静态资源配置:
Spring
MVC
的定制配置需要我们的配置类继承一个WebMvcConfigurerAdapter
类,并在此类使用@EnableWebMvc
注解,来开启对Spring
MVC
的配置支持,这样我们就可以重写这个类的方法,完成我们的常用配置。
我们将前面文章中的MyMvcConfig
配置类继承WebMvcConfigurerAdapter
,以后如果不做特别说明,则关于配置的相关内容都在MyMvcConfig
里面编写。
程序的静态文件(js
,css
,图片)等需要直接访问,这时我们可以在配置里重写addResourceHandlers
方法来实现。
添加静态资源
在src/main/resources
下建立assets/js
目录,并复制一个jquery.js
放置在该目录下
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
import org.springframework.web.servlet.view.JstlView;
@Configuration
@EnableWebMvc// ①
@ComponentScan("org.light4j.springMvc4")
public class MyMvcConfig extends WebMvcConfigurerAdapter {// ②
@Bean
public InternalResourceViewResolver viewResolver() {
InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
viewResolver.setPrefix("/WEB-INF/classes/views/");
viewResolver.setSuffix(".jsp");
viewResolver.setViewClass(JstlView.class);
return viewResolver;
}
@Override
public void addResourceHandlers(ResourceHandlerRegistry registry) {
registry.addResourceHandler("/assets/**").addResourceLocations("classpath:/assets/");// ③
}
}
① @EnableWebMvc
开启SpringMvc
支持,若无此句,重写WebMvcConfigurerAdapter
的方法无效。
② 继承WebMvcConfigurerAdapter
类,重写其方法可对Spring
MVC
进行配置。
③ addResourceLocations
指的是文件放置的目录,addResourceHandler
指的是对外暴露的访问路径。
拦截器配置:
拦截器(Interceptor
)实现对每一个请求处理前后进行相关的业务处理,类似于Servlet
的Filter
。
可让普通的Bean
实现HandlerInterceptor
接口或者继承HandlerInterceptorAdapter
类来实现自定义拦截器。
通过重写WebMvcConfigurerAdapter
的addInterceptors
方法来注册自定义的拦截器,下面演示一个简单的拦截器的开发和配置。业务含义为计算每一次请求的处理时间。
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;
/**
* ① 继承HandlerInterceptorAdapter类来实现自定义拦截器。
* ② 重写preHandle方法,在请求发生前执行。
* ③ 重写postHandle方法,在请求完成后执行。
*
*/
public class DemoInterceptor extends HandlerInterceptorAdapter {//①
@Override
public boolean preHandle(HttpServletRequest request, //②
HttpServletResponse response, Object handler) throws Exception {
long startTime = System.currentTimeMillis();
request.setAttribute("startTime", startTime);
return true;
}
@Override
public void postHandle(HttpServletRequest request, //③
HttpServletResponse response, Object handler,
ModelAndView modelAndView) throws Exception {
long startTime = (Long) request.getAttribute("startTime");
request.removeAttribute("startTime");
long endTime = System.currentTimeMillis();
System.out.println("本次请求处理时间为:" + new Long(endTime - startTime)+"ms");
request.setAttribute("handlingTime", endTime - startTime);
}
}
配置:
/**
* ① 配置拦截器的Bean
* ② 重写addInterceptors方法,注册拦截器。
* @return
*/
@Bean // ①
public DemoInterceptor demoInterceptor() {
return new DemoInterceptor();
}
@Override
public void addInterceptors(InterceptorRegistry registry) {// ②
registry.addInterceptor(demoInterceptor());
}
@ControllerAdvice注解
通过@ControllerAdvice
。我们可以将对于控制器的全局配置放置在同一个位置,注解了@ControllerAdvice
的类的方法可以使用@ExceptionHandler
,@InitBinder
,@ModelAttribute
注解到方法上,这对所有注解了@RequestMapping
的控制器内的方法有效。
@ExceptionHandler
:用于全局处理控制器里面的异常。@InitBinder
:用来设置WebDataBinder
,WebDataBinder
用来自动绑定前台请求参数到Model
中。@ModelAttribute
:@ModelAttribute
本来的作用是绑定键值对到Model
里,此处是让全局的@RequestMapping
都能获得在此处设置的键值对。
下面将使用@ExceptionHandler
处理全局异常,将异常信息更加人性化的输出给用户。
import org.springframework.ui.Model;
import org.springframework.web.bind.WebDataBinder;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.InitBinder;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.context.request.WebRequest;
import org.springframework.web.servlet.ModelAndView;
@ControllerAdvice //①
public class ExceptionHandlerAdvice {
@ExceptionHandler(value = Exception.class)//②
public ModelAndView exception(Exception exception, WebRequest request) {
ModelAndView modelAndView = new ModelAndView("error");// error页面
modelAndView.addObject("errorMessage", exception.getMessage());
return modelAndView;
}
@ModelAttribute //③
public void addAttributes(Model model) {
model.addAttribute("msg", "额外信息"); //④
}
@InitBinder //④
public void initBinder(WebDataBinder webDataBinder) {
webDataBinder.setDisallowedFields("id"); //⑤
}
}
① @ControllerAdvice
声明一个控制器建言,@ControllerAdvice
组合了@Component
注解,所以自动注册为Spring的Bean
。
② @ExceptionHandler
在此处定义全局处理,通过@ExceptionHandler
的value
属性可过滤拦截的条件,在此处可以看出拦截的是所有的Exception
。
③ 此处使用@ModelAttribute
注解将键值对添加到全局,所有注解了@RequestMapping
的方法可获得此键值对。
④ 通过@InitBinder
注解定制WebDataBinder
import org.light4j.springMvc4.domain.DemoObj;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
@Controller
public class AdviceController {
@RequestMapping("/advice")
public String getSomething(@ModelAttribute("msg") String msg,DemoObj obj){//①
throw new IllegalArgumentException("非常抱歉,参数有误/"+"来自@ModelAttribute:"+ msg);
}
}
在src/main/resources/views
下,新建error.jsp
,内容如下:
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@ page isELIgnored="false" %>
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>@ControllerAdvice Demo</title>
</head>
<body>
${errorMessage}
</body>
</html>
快捷的ViewController
此处无任何的业务处理,只是简单的页面跳转,写了至少三行有效的代码,在实际的开发中会涉及大量这样的页面转向,若都这样写会特别的麻烦,我们通过在配置类MyMvcConfig
里通过重写addViewControllers
来简化配置:
@RequestMapping("/index")//②
public String hello(){
return "index";
}
@Override
public void addViewControllers(ViewControllerRegistry registry) {
registry.addViewController("/index").setViewName("/index");
}
路径匹配参数配置
Spring
MVC
中,路径参数如果带”.”的话,”.”后面的值将被忽略,例如,访问http://localhost/springMvc4.x/anno/pathvar/xxx.yy
,此时,”.”后面的yy
被忽略;
通过重写configurePathMatch
方法可实现不忽略”.”后面的参数,在配置类MyMvcConfig
中增加代码如下:
@Override
public void configurePathMatch(PathMatchConfigurer configurer) {
configurer.setUseSuffixPatternMatch(false);
}
Spring Mvc更多配置
更多配置请查看WebMvcConfigurerAdater
类的API
。因其是WebMvcConfigurerAdater
接口的实现,所以WebMvcConfigurerAdater
的API
内的方法也可以用来配置MVC
。下面列出WebMvcConfigurerAdater
和WebMvcConfigurer
的源码供参考。
1. WebMvcConfigurerAdater
public abstract class WebMvcConfigurerAdapter implements WebMvcConfigurer {
/**
* {@inheritDoc}
* <p>This implementation is empty.
*/
@Override
public void addFormatters(FormatterRegistry registry) {
}
/**
* {@inheritDoc}
* <p>This implementation is empty.
*/
@Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
}
/**
* {@inheritDoc}
* <p>This implementation is empty.
*/
@Override
public void extendMessageConverters(List<HttpMessageConverter<?>> converters) {
}
/**
* {@inheritDoc}
* <p>This implementation returns {@code null}
*/
@Override
public Validator getValidator() {
return null;
}
/**
* {@inheritDoc}
* <p>This implementation is empty.
*/
@Override
public void configureContentNegotiation(ContentNegotiationConfigurer configurer) {
}
/**
* {@inheritDoc}
* <p>This implementation is empty.
*/
@Override
public void configureAsyncSupport(AsyncSupportConfigurer configurer) {
}
/**
* {@inheritDoc}
* <p>This implementation is empty.
*/
@Override
public void configurePathMatch(PathMatchConfigurer configurer) {
}
/**
* {@inheritDoc}
* <p>This implementation is empty.
*/
@Override
public void addArgumentResolvers(List<HandlerMethodArgumentResolver> argumentResolvers) {
}
/**
* {@inheritDoc}
* <p>This implementation is empty.
*/
@Override
public void addReturnValueHandlers(List<HandlerMethodReturnValueHandler> returnValueHandlers) {
}
/**
* {@inheritDoc}
* <p>This implementation is empty.
*/
@Override
public void configureHandlerExceptionResolvers(List<HandlerExceptionResolver> exceptionResolvers) {
}
/**
* {@inheritDoc}
* <p>This implementation is empty.
*/
@Override
public MessageCodesResolver getMessageCodesResolver() {
return null;
}
/**
* {@inheritDoc}
* <p>This implementation is empty.
*/
@Override
public void addInterceptors(InterceptorRegistry registry) {
}
/**
* {@inheritDoc}
* <p>This implementation is empty.
*/
@Override
public void addViewControllers(ViewControllerRegistry registry) {
}
/**
* {@inheritDoc}
* <p>This implementation is empty.
*/
@Override
public void configureViewResolvers(ViewResolverRegistry registry) {
}
/**
* {@inheritDoc}
* <p>This implementation is empty.
*/
@Override
public void addResourceHandlers(ResourceHandlerRegistry registry) {
}
/**
* {@inheritDoc}
* <p>This implementation is empty.
*/
@Override
public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
}
}
WebMvcConfigurer
public interface WebMvcConfigurer {
/**
* Add {@link Converter}s and {@link Formatter}s in addition to the ones
* registered by default.
*/
void addFormatters(FormatterRegistry registry);
/**
* Configure the {@link HttpMessageConverter}s to use for reading or writing
* to the body of the request or response. If no converters are added, a
* default list of converters is registered.
* <p><strong>Note</strong> that adding converters to the list, turns off
* default converter registration. To simply add a converter without impacting
* default registration, consider using the method
* {@link #extendMessageConverters(java.util.List)} instead.
* @param converters initially an empty list of converters
*/
void configureMessageConverters(List<HttpMessageConverter<?>> converters);
/**
* A hook for extending or modifying the list of converters after it has been
* configured. This may be useful for example to allow default converters to
* be registered and then insert a custom converter through this method.
* @param converters the list of configured converters to extend.
* @since 4.1.3
*/
void extendMessageConverters(List<HttpMessageConverter<?>> converters);
/**
* Provide a custom {@link Validator} instead of the one created by default.
* The default implementation, assuming JSR-303 is on the classpath, is:
* {@link org.springframework.validation.beanvalidation.OptionalValidatorFactoryBean}.
* Leave the return value as {@code null} to keep the default.
*/
Validator getValidator();
/**
* Configure content negotiation options.
*/
void configureContentNegotiation(ContentNegotiationConfigurer configurer);
/**
* Configure asynchronous request handling options.
*/
void configureAsyncSupport(AsyncSupportConfigurer configurer);
/**
* Helps with configuring HandlerMappings path matching options such as trailing slash match,
* suffix registration, path matcher and path helper.
* Configured path matcher and path helper instances are shared for:
* <ul>
* <li>RequestMappings</li>
* <li>ViewControllerMappings</li>
* <li>ResourcesMappings</li>
* </ul>
* @since 4.0.3
*/
void configurePathMatch(PathMatchConfigurer configurer);
/**
* Add resolvers to support custom controller method argument types.
* <p>This does not override the built-in support for resolving handler
* method arguments. To customize the built-in support for argument
* resolution, configure {@link RequestMappingHandlerAdapter} directly.
* @param argumentResolvers initially an empty list
*/
void addArgumentResolvers(List<HandlerMethodArgumentResolver> argumentResolvers);
/**
* Add handlers to support custom controller method return value types.
* <p>Using this option does not override the built-in support for handling
* return values. To customize the built-in support for handling return
* values, configure RequestMappingHandlerAdapter directly.
* @param returnValueHandlers initially an empty list
*/
void addReturnValueHandlers(List<HandlerMethodReturnValueHandler> returnValueHandlers);
/**
* Configure the {@link HandlerExceptionResolver}s to handle unresolved
* controller exceptions. If no resolvers are added to the list, default
* exception resolvers are added instead.
* @param exceptionResolvers initially an empty list
*/
void configureHandlerExceptionResolvers(List<HandlerExceptionResolver> exceptionResolvers);
/**
* Add Spring MVC lifecycle interceptors for pre- and post-processing of
* controller method invocations. Interceptors can be registered to apply
* to all requests or be limited to a subset of URL patterns.
* <p><strong>Note</strong> that interceptors registered here only apply to
* controllers and not to resource handler requests. To intercept requests for
* static resources either declare a
* {@link org.springframework.web.servlet.handler.MappedInterceptor MappedInterceptor}
* bean or switch to advanced configuration mode by extending
* {@link org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport
* WebMvcConfigurationSupport} and then override {@code resourceHandlerMapping}.
*/
void addInterceptors(InterceptorRegistry registry);
/**
* Provide a custom {@link MessageCodesResolver} for building message codes
* from data binding and validation error codes. Leave the return value as
* {@code null} to keep the default.
*/
MessageCodesResolver getMessageCodesResolver();
/**
* Configure simple automated controllers pre-configured with the response
* status code and/or a view to render the response body. This is useful in
* cases where there is no need for custom controller logic -- e.g. render a
* home page, perform simple site URL redirects, return a 404 status with
* HTML content, a 204 with no content, and more.
*/
void addViewControllers(ViewControllerRegistry registry);
/**
* Configure view resolvers to translate String-based view names returned from
* controllers into concrete {@link org.springframework.web.servlet.View}
* implementations to perform rendering with.
*/
void configureViewResolvers(ViewResolverRegistry registry);
/**
* Add handlers to serve static resources such as images, js, and, css
* files from specific locations under web application root, the classpath,
* and others.
*/
void addResourceHandlers(ResourceHandlerRegistry registry);
/**
* Configure a handler to delegate unhandled requests by forwarding to the
* Servlet container's "default" servlet. A common use case for this is when
* the {@link DispatcherServlet} is mapped to "/" thus overriding the
* Servlet container's default handling of static resources.
*/
void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer);
}