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java web 实现上传下载

2013-01-11 15:24 357 查看

jsp页面代码：

[html]
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<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<!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>上传文件</title>
</head>
<body>
<font color="red" size="3px"><b>${error}</b></font>
<table border="1" width="60%">
<tr>
<th>用户名</th>
<th>性别</th>
<th>头像</th>
<th>IP地址</th>
<th>上传文件名</th>
<th>操作</th>
</tr>
<c:forEach items="${list}" var="user">
<tr>
<td>${user.name}</td>
<td>${user.sex==true?"男":"女"}</td>
<td><img src="${user.pic}" height="120"></td>
<td>${user.ip}</td>
<td>${user.fileName}</td>
<td><a href="/upload?mode=download&id=${user.id}">下载</a></td>
</tr>
</c:forEach>
</table>
<form action="/upload?mode=upload" method="post">
<input type="submit" value="去上传..."/>
</form>
</body>
</html>

jsp页面代码：

[html]
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<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<!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>上传文件</title>
<script type="text/javascript">
var tag = true;
function go(){
if(tag){
document.forms[0].submit();
tag = false;
}else{
alert("正在提交中，请勿重复提交请求……");
}
}
</script>
</head>
<body>
<font color="red" size="3px"><b>${error}</b></font>
<form action="/upload?mode=add" method="post" enctype="multipart/form-data">
<input type="hidden" name="randomName" value="${randomName}"/>
<input type="hidden" name="randomValue" value="${randomValue}"/>
<table>
<tr>
<td>用户名：</td>
<td><input type="text" name="name"/></td>
</tr>
<tr>
<td>性别：</td>
<td><input type="radio" name="sex" value="true"/>男
<input type="radio" name="sex" value="false"/>女
</td>
</tr>
<tr>
<td>头像：</td>
<td><input type="file" name="pic"/></td>
</tr>

<tr>
<td>文件名：</td>
<td><input type="file" name="fileName"/></td>
</tr>
<tr>

<td colspan="2" align="center"><input type="submit" value="提交""/>
</tr>
</table>
</form>
</body>
</html>

User .java代码：

[java]
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package cn.itcast.cd.domain;

public class User {
private Long id;
private String name;
private Boolean sex;
private String pic;
private String ip;
private String fileName;
private String filePath;
private long fileSize;

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public Boolean getSex() {
return sex;
}

public void setSex(Boolean sex) {
this.sex = sex;
}

public String getFileName() {
return fileName;
}

public void setFileName(String fileName) {
this.fileName = fileName;
}

public String getFilePath() {
return filePath;
}

public void setFilePath(String filePath) {
this.filePath = filePath;
}

public Long getId() {
return id;
}

public void setId(Long id) {
this.id = id;
}

public String getIp() {
return ip;
}

public void setIp(String ip) {
this.ip = ip;
}

public String getPic() {
return pic;
}

public void setPic(String pic) {
this.pic = pic;
}

public long getFileSize() {
return fileSize;
}

public void setFileSize(long fileSize) {
this.fileSize = fileSize;
}

@Override
public String toString() {
return "User [id=" + id + ", name=" + name + ", sex=" + sex + ", pic="
+ pic + ", ip=" + ip + ", fileName=" + fileName + ", filePath="
+ filePath + ", fileSize=" + fileSize + "]";
}
}

IUserDAO 接口：

[java]
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package cn.itcast.cd.dao;

import java.util.List;

import cn.itcast.cd.domain.User;

public interface IUserDAO {
void add(User user);
List<User> list();
User get(Long id);
}

BaseDao .java代码：

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package cn.itcast.cd.daoImpl;

import java.sql.SQLException;

import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.ResultSetHandler;

import cn.itcast.cd.Utils.Utils;

public class BaseDao {
// 使用DbUtils中的QueryRunner对象.
private QueryRunner queryRunner = new QueryRunner(Utils.getDataSource());
/*
* 执行修改
*/
public void exeUpdate(String sql, Object... params) {
try {
queryRunner.update(sql, params);
} catch (SQLException e) {
e.printStackTrace();
}
}

/*
* 执行查询
*/
public <T> T exeQuery(String sql, ResultSetHandler<T> rsh, Object... params) {
try {
return queryRunner.query(sql, rsh, params);
} catch (SQLException e) {
e.printStackTrace();
}
return null;
}
}

UserDAOImpl .java实现类：

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package cn.itcast.cd.daoImpl;

import java.util.List;

import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;

import cn.itcast.cd.dao.IUserDAO;
import cn.itcast.cd.domain.User;

public class UserDAOImpl extends BaseDao implements IUserDAO {

@Override
public void add(User user) {
String sql = "insert into user values(null, ?, ?, ?, ?, ?, ?)";
Object[] params = { user.getName(), user.getSex(), user.getPic(), user.getIp(),
user.getFileName(), user.getFilePath() };
exeUpdate(sql, params);
}

@Override
public List<User> list() {
String sql = "select * from user";
return exeQuery(sql, new BeanListHandler<User>(User.class));
}

@Override
public User get(Long id) {
String sql = "select * from user where id=?";
return exeQuery(sql, new BeanHandler<User>(User.class), id);
}
}

BaseServlet .java代码：

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package cn.itcast.cd.servlet;

import java.io.IOException;
import java.lang.reflect.Method;

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

import org.apache.commons.lang3.StringUtils;

public class BaseServlet extends HttpServlet {

private static final long serialVersionUID = 1L;

@Override
protected void service(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
req.setCharacterEncoding("UTF-8");
String mode = req.getParameter("mode");

if (StringUtils.isNotBlank(mode)) {
try {
Method method = this.getClass().getMethod(mode,
HttpServletRequest.class, HttpServletResponse.class);
method.invoke(this, req, resp);
} catch (Exception e) {
e.printStackTrace();
}
} else {
doMethod(req, resp); // 默认调用
}
}

protected void doMethod(HttpServletRequest req, HttpServletResponse resp) {

}
}

MyHttpServletRequest .java类：

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package cn.itcast.cd.servlet;

import java.io.File;
import java.io.UnsupportedEncodingException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.UUID;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileItemFactory;
import org.apache.commons.fileupload.FileUploadBase.SizeLimitExceededException;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.io.FilenameUtils;

import cn.itcast.cd.Utils.MyException;
import cn.itcast.cd.Utils.UploadFileInfo;

public class MyHttpServletRequest extends HttpServletRequestWrapper {
// 装在普通表单元素的map
private Map<String, String> formFiledMap = new HashMap<String, String>();

// 装在上传表单元素的Map
private Map<String, FileItem> uploadFieldMap = new HashMap<String, FileItem>();

Boolean isMultipartContent = false;

public MyHttpServletRequest(HttpServletRequest request) {
super(request);
// 检查是否是文件上传请求
isMultipartContent = ServletFileUpload.isMultipartContent(request);
if (isMultipartContent) {
// 创建工程，设置上传最大的内存空间和临时文件存放位置.
FileItemFactory factory = new DiskFileItemFactory(1024 * 1024 * 10,
new File("D:/tmp"));
ServletFileUpload fileUpload = new ServletFileUpload(factory);
fileUpload.setFileSizeMax(1024 * 1024); // 设置单个文件上传的最大值为1M.
fileUpload.setSizeMax(1024 * 1024 * 5); // 设置整个表单的文件上传最大值为5M.
try {
List<FileItem> fileItems = fileUpload.parseRequest(request);
for (FileItem fileItem : fileItems) {
// 是否是普通表单元素，即type不为file的表单元素
if (fileItem.isFormField()) {
formFiledMap.put(fileItem.getFieldName(),
fileItem.getString("UTF-8"));
} else {
if (fileItem.getSize() > 0) {
uploadFieldMap.put(fileItem.getFieldName(),
fileItem);
}
}
}
} catch (SizeLimitExceededException e) {
throw new MyException("上传文件的大小超过限制！");
} catch (FileUploadException e) {
e.printStackTrace();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
}
}

// 包装原来的方法
@Override
public String getParameter(String name) {
// 是上传文件的表单，要得到参数值，直接根据name，取存在map中的值.
if (isMultipartContent) {
return formFiledMap.get(name);
} else {
return super.getParameter(name);
}
}

// 已经将Map修改了，覆盖原来的方法
@Override
public Map getParameterMap() {
if (isMultipartContent) {
return formFiledMap;
} else {
return super.getParameterMap();
}
}

/**
* 上传表单中指定表单元素中的文件.
*
* @param formFieldName
* 表单中元素的名称
* @param tagPath
* 上传的目标目录，即服务器上存放上传文件的目录.
*
* @return 由于上传成功后，我们需要将上传的文件名和文件地址存放到数据库，
* 也即需要返回给Servlet上传的文件信息，故将文件信息封装成一个对象返回.
*
*/
public UploadFileInfo upload(String formFieldName, String tagPath) {
FileItem fileItem = uploadFieldMap.get(formFieldName);
if (fileItem != null) {
// 得到文件名fileItem.getName()有些浏览器可能得到的是全路径，而这里只需要文件名
String srcFileName = FilenameUtils.getName(fileItem.getName());
long fileSize = fileItem.getSize();

//不同的用户可能上传相同的文件名，不处理就被覆盖，所以这里需要用唯一标示进行文件区分.
String tagFilePath = tagPath + "/" + UUID.randomUUID().toString() + "." + FilenameUtils.getExtension(srcFileName);

if (!tagPath.startsWith("/")){
tagPath = "/" + tagPath;
}

//判断目录是否存在，不存在就创建
File dir = new File(getSession().getServletContext().getRealPath("/") + tagPath);
if (!dir.exists()) {
dir.mkdirs();
}

//写到指定目录
try {
fileItem.write(new File(getSession().getServletContext().getRealPath("/"), tagFilePath));
} catch (Exception e) {
e.printStackTrace();
}
return new UploadFileInfo(srcFileName, tagFilePath, fileSize);
}
return null;
}
}

UploadServlet .java类：

[java]
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package cn.itcast.cd.servlet;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.util.List;
import java.util.UUID;

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

import org.apache.catalina.startup.SetAllPropertiesRule;
import org.apache.commons.lang3.StringUtils;

import cn.itcast.cd.Utils.MyException;
import cn.itcast.cd.Utils.UploadFileInfo;
import cn.itcast.cd.dao.IUserDAO;
import cn.itcast.cd.daoImpl.UserDAOImpl;
import cn.itcast.cd.domain.User;

/**
* Servlet implementation class UploadServlet
*/
public class UploadServlet extends BaseServlet {
private static final long serialVersionUID = 1L;

IUserDAO dao = null;

@Override
public void init() throws ServletException {
dao = new UserDAOImpl();
}

public void add(HttpServletRequest request, HttpServletResponse response)
throws InterruptedException {
// request不能接收上传文件的表单参数，返回全部为null，所以用MyHttpServletRequest类进行包装，单独处理.

// Thread.sleep(1000);

MyHttpServletRequest myRequest = null;
try {
myRequest = new MyHttpServletRequest(request);
} catch (MyException e) { // 捕捉自定义异常，提示用户上传文件的大小限制
request.setAttribute("error", e.getMessage());
upload(request, response);
return;
}

/*
* 从页面得到标示信息，由于是文件上传的请求，必须用myRequest
*/
String randomName = myRequest.getParameter("randomName");
String randomValue = myRequest.getParameter("randomValue");
//session中的标示.
String randomValueInSession = (String) myRequest.getSession().getAttribute(randomName);

// System.out.println(randomName + " " + randomValue + " " + randomValueInSession);

if(StringUtils.isNotBlank(randomValueInSession) &&
StringUtils.isNotBlank(randomValue) && StringUtils.isNotBlank(randomName)
&& randomValueInSession.equals(randomValue)){
// 接收普通表单元素的参数信息
String name = myRequest.getParameter("name");
String sex = myRequest.getParameter("sex");

// 封装对象
User user = new User();
user.setName(name);
user.setSex(Boolean.parseBoolean(sex));

String ip = request.getRemoteAddr();
user.setIp(ip);

// 上传头像信息
UploadFileInfo picInfo = myRequest.upload("pic", "/headPic");
if (picInfo != null) {
user.setPic(picInfo.getTagFilePath());
}

UploadFileInfo fileInfo = myRequest.upload("fileName",
"/WEB-INF/resource");
if (fileInfo != null) {
user.setFilePath(fileInfo.getTagFilePath());
user.setFileName(fileInfo.getSrcFileName());
user.setFileSize(fileInfo.getFileSize());
}

dao.add(user);

//提交完成移除session中设置的随机标示
request.getSession().removeAttribute(randomName);
} else {
request.setAttribute("error", "重复提交请求……");
}
list(request, response);
}

public void list(HttpServletRequest request, HttpServletResponse response) {
List<User> list = dao.list();
request.setAttribute("list", list);
try {
request.getRequestDispatcher("/WEB-INF/jsp/list.jsp").forward(
request, response);
} catch (ServletException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}

public void upload(HttpServletRequest request, HttpServletResponse response) {
try {
//防止重复提交
String randomName = UUID.randomUUID().toString();
String randomValue = UUID.randomUUID().toString();

request.setAttribute("randomName", randomName );
request.setAttribute("randomValue", randomValue);
//当前产生的标示放到session.
request.getSession().setAttribute(randomName, randomValue);

request.getRequestDispatcher("/WEB-INF/jsp/upload.jsp").forward(
request, response);

} catch (ServletException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}

@Override
protected void doMethod(HttpServletRequest request,
HttpServletResponse response) {
list(request, response);
}

public void download(HttpServletRequest request,
HttpServletResponse response) {
String id = request.getParameter("id");
User user = dao.get(Long.parseLong(id));

// 发送下载请求给浏览器
response.setContentType("application/x-msdownload");
try {
// 解决下载时文件名乱码问题.
response.setHeader("Content-Disposition", "attachment;filename="
+ URLEncoder.encode(user.getFileName(), "utf-8"));
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}

BufferedOutputStream bos = null;
BufferedInputStream bis = null;
try {
bos = new BufferedOutputStream(response.getOutputStream());
bis = new BufferedInputStream(new FileInputStream(new File(
getServletContext().getRealPath("/"), user.getFilePath())));

byte[] b = new byte[1024];

int lenth = 0;
while ((lenth = bis.read(b)) != -1) {
bos.write(b, 0, lenth);
bos.flush();
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
bos.close();
bis.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}

MyException .java类

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package cn.itcast.cd.Utils;

public class MyException extends RuntimeException {
public MyException(String message){
super(message);
}
}

UploadFileInfo.java类：

[java]
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package cn.itcast.cd.Utils;

public class UploadFileInfo {
private String srcFileName;
private String tagFilePath;
private long fileSize;
public String getSrcFileName() {
return srcFileName;
}
public void setSrcFileName(String srcFileName) {
this.srcFileName = srcFileName;
}
public String getTagFilePath() {
return tagFilePath;
}
public void setTagFilePath(String tagFilePath) {
this.tagFilePath = tagFilePath;
}
public long getFileSize() {
return fileSize;
}
public void setFileSize(long fileSize) {
this.fileSize = fileSize;
}
public UploadFileInfo(String srcFileName, String tagFilePath, long fileSize) {
super();
this.srcFileName = srcFileName;
this.tagFilePath = tagFilePath;
this.fileSize = fileSize;
}
}

Utils.java类：

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package cn.itcast.cd.Utils;

import java.util.Properties;

import javax.sql.DataSource;

import org.apache.commons.dbcp.BasicDataSourceFactory;

public class Utils {
private static DataSource dataSource;

static{
Properties properties = new Properties();
try {
properties.load(Utils.class.getClassLoader().getResourceAsStream("jdbc.properties"));
dataSource = BasicDataSourceFactory.createDataSource(properties);
} catch (Exception e) {
e.printStackTrace();
}
}

public static DataSource getDataSource(){
return dataSource;
}
}

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