Spring MVC项目搭建
添加依赖
(省略)
Spring MVC配置类
@Configuration
@EnableWebMvc
@ComponentScan("com.sjx.springmvc")
public class MyMvcConfig extends WebMvcConfigurerAdapter{
@Bean
public InternalResourceViewResolver viewResolver(){
InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
viewResolver.setPrefix("/WEB-INF/classes/views/");
viewResolver.setSuffix(".jsp");
viewResolver.setViewClass(JstlView.class);
return viewResolver;
}
}
Web配置,实现WebApplicationInitializer接口代替web.xml文件
public class WebInitializer implements WebApplicationInitializer {
@Override
public void onStartup(ServletContext servletContext) throws ServletException {
AnnotationConfigWebApplicationContext ctx = new AnnotationConfigWebApplicationContext();
ctx.register(MyMvcConfig.class);
ctx.setServletContext(servletContext);
Dynamic servlet = servletContext.addServlet("dispatcher", new DispatcherServlet(ctx));
servlet.addMapping("/");
servlet.setLoadOnStartup(1);
}
}
Spring MVC的常用注解
@controller
@controller注解在类上,表明这个类为Spring MVC的Controller,并讲Web请求映射到注解了@RequestMapping的方法上@RequestMapping
@RequestMapping是用来映射Web请求的的方法,可以注解在类上,方法上的@RequestMapping路径会继承类上的路基,并且produces属性可以设置请求的媒体类型@ResponseBody
@ResponseBody可以注解类上也可注解在方法上,支持把返回值放入response体内,而不是返回一个页面@RequestBody
@RequestBody注解在参数前,允许请求的参数在request体中,而不是直接放在链接地址的后面@PathVariable
@PathVariable用来接受路劲参数,次注解用在参数前面,如pathvar/{str},可接受参数str@RestController
@RestController是一个组合注解,是@Controller和@ResponseBody的组合
@Controller
@RequestMapping("/anno")
public class DemoAnnoController {
@RequestMapping(produces = "text/plain;charset=UTF-8")
public @ResponseBody String index(HttpServletRequest request) {
return "url" + request.getRequestURI() + "can access";
}
// http://localhost:8080/springmvc1/anno/pathvar/sjx
@RequestMapping(value = "pathvar/{str}", produces = "text/plain;charset=UTF-8")
public @ResponseBody String demoPathVar(@PathVariable String str, HttpServletRequest request) {
return "url" + request.getRequestURI() + " can access str:" + str;
}
// http://localhost:8080/springmvc1/anno/requestParam?id=25
@RequestMapping(value = "/requestParam", produces = "text/plain;charset=UTF-8")
public @ResponseBody String passRequestParam(Long id, HttpServletRequest request) {
return "url" + request.getRequestURI() + " can access id:" + id;
}
@RequestMapping(value = "/obj", produces = "application/json;charset=UTF-8")
@ResponseBody
public String passObj(DemoObj obj, HttpServletRequest request) {
return "url" + request.getRequestURI() + " can access, obj id:" + obj.getId() + " obj name:" + obj.getName();
}
@RequestMapping(value = { "/name1", "/name2" }, produces = "text/plain;charset=UTF-8")
public @ResponseBody String remove(HttpServletRequest request) {
return "url: " + request.getRequestURL() + " can access";
}
}
Spring MVC的基本配置
拦截器配置
- 拦截器类
- 继承HandlerInterceptorAdapter实现自定义拦截器
- 重写preHandle方法,请求发生时执行
- 重写postHandle方法,请求结束是执行
public class DemoInterceptor extends HandlerInterceptorAdapter {
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
long startTime = System.currentTimeMillis();
request.setAttribute("startTime", startTime);
return true;
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
Long startTime = (Long) request.getAttribute("startTime");
Long currentTime = System.currentTimeMillis();
long handlerTime = currentTime - startTime;
System.out.println("一次请求的时间为" + handlerTime + "ms");
request.setAttribute("handlerTime", handlerTime);
}
}
- 配置
- 配置拦截器的Bean
- 重写addInterceptors(InterceptorRegistry registry)方法,添加拦截器
@Configuration
@EnableWebMvc
@ComponentScan("com.sjx.springmvc")
public class MyMvcConfig extends WebMvcConfigurerAdapter{
@Bean
public InternalResourceViewResolver viewResolver(){
InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
viewResolver.setPrefix("/WEB-INF/classes/views/");
viewResolver.setSuffix(".jsp");
viewResolver.setViewClass(JstlView.class);
return viewResolver;
}
//自定义拦截器
@Bean
public DemoInterceptor handlerTimeInterceptor(){
return new DemoInterceptor();
}
//添加拦截器
@Override
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(handlerTimeInterceptor());
}
}
@ControllerAdvice
使用@ControllerAdvice注解可以将对于控制器的全局配置放在一起
- @ExceptionHandler 用于处理全局处理器中的异常
- @ModelAttribute 本来是用于将键值对绑定到Model里,这里用于让全局的@RequestMapping都能接收到此键值对
//声明一个全局通知 此注解包含了 @Component
@ControllerAdvice
public class ExceptionHandlerAdvice {
//拦截所有的异常 显示error界面
@ExceptionHandler(value = Exception.class)
public ModelAndView exception(Exception exception, WebRequest request) {
ModelAndView view = new ModelAndView("error");// error界面
view.addObject("errorMessage", exception.getMessage());
return view;
}
//所有用@RequestMapping注解的方法 都能获取这个键值对
@ModelAttribute
public void addAttribute(Model mode) {
mode.addAttribue("msg", "额外信息");
}
}
文件上传配置
- 添加依赖
commons-fileupload
commons-fileupload
1.2
commons-io
commons-io
2.4
- 上传页面
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
文件上传
- 添加upLoad的ViewController
//集中处理跳转页面
@Override
public void addViewControllers(ViewControllerRegistry registry) {
registry.addViewController("/toUpload").setViewName("/upload");
}
- 配置MultipartResolver
//配置MultipartResolver,用MultipartFile 接受文件上传
@Bean
public MultipartResolver multipartResolver(){
CommonsMultipartResolver multipartResolver = new CommonsMultipartResolver();
multipartResolver.setMaxUploadSize(1000000);
return multipartResolver;
}
- 控制器
@Controller
public class UploadController {
@RequestMapping(value = "upload", method = RequestMethod.POST)
public @ResponseBody String upload(MultipartFile file) {
try {
// 使用 commons-io包实现快读文件写入磁盘
FileUtils.writeByteArrayToFile(new File("e:/upload/" + file.getOriginalFilename()), file.getBytes());
return "success";
} catch (IOException e) {
e.printStackTrace();
return "fail";
}
}
}