1.文件上传的必要前提
(1)form 表单的 enctype 取值必须是：multipart/form-data
(默认值是:application/x-www-form-urlencoded) enctype:是表单请求正文的类型
(2)method 属性取值必须是 Post
(3)提供一个文件选择域<input type=”file” />
2.文件上传环境搭建
(1)项目结构
(2)部分重要代码
<1>web.xml
<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd" > <web-app> <display-name>Archetype Created Web Application</display-name> <!--配置前端控制器，让前端控制器去加载resources包下的springmvc.xml配置文件--> <servlet> <servlet-name>dispatcherServlet</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <!--全局的初始化参数--> <init-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:springmvc.xml</param-value> </init-param> </servlet> <servlet-mapping> <servlet-name>dispatcherServlet</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> <!--配置解决中文乱码的过滤器--> <filter> <filter-name>characterEncodingFilter</filter-name> <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class> <init-param> <param-name>encoding</param-name> <param-value>UTF-8</param-value> </init-param> </filter> <filter-mapping> <filter-name>characterEncodingFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> </web-app>
<2>spirngmvc.xml
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:context="http://www.springframework.org/schema/context" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"> <!-- 开启注解扫描 --> <context:component-scan base-package="lucky"/> <!-- 视图解析器对象 --> <bean id="internalResourceViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <!--配置控制器方法中return返回的字符串对应的同名文件所在目录--> <property name="prefix" value="/WEB-INF/pages/"/> <!--配置文件的后缀名--> <property name="suffix" value=".jsp"/> </bean> <!-- 开启SpringMVC框架注解的支持 --> <mvc:annotation-driven/> </beans>
<3>index.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Title</title> </head> <body> <h3>文件上传</h3> <form action="/day19_fileupload/user/fileUploadTest01" method="post" enctype="multipart/form-data"> 选择文件：<input type="file" name="upload"><br> <input type="submit" value="上传"> </form> </body> </html>
3.传统方式上传文件
package lucky.controller; import org.apache.commons.fileupload.FileItem; import org.apache.commons.fileupload.disk.DiskFileItemFactory; import org.apache.commons.fileupload.servlet.ServletFileUpload; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.File; import java.util.List; import java.util.UUID; @Controller @RequestMapping(path = "/user") public class UserController { //传统方式上传文件 @RequestMapping(path = "/fileUploadTest01") public String fileUploadTest01(HttpServletRequest request, HttpServletResponse response) throws Exception{ System.out.println("文件上传"); // 使用fileupload组件完成文件上传 // 上传的位置 String path = request.getSession().getServletContext().getRealPath("/uploads/"); System.out.println(path); //查看文件上传的路径 // 判断，该路径是否存在 File file = new File(path); if(!file.exists()){ // 创建该文件夹 file.mkdirs(); } // 解析request对象，获取上传文件项 DiskFileItemFactory factory = new DiskFileItemFactory(); ServletFileUpload upload = new ServletFileUpload(factory); // 解析request List<FileItem> items = upload.parseRequest(request); // 遍历 for(FileItem item:items){ // 进行判断，当前item对象是否是上传文件项 if(item.isFormField()){ // 说明普通表单向 }else{ // 说明上传文件项 // 获取上传文件的名称 String filename = item.getName(); // 把文件的名称设置唯一值，uuid String uuid = UUID.randomUUID().toString().replace("-", ""); filename = uuid+"_"+filename; // 完成文件上传 item.write(new File(path,filename)); // 删除临时文件 item.delete(); } } return "success"; } }
4.Springmvc方式文件上传
原理分析图：
package lucky.controller; import org.apache.commons.fileupload.FileItem; import org.apache.commons.fileupload.disk.DiskFileItemFactory; import org.apache.commons.fileupload.servlet.ServletFileUpload; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.multipart.MultipartFile; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.File; import java.util.List; import java.util.UUID; @Controller @RequestMapping(path = "/user") public class UserController { /** * springmvc方式上传文件 * 注意：请求参数MultipartFile upload 的名称upload必须与index.jsp中input标签的属性名一致，否则会造成空指针异常 * @return */ @RequestMapping(path = "/fileUploadTest02") public String fileUploadTest02(HttpServletRequest request, MultipartFile upload) throws Exception{ System.out.println("springmvc文件上传"); // 使用fileupload组件完成文件上传 // 上传的位置 String path = request.getSession().getServletContext().getRealPath("/uploads/"); System.out.println(path); //查看文件上传的路径 // 判断，该路径是否存在 File file = new File(path); if(!file.exists()){ // 创建该文件夹 file.mkdirs(); } // 说明上传文件项 // 获取上传文件的名称 String filename = upload.getOriginalFilename(); // 把文件的名称设置唯一值，uuid String uuid = UUID.randomUUID().toString().replace("-", ""); filename = uuid+"_"+filename; // 完成文件上传 upload.transferTo(new File(path,filename)); return "success"; } }
5.Springmvc异常处理
原理分析图：
(1)项目结构
(2)部分重要代码
<1>控制器类：UserController.java
package lucky.controller; import lucky.exception.CustomException; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; @Controller @RequestMapping(path = "/user") public class UserController { @RequestMapping(path = "/testException") public String testException() throws CustomException { System.out.println("testException执行了"); try { //模拟异常 int a=10/0; } catch (Exception e) { //抛出自定义异常 throw new CustomException("被除数有问题"); } return "success"; } }
<2>自定义异常类
package lucky.exception; /** * 自定义异常类 */ public class CustomException extends Exception{ //存储提示信息 private String message; public String getMessage() { return message; } public void setMessage(String message) { this.message = message; } public CustomException(String message) { this.message = message; } }
<3>异常处理器：CustomExceptionResolver.java
package lucky.exception; import org.springframework.web.servlet.HandlerExceptionResolver; import org.springframework.web.servlet.ModelAndView; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /** * 异常处理器 */ public class CustomExceptionResolver implements HandlerExceptionResolver { /** *处理异常的业务逻辑 */ @Override public ModelAndView resolveException(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) { //获取异常对象 CustomException customException=null; if(e instanceof CustomException){ customException= (CustomException) e; }else { customException=new CustomException("系统正在维护。。。"); } //创建ModelAndView ModelAndView mv=new ModelAndView(); mv.addObject("errormsg",e.getMessage()); mv.setViewName("error"); return mv; } }
<4>springmvc.xml文件中配置异常处理器
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:context="http://www.springframework.org/schema/context" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"> <!-- 开启注解扫描 --> <context:component-scan base-package="lucky"/> <!-- 视图解析器对象 --> <bean id="internalResourceViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <!--配置控制器方法中return返回的字符串对应的同名文件所在目录--> <property name="prefix" value="/WEB-INF/pages/"/> <!--配置文件的后缀名--> <property name="suffix" value=".jsp"/> </bean> <!--配置异常处理器--> <bean id="customExceptionResolver" class="lucky.exception.CustomExceptionResolver"/> <!-- 开启SpringMVC框架注解的支持 --> <mvc:annotation-driven/> </beans>
<6>相关jsp页面
index.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Title</title> </head> <body> <h3>异常处理</h3> <a href="/day19_exception/user/testException">异常处理</a> </body> </html>
error.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false" %> <html> <head> <title>Title</title> </head> <body> <h3>error.jsp</h3> ${errormsg} </body> </html>
(3)执行效果图
