第四章创建Web项目

创建Dynamic Entities from Tables servlet项目
1)servlet生命周期：一般情况下servlet在第一次访问服务器时 servlet被创建，在关闭服务器时servlet销毁；也可以自己设置servlet的销毁时间
2)servlet项目的分包
①分为5个层：
1.ctrl层
2.server层
3.dao层
4.utils
5.domain
3）//设置请求的编码（但是这种设置方式只对post方式有效）
request.setCharacterEncoding(“UTF-8”);
//设置输出的编码
response.setCharacterEncoding(“UTF-8”);
//设置html的编码
response.setContentType(“text/html;charset=UTF-8”);
I.
//get方式就只有自己做如下的转码了 哟(get方式最多只能传255个字符，不安全)
name = new String(name.getBytes(“iso8859-1”),“UTF-8”);
4)

request.setCharacterEncoding("utf-8");
	response.setCharacterEncoding("utf-8");
	response.setContentType("text/html;charset=UTF-8");
	String username = request.getParameter("username");
	String password = request.getParameter("password");
	String sex = request.getParameter("sex");
	String country= request.getParameter("country");
	String enjoy[] = request.getParameterValues("enjoy");
	String remark = request.getParameter("remark");
	response.getWriter().println(username);
	response.getWriter().println(password);	
	response.getWriter().println(sex);
	response.getWriter().println(country);	
	for (int i = 0; i < enjoy.length; i++) {
		response.getWriter().println(enjoy[i]);
	}
	response.getWriter().println(remark);

5）对domain中的对象进行操作
法1：使用get；set方法修改数据
法2：使用BeanUtius

try {
BeanUtils.populate(user, request.getParameterMap());
// System.out.println(user.getUsername());
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InvocationTargetException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

6)servlet中的6大对象
request
response
Servletconfig
servletcontext
cookie
session

7）编写servlet程序

public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		//方式二
		//String info = this.getServletConfig().getInitParameter("conf");
		//不写this.getServletConfig()也可以哈
		//String info = this.getInitParameter("conf");
		//response.getWriter().print(info);
		//同时取多个
		Enumeration uu = this.getServletConfig().getInitParameterNames();
		while(uu.hasMoreElements()){
			String key  = (String) uu.nextElement();
			String value = getInitParameter(key);
			response.getWriter().print(value);