springmvc

程序员文章站 2022-07-11 11:50:57

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springmvc主要由一个DispatcherServlet(不需要开发)，三个组件：处理器映射器，处理器适配器，视图解析器(不需要开发)

hanlder(需要开发)，view（需要开发）组成

springmvc

架构流程

用户发送请求至前端控制器DispatcherServlet
DispatcherServlet收到请求调用HandlerMapping处理器映射器。
处理器映射器根据请求url找到具体的处理器，生成处理器对象及处理器拦截器(如果有则生成)一并返回给DispatcherServlet。
DispatcherServlet通过HandlerAdapter处理器适配器调用处理器
执行处理器(Controller，也叫后端控制器)。
Controller执行完成返回ModelAndView
HandlerAdapter将controller执行结果ModelAndView返回给DispatcherServlet
DispatcherServlet将ModelAndView传给ViewReslover视图解析器
ViewReslover解析后返回具体View
DispatcherServlet对View进行渲染视图（即将模型数据填充至视图中）。
DispatcherServlet响应用户

springmvc与struts2不同

springmvc的入口是一个servlet即前端控制器，而struts2入口是一个filter过滤器。
springmvc是基于方法开发(一个url对应一个方法)，请求参数传递到方法的形参，可以设计为单例或多例(建议单例)，struts2是基于类开发，传递参数是通过类的属性，只能设计为多例。
Struts采用值栈存储请求和响应的数据，通过OGNL存取数据， springmvc通过参数解析器是将request请求内容解析，并给方法形参赋值，将数据和视图封装成ModelAndView对象，最后又将ModelAndView中的模型数据通过request域传输到页面。Jsp视图解析器默认使用jstl。

核心配置文件springmvc.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:mvc="http://www.springframework.org/schema/mvc"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd">



	<!-- 扫描@Controler @Service -->
	<context:component-scan base-package="lx" />

	<!-- 处理器映射器 -->
	<!-- <bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping"/> -->
	<!-- 处理器适配器 -->
	<!-- <bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter"/> -->
	<!-- 注解驱动 -->
	<mvc:annotation-driven conversion-service="conversionServiceFactoryBean" />

	<!-- 配置Conveter转换器 转换工厂 （日期、去掉前后空格）。。 -->
	<bean id="conversionServiceFactoryBean"
		class="org.springframework.format.support.FormattingConversionServiceFactoryBean">
		<!-- 配置 多个转换器 -->
		<property name="converters">
			<list>
				<bean class="lx.springmvc.conversion.DateConveter" />
			</list>
		</property>
	</bean>

	<!-- 视图解释器 -->
	<bean
		class="org.springframework.web.servlet.view.InternalResourceViewResolver">
		<property name="prefix" value="/WEB-INF/jsp/" />
		<property name="suffix" value=".jsp" />
	</bean>
	<!-- 配置异常处理器 -->
	<bean class="lx.springmvc.exception.CustomerExceptionResolver"></bean>
	<!-- 上传图片配置实现类 -->
	<bean id="multipartResolver"
		class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
		<!-- 上传图片的大小 B 5M 1*1024*1024*5 -->
		<property name="maxUploadSize" value="5000000" />
	</bean>

	<!-- SPringmvc的拦截器 -->
	<mvc:interceptors>
		<!-- 多个拦截器 -->
		<mvc:interceptor>
			<mvc:mapping path="/**" />
			<!-- 自定义的拦截器类 -->
			<bean class="lx.springmvc.interceptor.Interceptor1" />
		</mvc:interceptor>
		<!-- <mvc:interceptor> 
		<mvc:mapping path="/**"/> 
		自定义的拦截器类 
		<bean class="com.itheima.springmvc.interceptor.Interceptor2"/> 
		</mvc:interceptor> -->
	</mvc:interceptors>
</beans>

默认参数绑定

@RequestMapping("/itemEdit")
	public ModelAndView toEdit(HttpServletRequest request,HttpServletResponse response
			,Model model){
		//servlet时代
		String id = request.getParameter("id");
		Items items = itemService.selectById(Integer.parseInt(id));
		ModelAndView mav = new ModelAndView();
		mav.addObject("item", items);
		mav.setViewName("editItem");
		return mav;
	}

简单数据类型绑定

@RequestMapping("/itemEdit")
	public ModelAndView toEdit(
			/*@RequestParam(value="id",defaultValue="1",required=false)Integer idaa,*/
			Integer id,
			HttpServletRequest request,HttpServletResponse response
			,Model model){
		//servlet时代
//		String id = request.getParameter("id");
		Items items = itemService.selectById(id);
		ModelAndView mav = new ModelAndView();
		mav.addObject("item", items);
		mav.setViewName("editItem");
		return mav;
	}

绑定pojo

@RequestMapping("/updateitem")
	public ModelAndView updateItem(Items item){
		itemService.updateItem(item);
		ModelAndView mav = new ModelAndView();
		mav.setViewName("success");
		return mav;
	}

绑定包装的pojo

public class QueryVo {

	private Items item;
	private List<Items> itemsList;
	public List<Items> getItemsList() {
		return itemsList;
	}

	public void setItemsList(List<Items> itemsList) {
		this.itemsList = itemsList;
	}

	public Items getItem() {
		return item;
	}

	public void setItem(Items item) {
		this.item = item;
	}
}

	
@RequestMapping("/updateitem")
	public ModelAndView updateItem(QueryVo vo){
		itemService.updateItem(vo.getItem());
		ModelAndView mav = new ModelAndView();
		mav.setViewName("success");
		return mav;
	}	
页面

<td><input type="text" name="item.name" value="${item.name }" /></td>

绑定数组

@RequestMapping("/item/itemsupdate")
	public ModelAndView deleteItem(Integer[] ids){
		ModelAndView mav = new ModelAndView();
		mav.setViewName("success");
		return mav;
	}	
页面
可以批量删除和修改
<c:forEach items="${itemList }" var="item" varStatus="s">
<tr>
    <td><input type="checkbox" name="ids" value="${item.id}"></td>
	<td><input type="text" name="itemsList[${s.index}].name" value="${item.name}"></td>
	<td><input type="text" name="itemsList[${s.index}].price" value="${item.price}"></td>
	<td><fmt:formatDate value="${item.createtime}" pattern="yyyy-MM-dd HH:mm:ss"/></td>
<%-- 	<td>${item.createtime }</td> --%>
	<td>${item.detail }</td>
	
	<td><a href="${pageContext.request.contextPath }/itemEdit.action?id=${item.id}">修改</a></td>

</tr>
</c:forEach>

Controller方法返回值

1.ModelAndView 无敌的，带着数据返回视图路径。
@RequestMapping("/itemList")
	public ModelAndView itemList(){
		List<Items> list = itemService.queryItemList();
		ModelAndView model = new ModelAndView();
		model.addObject("itemList", list);
		model.setViewName("itemList");
		return model;
	}
2.String 返回视图路径，model带数据 （推荐：解耦，数据视图分离）
@RequestMapping(value = "/itemlist.action")
	public String itemList(Model model) {
		List<Items> list = itemService.selectItemsList();
        model.addAttribute("itemList", list);
		return "itemList";
	}
3.void ajax请求合适

重定向与转发

return "redirect:/item/itemlist.action";
return "forward:/item/itemlist.action";

异常处理

CustomerExceptionResolver.java

package lx.springmvc.exception;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.servlet.HandlerExceptionResolver;
import org.springframework.web.servlet.ModelAndView;
/**
 * 
 * @author lx
 *
 */
public class CustomerExceptionResolver implements HandlerExceptionResolver{

	@Override
	public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response, Object obj,
			Exception e) {
		ModelAndView mav = new ModelAndView();
		if(e instanceof MessageException){
			//已知异常
			mav.addObject("error",((MessageException) e).getMsg());
		}else{
		mav.addObject("error", "未知异常");
		}
		mav.setViewName("error");
		return mav;
	}

}

MessageException.java

package lx.springmvc.exception;

public class MessageException extends Exception{

	private String msg;

	public String getMsg() {
		return msg;
	}

	public void setMsg(String msg) {
		this.msg = msg;
	}

	public MessageException(String msg) {
		super();
		this.msg = msg;
	}
	
}

上传图片

先配置Tomcat虚拟目录

springmvc

@RequestMapping(value = "/updateitem.action")

	public String updateitem(Items items,MultipartFile pictureFile) throws Exception{
//D:\fileupload
		String name = UUID.randomUUID().toString().replaceAll("-", "");
		String ext = FilenameUtils.getExtension(pictureFile.getOriginalFilename());
		pictureFile.transferTo(new File ("D:\\fileupload\\" + name + "." + ext));
		items.setPic(name + "." + ext);
		itemService.updateItemsById(items);
		return "redirect:/item/itemlist.action";
		
	}

jsp

<!-- 上传图片是需要指定属性 enctype="multipart/form-data" -->
	<!-- <form id="itemForm" action="" method="post" enctype="multipart/form-data"> -->
	<form id="itemForm"	action="${pageContext.request.contextPath }/updateitem.action" method="post" enctype="multipart/form-data">

json数据交互

jsp

<script type="text/javascript">
 $(function(){
// alert(1);
var params = '{	"id": 1,"name": "测试商品","price": 99.9,"detail": "测试商品描述","pic": "123456.jpg"}';
   $.ajax({
	   url : "${pageContext.request.contextPath }/json.action",
	   data : params,
	   contentType : "application/json;charset=UTF-8",
	   type : "post",
	   dataType : "json",
	   success : function(data){
		   alert(data.name);
	   }
   });
});
</script>

@RequestMapping(value = "/json.action")

	public @ResponseBody 
	Items json(@RequestBody Items items){
		
//	System.out.println(items);
	return items;	
	}

@RequestMapping(value = "/json.action")

	public void json(@RequestBody Items items){
		
	System.out.println(items);
	}

拦截器

package lx.springmvc.interceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

public class Interceptor1 implements HandlerInterceptor{

	@Override
	public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object arg2, Exception arg3)
			throws Exception {
		System.out.println("页面渲染后");
		
	}

	@Override
	public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, ModelAndView arg3)
			throws Exception {
		System.out.println("方法后");
		
	}

	@Override
	public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object arg2) throws Exception {
		System.out.println("方法前");
				// URL  http://localhost:8080/springmvc-mybatis/login.action
				//URI /login.action
				String requestURI = request.getRequestURI();
				if(!requestURI.contains("/login")){
					String username = (String) request.getSession().getAttribute("USER_SESSION");
					if(null == username){
						response.sendRedirect(request.getContextPath() + "/login.action");
						return false;
					}
				}
				return true;
	}

	
}

@RequestMapping(value = "/login.action",method = RequestMethod.GET)
	public String login(){
		return "login";
	}
	@RequestMapping(value = "/login.action",method = RequestMethod.POST)
	public String login(String username,HttpSession httpSession){
		httpSession.setAttribute("USER_SESSION", username);
		return "redirect:/item/itemlist.action";
	}

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