0310 HttpServletRequest01

2021-03-12 01:30

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YPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

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回顾一下 servlet运行流程

技术图片

通过request获得请求行

获得客户端的请求方式：String getMethod()

获得请求的资源:

获取请求地址uri: String getRequestURI()

获取请求地址url:StringBuffer getRequestURL()

获取去web应用名称:String getContextPath()

获取get请求提交的参数:String getQueryString()

获取客户端的IP地址:getRemoteAddr()

代码展示

Insert title here

　　LineServlet

public class LineServlet extends HttpServlet {

	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		//获取哦请求方式
		String method=request.getMethod();
		System.out.println("请求方式"+method);
		//获取请求地址uri
		String uri=request.getRequestURI();
		System.out.println("请求地址uri:"+uri);
		//获取请求地址
		StringBuffer url=request.getRequestURL();
		System.out.println("请求地址url是："+url);
		//获取去web应用名称
		String name=request.getContextPath();
		System.out.println("web应用名称是："+name);
		//获取get请求提交的参数
		String query=request.getQueryString();
		System.out.println("get请求提交的参数"+query);
		//获取客户端的IP地址
		String ip=request.getRemoteAddr();
		System.out.println("客户端IP地址是："+ip);	
	}

	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doGet(request, response);
	}
}

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如果jsp文件的提交方式改成post那么这个get请求提交参数就是null

通过request获得请求头

String getHeader();

referer头的作用：获取该访问的的来源

代码展示

public class HeadServlet extends HttpServlet {

	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		//获取refer头
		String refer=request.getHeader("referer");
		System.out.println(refer);
	}

	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doGet(request, response);
	}
}

　　还是使用register.jsp的代码将action中的路径改成/WEB04/HeadServlet

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referer头可以做一个防盗链的作用就是可以判断这个访问来自哪里如果不是我指定的访问路径就不让他链接

代码展示

referer.jsp




Insert title here
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public class RefererServlet extends HttpServlet {

	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		//获取referer头
		String refer=request.getHeader("referer");
		//解决响应乱码
		response.setContentType("text/html;charset=utf-8");
		if(refer.startsWith("http://localhost")){
			response.getWriter().write("这是一跳爆炸新闻");
		}else{
			response.getWriter().write("到连着 可耻");
		}
	}

	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doGet(request, response);
	}
}

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通过request获得请求体

获取请求体:

String getParameter(String key);

String[] getParameterValues(String name)

Map getParameterMap()

解决post请求乱码

setCharacterEncoding("UTF-8") 指定码表

解决get 请求乱码

当客户端提交中文，那么先将数据提交，请求行会按照ISO8859-1码表进行解析存到 request对象中然后再传到服务器进行解析，因为服务器是utf-8码表所以解析不出来，所以就会响应给客户端一个乱码，这个解决这个乱码，我们可以再按照这个编码给他编译回去。

运用到

getbytes（“码表”）可以指定码表

new String（bytes,"码表"）也可以指定码表

例：new String(parameter.getbytes("iso8859-1"),"utf-8")

代码展示




Insert title here

public class BodyServlet extends HttpServlet {

	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		//解决post请求乱码
		request.setCharacterEncoding("UTF-8");
		//获取请求体
		String uname=request.getParameter("uname");
		//解决get请求乱码
		//uname=new String(uname.getBytes("ISO8859-1"),"UTF-8");
		System.out.println("用户名"+uname);
		String pwd=request.getParameter("pwd");
		System.out.println("密码"+pwd);
		String[] hobbys=request.getParameterValues("hobby");
		for(String s:hobbys){
			System.out.println(s);
		}
		//获取所有参数所在的map集合
		Map map=request.getParameterMap();
		//获取所有key躲在的set集合
		Set keys=map.keySet();
		for(String key:keys){
			System.out.print(key+":");
			String[] values=map.get(key);
			for(String value:values){
				System.out.print(value+" ");
			}
			System.out.println();
		}
	}

	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doGet(request, response);
	}
}

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