文件上传：
三种上传方案
1、上传到tomcat服务器 上传图片的存放位置与tomcat服务器的耦合度太高
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

package com.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.opensymphony.xwork2.ModelDriven;
import com.crud.dao.ClazzDao;
import com.crud.entity.Clazz;
import com.crud.uitl.BaseAction;
import com.crud.uitl.PageBean;

public class ClazzAction extends BaseAction implements ModelDriven<Clazz>{
	private Clazz clz = new Clazz();
	private ClazzDao clzDao=new ClazzDao();

	private File file;

	private String fileFileName;

	private String fileConentType;
	
	/**
	 * 跳转上传图片界面
	 * @return
	 */
	public String preUpload() {
			try {
				this.result = this.clzDao.list(clz, null).get(0);
			} catch (Exception e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		return "preUpload";
	}
	
	public String upload() {
		String realDir = "D:/tanzhixian";
		String severDir="/upload";
		try {
//			FileUtils.copyFile(file, new File(realDir +"/"+fileFileName ));

			copyFile(file, new File(realDir +"/"+fileFileName));
			clz.setPic(severDir+"/"+fileFileName);
			this.clzDao.edit(clz);
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (NoSuchFieldException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (SecurityException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IllegalArgumentException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IllegalAccessException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	return "toList";
}
	
	/**
	 * 缓冲流进行拷贝
	 * @param source
	 * @param target
	 * @throws IOException 
	 */
	public void copyFile(File source, File target) throws IOException {
		BufferedInputStream in =new  BufferedInputStream(new FileInputStream(source));
		BufferedOutputStream out=new BufferedOutputStream(new FileOutputStream(target));
		byte[] buf = new byte[1024];
		int len=0;
		while((len = in.read(buf)) !=-1) {
			out.write(buf, 0, len);
		}
		in.close();
		out.close();
	}

	
	public String list() {
		PageBean pageBean = new PageBean();
		pageBean.setRequest(request);
		try {
			List<Clazz> list = this.clzDao.list(clz, pageBean);
			request.setAttribute("clzList", list);
			request.setAttribute("pageBean", pageBean);
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return "list";
	}
	
	/**
	 * 跳转界面
	 * @return
	 */
	public String preSave() {
		if(clz.getCid() !=0) {
			try {
				this.result = this.clzDao.list(clz, null).get(0);
			} catch (Exception e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		return "preSave";
	}
	
	public String add() {
		try {
			this.clzDao.add(clz);
		} catch (NoSuchFieldException | SecurityException | IllegalArgumentException | IllegalAccessException
				| SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return "toList";
	}
	
	public String edit() {
		try {
			this.clzDao.edit(clz);
		} catch (NoSuchFieldException | SecurityException | IllegalArgumentException | IllegalAccessException
				| SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return "toList";
	}
	
	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 getFileFileName() {
		return fileFileName;
	}

	public void setFileFileName(String fileFileName) {
		this.fileFileName = fileFileName;
	}

	public String getFileConentType() {
		return fileConentType;
	}

	public void setFileConentType(String fileConentType) {
		this.fileConentType = fileConentType;
	}
	
	
	

}

　　

<?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">
		
		
		<action name="/clz_*" class="com.crud.web.ClazzAction" method="{1}">
			<result name="list">/clzList.jsp</result>
			<result name="preSave">/clzEdit.jsp</result>
			<result name="preUpload">/clzUpload.jsp</result>
			<result name="toList" type="redirectAction">/clz_list</result>
		</action>
		
	</package>
</struts>

　　jsp界面

<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8"%>
    <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
    <%@ taglib uri="/lingerqi" prefix="z" %>
    
<!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>班级主界面</title>
</head>
<body>
<h2>小说目录</h2>
	<br>

	<form action="${pageContext.request.contextPath}/sy/clz_list.action"
		method="post">
		书名：<input type="text" name="bname"> <input type="submit"
			value="确定">
		<!-- <input type="hidden" name="pagination" value="false"> 
			<input type="hidden" name="rows" value="10"> -->
	</form>
	<a href="${pageContext.request.contextPath}/sy/clz_preSave.action">增加</a>
	<table border="1" width="100%">
		<tr>
			<td>编号</td>
			<td>班级名称</td>
			<td>教员</td>
			<td>班级图片</td>
			<td>操作</td>
		</tr>
		<c:forEach items="${clzList }" var="b">
			<tr>
				<td>${b.cid }</td>
				<td>${b.cname }</td>
				<td>${b.cteacher }</td>
				<td>
					<img src="${pageContext.request.contextPath}${b.pic }" style="width: 50px; height: 50px;">
				</td>
				<td><a href="${pageContext.request.contextPath}/sy/clz_preSave.action?cid=${b.cid}">修改</a> </td>
			    <td><a href="${pageContext.request.contextPath}/sy/clz_del.action?cid=${b.cid}">删除</a> </td>
			    <td><a href="${pageContext.request.contextPath}/sy/clz_preUpload.action?cid=${b.cid}">图片上传</a></td>
			</tr> 
		</c:forEach>
	</table>
	<z:page pageBean="${pageBean}"></z:page>
</body>

</html>

　　

<%@ 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>图片上传</title>
</head>
<body>
<form action="${pageContext.request.contextPath}/sy/clz_upload.action" method="post" enctype="multipart/form-data">
	<input type="hidden" name="cid" value="${result.cid }"><br>
	<input type="hidden" name="cname" value="${result.cname }"><br>
	<input type="hidden" name="cteacher" value="${result.cteacher }"><br>
	<input type="file" name="file">
	<input type="submit">
</form>
</body>
</html>

　　在server.xml最后加入：<Context path="/struts/upload" docBase="（路径）" ></Context>