1、内置异常处理解析器

org.springframework.web.servlet.HandlerExceptionResolver=org.springframework.web.servlet.mvc.method.annotation.ExceptionHandlerExceptionResolver,\
org.springframework.web.servlet.mvc.annotation.ResponseStatusExceptionResolver,\
org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver

2、统一异常处理

2.1、获得Java处理类的异常信息并输出

@Controller
public class ExceptionController {
    @RequestMapping("/exception01")
    public String exception01(@RequestParam("name") String name){
        System.out.println("方法处理中01");
        return "show";
    }

    @RequestMapping("/exception02")
    public String exception02(@RequestParam("name") String name){
        System.out.println("方法处理中02");
        return "show";
    }

    @ExceptionHandler(Exception.class)
    public ModelAndView handleException(Exception ex){
        ModelAndView modelAndView = new ModelAndView();
        modelAndView.setViewName("error");
        modelAndView.addObject("ex",ex);
        //日志记录
        System.out.println(ex.getMessage());
        return modelAndView;
    }
}

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
        出错了。<br/>
        <%= ((Exception)request.getAttribute("ex")).getMessage() %>
</body>
</html>

2.2、Java异常栈信息输出

public static String getStackTrace(Throwable throwable){
    StringWriter sw = new StringWriter();
    PrintWriter pw = new PrintWriter(sw);
    try {
        throwable.printStackTrace(pw);
        return sw.toString();
    } finally {
        pw.close();
    }
}

@ExceptionHandler(Exception.class)
public ModelAndView handleException(Exception ex){
    ModelAndView modelAndView = new ModelAndView();
    modelAndView.setViewName("error");
    modelAndView.addObject("ex",ex);
    //日志记录，获取到完整的堆栈信息
    System.out.println(getStackTrace(ex));
    return modelAndView;
}

public static String getStackTrace(Throwable throwable){
    StringWriter sw = new StringWriter();
    PrintWriter pw = new PrintWriter(sw);
    try {
        throwable.printStackTrace(pw);
        return sw.toString();
    } finally {
        pw.close();
    }
}

在这里插入图片描述

2.3、处理全局异常

@ControllerAdvice注解标注在类上时，代表处理全局异常

@ControllerAdvice
public class GeneralExceptionHandler {

    /**
     * 全局异常处理
     * @param ex
     * @return
     */
    @ExceptionHandler(Exception.class)
    public ModelAndView handleException01(Exception ex){
        System.out.println("全局异常处理。");
        ModelAndView modelAndView = new ModelAndView();
        modelAndView.setViewName("error");
        modelAndView.addObject("ex",ex);
        //日志记录，获取到完整的堆栈信息
        System.out.println(getStackTrace(ex));
        return modelAndView;
    }

    @ExceptionHandler(MissingServletRequestParameterException.class)
    public ModelAndView handleException02(Exception ex){
        System.out.println("全局异常处理，参数找不到了。");
        ModelAndView modelAndView = new ModelAndView();
        modelAndView.setViewName("error");
        modelAndView.addObject("ex",ex);
        //日志记录，获取到完整的堆栈信息
        System.out.println(getStackTrace(ex));
        return modelAndView;
    }

    public static String getStackTrace(Throwable throwable){
        StringWriter sw = new StringWriter();
        PrintWriter pw = new PrintWriter(sw);
        try {
            throwable.printStackTrace(pw);
            return sw.toString();
        } finally {
            pw.close();
        }
    }
}

2.4、统一处理异常（json或页面）

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-core</artifactId>
    <version>2.10.3</version>
</dependency>

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.10.3</version>
</dependency>

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-annotations</artifactId>
    <version>2.10.3</version>
</dependency>

/* 1、根据用户请求的方法是否是一个需要返回json数据的方法
        // 获得类上面的某个注解
        RestController restController = handlerMethod.getClass().getAnnotation(RestController.class);
        // 获得方法上的某个注解
        ResponseBody responseBody = handlerMethod.getMethod().getAnnotation(ResponseBody.class);
        // 如果当前请求是ajax就返回json
        if(restController != null || responseBody != null){}*/package cool.ale.exception;

import org.springframework.http.HttpStatus;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.MissingPathVariableException;
import org.springframework.web.bind.MissingServletRequestParameterException;
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.RestController;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.view.json.MappingJackson2JsonView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.StringWriter;

/**
 * @author dujlc
 *
 *
 *   统一异常处理：同时返回普通请求和ajax请求
 *      普通请求：返回视图，错误信息
 *      ajax：返回json
 *      {
 *          code
 *          message
 *      }
 *
 */
@ControllerAdvice
public class GeneralExceptionHandler {

    /**
     * 全局异常处理
     * @param ex
     * @return
     */
    @ExceptionHandler(Exception.class)
    public ModelAndView handleException01(HttpServletRequest request,
                                          HttpServletResponse response,
                                          HandlerMethod handlerMethod,
                                          Exception ex) throws IOException {
        System.out.println("全局异常处理。");
        /* 1、根据用户请求的方法是否是一个需要返回json数据的方法
        // 获得类上面的某个注解
        RestController restController = handlerMethod.getClass().getAnnotation(RestController.class);
        // 获得方法上的某个注解
        ResponseBody responseBody = handlerMethod.getMethod().getAnnotation(ResponseBody.class);
        // 如果当前请求是ajax就返回json
        if(restController != null || responseBody != null){}*/

        // 2、如果请求头中的类型包含了 Content-Type 包含 application/json
        if (!StringUtils.isEmpty(request.getHeader("Content-Type")) && request.getHeader("Content-Type").indexOf("application/json") > -1){
            // 可直接依照下面的方式输出
            //response.getWriter().write("sss");
            // 但是我们一般是集成jackson，返回json
            // ModelAndView既支持json返回、也支持视图返回
            // ResponseBody的底层也是做了这个MappingJackson2JsonView
            ModelAndView modelAndView = new ModelAndView(new MappingJackson2JsonView());
            // 通常会根据不同的异常返回不同的编码，这里为了简单，先随便写一种s
            modelAndView.addObject("code", HttpStatus.INTERNAL_SERVER_ERROR.value());
            modelAndView.addObject("message",ex.getMessage());
            return modelAndView;
        }
        else{
            ModelAndView modelAndView = new ModelAndView();
            modelAndView.setViewName("error");
            modelAndView.addObject("ex",ex);
            //日志记录，获取到完整的堆栈信息
            System.out.println(getStackTrace(ex));
            return modelAndView;
        }
    }

    public static String getStackTrace(Throwable throwable){
        StringWriter sw = new StringWriter();
        PrintWriter pw = new PrintWriter(sw);
        try {
            throwable.printStackTrace(pw);
            return sw.toString();
        } finally {
            pw.close();
        }
    }
}

2.5、处理404页面

<mvc:resources mapping="/404.html" location="/"></mvc:resources>

<error-page>
    <error-code>404</error-code>
    <location>/404.html</location>
</error-page>