get 与post

Get与post的区别解码是不同的

request.setCharacterEncoding("UTF-8");

String user = request.getParameter("user");

String email = request.getParameter("email");

String[] types = request.getParameterValues("type");

String un = new String(user.getBytes("ISO-8859-1"),"UTF-8");

String em = new String(email.getBytes("ISO-8859-1"),"UTF-8");

for(int i=0;i<types.length;i++){

types[i] = new String (types[i].getBytes("ISO-8859-1"),"UTF-8");

}

Servlet初始参数的设置和获取

保存数据的问题通常是在数据库中的，但在比较小 的数据放在文件里

Web应用程序的某个目录的有哪些文件

Iterator<String> avatars = getServletContext().getResourcePaths("/avatars").iterator();

获取根目录下avatars子目录下的所有文件集合的迭代器

while(avatars.hasNext()){

String avatar = avatars.next().replaceFirst("/", "");

out.println("<img src=\""+avatar+"\">");

}

两个图片之间的切换

Servlet的配置

<context-param>

<param-name>name2</param-name>

<param-value>/avatars</param-value>

</context-param>

<listener>

<listener-class>cn.hnpi.Listener.AvatarInializer</listener-class>

</listener>

建一个AvatarInializer implements ServletContextListener listener

public void contextInitialized(ServletContextEvent sce) {

//获取代表整个web应用程序的对象context

ServletContext context = sce.getServletContext();

String avatars = context.getInitParameter("name2");

//设置

context.setAttribute("pp", avatars);

}

String avatarDir = (String) getServletContext().getAttribute("pp");

Iterator<String> avatars = getServletContext().getResourcePaths(avatarDir).iterator();

while(avatars.hasNext()){

String avatar = avatars.next().replaceFirst("/", "");

out.println("<img src=\""+avatar+"\">");

}