struts2文件的上传和下载 -

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struts2文件的上传和下载

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struts

【Java EE】struts2文件的上传和下载

（一）从底层透析文件上传的实现，此时并没有介入struts2
1、upload.jsp，在form中属性method默认为get，涉及文件上传时必须改为post，默认enctype="application/x-www-form-urlencoded" ，我们暂且不修改，看会有什么结果

<%@ page language="java" contentType="text/html; charset=GBK"
2

pageEncoding="GBK"%>
3

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
4

<html>
5

<head>
6

<title>Insert title here</title>
8

</head>
9

<body>
10

<form action="result.jsp" method="post"
11

enctype="application/x-www-form-urlencoded">
12

Information:
13

<input type="text" name="info">
14

<br>
15

File:
16

<input type="file" name="file">
17

<br>
18

<input type="submit" name="submit" value=" submit ">
19

</form>
20

</body>
21

</html>

result.jsp

<%@ page language="java" contentType="text/html; charset=GBK"
2

pageEncoding="GBK"%>
3

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
4

<html>
5

<head>
6

<title>Insert title here</title>
8

</head>
9

<body>
10

Information:<%=request.getParameter("info")%><br>
11

File:<%=request.getParameter("file")%><br>
12

</body>
13

</html>

结果：

2、修改result.jsp页面代码，输出读入的流

<%@ page import="java.io.*"%>

<body>

InputStream is = request.getInputStream();

BufferedReader br = new BufferedReader(new InputStreamReader(is));

String buffer = null;

while ((buffer = br.readLine()) != null) {

out.print(buffer + "<br>");

}

</body>

结果：

这个结果可以断定，文件的上传并没有成功，而仅仅是上传了文件的路径信息而已

3、把upload.jsp中form的enctype属性改为enctype="multipart/form-data"

Information:

<br>

File:

<br>

</form>

结果：

说明文件上传是成功的。

（二）手动采用fileupload组建进行文件上传
upload2.jsp

<%@ page language="java" contentType="text/html; charset=GB18030"
2

pageEncoding="GB18030"%>
3

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
4

<html>
5

<head>
6

<title>Insert title here</title>
8

</head>
9

<body>
10

<form action="/MyStruts2/UploadServlet" method="post" enctype="multipart/form-data">
11

username:
12

<input type="text" name="username">
13

<br>
14

password:
15

<input type="password" name="password">
16

<br>
17

file1:
18

<input type="file" name="file1">
19

<br>
20

file2:
21

<input type="file" name="file2">
22

<br>
23

<input type="submit" value=" submit ">
24

</form>
25

</body>
26

</html>

web.xml中的配置

<servlet-name>UploadServlet</servlet-name>

<servlet-class>com.test.servlet.UploadServlet</servlet-class>

</servlet>

<servlet-mapping>

<servlet-name>UploadServlet</servlet-name>

<url-pattern>/UploadServlet</url-pattern>

</servlet-mapping>

UploadServle.java

package com.test.servlet;
2

import java.io.File;
4

import java.io.FileOutputStream;
5

import java.io.IOException;
6

import java.io.InputStream;
7

import java.io.OutputStream;
8

import java.util.List;
9

import javax.servlet.ServletException;
11

import javax.servlet.http.HttpServlet;
12

import javax.servlet.http.HttpServletRequest;
13

import javax.servlet.http.HttpServletResponse;
14

import org.apache.commons.fileupload.FileItem;
16

import org.apache.commons.fileupload.FileUploadException;
17

import org.apache.commons.fileupload.disk.DiskFileItemFactory;
18

import org.apache.commons.fileupload.servlet.ServletFileUpload;
19

@SuppressWarnings("serial")
21

public class UploadServlet extends HttpServlet {
22

@SuppressWarnings( { "unchecked", "deprecation" })
23

public void doPost(HttpServletRequest request, HttpServletResponse response)
24

throws ServletException, IOException {
25

DiskFileItemFactory factory = new DiskFileItemFactory();
27

String path = request.getRealPath("/upload");
29

factory.setRepository(new File(path));
31

factory.setSizeThreshold(1024 * 1024);
33

ServletFileUpload upload = new ServletFileUpload(factory);
35

try {
37

List<FileItem> list = upload.parseRequest(request);
38

for (FileItem item : list) {
40

if (item.isFormField()) {
41

String name = item.getFieldName();
42

String value = item.getString("gbk");
44

System.out.println(name);
46

request.setAttribute(name, value);
48

} else {
49

String name = item.getFieldName();
50

String value = item.getName();
52

int start = value.lastIndexOf("\\");
54

String fileName = value.substring(start + 1);
56

request.setAttribute(name, fileName);
58

item.write(new File(path, fileName));
60

OutputStream os = new FileOutputStream(new File(path,
62

fileName));
63

InputStream is = item.getInputStream();
65

byte[] buffer = new byte[400];
67

int length = 0;
69

while ((length = is.read(buffer)) > 0) {
71

os.write(buffer, 0, length);
72

}
73

os.close();
75

is.close();
77

}
79

}
80

}
81

catch (Exception ex) {
83

ex.printStackTrace();
84

}
85

request.getRequestDispatcher("upload/result2.jsp").forward(request,
86

response);
87

}
88

}

结果：

（三）使用struts2进行文件上传、下载
需引入两个jar包

commons-fileupload-1.2.1.jar

commons-io-1.3.2.jar

这两个jar包在struts2.1.6版本中已经自带，较低版本需到apache网站下载，网址：http://commons.apache.org/

1、单文件上传
upload3.jsp

<%@ page language="java" contentType="text/html; charset=GB18030"
2

pageEncoding="GB18030"%>
3

<%@ taglib prefix="s" uri="/struts-tags"%>
4

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
5

<html>
6

<head>
7

<title>Insert title here</title>
9

</head>
10

<body>
11

<s:form action="upload" method="post" theme="simple"
12

enctype="multipart/form-data">
13

<table align="center" width="50%" border="1">
14

<tr>
15

<td>
16

username
17

</td>
18

<td>
19

<s:textfield name="username"></s:textfield>
20

</td>
21

</tr>
22

<tr>
23

<td>
24

password
25

</td>
26

<td>
27

<s:password name="password"></s:password>
28

</td>
29

</tr>
30

<tr>
31

<td>
32

file
33

</td>
34

<td>
36

<s:file name="file"></s:file>
37

</td>
39

</tr>
40

<tr>
41

<td>
42

<s:submit value=" submit "></s:submit>
43

</td>
44

<td>
45

<s:reset value=" reset "></s:reset>
46

</td>
47

</tr>
48

</table>
49

</s:form>
50

</body>
51

</html>

web.xml中的配置

<filter-name>struts2</filter-name>

<filter-class>

org.apache.struts2.dispatcher.FilterDispatcher

</filter-class>

</filter>

<filter-mapping>

<filter-name>struts2</filter-name>

<url-pattern>/*</url-pattern>

</filter-mapping>

struts.xml中的配置

<?xml version="1.0" encoding="GBK" ?>
2

<!DOCTYPE struts PUBLIC
3

"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
4

"http://struts.apache.org/dtds/struts-2.0.dtd">
5

<struts>
7

<constant name="struts.i18n.encoding" value="gbk"></constant>
8

<constant name="struts.multipart.saveDir" value="c:\"></constant>
9

<package name="struts2" extends="struts-default">
10

<action name="upload" class="com.test.action.UploadAction">
11

<result name="success">/upload/result3.jsp</result>
12

</action>
13

</package>
14

</struts>

UploadAction.java

package com.test.action;
2

import java.io.File;
4

import java.io.FileInputStream;
5

import java.io.FileOutputStream;
6

import java.io.InputStream;
7

import java.io.OutputStream;
8

import org.apache.struts2.ServletActionContext;
10

import com.opensymphony.xwork2.ActionSupport;
12

@SuppressWarnings("serial")
14

public class UploadAction extends ActionSupport {
15

private String username;
16

private String password;
17

private File file;
18

private String fileFileName;
19

private String fileContentType;
20

public String getUsername() {
22

return username;
23

}
24

public void setUsername(String username) {
26

this.username = username;
27

}
28

public String getPassword() {
30

return password;
31

}
32

public void setPassword(String password) {
34

this.password = password;
35

}
36

public File getFile() {
38

return file;
39

}
40

public void setFile(File file) {
42

this.file = file;
43

}
44

public String getFileFileName() {
46

return fileFileName;
47

}
48

public void setFileFileName(String fileFileName) {
50

this.fileFileName = fileFileName;
51

}
52

public String getFileContentType() {
54

return fileContentType;
55

}
56

public void setFileContentType(String fileContentType) {
58

this.fileContentType = fileContentType;
59

}
60

@SuppressWarnings("deprecation")
62

@Override
63

public String execute() throws Exception {
64

InputStream is = new FileInputStream(file);
65

String root = ServletActionContext.getRequest().getRealPath("/upload");
66

File destFile = new File(root, this.getFileFileName());
67

OutputStream os = new FileOutputStream(destFile);
68

byte[] buffer = new byte[400];
69

int length = 0;
71

while ((length = is.read(buffer)) > 0) {
73

os.write(buffer, 0, length);
74

}
75

is.close();
76

os.close();
77

return SUCCESS;
78

}
79

}

结果：

2、多文件上传
修改action

private List<File> file;

private List<String> fileFileName;

private List<String> fileContentType;

public String execute() throws Exception {

for (int i = 0; i < file.size(); ++i) {

InputStream is = new FileInputStream(file.get(i));

String root = ServletActionContext.getRequest().getRealPath(

"/upload");

File destFile = new File(root, this.getFileFileName().get(i));

OutputStream os = new FileOutputStream(destFile);

byte[] buffer = new byte[400];

int length = 0;

while ((length = is.read(buffer)) > 0) {

os.write(buffer, 0, length);

}

is.close();

os.close();

}

return SUCCESS;

}

修改upload3.jsp

<tr>

<td>

file1

</td>

<td>

<s:file name="file"></s:file>

</td>

</tr>

<tr>

<td>

file2

</td>

<td>

<s:file name="file"></s:file>

</td>

</tr>

<tr>

<td>

file3

</td>

<td>

<s:file name="file"></s:file>

</td>

</tr>

结果：

3、任意数量文件上传
在多文件上传的基础上修改upload3.jsp

function addMore()

{

var td = document.getElementById("more");

var br = document.createElement("br");

var input = document.createElement("input");

var button = document.createElement("input");

input.type = "file";

input.name = "file";

button.type = "button";

button.value = "Remove";

button.onclick = function()

{

td.removeChild(br);

td.removeChild(input);

td.removeChild(button);

}

td.appendChild(br);

td.appendChild(input);

td.appendChild(button);

}

</script>

<tr>

<td>

file1

</td>

<s:file name="file"></s:file>

</td>

</tr>

结果：

（四）文件上传类型、大小的限制
使用struts的拦截器，struts2-core-2.1.6.jar/org.apache.struts2.interceptor.FileUploadInterceptor.class的源码中我们可以看到：

public class FileUploadInterceptor extends AbstractInterceptor {

private static final long serialVersionUID = -4764627478894962478L;

protected static final Logger LOG = LoggerFactory.getLogger(FileUploadInterceptor.class);

private static final String DEFAULT_MESSAGE = "no.message.found";

protected boolean useActionMessageBundle;

protected Long maximumSize;

protected Set<String> allowedTypesSet = Collections.emptySet();

protected Set<String> allowedExtensionsSet = Collections.emptySet();

所以我们只需的struts.xml中配置它的属性allowedTypesSet即可。在action节点中修改拦截器（默认的拦截器中已经有fileUpload拦截器，我们必须提取出来进行参数设置，然后在加上默认的拦截器）。

<result name="success">/upload/result3.jsp</result>

<result name="input">/upload/upload3.jsp</result>

<interceptor-ref name="fileUpload">

application/vnd.ms-powerpoint

</param>

</interceptor-ref>

<interceptor-ref name="defaultStack"></interceptor-ref>

</action>

其中<param name="allowedTypes">application/vnd.ms-powerpoint</param>的allowedTypes的值可在C:\Tomcat 6.0\conf的web.xml文件中查找。

报错信息：

严重: Content-Type not allowed: file "intrl.txt" "upload__138d8aca_120b73e9cf4__8000_00000002.tmp" text/plain

（五）文件的下载
download.jsp

<s:a href="/MyStruts2/download.action">download</s:a>

DownloadAction.java

package com.test.action;
2

import java.io.InputStream;
4

import org.apache.struts2.ServletActionContext;
6

import com.opensymphony.xwork2.ActionSupport;
8

public class DownloadAction extends ActionSupport {
10

public InputStream getDownloadFile() {
11

return ServletActionContext.getServletContext().getResourceAsStream(
12

"/upload/intrl.ppt");
13

}
14

@Override
16

public String execute() throws Exception {
17

return SUCCESS;
18

}
19

}
20

web.xml中action配置

<action name="download"

class="com.test.action.DownloadAction">

application/vnd.ms-powerpoint

</param>

filename="intrl.ppt"

</param>

<param name="inputName">downloadFile</param>

</result>

</action>

结果：

FROM:http://www.cnitblog.com/intrl/archive/2009/04/18/56447.html

分享到：

Struts2.1.6+Spring2.5.6+Hibernate3.3.1整 ... | ANT+Xdoclet自动生成Hibernate配置文件

2011-08-01 10:56
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