利用Struts2拦截器完成文件上传功能
Struts2的图片上传以及页面展示图片
在上次的CRUD基础上加上图片上传功能 （https://www.cnblogs.com/liuwenwu9527/p/11108611.html）
文件上传：
三种上传方案
1、上传到tomcat服务器
2、上传到指定文件目录，添加服务器与真实目录的映射关系，从而解耦上传文件与tomcat的关系
文件服务器
3、在数据库表中建立二进制字段，将图片存储到数据库(现在基本不用了)
我们使用第二种方法实现图片上传 实现效果如下：
首先是展示页面 clzList.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%> <%@taglib prefix="z" uri="/zking" %> <!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>Insert title here</title> </head> <body> <h2>班级</h2><br> <form action="${pageContext.request.contextPath }/sy/clz_list.action" method="post"> 班级名：<input type="text" name="cname"> <input type="submit" value="确定"> </form> <a href="${pageContext.request.contextPath }/sy/clz_preSave.action">新增</a> <table border="1" width="100%"> <tr> <td>编号</td> <td>班级名</td> <td>教员</td> <td>图片</td> <td>操作</td> </tr> <c:forEach items="${clzList }" var="c"> <tr> <td>${c.cid }</td> <td>${c.cname }</td> <td>${c.cteacher}</td> <td> <img alt="" style="width: 60px;height: 60px" src="${pageContext.request.contextPath }${c.pic }"> </td> <td> <a href="${pageContext.request.contextPath }/sy/clz_preSave.action?cid=${c.cid}">修改</a> <a href="${pageContext.request.contextPath }/sy/clz_del.action?cid=${c.cid}">删除</a> <a href="${pageContext.request.contextPath }/sy/clz_preUpload.action?cid=${c.cid}">图片上传</a> </td> </tr> </c:forEach> </table> <z:page pageBean="${pageBean }"></z:page> </body> </html>
图片上传界面 upload.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<form action="${pageContext.request.contextPath}/sy/clz_upload.action" method="post" enctype="multipart/form-data">
<input type="hidden" name="cid" value="${clz.cid }"><br>
<input type="hidden" name="cname" value="${clz.cname }"><br>
<input type="hidden" name="cteacher" value="${clz.cteacher }"><br>
<!-- 注意：name对应的值决定了，子控制器action属性的命名 -->
<input type="file" name="file" >
<input type="submit" >
</form>
</body>
</图片上传界面 upload.jsphtml>
ClazzAction类
package com.liuwenwu.crud.web; import java.io.BufferedInputStream; import java.io.BufferedOutputStream; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.sql.SQLException; import java.util.List; import org.apache.commons.io.FileUtils; import com.liuwenwu.crud.dao.ClazzDao; import com.liuwenwu.crud.entity.Clazz; import com.liuwenwu.crud.util.PageBean; import com.opensymphony.xwork2.ModelDriven; public class ClazzAction extends BaseAction implements ModelDriven<Clazz>{ private ClazzDao clzDao=new ClazzDao(); private Clazz clz=new Clazz(); // img/img/imgContentType/imgFileName private File file; private String fileContentType; private String fileFileName; public String list() { PageBean pageBean=new PageBean(); pageBean.setRequest(request); try { List<Clazz> list= this.clzDao.list(clz, pageBean); // this.result=this.clzDao.list(clz, pageBean); request.setAttribute("clzList", list); request.setAttribute("pageBean", pageBean); } catch (Exception e) { e.printStackTrace(); } return "list"; } /** * 直接上传图片 * @return */ public String upload() { try { // 注意：在linux下是没有F盘的，linux下只有一个盘符，那么意味着，当打包到linux服务器的时候需要改动代码 // 这个时候通常是这么解决的，将targetPath对应的目录串，配置到资源文件中，通过Properties类进行动态读取 // 那么当需要将项目发布到linux服务器的时候，只需要改变xxx.properties文件中的targetPath=/zking/T224/img // 实际图片存储的位置 String targetDir="F:/zz"; // 存储到数据库中的地址 String serverPath="/upload"; FileUtils.copyFile(file, new File(targetDir+"/"+fileFileName)); // 注意：数据库存放的是网络请求地址 ，而不是本地图片存放地址 clz.setPic(serverPath+"/"+fileFileName); this.clzDao.edit(clz); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } return "toList"; } /** * 跳转文件上传页面 * @return */ public String preUpload() { try { Clazz c = this.clzDao.list(clz, null).get(0); request.setAttribute("clz", c); } catch (Exception e) { e.printStackTrace(); } return "toUpload"; } /** * 跳转新增修改页面的公用方法 * @return */ public String preSave() { if(clz.getCid()!=0) { try { Clazz c = this.clzDao.list(clz, null).get(0); request.setAttribute("clz", c); } catch (Exception e) { e.printStackTrace(); } } return "preSave"; } /** * 新增 * @return */ public String add() { try { result=this.clzDao.add(clz); } catch (NoSuchFieldException | SecurityException | IllegalArgumentException | IllegalAccessException | SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return "toList"; } /** * 修改 * @return */ public String edit() { try { this.clzDao.edit(clz); } catch (NoSuchFieldException | SecurityException | IllegalArgumentException | IllegalAccessException | SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return "toList"; } /** * 删除 * @return */ public String del() { try { this.clzDao.del(clz); } catch (NoSuchFieldException | SecurityException | IllegalArgumentException | IllegalAccessException | SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return "toList"; } @Override public Clazz getModel() { // TODO Auto-generated method stub return clz; } public File getFile() { return file; } public void setFile(File file) { this.file = file; } public String getFileContentType() { return fileContentType; } public void setFileContentType(String fileContentType) { this.fileContentType = fileContentType; } public String getFileFileName() { return fileFileName; } public void setFileFileName(String fileFileName) { this.fileFileName = fileFileName; } }
struts-sy.xml的配置
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.5//EN" "http://struts.apache.org/dtds/struts-2.5.dtd"> <struts> <!-- /user/bookAction?methodName=list /sy/bookAction?methodName=list --> <package name="sy" extends="base" namespace="/sy"> <action name="/demo_*" class="com.liuwenwu.web.HelloAction" method="{1}"> <result name="rs">/rs.jsp</result> </action> <action name="/stack_*" class="com.liuwenwu.test.DemoAction" method="{1}"> <result name="rs">/rs.jsp</result> </action> <action name="/clz_*" class="com.liuwenwu.crud.web.ClazzAction" method="{1}"> <result name="list">/clzList.jsp</result> <result name="preSave">/clzEdit.jsp</result> <result name="toList" type="redirectAction">/clz_list</result> <result name="toUpload">/upload.jsp</result> </action> </package> </struts>
eclipse中修改Tomcat服务器配置文件 添加服务器与真实目录映射关系
添加
<Context path="/T224_struts/upload" docBase="F:/zz/"/>
path是指服务器路径 docBase是指服务器本地映射地址
理解图片上传的原理 自己写一个通过缓冲区增强的图片上传方法
/** * FileUtils.copyFile的底层，并且通过缓冲区进行了增强 * @param source * @param target * @throws Exception */ public void conpyBufFile(File source,File target) throws Exception{ //读取 BufferedInputStream in=new BufferedInputStream(new FileInputStream(source)); //写入 BufferedOutputStream out=new BufferedOutputStream(new FileOutputStream(target)); byte[] bbuf=new byte[1024]; int len=0; while((len=in.read(bbuf))!=-1){ out.write(bbuf, 0, len); } in.close(); out.close(); }
拦截器 Interceptor：
实现的2种方法：
implements Interceptor
extends AbstractInterceptor
先定义两个拦截器
package com.liuwenwu.crud.interceptor; import com.opensymphony.xwork2.ActionInvocation; import com.opensymphony.xwork2.interceptor.Interceptor; public class OneInterceptor implements Interceptor{ @Override public void destroy() { // TODO Auto-generated method stub } @Override public void init() { // TODO Auto-generated method stub } @Override public String intercept(ActionInvocation invocation) throws Exception { // TODO Auto-generated method stub System.out.println("=======OneInterceptor==========1"); String invoke = invocation.invoke(); System.out.println("=======OneInterceptor==========2"); return invoke; } }
package com.liuwenwu.crud.interceptor; import com.opensymphony.xwork2.ActionInvocation; import com.opensymphony.xwork2.interceptor.Interceptor; public class TwoInterceptor implements Interceptor{ @Override public void destroy() { // TODO Auto-generated method stub } @Override public void init() { // TODO Auto-generated method stub } @Override public String intercept(ActionInvocation invocation) throws Exception { // TODO Auto-generated method stub System.out.println("=======TwoInterceptor==========1"); String invoke = invocation.invoke(); System.out.println("=======TwoInterceptor==========2"); return invoke; } }
拦截器的工作原理：
在struts-sy.xml中配置拦截器
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.5//EN" "http://struts.apache.org/dtds/struts-2.5.dtd"> <struts> <package name="sy" extends="base" namespace="/sy"> <interceptors> <interceptor name="one" class="com.liuwenwu.crud.interceptor.OneInterceptor"></interceptor> <interceptor name="two" class="com.liuwenwu.crud.interceptor.TwoInterceptor"></interceptor> </interceptors> <action name="/demo_*" class="com.liuwenwu.web.HelloAction" method="{1}"> <result name="rs">/rs.jsp</result> </action> <action name="/stack_*" class="com.liuwenwu.test.DemoAction" method="{1}"> <result name="rs">/rs.jsp</result> </action> <action name="/clz_*" class="com.liuwenwu.crud.web.ClazzAction" method="{1}"> <interceptor-ref name="one"></interceptor-ref> <interceptor-ref name="two"></interceptor-ref> <result name="list">/clzList.jsp</result> <result name="preSave">/clzEdit.jsp</result> <result name="toList" type="redirectAction">/clz_list</result> <result name="toUpload">/upload.jsp</result> </action> </package> </struts>
当拦截器起作用
