jsp if不能判断 郁闷

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@ page language="java" import="java.sql.*" %>
<jsp:useBean id="DA" class="Database.Databasefw" scope="page"/>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
String act=request.getParameter("act");
String title=request.getParameter("title");
String content=request.getParameter("content");
//act=act.trim();
out.println(act);
out.println(title);
if (act=="add")
{
request.setCharacterEncoding("utf-8");
String sql="insert into blog (title,content) value ('"+title+"','"+content+"')";
DA.connDB();
DA.executeUpdat

JSP中while循环中不能嵌套if 条件吗?我的怎么一直报错? ASP IF判断 EXCEL if 判断句 if else 判断问题！！！ C语言IF判断 ASP if判断 excel if 判断值 jsp整型判断大小 JSP页面判断跳转 JSP 判断字符串