默认效果：
1）、浏览器，返回一个默认的错误页面
1.1 请求头
1.2返回结果
2）、如果是其他客户端，默认响应一个json数据
2.1请求头
2.2返回结果
{
"timestamp": "2018-11-25T08:22:36.343+0000",
"status": ,
"error": "Not Found",
"message": "No message available",
"path": "/golden"
}
步骤：
1）系统出现4xx或者5xx之类的错误；ErrorPageCustomizer就会生效（定制错误的响应规则）；
2） 根据相应规则来到/error请求；被BasicErrorController处理；
3）响应页面；被Controller处理后去哪个页面是由DefaultErrorViewResolver解析得到的；
源码解析
public class ErrorMvcAutoConfiguration {
// 系统出现错误以后来到error请求进行处理；（相当于web.xml注册错误页面规则）
@Bean
public ErrorPageCustomizer errorPageCustomizer() {
return new ErrorPageCustomizer(this.serverProperties, this.dispatcherServletPath);
}
/**
* {@link WebServerFactoryCustomizer} that configures the server's error pages.
*/
private static class ErrorPageCustomizer implements ErrorPageRegistrar, Ordered {
private final ServerProperties properties;
private final DispatcherServletPath dispatcherServletPath;
protected ErrorPageCustomizer(ServerProperties properties,
DispatcherServletPath dispatcherServletPath) {
this.properties = properties;
this.dispatcherServletPath = dispatcherServletPath;
}
@Override
public void registerErrorPages(ErrorPageRegistry errorPageRegistry) {
ErrorPage errorPage = new ErrorPage(this.dispatcherServletPath
.getRelativePath(this.properties.getError().getPath()));
errorPageRegistry.addErrorPages(errorPage);
}
@Override
public int getOrder() {
return 0;
}
}
}
public class ErrorProperties {
/**
* Path of the error controller.
*/
@Value("${error.path:/error}")
private String path = "/error";
}
public class ErrorMvcAutoConfiguration {
// 系统出现错误以后来到error请求进行处理；（相当于web.xml注册错误页面规则）
@Bean
public ErrorPageCustomizer errorPageCustomizer() {
return new ErrorPageCustomizer(this.serverProperties, this.dispatcherServletPath);
}
/**
* {@link WebServerFactoryCustomizer} that configures the server's error pages.
*/
private static class ErrorPageCustomizer implements ErrorPageRegistrar, Ordered {
private final ServerProperties properties;
private final DispatcherServletPath dispatcherServletPath;
protected ErrorPageCustomizer(ServerProperties properties,
DispatcherServletPath dispatcherServletPath) {
this.properties = properties;
this.dispatcherServletPath = dispatcherServletPath;
}
@Override
public void registerErrorPages(ErrorPageRegistry errorPageRegistry) {
ErrorPage errorPage = new ErrorPage(this.dispatcherServletPath
.getRelativePath(this.properties.getError().getPath()));
errorPageRegistry.addErrorPages(errorPage);
}
@Override
public int getOrder() {
return 0;
}
}
@Configuration
@ConditionalOnProperty(prefix = "server.error.whitelabel", name = "enabled", matchIfMissing = true)
@Conditional(ErrorTemplateMissingCondition.class)
protected static class WhitelabelErrorViewConfiguration {
//默认的SpringBoot错误页面
private final SpelView defaultErrorView = new SpelView(
"<html><body><h1>Whitelabel Error Page</h1>"
+ "<p>This application has no explicit mapping for /error, so you are seeing this as a fallback.</p>"
+ "<div id='created'>${timestamp}</div>"
+ "<div>There was an unexpected error (type=${error}, status=${status}).</div>"
+ "<div>${message}</div></body></html>");
@Bean(name = "error")
@ConditionalOnMissingBean(name = "error")
public View defaultErrorView() {
return this.defaultErrorView;
}
// If the user adds @EnableWebMvc then the bean name view resolver from
// WebMvcAutoConfiguration disappears, so add it back in to avoid disappointment.
@Bean
@ConditionalOnMissingBean
public BeanNameViewResolver beanNameViewResolver() {
BeanNameViewResolver resolver = new BeanNameViewResolver();
resolver.setOrder(Ordered.LOWEST_PRECEDENCE - 10);
return resolver;
}
}
}
public class ErrorProperties {
/**
* Path of the error controller.
*/
@Value("${error.path:/error}")
private String path = "/error";
}
public class ErrorMvcAutoConfiguration {
@Bean
@ConditionalOnMissingBean(value = ErrorController.class, search = SearchStrategy.CURRENT)
public BasicErrorController basicErrorController(ErrorAttributes errorAttributes) {
return new BasicErrorController(errorAttributes, this.serverProperties.getError(),
this.errorViewResolvers);
}
}
public abstract class AbstractErrorController implements ErrorController {
private final ErrorAttributes errorAttributes;
private final List<ErrorViewResolver> errorViewResolvers;
public AbstractErrorController(ErrorAttributes errorAttributes) {
this(errorAttributes, null);
}
//解析错误页面
protected ModelAndView resolveErrorView(HttpServletRequest request,
HttpServletResponse response, HttpStatus status, Map<String, Object> model) {
for (ErrorViewResolver resolver : this.errorViewResolvers) {
ModelAndView modelAndView = resolver.resolveErrorView(request, status, model);
if (modelAndView != null) {
return modelAndView;
}
}
return null;
}
}
/**取出配置項：server.error.path中的值。如果沒有，則取error.path的值，如果還沒有，則默認為/error路徑*/
@Controller
@RequestMapping("${server.error.path:${error.path:/error}}")
public class BasicErrorController extends AbstractErrorController {
@RequestMapping(produces = "text/html")//产生html类型的数据；浏览器发送的请求来到这个方法处理
public ModelAndView errorHtml(HttpServletRequest request,
HttpServletResponse response) {
HttpStatus status = getStatus(request);
Map<String, Object> model = Collections.unmodifiableMap(getErrorAttributes(
request, isIncludeStackTrace(request, MediaType.TEXT_HTML)));
response.setStatus(status.value());
//去哪个页面作为错误页面；包含页面地址和页面内容
ModelAndView modelAndView = resolveErrorView(request, response, status, model);
//如果为空，返回error视图（在ErrorMvcConfiguration中配置的@Bean）
return (modelAndView != null) ? modelAndView : new ModelAndView("error", model);
}
//产生json数据，其他客户端来到这个方法处理；
@RequestMapping
@ResponseBody
public ResponseEntity<Map<String, Object>> error(HttpServletRequest request) {
Map<String, Object> body = getErrorAttributes(request,
isIncludeStackTrace(request, MediaType.ALL));
HttpStatus status = getStatus(request);
return new ResponseEntity<>(body, status);
}
}
public class DefaultErrorViewResolver implements ErrorViewResolver, Ordered {
private static final Map<Series, String> SERIES_VIEWS;
private final ResourceProperties resourceProperties;
static {
Map<Series, String> views = new EnumMap<>(Series.class);
views.put(Series.CLIENT_ERROR, "4xx");
views.put(Series.SERVER_ERROR, "5xx");
SERIES_VIEWS = Collections.unmodifiableMap(views);
}
@Override
public ModelAndView resolveErrorView(HttpServletRequest request, HttpStatus status,
Map<String, Object> model) {
ModelAndView modelAndView = resolve(String.valueOf(status), model);
if (modelAndView == null && SERIES_VIEWS.containsKey(status.series())) {
modelAndView = resolve(SERIES_VIEWS.get(status.series()), model);
}
return modelAndView;
}
private ModelAndView resolve(String viewName, Map<String, Object> model) {
//默认SpringBoot可以去找到一个页面？ error/404
String errorViewName = "error/" + viewName;
//模板引擎可以解析这个页面地址就用模板引擎解析
TemplateAvailabilityProvider provider = this.templateAvailabilityProviders
.getProvider(errorViewName, this.applicationContext);
if (provider != null) {
//模板引擎可用的情况下返回到errorViewName指定的视图地址
return new ModelAndView(errorViewName, model);
}
//模板引擎不可用
return resolveResource(errorViewName, model);
}
//
private ModelAndView resolveResource(String viewName, Map<String, Object> model) {
//从静态资源文件夹下解析对应的页面 error/404.html
for (String location : this.resourceProperties.getStaticLocations()) {
try {
Resource resource = this.applicationContext.getResource(location);
resource = resource.createRelative(viewName + ".html");
if (resource.exists()) {
return new ModelAndView(new HtmlResourceView(resource), model);
}
}
catch (Exception ex) {
}
}
return null;
}
}
静态资源文件夹路径
@ConfigurationProperties(prefix = "spring.resources", ignoreUnknownFields = false)
public class ResourceProperties { private static final String[] CLASSPATH_RESOURCE_LOCATIONS = {
"classpath:/META-INF/resources/", "classpath:/resources/",
"classpath:/static/", "classpath:/public/" }; /**
* Locations of static resources. Defaults to classpath:[/META-INF/resources/,
* /resources/, /static/, /public/].
*/
private String[] staticLocations = CLASSPATH_RESOURCE_LOCATIONS; }
2）、如果定制错误响应
1、如何定制错误的页面
1）、有模板引擎的情况下；error/状态码; 【将错误页面命名为 错误状态码.html 放在模板引擎文件夹里面的error文件夹下】，发生此状态码的错误就会来到 对应的页面；
我们可以使用4xx和5xx作为错误页面的文件名来匹配这种类型的所有错误，精确优先（优先寻找精确的状态码.html）；
页面能获取的信息：
timestamp：时间戳
status：状态码
error：错误提示
exception：异常对象
message：异常消息
errors：JSR303数据校验的错误都在这里
2）、没有模板引擎（模板引擎找不到这个错误页面），静态资源文件夹下找
3）、以上都没有错误页面，就是默认来到SpringBoot默认的错误提示页面
2、如何定制错误的json数据；
1）、自定义异常处理&返回定制json数据；
一、页面请求出错
1. 自定义异常：
public class UserNotExistException extends RuntimeException {
private static final long serialVersionUID = -7200824453209817228L;
public UserNotExistException() {
super("用户不存在");
}
}
2. Controller调用
@Controller
public class HelloController {
@RequestMapping("/hello")
@ResponseBody
public String createInvoice(@RequestParam("user") String user) {
if(user.equals("aaa")) {
throw new UserNotExistException();
}
return "hello world";
}
}
3. 5xx.html
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8">
<title>5xx.html</title>
</head>
<body>
timestamp:[[${timestamp}]] <br>
status:[[${status}]] <br>
error:[[${error}]] <br>
exception:[[${exception}]] <br>
errors:[[${errors}]] <br>
message:[[${message}]] <br>
</body>
</html>
4. 正确结果
5. 错误结果
二、json错误定制
1.编写异常处理器
@ControllerAdvice
public class MyExceptionHandler {
//1、浏览器客户端返回的都是json
@ResponseBody
@ExceptionHandler(UserNotExistException.class)
public Map<String,Object> handleException(Exception e){
Map<String,Object> map = new HashMap<>();
map.put("code","user.notexist");
map.put("message",e.getMessage());
return map;
}
}
请求：
页面也显示json数据
但若想让浏览器返回错误页面，客户端返回json数据，且是自适应的，怎么办呢？
源码解析
@Controller
@RequestMapping("${server.error.path:${error.path:/error}}")
public class BasicErrorController extends AbstractErrorController { @RequestMapping(produces = MediaType.TEXT_HTML_VALUE)
public ModelAndView errorHtml(HttpServletRequest request,
HttpServletResponse response) {
HttpStatus status = getStatus(request); //status就是端口号
Map<String, Object> model = Collections.unmodifiableMap(getErrorAttributes(
request, isIncludeStackTrace(request, MediaType.TEXT_HTML)));
response.setStatus(status.value());
ModelAndView modelAndView = resolveErrorView(request, response, status, model);
return (modelAndView != null) ? modelAndView : new ModelAndView("error", model);
} } public abstract class AbstractErrorController implements ErrorController {
protected HttpStatus getStatus(HttpServletRequest request) {
Integer statusCode = (Integer) request
.getAttribute("javax.servlet.error.status_code");
if (statusCode == null) {
return HttpStatus.INTERNAL_SERVER_ERROR;
}
try {
return HttpStatus.valueOf(statusCode);
}
catch (Exception ex) {
return HttpStatus.INTERNAL_SERVER_ERROR;
}
}
}
@ControllerAdvice
public class MyExceptionHandler {
@ExceptionHandler(UserNotExistException.class)
public String handleException(Exception e, HttpServletRequest request){
Map<String,Object> map = new HashMap<>();
//传入我们自己的错误状态码 4xx 5xx
/**
* Integer statusCode = (Integer) request
.getAttribute("javax.servlet.error.status_code");
*/
request.setAttribute("javax.servlet.error.status_code",);
map.put("code","user.notexist");
map.put("message","用户出错啦"); request.setAttribute("ext",map); //下面自定义异常返回结果时，将获取到此request作用域中的数据
//转发到/error
return "forward:/error";
}
}
但是这种方式无法返回map对象里自定义的数据到页面
Spring Boot 默认的实现原理如下：
public class BasicErrorController extends AbstractErrorController {
//SpringBoot 默认的返回错误html页面代码
@RequestMapping(produces = MediaType.TEXT_HTML_VALUE)
public ModelAndView errorHtml(HttpServletRequest request,
HttpServletResponse response) {
HttpStatus status = getStatus(request);
Map<String, Object> model = Collections.unmodifiableMap(getErrorAttributes(
request, isIncludeStackTrace(request, MediaType.TEXT_HTML)));
response.setStatus(status.value());
ModelAndView modelAndView = resolveErrorView(request, response, status, model);
return (modelAndView != null) ? modelAndView : new ModelAndView("error", model);
}
//Spring Boot 默认的返回json数据请求
@RequestMapping
public ResponseEntity<Map<String, Object>> error(HttpServletRequest request) {
Map<String, Object> body = getErrorAttributes(request,
isIncludeStackTrace(request, MediaType.ALL));
HttpStatus status = getStatus(request);
return new ResponseEntity<>(body, status);
}
}
public abstract class AbstractErrorController implements ErrorController {
private final ErrorAttributes errorAttributes;
protected Map<String, Object> getErrorAttributes(HttpServletRequest request,
boolean includeStackTrace) {
WebRequest webRequest = new ServletWebRequest(request);
return this.errorAttributes.getErrorAttributes(webRequest, includeStackTrace);
}
}
@Order(Ordered.HIGHEST_PRECEDENCE)
public class DefaultErrorAttributes
implements ErrorAttributes, HandlerExceptionResolver, Ordered {
@Override
public Map<String, Object> getErrorAttributes(WebRequest webRequest,
boolean includeStackTrace) {
Map<String, Object> errorAttributes = new LinkedHashMap<>();
errorAttributes.put("timestamp", new Date());
addStatus(errorAttributes, webRequest);
addErrorDetails(errorAttributes, webRequest, includeStackTrace);
addPath(errorAttributes, webRequest);
return errorAttributes;
}
}
3）、将我们的定制数据携带出去
出现错误以后，会来到/error请求，会被BasicErrorController处理，响应出去可以获取的数据是由
getErrorAttributes得到的（是AbstractErrorController（ErrorController）规定的方法）；
1、完全来编写一个ErrorController的实现类【或者是编写AbstractErrorController的子类】，放在容器中；
2、页面上能用的数据，或者是json返回能用的数据都是通过errorAttributes.getErrorAttributes得到；
容器中DefaultErrorAttributes.getErrorAttributes()；默认进行数据处理的；
@AutoConfigureBefore(WebMvcAutoConfiguration.class)
@EnableConfigurationProperties({ ServerProperties.class, ResourceProperties.class,WebMvcProperties.class })
public class ErrorMvcAutoConfiguration { private final ServerProperties serverProperties; //当容器中没有ErrorAttributes类型的bean时，才走默认的，所以我们自定义ErrorAttributes的实现类就可以实现定制化
@Bean
@ConditionalOnMissingBean(value = ErrorAttributes.class, search = SearchStrategy.CURRENT)
public DefaultErrorAttributes errorAttributes() {
return new DefaultErrorAttributes(
this.serverProperties.getError().isIncludeException());
}
}
Spring Boot1.5.10版本
//给容器中加入我们自己定义的ErrorAttributes,用其实现类，避免重写多个无需改造的方法
@Component
public class MyErrorAttributes extends DefaultErrorAttributes {
@Override
public Map<String, Object> getErrorAttributes(RequestAttributes requestAttributes,boolean includeStackTrace) {
Map<String, Object> map = super.getErrorAttributes(requestAttributes,includeStackTrace);
map.put("company","everjiankang"); //自定义属性
map.put("name","超轶绝尘");
return map;
}
}
Spring Boot 2.0 版本
import java.util.Map;
//
import org.springframework.boot.web.servlet.error.DefaultErrorAttributes; servlet的可以成功执行
//import org.springframework.boot.web.reactive.error.DefaultErrorAttributes; reactive 也有这个类，但是执行不了
import org.springframework.stereotype.Component;
import org.springframework.web.context.request.WebRequest; @Component
public class MyErrorAttributes extends DefaultErrorAttributes{
@Override
public Map<String, Object> getErrorAttributes(WebRequest webRequest, boolean includeStackTrace) {
//获取到上文中异常处理类中设置到request作用域中的“ext”属性 requeste.setAtrribute("exgt",map);
Map<String,Object> extMap = (Map<String, Object) webRequest.getAttribute("ext", RequestAttributes.SCOPE_REQUEST);
Map<String,Object> map = super.getErrorAttributes(webRequest, includeStackTrace);
map.put("name", "xiaochao");
map.put("ext", extMap); //将异常处理类中的自定义信息返回给页面
return map;
} } public interface WebRequest extends RequestAttributes { }
public interface RequestAttributes {
int SCOPE_REQUEST = 0;
int SCOPE_SESSION = 1;
}
Spring Webflux 版本，执行未成功
在Spring boot 2.1.0版本中，第一个参数变成了org.springframework.web.reactive.function.server.ServerRequest类型，需要引入jar包
但是此段代码不能适用。如何自定义详情查看Spring Boot官方文档
Spring 5 之 Spring Webflux 开发 Reactive 应用
<!-- 此依赖 会依赖于Netty -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-webflux</artifactId> <!--【改】增加“flux”四个字符-->
</dependency>
//import org.springframework.boot.web.reactive.error.DefaultErrorAttributes; reactive 也有这个类，但是执行不了