jsp页面表单元素取值

1

<% String username = request.getParameter("username");
       String authority = request.getParameter("authority");
    %>
    
    
    <form action="UserLoginServlet" method="post">
    
    username: <input type="text" name="username" value='<%= null == username ? "" : username %>'><br>
    password: <input type="password" name="password"><br>
    
    authority: 
    <select name="authority">
    	<option value="1" <%= "1".equals(authority) ?  "selected='selected'" : ""%>>common user</option>
    	<option value="2" <%= "2".equals(authority) ?  "selected='selected'" : "" %>>administrator</option>
    </select>
    
    <br>
    
    <input type="submit" value="submit">
    
    </form>

 2 select默认选中第一项，所以不用做默认值判断

radio默认不选中，所以用个三元表达式

<input type="radio" name="abc" value="0" <%= null==cssType?"checked='checked'":(0==Integer.parseInt(cssType)?"checked='checked'":"") %>  />1&nbsp;&nbsp;<input type="radio" name="abc" value="1" <%= null==cssType?"":(1==Integer.parseInt(cssType)?"checked='checked'":"") %>/>2

 

当然，最好用equal方法代替==，可以不用转换类型