.status = status;
    }

    public RequestResult(String message, StudentExceptionEnum requestExceptionEnum) {
        this.message = message;
        this.status = requestExceptionEnum.getStatus();
    }

    public RequestResult() {
        status = ;
        message = "ok";
    }

    public static RequestResult OK(Object data) {
        RequestResult result = new RequestResult();
        result.setData(data);
        return result;
    }

    public static RequestResult EXCEPTION(String message, Integer status) {
        return new RequestResult(message, status);
    }

    public static RequestResult EXCEPTION(String message, StudentExceptionEnum requestExceptionEnum) {
       return new RequestResult(message, requestExceptionEnum);
    }

}

3 实体类 Student

@Data
public class Student implements Serializable{
    private String id;
    private String nickname;
    private String name;
    private int age;
    private String sex;
    private String address;

    @Override
    public String toString() {
        return ToStringBuilder.reflectionToString(this);
    }
}

4 处理请求，添加学生，nickname 必填项。此处只显示 Service 片段代码

@Override
    public RequestResult addStudent(Student student) {
        if (studentDao.queryIdByNickname(student.getNickname()) == null) {
            studentDao.addStudent(student);
            System.out.println("添加成功");
            student = studentDao.queryByNickname(student.getNickname());
            return RequestResult.OK(student);
        } else {
            return RequestResult.EXCEPTION("用户" + student.getNickname() + "已存在", StudentExceptionEnum.STUDENT_EXIST);
        }
    }

5 此时，已经完成了基本的处理情况。下面就进行基本的测试了

5.1 添加一个新同学信息

5.2 再次添加让其出现异常测试

二、到此基本已大功告成，但是，对于基本的运行时异常没有处理，直接返回给前端会很不友好。所以要定义一个全局的 RuntimeException 异常处理类。

此处需要使用的关键标注： @ExceptionHandler

用法有两种 1）在处理请求的 Controller 中添加 @ExceptionHandler，此时该方法只会处理该 Controller 抛出的异常。

2）将其用在全局的异常处理类中，全局异常处理类需要使用  @RestControllerAdvice 或 @ControllerAdvice 标记

我们需要处理全局的 RuntimeException，所以我们使用第二种方法。当然，这样处理是为了客户友好型，我们还是要处理这种错误，怎么办？就需要将错误的信息记录下来，方便以后分析处理。此处使用 logger 进行记录。代码如下

@RestControllerAdvice
public class BaseExceptionHandler {
    private static Logger logger = LoggerFactory.getLogger(BaseExceptionHandler.class);

    @ExceptionHandler(value = RuntimeException.class)
    public RequestResult exceptionHandler(HttpServletRequest request,Exception e) {
        logError(request,e);
        return RequestResult.EXCEPTION("内部处理异常，工程师正在抓紧抢修，请稍后再来...",);
    }

    public static void logError(HttpServletRequest request, Exception e) {

        logger.error("请求地址：" + request.getRequestURL());
        logger.error("请求方法：" + request.getMethod());
        logger.error("请求IP：" + getRemoteIp(request));
        logger.error("错误详情：");
        StackTraceElement[] error = e.getStackTrace();
        for (StackTraceElement stackTraceElement : error) {
            logger.error(stackTraceElement.toString());
        }
    }

    public static String getRemoteIp(HttpServletRequest request) {
        String ip = request.getHeader("X-Forwarded-For");
        if (ip == null || ip.length() ==  || "unknown".equalsIgnoreCase(ip)) {
            if (ip == null || ip.length() ==  || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("Proxy-Client-IP");
            }
            if (ip == null || ip.length() ==  || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("WL-Proxy-Client-IP");
            }
            if (ip == null || ip.length() ==  || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("HTTP_CLIENT_IP");
            }
            if (ip == null || ip.length() ==  || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("HTTP_X_FORWARDED_FOR");
            }
            if (ip == null || ip.length() ==  || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getRemoteAddr();
            }
        } else if (ip.length() > ) {
            String[] ips = ip.split(",");
            for (int index = ; index < ips.length; index++) {
                String strIp = (String) ips[index];
                if (!("unknown".equalsIgnoreCase(strIp))) {
                    ip = strIp;
                    break;
                }
            }
        }
        return ip;
    }
}

进行测试看是否生效：

修改添加学生信息代码如下：

public RequestResult addStudent(Student student) {
        int a = /;

        if (studentDao.queryIdByNickname(student.getNickname()) == null) {
            studentDao.addStudent(student);
            System.out.println("添加成功");
            student = studentDao.queryByNickname(student.getNickname());
            return RequestResult.OK(student);
        } else {
            return RequestResult.EXCEPTION("用户'" + student.getNickname() + "'已存在", StudentExceptionEnum.STUDENT_EXIST);
        }
    }

进行测试

后台打印错误信息

-- ::19.125 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : 请求地址：http://localhost:8080/demo1/student
-- ::19.125 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : 请求方法：POST
-- ::19.125 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : 请求IP：:::::::
-- ::19.125 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : 错误详情：
-- ::19.125 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : com.huitong.demo.service.StudentService.addStudent(StudentService.java:)
-- ::19.125 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : com.huitong.demo.controller.StudentController.addStudent(StudentController.java:)
-- ::19.125 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
-- ::19.125 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:)
-- ::19.125 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:)
-- ::19.125 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : java.lang.reflect.Method.invoke(Method.java:)
-- ::19.125 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:)
-- ::19.125 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:)
-- ::19.125 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:)
-- ::19.125 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:)
-- ::19.125 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:)
-- ::19.125 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:)
-- ::19.129 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:)
-- ::19.129 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:)
-- ::19.129 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:)
-- ::19.129 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:)
-- ::19.129 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : javax.servlet.http.HttpServlet.service(HttpServlet.java:)
-- ::19.129 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:)
-- ::19.130 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : javax.servlet.http.HttpServlet.service(HttpServlet.java:)
-- ::19.130 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:)
-- ::19.130 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:)
-- ::19.130 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:)
-- ::19.130 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:)
-- ::19.130 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:)
-- ::19.130 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : com.alibaba.druid.support.http.WebStatFilter.doFilter(WebStatFilter.java:)
-- ::19.130 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:)
-- ::19.130 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:)
-- ::19.130 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:)
-- ::19.130 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:)
-- ::19.130 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:)
-- ::19.130 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:)
-- ::19.130 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:)
-- ::19.130 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:)
-- ::19.130 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:)
-- ::19.131 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:)
-- ::19.131 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:)
-- ::19.131 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:)
-- ::19.131 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:)
-- ::19.131 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:)
-- ::19.131 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:)
-- ::19.131 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:)
-- ::19.131 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:)
-- ::19.131 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:)
-- ::19.131 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:)
-- ::19.131 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:)
-- ::19.131 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:)
-- ::19.131 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:)
-- ::19.131 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:)
-- ::19.131 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:)
-- ::19.131 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:)
-- ::19.131 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:)
-- ::19.131 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:)
-- ::19.131 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:)
-- ::19.131 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:)
-- ::19.131 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:)
-- ::19.131 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:)
-- ::19.131 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:)
-- ::19.131 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:)
-- ::19.131 ERROR  --- [nio--exec-] c.h.d.controller.BaseExceptionHandler    : java.lang.Thread.run(Thread.java:)
-- ::19.133  WARN  --- [nio--exec-] .m.m.a.ExceptionHandlerExceptionResolver : Resolved exception caused by Handler execution: java.lang.ArithmeticException: / by zero