springmvc文件上传和拦截器

文件上传

用到这两个包


配置视图解析器:springmvc配置文件配置

	<!-- id必需要是“multipartResolver” -->
	<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
		<!-- maxUploadSize文件上传的最大值。单位是byte -->
		<property name="maxUploadSize" value="1024000000"></property>
	</bean>
Form.jsp

   <form action="test/toPerson8.do" method="post" enctype="multipart/form-data">
	   	name:<input name="name" type="text"><br/>
	   	age:<input name="age" type="text"><br/>
	   	address:<input name="address" type="text"><br/>
	   	birthday:<input name="birthday" type="text"><br/>
	   	pic:<input type="file" name="pic"><br/>
   			<input type="submit"><br/>
   </form>

新建目录 upload在webroot下;存放上传的文件;
提交表单:

	@RequestMapping(value="/toPerson8.do")
	public String toPerson8(Person person,HttpServletRequest request) throws Exception{
		//第一步转化request
		MultipartHttpServletRequest rm = (MultipartHttpServletRequest) request;
		//获得文件
		CommonsMultipartFile cfile = (CommonsMultipartFile) rm.getFile("pic");
		//获得文件的字节数组
		
		byte[] bfile = cfile.getBytes();
		String fileName = "";
		//获得当前时间的最小精度
		SimpleDateFormat format =  new SimpleDateFormat("yyyyMMddHHmmssSSS");
		fileName = format.format(new Date());
		//获得三位随机数
		Random random = new Random();
		for(int i = 0; i < 3; i++){
			fileName = fileName + random.nextInt(9);
		}
		//获得原始文件名称
		String origFileName = cfile.getOriginalFilename();
		//XXX.jpg
		String suffix = origFileName.substring(origFileName.lastIndexOf("."));
		//拿到项目的部署路径
		String path = request.getSession().getServletContext().getRealPath("/");
		//定义文件的输出流
		OutputStream out = new FileOutputStream(new File(path+"/upload/"+fileName+suffix));
		out.write(bfile);
		out.flush();
		out.close();
		
		return "jsp/index";
	}
重新启动tomcat 
http://localhost:8080/springmvc-2/test1/toForm.do
选择一个文件 提交,成功。
多了一个图片
在tomcat下:
D:javaapache-tomcat-6.0.37webappsspringmvc-2upload

拦截器:

新建包:cn.edu.hqu.interceptor
类:MyInterceptor implements HandlerInterceptor;

三个方法分别相应前面图三个拦截,


Perihandle前置拦截:最多的是对权限的拦截

	/**
	 * 运行时机:在运行controller之前来运行
	 * 返回值类型:boolean:true代表放行能够訪问controller,
	 * false表示不能够訪问controller
	 */
	public boolean preHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2) throws Exception {
		return false;
	}
}
Posthandle后置拦截:

	/**
	 * 运行时机:controller运行完,视图解析器没有把视图解析成页面
	 * 对视图做统一的改动,主要提现的Model上
	 */
	public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, ModelAndView mv) throws Exception {
	
	}

终于拦截:

	/**
	 * 运行时机:视图已经被解析完成,相似try catch 后的finally
	 */
	public void afterCompletion(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, Exception arg3) throws Exception {

	}
在每一个方法输出一句话:

           System.out.println("afterCompletion...");

           System.out.println("postHandle...");

           System.out.println("preHandle...");

将前置拦截改成true;


配置拦截器:在springmvc配置文件配置
	<mvc:interceptors>
		<mvc:interceptor>
			<!-- 对全部的请求都拦截,使用/**。对某个模块下的请求做拦截/模块名/* -->
			<mvc:mapping path="/**"/>
			<bean class="cn.edu.hqu.interceptor.MyInterceptor"></bean>
		</mvc:interceptor>
	</mvc:interceptors>

重新启动tomcat 訪问
http://localhost:8080/springmvc-2/test/toForm.do
控制台输出:
preHandle...
postHandle...
afterCompletion...


将前置拦截改成false
訪问 
http://localhost:8080/springmvc-2/test/toForm.do
无法进行跳转;控制台输出:
preHandle...


前置拦截 改成true
输出拦截器的test 
后置拦截:

	public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, ModelAndView mv) throws Exception {
		System.out.println("postHandle...");
		Map<String, Object> map = mv.getModel();
		map.put("test", "addpend something by Jerome");
	}

Jsp/index.jsp
加   <h5>${test}</h5>

重新启动tomcat 訪问 
http://localhost:8080/springmvc-2/test/toPerson5.do
输出:

addpend something by Jerome


模拟异常:

	public void afterCompletion(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, Exception ex) throws Exception {
		System.out.println("afterCompletion...");
		ex.printStackTrace();
		System.out.println("===========");
	}
在页面输出 :jsp/index.jsp以下加 <%=1/0 %>
訪问:http://localhost:8080/springmvc-2/test/toPerson5.do
异常:控制台

拦截器里面方法的输出;这捕捉到异常能够做日志监控方面的工作;


补充:

载入配置文件,我们配置文件一般放在config下,名字也能够自己取。
仅仅要在web.xml配置

  <!-- springmvc的中央控制器 -->
  <servlet>
  	<servlet-name>springmvc</servlet-name>
  	<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
  	<init-param>
  		<param-name>contextConfigLocation</param-name>
  		<param-value>classpath:springmvc.xml</param-value>
  	</init-param>
  </servlet>
初始化配置文件;


源代码下载:http://pan.baidu.com/s/1mg3GcLq

原文地址:https://www.cnblogs.com/yjbjingcha/p/6851539.html