File download in Struts 2

Question

I am trying to download a file from my web server running Struts2, Hibernate and Spring but I am always getting this exception.

java.lang.IllegalArgumentException: Can not find a java.io.InputStream with the name [inputName] in the invocation stack. Check the <param name="inputName"> tag specified for this action.
    org.apache.struts2.dispatcher.StreamResult.doExecute(StreamResult.java:237)
    org.apache.struts2.dispatcher.StrutsResultSupport.execute(StrutsResultSupport.java:186)
    com.opensymphony.xwork2.DefaultActionInvocation.executeResult(DefaultActionInvocation.java:371)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:275)
    org.apache.struts2.interceptor.DeprecationInterceptor.intercept(DeprecationInterceptor.java:41)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
    org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:256)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
    com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:167)
    com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
    com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:265)
    org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68)
    com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
    com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:138)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
    com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:249)
    com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
    com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:249)
    com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
    com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:191)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
    org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:73)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
    org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:91)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
    org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:252)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
    com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:100)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
    com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:141)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
    com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:145)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
    com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:171)
    com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
    com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:139)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
    org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
    com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:193)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
    com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:189)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
    com.riteshsangwan.ossoc.core.interceptors.AuthenticationInterceptor.intercept(AuthenticationInterceptor.java:34)
    com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
    org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:54)
    org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:562)
    org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)
    org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:99)

I have checked the inputName parameter and debugged the project to find out that InputStream is not null.

This is the download class:

inputName= new ByteArrayInputStream(mf.getFileContent());

and this is Struts 2 mapping:

       <action name="downloadfile" class="com.riteshsangwan.ossoc.core.actions.DownloadFile">
            <result name="success" type="stream">
                
                <param name="inputName">inputName</param>
                <param name="contentDisposition">attachment;filename=${fileName}</param>
                <param name="contentType">${contentType}</param>
                <param name="bufferSize">1024</param>
                <param name="contentLength">${contentLength}</param>
                <param name="allowCaching">false</param>
                
            </result>
            <result name="input">/user/files.jsp</result>
        </action>

Is the exception because of ByteArrayInputStream or any other reason. I have public getter and setter method for all variables and I have checked that none of them is null.

EDIT:

DownloadFile class:

package com.riteshsangwan.ossoc.core.actions;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;
import com.riteshsangwan.ossoc.core.dao.FilesBo;
import com.riteshsangwan.ossoc.core.entities.Files;
import com.riteshsangwan.ossoc.core.entities.Users;
import com.riteshsangwan.ossoc.core.util.MyFile;
import com.riteshsangwan.ossoc.core.util.Operations;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
import java.util.Map;
import javax.servlet.ServletContext;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.context.ServletContextAware;


public class DownloadFile extends ActionSupport implements ServletContextAware{
    
    private long fid;
    private String contentType;
    private long contentLength;
    private String fileName;
    private InputStream inputName;
    
    
    private ServletContext context;
    private String downloadStatus;
    private String downloadpassword;
    private List fileList;
    private Map<String,Object> session;

    public String getFileName() {
        return fileName;
    }

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

    public List getFileList() {
        return fileList;
    }

    public void setFileList(List fileList) {
        this.fileList = fileList;
    }
    

    public String getDownloadStatus() {
        return downloadStatus;
    }

    public void setDownloadStatus(String downloadStatus) {
        this.downloadStatus = downloadStatus;
    }

    public String getDownloadpassword() {
        return downloadpassword;
    }

    public void setDownloadpassword(String downloadpassword) {
        this.downloadpassword = downloadpassword;
    }
    
    public String getStatus() {
        return downloadStatus;
    }

    public void setStatus(String downloadStatus) {
        this.downloadStatus = downloadStatus;
    }
    
    @Autowired
    private FilesBo fbo;
    
    @Autowired
    private Operations operation;

    public Operations getOperation() {
        return operation;
    }

    public void setOperation(Operations operation) {
        this.operation = operation;
    }
    
    public FilesBo getFbo() {
        return fbo;
    }

    public void setFbo(FilesBo fbo) {
        this.fbo = fbo;
    }
    

    public long getFid() {
        return fid;
    }

    public void setFid(long fid) {
        this.fid = fid;
    }

    public String getContentType() {
        return contentType;
    }

    public void setContentType(String contentType) {
        this.contentType = contentType;
    }

    public long getContentLength() {
        return contentLength;
    }

    public void setContentLength(long contentLength) {
        this.contentLength = contentLength;
    }
    

    public InputStream getInputName() {
        return inputName;
    }

    public void setInputName(InputStream inputName) {
        this.inputName = inputName;
    }

    
    @Override
    public String execute(){
        String response;
        int a=10;
        try
        {
            session=ActionContext.getContext().getSession();
            Users u= (Users) session.get("user");
            long uid=u.getUid();
            fileList=fbo.getAllFiles(uid);
            Files f=getFbo().getFileWithData(getFid());
            MyFile mf=new MyFile();
            mf.setFileContent(f.getFileData());
            mf.setFileContentType(f.getFileContentType());
            mf.setFileHash(f.getFileHash());
            mf.setFileName(f.getFileName());
            mf.setFileSize(f.getFileSize());
            mf.setPassword(downloadpassword);
            mf=operation.decrypt(mf);
            
            fileName=mf.getFileName();
            contentLength=mf.getFileSize();
            contentType=mf.getFileContentType();
            
            inputName=new ByteArrayInputStream(mf.getFileContent());
            
            response=ActionSupport.SUCCESS;
        }
        catch(IOException e)
        {
            if(e.getMessage().equalsIgnoreCase("Message has been altered or password incorrect"))
            {
                downloadStatus="Message has been altered or incorrect password. Try again.";
            }
            response=ActionSupport.INPUT;
        }
        catch(Exception e)
        {
            downloadStatus="Some error occured. Try Again";
            response=ActionSupport.INPUT;
        }
        return response;
    }

    @Override
    public void setServletContext(ServletContext servletContext) {
        this.context=servletContext;
    }
    
}

Answer 1

Alright, change inputName to inputStream. Like this

private InputStream inputStream;

public InputStream getInputStream() {
    return inputStream;
}

public void setInputStream(InputStream inputStream) {
    this.inputStream= inputStream;
}

the default setting for the parameter inputName is inputStream, so, you could remove that. Also note that parameter's names in result are looked up in the value stack. So, if you expose a getter like getInputName in the action means that you want to override the value in the configuration.