我有一个JSP文件，有后端帮助类。从后端帮助器我需要将PDF文件作为附件发送到JSP。我怎样才能做到这一点？
答案 0 :(得分：0)
我建议您使用Apache Commons File Upload组件。这可能是最好的方式，而不是重新发明轮子。 ;）
答案 1 :(得分：0)
由于您没有告诉我们您是使用任何MVC框架还是仅使用普通的Servlet，我将继续使用基础知识。
如果您要上传文件，Apache Commons文件上传是最好的库，可以翻译您的multipart/form-data编码HttpServletRequest邮件，并为您提供上传的文件（InputStream格式，最喜欢的。）
由开发人员决定将数据写回您选择的持久存储中。
相反，它是取文件，获取适当的MIME类型，内容长度（文件大小）和文件数据（如果可能的话InputStream）并将其渲染回{{1} }）。
此代码（完全正常并由我编写）确实将文件作为附件/内联。
HttpServletResponse最重要的方法是import java.io.BufferedInputStream;
import java.io.ByteArrayOutputStream;
import java.io.Closeable;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletResponse;
/**
* @author Buhake Sindi (The Elite Gentleman)
* @since 01 September 2011
*/
public class FileServletRenderer implements ServletRenderer {
private static final int DEFAULT_BUFFER_SIZE = 10240; // 10KB
private static final String OCTECT_STREAM_MIME_TYPE = "application/octect-stream";
private String contentType = OCTECT_STREAM_MIME_TYPE;
private long contentLength;
private String contentDisposition = "inline";
private String fileName;
private InputStream inputStream;
/**
* @return the contentType
*/
public String getContentType() {
return contentType;
}
/**
* @param contentType
* the contentType to set
*/
public void setContentType(String contentType) {
this.contentType = contentType;
}
/**
* @return the contentLength
*/
public long getContentLength() {
return contentLength;
}
/**
* @param contentLength
* the contentLength to set
*/
public void setContentLength(long contentLength) {
this.contentLength = contentLength;
}
/**
* @return the contentDisposition
*/
public String getContentDisposition() {
return contentDisposition;
}
/**
* @param contentDisposition
* the contentDisposition to set
*/
public void setContentDisposition(String contentDisposition) {
this.contentDisposition = contentDisposition;
}
/**
* @return the fileName
*/
public String getFileName() {
return fileName;
}
/**
* @param fileName
* the fileName to set
*/
public void setFileName(String fileName) {
this.fileName = fileName;
}
/**
* @return the inputStream
*/
public InputStream getInputStream() {
return inputStream;
}
/**
* @param inputStream
* the inputStream to set
*/
public void setInputStream(InputStream inputStream) {
this.inputStream = inputStream;
}
public void setFile(File file) throws IOException {
if (file == null) {
throw new IOException("file is null.");
}
setInputStream(new BufferedInputStream(new FileInputStream(file)));
setContentLength(file.length());
}
/*
* (non-Javadoc)
*
* @see org.bfs.bayweb.util.renderer.ServletViewRenderer#render(javax.servlet.
* ServletRequest, javax.servlet.ServletResponse)
*/
public void render(ServletRequest request, ServletResponse response) throws IOException {
// TODO Auto-generated method stub
BufferedOutputStream bos = new BufferedOutputStream(response.getOutputStream());
try {
byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
int inputStreamLength = 0;
int length = 0;
if (contentType == null) {
contentType = request.getServletContext().getMimeType(getFileName());
}
//We couldn't determine Content-Type
if (contentType == null) {
contentType = OCTECT_STREAM_MIME_TYPE;
}
while ((length = getInputStream().read(buffer)) > 0) {
inputStreamLength += length;
bos.write(buffer, 0, length);
}
if (inputStreamLength != getContentLength()) {
setContentLength(inputStreamLength);
}
if (response instanceof HttpServletResponse) {
HttpServletResponse httpResponse = (HttpServletResponse) response;
httpResponse.reset();
httpResponse.setHeader("Content-Type", getContentType());
httpResponse.setHeader("Content-Length", String.valueOf(getContentLength()));
httpResponse.setHeader("Content-Disposition", "\"" + getContentDisposition() + "\""
+ ((getFileName() != null && !getFileName().isEmpty()) ? "; filename=\"" + getFileName() + "\"" : ""));
httpResponse.setHeader("Content-Type", getContentType());
}
// finally
bos.flush();
// clear
} finally {
// TODO Auto-generated catch block
close(bos);
close(getInputStream());
}
}
private void close(Closeable resource) throws IOException {
if (resource != null) {
resource.close();
}
}
}
。