JSF 文件下载

最新推荐文章于 2018-10-26 17:47:00 发布

yixiaotian1988

最新推荐文章于 2018-10-26 17:47:00 发布

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分类专栏： JSF 文章标签： jsf string file exception null buffer

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最近的项目上用到的是JSF，需求是做一个页面在的下载，实现可以下载文件到客户端。并且和单独的文件下载不同的是，此下载是ZIP文件，就是先把指定目录下的文件先压缩，再进行页面下载。具体代码如下：

/**
* 程序自动打包
* @throws IOException
*/
public String getZipData(String fileName) throws IOException{

ZipOutputStream zos = null;

FileOutputStream fos = null;

DataOutputStream dos = null;

String zipFileName = ""; //--压缩的文件名

String realInputFilePath = ""; //--压缩文件输入流路径

try{

String realNewFilePath = "d:/xxx"; //--压缩文件的路径

zipFileName = realNewFilePath + fileName + ".zip";

realInputFilePath ="e:/xxx"; //--要压缩文件的路径

File directory = new File(realInputFilePath);

File[] files = directory.listFiles(); //--得到指定目录下所有文件名

if(null != files){

int fileLen = files.length;

fos = new FileOutputStream(zipFileName); //--打包后路径 + 文件名

dos = new DataOutputStream(fos);

zos = new ZipOutputStream(dos); //--定义zip输流

for(int i=0; i<fileLen; i++){

FileInputStream fis = null;

DataInputStream dis = null;

String tempfilePath = files[i].getAbsolutePath(); //--得到每个文件绝对路径 + 文件名

fis = new FileInputStream(tempfilePath);

dis = new DataInputStream(fis);

ZipEntry ze = new ZipEntry(files[i].getName()); //--解压文件后直接得到文件，没有目录结构

zos.putNextEntry(ze);

zos.setEncoding("UTF-8"); //--指定编码,否则文件名乱码

int c=0;

while((c=dis.read()) != -1){

zos.write(c);

}

zos.closeEntry();

if(null != fis){

fis.close();

}

if(null != dis){

dis.close();

}

}catch(Exception e){

e.printStackTrace();

} finally{

if(null != zos){

zos.close();

}

if(null != dos){

dos.close();

}

if(null != fos){

fos.close();

}

}

return zipFileName;

}

在action中调用此方法

String zipFileName = batchDownloadService.getZipData(); //--进行文件的自动打包

batchDownloadService.downloadFile(zipFileName,fileName,pagebatchDownloadModel); //--下载文件到客户端

dao中的方法：

/**
* 下载文件到客户端
*/
public void downloadFile(String zipFileName,String fileName,BatchDownloadModel pagebatchDownloadModel){

HttpServletResponse response = (HttpServletResponse) FacesContext.getCurrentInstance().getExternalContext().getResponse();

HttpServletRequest request = (HttpServletRequest) FacesContext.getCurrentInstance().getExternalContext().getRequest();

try{

File zipFile = new File(zipFileName);

if(zipFile.exists()){

String downloadZipName = fileName+"_"+ "xx年_" + "xx月"+".zip";

response.reset();

response.setContentType("APPLICATION/OCTET-STREAM");
response.addHeader("Content-disposition", "attachment;filename="+new String(downloadZipName.getBytes("GB2312"),"ISO8859-1") );
response.setHeader("Content-Transfer-Encoding","binary");
response.setHeader("Cache-Control", "must-revalidate, post-check=0, pre-check=0");
response.setHeader("Pragma", "public");

ServletOutputStream outstream =response.getOutputStream();

FileInputStream fis = new FileInputStream(zipFile);

BufferedInputStream bufInStrm = new BufferedInputStream (fis);

int readBytes = 0;

int bufferSize = 8192;

byte[] buffer = new byte[bufferSize];

while ((readBytes = bufInStrm.read(buffer)) != -1){

if (readBytes == bufferSize) {

outstream.write(buffer);

}else{

outstream.write(buffer, 0, readBytes);

}

outstream.flush();

response.flushBuffer();

}

if(null != fis){

fis.close();

}

if(null != bufInStrm){

bufInStrm.close();

}

if(null != outstream){

outstream.close();

}

FacesContext.getCurrentInstance().responseComplete(); //--非常关键，否则提示文件损坏

}

else{

response.setCharacterEncoding("UTF-8");

response.setContentType("text/html");

//response.getWriter().write("<script type='text/javascript'>alert('当前条件未查询到任何数据!')</script>");

response.getWriter().write("<script>location.href='"+request.getContextPath() + "/faces/sysMag/batchDownload/downloadFail.jsp"+"'</script>");

FacesContext.getCurrentInstance().responseComplete(); //--非常关键，否则提示文件损坏

}

}catch(Exception e){

e.printStackTrace();

}

}

/**
* 删除指定文件夹目录即目录中文件
*/
public void deleteDir(File dir) {
if (dir == null || !dir.exists() || !dir.isDirectory()) //-- 检查参数
return;
for (File file : dir.listFiles()) {
if (file.isFile())
file.delete(); //--删除所有文件
else if (file.isDirectory())
deleteDir(file); //--递规的方式删除文件夹
}
dir.delete(); //--删除目录本身
}