struts文件下载

　　//DownloadAction类
package action;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStream;

import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.Action;

public class DownloadAction {
    // 请求参数
    private String fileName;
    // action下载的目录
    private String inputPath;

    // 定义get方法，用于获取输入流
    public InputStream getInputStream() throws FileNotFoundException {

        String absInputPath = ServletActionContext.getServletContext()
                .getRealPath(inputPath);
        FileInputStream fis = new FileInputStream(absInputPath + File.separator
                + fileName);
        BufferedInputStream bis = new BufferedInputStream(fis);
        return bis;

    }

    public String execute() {

        return Action.SUCCESS;

    }

    public String getFileName() {
        return fileName;
    }

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

    public String getInputPath() {
        return inputPath;
    }

    public void setInputPath(String inputPath) {
        this.inputPath = inputPath;
    }

}
　　

//struts.xml
<action name="download" class="action.DownloadAction">
<param name="inputPath">/upload</param>
<result name="success" type="stream">
<param name="contentType">application/octet-stream</param>
<param name="inputName">inputStream</param>
<param name="contentDisposition">
attachment;fileName="${fileName}"
</param>
<param name="bufferSize">4096</param>
</result>
</action>