文件上传struts2 实现文件上传功能(4)

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

        <script type="text/javascript">
        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>
                    <td id="more">
                        <s:file name="file"></s:file>
                        <input type="button" value="Add More.." onclick="addMore()">
                    </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）。

        <action name="upload" class="com.test.action.UploadAction">
            <result name="success">/upload/result3.jsp</result>
            <result name="input">/upload/upload3.jsp</result>
            <interceptor-ref name="fileUpload">
                <param name="maximumSize">409600</param>
                <param name="allowedTypes">
                    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

 1package com.test.action;
 2
 3import java.io.InputStream;
 4
 5import org.apache.struts2.ServletActionContext;
 6
 7import com.opensymphony.xwork2.ActionSupport;
 8
 9public class DownloadAction extends ActionSupport {
10    public InputStream getDownloadFile() {
11        return ServletActionContext.getServletContext().getResourceAsStream(
12                "/upload/intrl.ppt");
13    }
14
15    @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">
            <result name="success" type="stream">
                <param name="contentType">
                    application/vnd.ms-powerpoint
                </param>
                <param name="contentDisposition">
                    filename="intrl.ppt"
                </param>
                <param name="inputName">downloadFile</param>
            </result>
        </action>

结果：