struts2的下载及注意事项

先看action类。

package actions;

import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;

import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionSupport;

public class FileDownAction extends ActionSupport {

    //读取下载文件的目录
    private String inputPath;
    //下载文件的文件名
    private String fileName;
    //读取下载文件的输入流
    private InputStream inputStream;

    //下载文件的类型
    private String  ContentType;

    public String getInputPath() {
        return inputPath;
    }

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

    public String getFileName() throws UnsupportedEncodingException {
        fileName=URLEncoder.encode(fileName, "utf-8");
        return fileName;
    }

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



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

    public String getContentType() {
        return ContentType;
    }

    public void setContentType(String contentType) {
        ContentType = contentType;
    }

    public InputStream getInputStream() throws FileNotFoundException{
        String path=ServletActionContext.getServletContext().getRealPath(inputPath);
        return new BufferedInputStream(new FileInputStream(path+"\\"+fileName));
    }

    public String execute(){
        return SUCCESS;
    }   
}

一个简单的jsp页面：

 <a href="download.action">下载</a>

action的配置

<action name="download" class="actions.FileDownAction" method="execute">
            <param name="inputPath">/image</param>
            <param name="fileName">图片001.jpg</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">4000</param>
            </result>
        </action>

这里至少要配置两个：inputName，contentDisposition。
当然了，若图片的名字是中文，要做乱码处理。

    public String getFileName() throws UnsupportedEncodingException {
        fileName=URLEncoder.encode(fileName, "utf-8");
        return fileName;
    }