WBE15_HttpServletRequest
生活随笔
收集整理的這篇文章主要介紹了
WBE15_HttpServletRequest
小編覺得挺不錯的,現在分享給大家,幫大家做個參考.
1．HttpServletRequest概述
我們在創建Servlet時會覆蓋service()方法，或doGet()/doPost(),這些方法都有兩個參數，一個為代表請求的request和代表響應response。
service方法中的request的類型是ServletRequest，而doGet/doPost方法的request的類型是HttpServletRequest，HttpServletRequest是ServletRequest的子接口，功能和方法更加強大，今天我們學習HttpServletRequest。
2．request的運行流程
3．通過抓包工具抓取Http請求
因為request代表請求，所以我們可以通過該對象分別獲得Http請求的請求行，請 求頭和請求體
4．通過request獲得請求行
獲得客戶端的請求方式：String getMethod()
獲得請求的資源：
String getRequestURI() StringBuffer getRequestURL() String getContextPath() ---web應用的名稱String getQueryString() ---- get提交url地址后的參數字符串username=zhangsan&password=123注意：
request獲得客戶機（客戶端）的一些信息
request.getRemoteAddr() --- 獲得訪問的客戶端IP地址 //1、獲得請求方式String method = request.getMethod();System.out.println("method:" + method);//2.獲得請求的資源相關的內容String requestURI = request.getRequestURI();System.out.println("uri:"+requestURI);StringBuffer requestURL = request.getRequestURL();System.out.println("url:"+requestURL);//獲得Web應用的名稱String contextPath = request.getContextPath();System.out.println("web應用：" + contextPath);//地址后的參數字符串String queryString = request.getQueryString();System.out.println(queryString);//3.獲得客戶端的信息--獲得訪問者的IP地址String remoteAddr = request.getRemoteAddr();System.out.println(remoteAddr);method:post
5．通過request獲得請求頭
long getDateHeader(String name)String getHeader(String name)Enumeration getHeaderNames()Enumeration getHeaders(String name)int getIntHeader(String name) //1.獲得指定的頭String header = request.getHeader("User-Agent");System.out.println(header);//2.獲得所有頭的名稱Enumeration<String> headerNames = request.getHeaderNames();while(headerNames.hasMoreElements()){String headerName = headerNames.nextElement();String headerValue = request.getHeader(headerName);System.out.println(headerName + ":" + headerValue);}輸出：
Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:65.0) Gecko/20100101 Firefox/65.0 host:localhost:8080 user-agent:Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:65.0) Gecko/20100101 Firefox/65.0 accept:text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8 accept-language:zh-CN,zh;q=0.8,zh-TW;q=0.7,zh-HK;q=0.5,en-US;q=0.3,en;q=0.2 accept-encoding:gzip, deflate connection:keep-alive upgrade-insecure-requests:1
referer頭的作用：執行該此訪問的的來源
做防盜鏈
//對新聞的來源進行判斷String header = request.getHeader("referer");if(header != null && header.startsWith("http://localhost")){//從自己網站跳轉過來,可以看新聞response.setContentType("text/html;charset=UTF-8");response.getWriter().write("獎牌");}else{response.setContentType("text/html;charset=UTF-8");response.getWriter().write("盜鏈者,可恥");}
6．通過request獲得請求體
請求體中的內容是通過post提交的請求參數，格式是：
username=zhangsan&password=123&hobby=football&hobby=basketball
key ---------------------- value
username [zhangsan]
password [123]
hobby [football，basketball]
以上面參數為例，通過一下方法獲得請求參數：
String getParameter(String name)
String[] getParameterValues(String name)
Enumeration getParameterNames()
Map<String,String[]> getParameterMap()
注意：get請求方式的請求參數 上述的方法一樣可以獲得
解決post提交方式的亂碼：request.setCharacterEncoding("UTF-8");解決get提交的方式的亂碼：parameter = new String(parameter.getbytes("iso8859-1"),"utf-8"); //1.獲得單個表單值String username = request.getParameter("username");System.out.println(username);//zhangsanString password = request.getParameter("password");System.out.println(password);//123//2.獲得多個表單的值String[] hobbys = request.getParameterValues("hobby");for(String hobby : hobbys){System.out.println(hobby);}//3.獲得所有請求參數的名稱Enumeration<String> parameterNames = request.getParameterNames();while(parameterNames.hasMoreElements()){System.out.println(parameterNames.nextElement());}System.out.println("---------------------------");Map<String, String[]> parameterMap = request.getParameterMap();for(Map.Entry<String, String[]> entry : parameterMap.entrySet()){System.out.println(entry.getKey());for(String str : entry.getValue()){System.out.println(str);}System.out.println("---------------------------");}7．request的其他功能
(1) request是一個域對象
request對象也是一個存儲數據的區域對象，所以也具有如下方法：
setAttribute(String name, Object o)
getAttribute(String name)
removeAttribute(String name)
注意：request域的作用范圍：一次請求中（重定向就沒有數據,原因還是出在只在一次請求中，而重定向是兩次請求）
(2) request完成請求轉發
獲得請求轉發器----path是轉發的地址
通過轉發器對象轉發
requestDispathcer.forward(ServletRequest request, ServletResponse response)注意：ServletContext域與Request域的生命周期比較？
ServletContext：創建：服務器啟動銷毀：服務器關閉域的作用范圍：整個web應用request：創建：訪問時創建request銷毀：響應結束request銷毀域的作用范圍：一次請求中注意：轉發與重定向的區別？
1）重定向兩次請求，轉發一次請求2）重定向地址欄的地址變化，轉發地址不變3）重新定向可以訪問外部網站 轉發只能訪問內部資源4）轉發的性能要優于重定向
Servlet1
Servlet2
//從request域中取出數據Object attribute = request.getAttribute("name");response.getWriter().write("hello haohao..." + attribute);注意：客戶端地址與服務器端地址的寫法？
客戶端地址：是客戶端去訪問服務器的地址，服務器外部的地址，特點：寫上web應用名稱 直接輸入地址：重定向服務器端地址：服務器內部資源的跳轉的地址，特點：不需要寫web應用的名稱轉發案例一、完成用戶注冊
/WEB15A/WebContent/register.jsp
/WEB15A/src/cn/ithiema/register/RegisterServlet.java
package cn.ithiema.register;import java.io.IOException; import java.lang.reflect.InvocationTargetException; import java.sql.SQLException; import java.util.Map; import java.util.UUID;import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse;import org.apache.commons.beanutils.BeanUtils; import org.apache.commons.dbutils.QueryRunner;import cn.ithiema.utils.DataSourceUtils;public class RegisterServlet extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//設置request的編碼---只適合post方式request.setCharacterEncoding("UTF-8");//get方式亂碼解決//String username = request.getParameter("username");//亂碼//先用iso8859-1編碼 在使用utf-8解碼//username = new String(username.getBytes("iso8859-1"),"UTF-8");//1、獲取數據String username = request.getParameter("username");System.out.println(username);//String password = request.getParameter("password");//.....//2、將散裝的封裝到javaBean//User user = new User();//user.setUsername(username);//user.setPassword(password);//使用BeanUtils進行自動映射封裝//BeanUtils工作原理：將map中的數據 根據key與實體的屬性的對應關系封裝//只要key的名字與實體的屬性 的名字一樣 就自動封裝到實體中Map<String, String[]> properties = request.getParameterMap();User user = new User();try {BeanUtils.populate(user, properties);} catch (IllegalAccessException | InvocationTargetException e) {e.printStackTrace();}//現在這個位置 user對象已經封裝好了//手動封裝uid----uuid---隨機不重復的字符串32位--java代碼生成后是36位user.setUid(UUID.randomUUID().toString());//3、將參數傳遞給一個業務操作方法try {regist(user);} catch (SQLException e) {e.printStackTrace();}//4、認為注冊成功跳轉到登錄頁面//response.sendRedirect(request.getContextPath()+"/login.jsp");}//注冊的方法public void regist(User user) throws SQLException{//操作數據庫QueryRunner runner = new QueryRunner(DataSourceUtils.getDataSource());String sql = "insert into user values(?,?,?,?,?,?,?,?,?,?)";runner.update(sql,user.getUid(),user.getUsername(),user.getPassword(),user.getName(),user.getEmail(),null,user.getBirthday(),user.getSex(),null,null);}public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doGet(request, response);} }/WEB15A/src/cn/ithiema/register/User.java
package cn.ithiema.register;public class User {private String uid;private String username;private String password;private String name;private String email;private String sex;private String birthday;public String getUid() {return uid;}public void setUid(String uid) {this.uid = uid;}public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getEmail() {return email;}public void setEmail(String email) {this.email = email;}public String getSex() {return sex;}public void setSex(String sex) {this.sex = sex;}public String getBirthday() {return birthday;}public void setBirthday(String birthday) {this.birthday = birthday;}@Overridepublic String toString() {return "User [uid=" + uid + ", username=" + username + ", password=" + password + ", name=" + name + ", email="+ email + ", sex=" + sex + ", birthday=" + birthday + "]";}}
注冊亂碼的解決：
當method=“post”，
//設置request的編碼—只適合post方式
//request.setCharacterEncoding(“UTF-8”);
亂碼的情況：
當method=“get”，
//設置request的編碼—只適合post方式
//request.setCharacterEncoding(“UTF-8”);
亂碼的情況：
案例二、完成登錄錯誤信息的回顯
<%@ page language="java" contentType="text/html; charset=UTF-8"pageEncoding="UTF-8"%> <!DOCTYPE html> <html> <head> <meta name="viewport" content="width=device-width, initial-scale=1"> <title>會員登錄</title> <link rel="stylesheet" href="css/bootstrap.min.css" type="text/css" /> <script src="js/jquery-1.11.3.min.js" type="text/javascript"></script> <script src="js/bootstrap.min.js" type="text/javascript"></script> <!-- 引入自定義css文件 style.css --> <link rel="stylesheet" href="css/style.css" type="text/css" /><style> body {margin-top: 20px;margin: 0 auto; }.carousel-inner .item img {width: 100%;height: 300px; }.container .row div {/* position:relative;float:left; */}font {color: #666;font-size: 22px;font-weight: normal;padding-right: 17px; } </style> </head> <body><!-- 引入header.jsp --><jsp:include page="/header.jsp"></jsp:include><div class="container"style="width: 100%; height: 460px; background: #FF2C4C url('images/loginbg.jpg') no-repeat;"><div class="row"><div class="col-md-7"><!--<img src="./image/login.jpg" width="500" height="330" alt="會員登錄" title="會員登錄">--></div><div class="col-md-5"><divstyle="width: 440px; border: 1px solid #E7E7E7; padding: 20px 0 20px 30px; border-radius: 5px; margin-top: 60px; background: #fff;"><font>會員登錄</font>USER LOGIN<div><%=request.getAttribute("loginInfo")==null?"":request.getAttribute("loginInfo") %></div><form class="form-horizontal" action="/WEB15/login" method="post"><div class="form-group"><label for="username" class="col-sm-2 control-label">用戶名</label><div class="col-sm-6"><input type="text" class="form-control" id="username" name="username"placeholder="請輸入用戶名"></div></div><div class="form-group"><label for="inputPassword3" class="col-sm-2 control-label">密碼</label><div class="col-sm-6"><input type="password" class="form-control" id="inputPassword3" name="password"placeholder="請輸入密碼"></div></div><div class="form-group"><label for="inputPassword3" class="col-sm-2 control-label">驗證碼</label><div class="col-sm-3"><input type="text" class="form-control" id="inputPassword3"placeholder="請輸入驗證碼"></div><div class="col-sm-3"><img src="./image/captcha.jhtml" /></div></div><div class="form-group"><div class="col-sm-offset-2 col-sm-10"><div class="checkbox"><label> <input type="checkbox"> 自動登錄</label> <label> <inputtype="checkbox"> 記住用戶名</label></div></div></div><div class="form-group"><div class="col-sm-offset-2 col-sm-10"><input type="submit" width="100" value="登錄" name="submit"style="background: url('./images/login.gif') no-repeat scroll 0 0 rgba(0, 0, 0, 0); height: 35px; width: 100px; color: white;"></div></div></form></div></div></div></div><!-- 引入footer.jsp --><jsp:include page="/footer.jsp"></jsp:include></body> </html> package cn.ithiema.login;import java.io.IOException; import java.sql.SQLException;import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse;import org.apache.commons.dbutils.QueryRunner; import org.apache.commons.dbutils.handlers.BeanHandler;import cn.ithiema.register.User; import cn.ithiema.utils.DataSourceUtils;public class LoginServlet extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//設置request的編碼---只適合post方式request.setCharacterEncoding("UTF-8");//1.獲得用戶名和密碼String username = request.getParameter("username");String password = request.getParameter("password");//2.調用一個業務方法進行該用戶查詢User login = null;try {login = login(username, password);} catch (Exception e) {System.out.println(e);}//3.通過user是否為null,判斷用戶名和密碼是否正確if(login != null){//用戶名和密碼正確//登錄成功,跳轉到網站的首頁response.sendRedirect(request.getContextPath());}else{//用戶名或密碼錯誤//跳回當前login.jsp//使用轉發,轉發到login.jsp 向request域中存儲錯誤信息request.setAttribute("loginInfo", "用戶名或密碼錯誤");request.getRequestDispatcher("/login.jsp").forward(request, response);}}public User login(String username,String password){User user = null;try {QueryRunner runner = new QueryRunner(DataSourceUtils.getDataSource());String sql = "select * from user where username=? and password=?";user = runner.query(sql, new BeanHandler<User>(User.class),username,password);} catch (SQLException e) { e.printStackTrace();}return user;}public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doGet(request, response);} }注冊界面
登錄成功
總結：
request獲得行的內容
request.getMethod() request.getRequestURI() request.getRequestURL() request.getContextPath() request.getRemoteAddr()request獲得頭的內容
request.getHeader(name)request獲得體（請求參數）
String request.getParameter(name) Map<String,String[]> request.getParameterMap(); String[] request.getParameterValues(name); 注意：客戶端發送的參數 到服務器端都是字符串獲得中文亂碼的解決：
post:request.setCharacterEncoding(“UTF-8”); get: //get方式亂碼解決 String username = request.getParameter("username");//亂碼 //先用iso8859-1編碼 在使用utf-8解碼 username = new String(username.getBytes("iso8859-1"),"UTF-8");request轉發和域
request.getRequestDispatcher(轉發的地址).forward(req,resp); request.setAttribute(name,value) request.getAttribute(name)總結
以上是生活随笔為你收集整理的WBE15_HttpServletRequest的全部內容，希望文章能夠幫你解決所遇到的問題。
- 上一篇： EndNote X7集成到office
- 下一篇： mongodb详细优化策略方案