Struts2 文件下载及找不到文件的处理办法

 1public class StreamResult extends StrutsResultSupport {
 2
 3    private static final long serialVersionUID = -1468409635999059850L;
 4
 5    protected static final Logger LOG = LoggerFactory.getLogger(StreamResult.class);
 6
 7    public static final String DEFAULT_PARAM = "inputName";
 8
 9    protected String contentType = "text/plain";
10    protected String contentLength;
11    protected String contentDisposition = "inline";
12    protected String contentCharSet ;
13    protected String inputName = "inputStream";
14    protected InputStream inputStream;
15    protected int bufferSize = 1024;
16    protected boolean allowCaching = true;
17 
18    .......................

 1<action name="down/pro" method="down">
 2    <param name="fileDir">c:/downloads/</param>
 3    <result name="fileNotFound">errors/page_404.html</result>
 4    <result type="stream">
 5        <param name="contentType">application/pdf</param>
 6        <param name="inputName">targetFile</param>
 7        <param name="contentDisposition">filename="${fileName}"</param>
 8        <param name="buttferSize">4096</param>
 9    </result>
10</action>

 1package cc.unmi.download;
 2
 3import java.io.File;
 4import java.io.FileInputStream;
 5import java.io.FileNotFoundException;
 6import java.io.InputStream;
 7
 8import com.opensymphony.xwork2.ActionSupport;
 9
10
11public class DownloadAction extends ActionSupport{
12
13    private String fileDir;
14    private String fileName;
15
16    public InputStream getTargetFile() {
17        try {
18            String filePath = fileDir + fileName;
19            return new FileInputStream(filePath);
20        } catch (FileNotFoundException e) {
21            e.printStackTrace();
22        }
23        return null;
24    }
25
26    public String down(){
27
28        //这里判断文件存不存在，不存在则转向到 fileNotFound 页面
29        String filePath = fileDir + fileName;
30        if(!new File(filePath).exists()){
31            return "fileNotFound";
32        }
33
34        //由 StreamResult 来处理后续的部分了
35        return SUCCESS;
36    }
37
38
39    public String getFileDir() {
40        return fileDir;
41    }
42
43    public void setFileDir(String fileDir) {
44        this.fileDir = fileDir;
45    }
46
47    public void setFileName(String fileName) {
48        this.fileName = fileName;
49    }
50
51    public String getFileName() {
52        return fileName;
53    }
54}