Servlet中使用IText作打印，它返回给客户端的却总是一个空白的页面。不知为什么？
 
Servlet的代码如下：

package itext;
import java.io.PrintWriter;
import java.io.IOException;
import java.io.File;
import java.io.*;

import java.util.Date;

import javax.servlet.http.*;
import javax.servlet.*;

import com.lowagie.text.*;
import com.lowagie.text.pdf.PdfWriter;
import com.lowagie.text.html.HtmlWriter;

public class reportservlettest extends HttpServlet {
    
    public void doGet (HttpServletRequest request, HttpServletResponse response)
    throws IOException, ServletException {     
           
             
        Document document = new Document();

         ServletOutputStream out = response.getOutputStream();
      
        try {                       
           
                //设置ContentType
                response.setContentType("application/pdf");
                
                ByteArrayOutputStream ba = new ByteArrayOutputStream();
                
                PdfWriter.getInstance(document, ba);

                //设置contentLength
                 response.setContentLength(ba.size());            
                      
          ba.writeTo(out);
               
                       
            document.open();
            
            document.add(new Paragraph("Hello World"));

        }
        catch(DocumentException de) {
            de.printStackTrace();
            System.err.println("document: " + de.getMessage());
        }
        
        document.close();
        out.flush();
    }
}

是不是执行 ba.writeTo(out);太早了
放到document.close();后面试试

把哪个servlet对应的url加一个.pdf后缀
如
reportservlettest可以在web.xml中映射成report.pdf

try {
response.setContentType("application/pdf");
ServletOutputStream out = response.getOutputStream();
PdfWriter.getInstance(document,out);
document.open();
document.add(new Paragraph("Hello World"));
document.close();
out.flush();
}
catch (Exception e) {
e.printStackTrace(System.err);
}