Question

这是我的下载文件操作类，它将在浏览器中显示内容。该文件在某个路径中指定。但我需要的文件名和内容应该来自数据库，它必须显示为你想要保存/打开对话框。

package demo;

import com.opensymphony.xwork2.Action;
import org.apache.struts2.dispatcher.StreamResult;
import com.opensymphony.xwork2.ActionInvocation;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStream;
import javax.servlet.http.HttpServletRequest;
import org.apache.struts2.interceptor.ServletRequestAware;

/**
 *
 * @author janardhan.y
 */
public class DynamicStreamResult extends StreamResult implements ServletRequestAware {

    private String name;
//holds name of downloaded file
    private InputStream inputStream;
//holds stream of downloaded file
    private String description;
//holds the content type of the downloaded file
    private long size;
//holds the content size of the downloaded file   
    private HttpServletRequest servletRequest;

    @Override
    public void doExecute(String finalLocation, ActionInvocation invocation) throws Exception {
        System.out.println("DDDDDDDDDDDDDDDDDD ");
        //get name of downloaded file 
        String downloadedFileName = (String) invocation.getStack().findValue(conditionalParse("name", invocation));
        System.out.println("SSSSSSSSS " +downloadedFileName);
        contentDisposition = "filename=\""+ downloadedFileName + "\"";
        System.out.println("FFFFFFFFFFFFF " +contentDisposition);
        //get file size
        contentLength = "" + invocation.getStack().findValue(conditionalParse("size", invocation));
        // get type of file
        contentType = "" + invocation.getStack().findValue(conditionalParse("description", invocation));
        /*
         Executes the result given a final location 
         (jsp page, action, etc) and 
         the action invocation (the state in which 
         the action was executed).
         */

        super.doExecute(finalLocation, invocation);

    }

    public String downloadFile() throws FileNotFoundException {

        /*
         let, method searchFile(String fileName) 
         does the searching for us
         & returns InputStream of the file if found 
         and null otherwise.
         */
        this.inputStream = searchFile(name);
        System.out.println("IIIII " +inputName.toString());

        if (inputStream != null) {
            System.out.println("IIIIIIIIIIIN");
            return Action.SUCCESS;

        } else {
            //handle error
            System.out.println("EEEEEEEEEEEEEE");
            return Action.ERROR;

        }


    }

    public InputStream getInputStream() throws Exception {
        return inputStream;

    }

    public String getName() {
        return name;
    }

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

    public String getDescription() {
        return this.description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public long getSize() {
        return size;
    }

    public void setSize(long size) {
        this.size = size;
    }

    public InputStream searchFile(String name) throws FileNotFoundException {
        String filePath = servletRequest.getSession().getServletContext().getRealPath("/");
        System.out.println("FFFFFFFFFFFFF " + filePath);
        System.out.println("NNNNNNNNNNNNNNN " + name);
       // File file = new File(filePath,name);
        File file = new File("D:\\Desktop13\\All Document\\MY Projects\\New Folder (2)\\STRUTS2CRUD\\build\\web\\j.txt");
        System.out.println("JJJJJJ " + file.toString());
        inputStream = new FileInputStream(file.toString());
        return inputStream;

    }

    public HttpServletRequest getServletRequest() {
        return servletRequest;
    }

    @Override
    public void setServletRequest(HttpServletRequest servletRequest) {
        this.servletRequest = servletRequest;
    }
}

这是我的struts.xml代码

<struts>
<package name="default" extends="hibernate-default">
        <result-types>
            <result-type name="myStream" default="false" class="demo.DynamicStreamResult" />
        </result-types>
        <!-- action for downloading file-->
        <action name="downloadFile" method="downloadFile"  class="demo.DynamicStreamResult">
            <result  type="myStream"/> 
            <result name="error">jsps/your_error_page.jsp</result> 

            <result name="success" type="stream">
                <param name="contentType">image/jpeg, text/plain</param>
                <param name="inputName">imageStream</param>
                <param name="contentDisposition">filename="j.txt"</param>

                <param name="bufferSize">1024</param>
            </result>


        </action>    
    </package>  

</struts>

Answer 1

检查以下代码。

这将采取文件＆amp;数据库中的文件名＆amp;将显示保存/打开对话框。

public class DownloadResume extends ActionSupport implements SessionAware {

private int stud_id;
private Map session;
private String fileName;
private String contentType;
private String emessage;

// getters & setters

@Override
public String execute() throws Exception {
    getResume();
    return "none";
}

//Download Resume from database
private void getResume() throws Exception {
    int id = getStud_id();
    Blob b;
    String fileName = "";
    Connection con = DatabaseConnection.GetConnection();
    PreparedStatement ps = con.prepareStatement("select stud_resume, stud_resume_content_type, stud_resume_file_name from table_stud_resume where stud_id=?");
    ps.setInt(1, id);
    ResultSet rs = ps.executeQuery();
    while (rs.next()) {
        fileName = rs.getString("stud_resume_file_name");
        b = rs.getBlob("stud_resume");

        //Download resume directly on client side without downloading on server
        HttpServletResponse response = ServletActionContext.getResponse();
        response.reset();
        response.addHeader("Content-Disposition", "attachment; filename=\""+fileName+"\"");
        response.getOutputStream().write(b.getBytes(1, (int)b.length()));
        response.getOutputStream().flush();
        response.getOutputStream().close();
    }
}

struts.xml配置

<action name="DownloadResume" class="myPackage.DownloadResume">
</action>

这里我们直接将内容写入outputstream，因此无需返回任何结果或结果类型（即流）。

希望这能解决您的问题。

Answer 2

我认为您的以下行正在产生问题。

inputStream = new FileInputStream(file.toString());

为什么在这里使用file.toString()。

只需将您的文件传递给以下＆amp;检查。

inputStream = new FileInputStream(file);

使用struts2从数据库动态下载文件

2 个答案: