goby2008

public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		 //报表编译之后生成的.jasper文件的存放位置
		 String type=request.getParameter("type");
		 String grade=request.getParameter("grade");
		 String class_1= request.getParameter("class");
		 String sql="select * from print where type='"+type+"'";
		 if(!grade.equals("")){
		 	sql=sql+" and grade='"+grade+"'";
		 }
		 if(!class_1.equals("")){
		 	sql=sql+" and class='"+grade+class_1+"'";
		 }
		 System.out.println(sql);
		 String path="";
		if(type.equals("优秀队员") || type.equals("五小标兵")){
		 	path="print_x";
		 }
		 if(type.equals("优秀督导队员") || type.equals("成绩有进步奖")){
		 	path="print_xx";
		 }
		  if(type.equals("读书积极分子")){
		 	path="print_xxx";
		 }
		  if(type.equals("劳动积极分子")){
		 	path="print_xxxx";
		 }
		String u="/print/"+path;
		System.out.println(u);
		//String u="/print/print_x.jasper";
		 File reportFile = new File(this.getServletContext().getRealPath(u));
		 
		 String url="jdbc:mysql://localhost:3306/jmzc";
		 try{
				 Class.forName("com.mysql.jdbc.Driver");
				 Map parameters = new HashMap();
				 //parameters.put("SQLSTR",sql); //"SQLSTR"是报表中定义的一个参数名称,其类型为String 型
				 Connection conn = DriverManager.getConnection(url,"root", "seebig");
				 Statement stmt=conn.createStatement();   
				 ResultSet rs=stmt.executeQuery(sql);
				 String pp=this.getServletContext().getRealPath(u);
				 System.out.println(pp);
				JasperFillManager.fillReportToFile(pp+".jasper",parameters,new JRResultSetDataSource(rs));
				JRViewer jr = new JRViewer(pp+".jrprint",false);
				JFrame jf = new JFrame(type);
				jf.add(jr);
				jf.pack();
				jf.setSize(1024, 600);
				jf.setVisible(true);
		 }catch(Exception ex){
				ex.printStackTrace();
			}
	}

 这个servlet 中,我使用iReport中JRViewer编写显示打印预览, 当我在客户端的电脑里点击网页中的打印预览，没有任何显示，回头看服务端就有一个显示JRViewer打印预览的程序，为何这样呢？