本文共 2771 字，大约阅读时间需要 9 分钟。

Struts2的配置就不讲了，重点讲下Action的写法。

DownloadAction.java：

package com.zrar.cms.action.front.suqiu.soft;import java.io.File;import java.io.FileInputStream;import java.io.InputStream;import java.io.UnsupportedEncodingException;import java.net.URLEncoder;import org.apache.commons.lang.StringUtils;import org.apache.struts2.convention.annotation.Result;import org.apache.struts2.convention.annotation.Results;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.beans.factory.annotation.Qualifier;import com.opensymphony.xwork2.ActionSupport;import com.zrar.cms.service.suqiu.ContentAttachService;import com.zrar.cms.suqiu2_Entity.ContentAttach;import com.zrar.cms.util.FilePathSptUtil;@Results({@Result(name = "download", type = "stream", params = {		"contentType", "application/octet-stream",		"inputName", "inputStream", "contentDisposition",		"attachment;filename=\"${downloadFileName}\"", "bufferSize",		"4096" })})public class DownloadAction extends ActionSupport {private static final long serialVersionUID = 1L;	private String attachid;//附件id	private String fileName;// 初始的通过param指定的文件名属性	private ContentAttach contentAttachs;//附件对象 	public ContentAttach getContentAttachs() {		return contentAttachs;	}	public void setContentAttachs(ContentAttach contentAttachs) {		this.contentAttachs = contentAttachs;	}	@Autowired	@Qualifier("contentAttachServiceImpl")	private ContentAttachService contenAttachService;		public String execute() throws Exception {		if(StringUtils.isNotBlank(attachid)){			contentAttachs = contenAttachService.getContentAttach(attachid);			setFileName(contentAttachs.getAttachName());		}		return "download";	}	public InputStream getInputStream() throws Exception {               // root项目上传图片路径，UPLOAD_ROOT_PATH定义为常量，从配置文件里取值               // url就是附件在服务器上对应的路径		String root = FilePathSptUtil.UPLOAD_ROOT_PATH;		String url=root+contentAttachs.getAttachUrl();		 		return new FileInputStream(new File(url));	}	public String getDownloadFileName() {		return fileName;	}	public void setFileName(String fileName) throws UnsupportedEncodingException {		String agent = ServletActionContext. getRequest().getHeader("User-agent");		//如果浏览器是IE浏览器，就得进行编码转换		if(agent.contains("MSIE")){			this.fileName = URLEncoder.encode(fileName, "UTF-8");		}else{			this.fileName = new String(fileName.getBytes(),"ISO-8859-1");  		}	}	public String getAttachid() {		return attachid;	}	public void setAttachid(String attachid) {		this.attachid = attachid;	}}

其中主要使用的参数是：

contentType 指定下载文件的文件类型 —— application/octet-stream表示无限制

inputName 流对象名 ——比如这里写inputStream，它就会自动去找Action中的getInputStream方法。

contentDisposition 使用经过转码的文件名作为下载文件名 ——默认格式是attachment;filename="${fileName}"，将调用该Action中的getFileName方法。

bufferSize 下载文件的缓冲大小

Jsp页面调用：

">
   

前台页面点击效果如下：

转载地址：http://qphji.baihongyu.com/