HttpServletRequest
来源:互联网 发布:淘宝直通车和百度竞价 编辑:程序博客网 时间:2024/05/21 05:56
1、HttpServletRequest
service方法中的request的类型是ServletRequest,而doGet/doPost方法的request的类型是HttpServletRequest,HttpServletRequest是ServletRequest的子接口,功能和方法更加强大。
request的运行流程:
1.1、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:String getRequestURI() StringBuffer getRequestURL() String getContextPath() ---web应用的名称String getQueryString() ---- get提交url地址后的参数字符串username=zhangsan&password=123
注意:request获得客户机(客户端)的一些信息
request.getRemoteAddr() — 获得访问的客户端IP地址
html:
<!DOCTYPE html><html><head><meta charset="UTF-8"><title>Insert title here</title></head><body> <form action="/WEB15/line" method="post"> <input type="text" name="username"><br> <input type="password" name="password"><br> <input type="submit" name="提交"><br> </form></body></html>
servlet:
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //1、获得请求方式 String method = request.getMethod(); System.out.println("method:"+method); //2、获得请求的资源相关的内容 String requestURI = request.getRequestURI(); StringBuffer requestURL = request.getRequestURL(); System.out.println("uri:"+requestURI); System.out.println("url:"+requestURL); //获得web应用的名称 String contextPath = request.getContextPath(); System.out.println("web应用:"+contextPath); //地址后的参数的字符串 String queryString = request.getQueryString(); System.out.println(queryString); //3、获得客户机的信息---获得访问者IP地址 String remoteAddr = request.getRemoteAddr(); System.out.println("IP:"+remoteAddr);}
打印结果:
method:POSTuri:/WEB15/lineurl:http://localhost:8080/WEB15/lineweb应用:/WEB15nullIP:0:0:0:0:0:0:0:1
1.2、通过request获得请求头
long getDateHeader(String name)String getHeader(String name)Enumeration getHeaderNames()Enumeration getHeaders(String name)int getIntHeader(String name)referer头的作用:执行该此访问的的来源,做防盗链
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //1、获得指定的头 String header = request.getHeader("User-Agent"); System.out.println(header); //2、获得所有的头的名称 Enumeration<String> headerNames = request.getHeaderNames(); while(headerNames.hasMoreElements()){ String headerName = headerNames.nextElement(); String headerValue = request.getHeader(headerName); System.out.println(headerName+":"+headerValue); }}
打印出结果:
Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:56.0) Gecko/20100101 Firefox/56.0host:localhost:8080user-agent:Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:56.0) Gecko/20100101 Firefox/56.0accept:text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8accept-language:zh-CN,zh;q=0.8,en-US;q=0.5,en;q=0.3accept-encoding:gzip, deflateconnection:keep-aliveupgrade-insecure-requests:1Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:56.0) Gecko/20100101 Firefox/56.0host:localhost:8080user-agent:Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:56.0) Gecko/20100101 Firefox/56.0accept:text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8accept-language:zh-CN,zh;q=0.8,en-US;q=0.5,en;q=0.3accept-encoding:gzip, deflateconnection:keep-aliveupgrade-insecure-requests:1
连接跳转的时候,referer:
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //对来源的进行判断 String header = request.getHeader("referer"); if(header!=null&&header.startsWith("http://localhost")){ //是从我自己的网站跳转过来的 可以看 response.setContentType("text/html;charset=UTF-8"); response.getWriter().write("中国确实已经拿到100块金牌...."); }else{ response.getWriter().write("你是盗链者,可耻!!"); }}
1.3、通过request获得请求体
html
<form action="/WEB15/content" method="get"> <input type="text" name="username"><br> <input type="password" name="password"><br> <input type="checkbox" name="hobby" value="zq">足球 <input type="checkbox" name="hobby" value="pq">排球 <input type="checkbox" name="hobby" value="ppq">乒乓球<br> <input type="submit" value="提交"><br></form>
请求体中的内容是通过post提交的请求参数,格式是:
username=zhangsan&password=123&hobby=football&hobby=basketball
方法获得请求参数:
String getParameter(String name) String[] getParameterValues(String name)Enumeration getParameterNames()Map<String,String[]> getParameterMap()
servlet
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //1、获得单个表单值 String username = request.getParameter("username"); System.out.println(username); String password = request.getParameter("password"); System.out.println(password); //2、获得多个表单的值 String[] hobbys = request.getParameterValues("hobby"); for(String hobby:hobbys){ System.out.println(hobby); } //3、获得所有的请求参数的名称 Enumeration<String> parameterNames = request.getParameterNames(); while(parameterNames.hasMoreElements()){ System.out.println(parameterNames.nextElement()); } System.out.println("------------------"); //4、获得所有的参数 参数封装到一个Map<String,String[]> 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("---------------------------"); }}
注意:get请求方式的请求参数 上述的方法一样可以获得
解决post提交方式的乱码:request.setCharacterEncoding("UTF-8");解决get提交的方式的乱码:parameter = new String(parameter.getbytes("iso8859-1"),"utf-8");
1.4、request是一个域对象
request对象也是一个存储数据的区域对象,所以也具有如下方法:
setAttribute(String name, Object o)getAttribute(String name)removeAttribute(String name)
注意:request域的作用范围:一次请求中
1.5、request完成请求转发
//获得请求转发器----path是转发的地址RequestDispatcher getRequestDispatcher(String path)//通过转发器对象转发requestDispathcer.forward(ServletRequest request, ServletResponse response)
servlet1
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //想request域中存储数据 request.setAttribute("name", "tom"); //servlet1 将请求转发给servlet2 RequestDispatcher dispatcher = request.getRequestDispatcher("/servlet2"); //执行转发的方法 dispatcher.forward(request, response);}
servlet2
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //从request域中取出数据 Object attribute = request.getAttribute("name"); response.getWriter().write("hello haohao..."+attribute);}
1.6、细节问题
ServletContext域与Request域的生命周期比较
ServletContext:创建:服务器启动;销毁:服务器关闭;域的作用范围:整个web应用
request:创建:访问时创建request;销毁:响应结束request销毁;域的作用范围:一次请求中
转发与重定向的区别
重定向两次请求,转发一次请求;
重定向地址栏的地址变化,转发地址不变;
重新定向可以访问外部网站 转发只能访问内部资源;
转发的性能要优于重定向。
户端地址与服务器端地址的写法
客户端地址:是客户端去访问服务器的地址,服务器外部的地址,特点:写上web应用名称、直接输入地址:重定向;
服务器端地址:服务器内部资源的跳转的地址,特点:不需要写web应用的名称、转发。
2、用户注册案例
建表
CREATE TABLE `user` ( `uid` varchar(32) NOT NULL, `username` varchar(20) DEFAULT NULL, `password` varchar(20) DEFAULT NULL, `name` varchar(20) DEFAULT NULL, `email` varchar(30) DEFAULT NULL, `telephone` varchar(20) DEFAULT NULL, `birthday` varchar(20) DEFAULT NULL, `sex` varchar(10) DEFAULT NULL, `state` int(11) DEFAULT NULL, `code` varchar(64) DEFAULT NULL, PRIMARY KEY (`uid`))
导入jar包和c3p0
Servlet
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 com.ithiema.utils.DataSourceUtils;public class RegisterServlet extends HttpServlet { protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //设置request的编码---只适合post方式 request.setCharacterEncoding("UTF-8"); //get方式乱码解决 //String username = request.getParameter("username");//乱码 //先用iso8859-1编码 在使用utf-8解码 //username = new String(username.getBytes("iso8859-1"),"UTF-8"); //1、获取数据 //2、将散装的封装到javaBean //使用BeanUtils进行自动映射封装 //BeanUtils工作原理:将map中的数据 根据key与实体的属性的对应关系封装 //只要key的名字与实体的属性 的名字一样 就自动封装到实体中 Map<String, String[]> properties = request.getParameterMap(); User user = new User(); try { BeanUtils.populate(user, properties); } catch (IllegalAccessException | InvocationTargetException e) { e.printStackTrace(); } //现在这个位置 user对象已经封装好了 //手动封装uid----uuid---随机不重复的字符串32位--java代码生成后是36位 user.setUid(UUID.randomUUID().toString()); //3、将参数传递给一个业务操作方法 try { regist(user); } catch (SQLException e) { e.printStackTrace(); } //4、认为注册成功跳转到登录页面 response.sendRedirect(request.getContextPath()+"/login.jsp"); } //注册的方法 public void regist(User user) throws SQLException{ //操作数据库 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); } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); }}
登陆servlet
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 com.ithiema.register.User;import com.ithiema.utils.DataSourceUtils;public class LoginServlet extends HttpServlet { protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.setCharacterEncoding("UTF-8"); //1、获得用户名和密码 String username = request.getParameter("username"); String password = request.getParameter("password"); //2、调用一个业务方法进行该用户查询 User login = null; try { login = login(username,password); } catch (SQLException e) { e.printStackTrace(); } //3、通过user是否为null判断用户名和密码是否正确 if(login!=null){ //用户名和密码正确 //登录成功 跳转到网站的首页 response.sendRedirect(request.getContextPath()); }else{ //用户名或密码错误 //跳回当前login.jsp //使用转发 转发到login.jsp 向request域中存储错误信息 request.setAttribute("loginInfo", "用户名或密码错误"); request.getRequestDispatcher("/login.jsp").forward(request, response); } } public User login(String username,String password) throws SQLException{ QueryRunner runner = new QueryRunner(DataSourceUtils.getDataSource()); String sql = "select * from user where username=? and password=?"; User user = runner.query(sql, new BeanHandler<User>(User.class), username,password); return user; } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); }}
- HttpServletRequest
- Httpservletrequest
- HttpServletRequest
- HttpServletRequest
- HttpServletRequest
- HttpServletRequest
- httpservletrequest
- HttpServletRequest
- HttpServletRequest
- HttpServletRequest
- HttpServletRequest
- HttpServletRequest
- HttpServletRequest
- HttpServletRequest
- HttpServletRequest
- HttpServletRequest
- HttpServletRequest
- HttpServletRequest
- Get,Post请求中文乱码问题有效解决方法
- date命令
- 【廖雪峰Python习题集】循环
- C++\String常用操作
- TensorFlow学习日记28
- HttpServletRequest
- 作业
- Java的同步机制
- 整数运算、浮点运算与溢出
- SSH与SSM学习之Spring22——Spring事务之xml配置方式管理事务
- 常见正则表达式_1
- 前缀和
- bzoj4719 [Noip2016]天天爱跑步(树+lca+树上差分+思路题)
- Session机制详解