我在 Google gcm 应用程序中工作，在这里我通过正确的 ID 和密码对应用程序用户进行身份验证。身份验证工作正常。
我正在通过 Run as -> Run on Server(Homeservlet.java) 运行此页面，即使对于正确的员工和密码，它也没有显示书面的 jsp 代码（在 if 条件中编写）并转到 else -部分。
在 Eclipse 控制台中：我可以看到员工姓名和密码。但我的问题是如何设置这些值，以便当我运行这个页面时它会显示里面的那个 jsp 页面。
我正在使用 set 参数来设置值，但是每当我在 Tomcat 服务器中运行此页面时，它都会显示IllegalArgumentException。我发现它很安静，因为当我运行时，没有设置值。
其实我想要的是正确的员工和相应的密码，......它会显示那个jsp页面；否则（我的意思是在其他部分，它不会）
public class HomeServlet extends BaseServlet {
static final String ATTRIBUTE_STATUS = "status";
private static final int HTTP_STATUS = 200;
// private static final String HTTP = "OK";
protected void doGet(HttpServletRequest req, HttpServletResponse resp)throws IOException {
PreparedStatement stmt = null;
String employee=req.getParameter("employeeid"); //getting the value from app User
String password=req.getParameter("password"); //corresponding password
req.setAttribute(employee, employee);
req.setAttribute(password, password);
try {
String url="jdbc:mysql://localhost/apps";
Class.forName("com.mysql.jdbc.Driver");
Connection con=DriverManager.getConnection(url,"root","root");
stmt = con.prepareStatement("select * from regid where emp_id=? and password=?");
stmt.setString(1, employee);
stmt.setString(2, password);
ResultSet rs = stmt.executeQuery();
if(rs.next()) {
System.out.println("2> Employee Id : "+employee+" && Password : "+password);
System.out.println("3> This employee "+employee+" exsists in the database and will be there");
resp.setContentType("text/html");
PrintWriter out = resp.getWriter();
out.print("<html>"); //1> want to run this portion from here
out.print("<head>");
out.print("<title>Policy Page</title>");
out.print("<link rel='icon' href='../images/favicon.png'/>");
out.print("</head>");
out.print("<body>");
String status = (String) req.getAttribute(ATTRIBUTE_STATUS);
if (status != null)
{
out.print("Status : "+status);
}
List<String> devices = Datastore.getDevices();
if (devices.isEmpty())
{
out.print("<h2>No devices registered!</h2>");
}
else
{
out.print("<h2>" + devices.size() + " device(s) registered!</h2>");
out.print("<form name='form' method='POST' action='sendAll'>");
out.print("<input type='text' name='policy'>");
resp.setStatus(HttpServletResponse.SC_OK);
out.print("<input type='submit' value='Apply Policy'>");
out.print("</form>");
// getServletContext().getRequestDispatcher("/home").forward(req, resp);
}
out.print("</body></html>"); //2> to here
resp.setStatus(HttpServletResponse.SC_OK);
}
else { //else-part
resp.setStatus(HttpServletResponse.SC_BAD_REQUEST);
System.out.println(HttpServletResponse.SC_BAD_REQUEST);
System.out.println("4> This employee "+employee+" does not exsist in the database");
}
}
catch(Exception e) {
e.printStackTrace();
}
finally {
try {
stmt.close();
} catch(Exception x) {}
}
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws IOException {
doGet(req, resp);
}
}
当应用程序用户提供 id-password 时，控制台中的输出为：
2> Employee Id : P1 && Password : ppp
3> This employee P1 exsists in the database and will be there
但我正在运行页面（运行为->在 server-tomcat-6 上运行），它显示了这个（而不是显示 jsp 页面）
HTTP Status 500
java.lang.IllegalArgumentException: Cannot call setAttribute with a null name
at org.apache.catalina.connector.Request.setAttribute(Request.java:1431)
at org.apache.catalina.connector.RequestFacade.setAttribute(RequestFacade.java:50
任何想法.......我哪里出错了。