HttpServletRequest：
我们在创建Servlet时会覆盖service()方法，或doGet()/doPost(),这些方法都有两个参数，一个为代表请求的request和代表响应response。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。
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();
获得web应用的名称：
String getContextPath();
get提交url地址后的字符串： username=zhangsan&password=123;
String getQueryString();
获得访问的客户端的ip地址：
request.getRemoteAddr();
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> </head> <body> <form action="/WEB04/BodyServlet" method="post"> 用户名：<input type="text" name="username"><br> 密码：<input type="password" name="pwd"><br> 性别：男<input type="radio" name="sex" value="nan"> 女<input type="radio" name="sex" value="nv"><br> 爱好：足球<input type="checkbox" name="hobby" value="zq"> 篮球<input type="checkbox" name="hobby" value="lq"> 兵乓球<input type="checkbox" name="hobby" value="ppq"><br> <input type="submit" name="注册"> </form> </body>
public class LineServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //获取请求方式 String method=request.getMethod(); System.out.println("当前请求方式为"+method); //获取请求地址 String URI=request.getRequestURI(); System.out.println("URI:"+URI); //获取请求地址URL StringBuffer URL=request.getRequestURL(); System.out.println("URL"+URL); //获取项目名 String name=request.getContextpath(); System.out.println("WEB应用名称："+name); //如果是get请求，则获取url地址后面的字符串 String query=request.getQueryString(); System.out.println("get请求参数:"+query); // String ip=request.getRemoveAddr(); System.out.println("Ip地址为："+ip); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }
获得请求头：
refer头的作用:获取该访问的来源，做防盗链。
agent头的作用：区别浏览器
public class HeadServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //获取请求头 String refer=request.getHeader("referer"); System.out.println("referer"+refer); //获得agent头 String agent=request.getHeader("User-Agent"); System.out.println(agent); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }
获得请求体：
String getParameter(String name):获取不重名的属性的方法。
String[] getParameterValues(String name);获取重名的属性的方法。
Map<String,String[]> getParameterMap():获取mao集合的方法。
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");
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> </head> <body> <form action="/WEB04/BodyServlet" method="post"> 用户名：<input type="text" name="username"><br> 密码：<input type="password" name="pwd"><br> 性别：男<input type="radio" name="sex" value="nan"> 女<input type="radio" name="sex" value="nv"><br> 爱好：足球<input type="checkbox" name="hobby" value="zq"> 篮球<input type="checkbox" name="hobby" value="lq"> 兵乓球<input type="checkbox" name="hobby" value="ppq"><br> <input type="submit" name="注册"> </form> </body> </html>
public class BodyServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//解决post请求中文乱码
//request.setCharacterEncoding("UTF-8"); /* //获取请求参数 String uname=request.getParameter("username");
//解决get请求中文乱码
uname=new String(uname.getBytes("ISO8859-1"),"UTF-8"); String pwd=request.getParameter("pwd"); String sex=request.getParameter("sex"); System.out.println("用户名："+uname); System.out.println("密码："+pwd); System.out.println("性别:"+sex); //获取请求参数数组 爱好 String hobbys[]=request.getParameterValues("hobby"); System.out.println("爱好为："); for(String hobby:hobbys){ System.out.println(hobby+""); }*/ //获取所有参数所在的map集合 Map<String, String[]> map=request.getParameterMap(); //keySet加增强for //获取所有key所在的set集合 Set<String> set=map.keySet(); //遍历 for(String key:set){ 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); } }
验证码：
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> <script type="text/javascript"> function change(obj){ obj.src="/Web03/CheckImgServlet?time="+new Date().getTime(); } </script> </head> <body> <input type="text" name="code"> <img alt="" src="/Web03/CheckImgServlet" onclick="change(this)"> </body> </html>
package com.oracle.demo03; import java.awt.Color; import java.awt.Font; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.image.BufferedImage; import java.io.BufferedReader; import java.io.FileReader; import java.io.IOException; import java.util.ArrayList; import java.util.List; import java.util.Random; import javax.imageio.ImageIO; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /** * 验证码生成程序 * * * */ public class CheckImgServlet extends HttpServlet { // 集合中保存所有成语 private List<String> words = new ArrayList<String>(); @Override public void init() throws ServletException { // 初始化阶段，读取new_words.txt // web工程中读取 文件，必须使用绝对磁盘路径 String path = getServletContext().getRealPath("/WEB-INF/new_words.txt"); try { BufferedReader reader = new BufferedReader(new FileReader(path)); String line; while ((line = reader.readLine()) != null) { words.add(line); } reader.close(); } catch (IOException e) { e.printStackTrace(); } } public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // 禁止缓存 // response.setHeader("Cache-Control", "no-cache"); // response.setHeader("Pragma", "no-cache"); // response.setDateHeader("Expires", -1); int width = 120; int height = 30; // 步骤一 绘制一张内存中图片 BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); // 步骤二 图片绘制背景颜色 ---通过绘图对象 Graphics graphics = bufferedImage.getGraphics();// 得到画图对象 --- 画笔 // 绘制任何图形之前 都必须指定一个颜色 graphics.setColor(getRandColor(200, 250)); graphics.fillRect(0, 0, width, height); // 步骤三 绘制边框 graphics.setColor(Color.WHITE); graphics.drawRect(0, 0, width - 1, height - 1); // 步骤四 四个随机数字 Graphics2D graphics2d = (Graphics2D) graphics; // 设置输出字体 graphics2d.setFont(new Font("宋体", Font.BOLD, 18)); Random random = new Random();// 生成随机数 int index = random.nextInt(words.size()); String word = words.get(index);// 获得成语 // 定义x坐标 int x = 10; for (int i = 0; i < word.length(); i++) { // 随机颜色 graphics2d.setColor(new Color(20 + random.nextInt(110), 20 + random .nextInt(110), 20 + random.nextInt(110))); // 旋转 -30 --- 30度 int jiaodu = random.nextInt(60) - 30; // 换算弧度 double theta = jiaodu * Math.PI / 180; // 获得字母数字 char c = word.charAt(i); // 将c 输出到图片 graphics2d.rotate(theta, x, 20); graphics2d.drawString(String.valueOf(c), x, 20); graphics2d.rotate(-theta, x, 20); x += 30; } // 将验证码内容保存session request.getSession().setAttribute("checkcode_session", word); // 步骤五 绘制干扰线 graphics.setColor(getRandColor(160, 200)); int x1; int x2; int y1; int y2; for (int i = 0; i < 30; i++) { x1 = random.nextInt(width); x2 = random.nextInt(12); y1 = random.nextInt(height); y2 = random.nextInt(12); graphics.drawLine(x1, y1, x1 + x2, x2 + y2); } // 将上面图片输出到浏览器 ImageIO graphics.dispose();// 释放资源 //将图片写到response.getOutputStream()中 ImageIO.write(bufferedImage, "jpg", response.getOutputStream()); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } /** * 取其某一范围的color * * @param fc * int 范围参数1 * @param bc * int 范围参数2 * @return Color */ private Color getRandColor(int fc, int bc) { // 取其随机颜色 Random random = new Random(); if (fc > 255) { fc = 255; } if (bc > 255) { bc = 255; } int r = fc + random.nextInt(bc - fc); int g = fc + random.nextInt(bc - fc); int b = fc + random.nextInt(bc - fc); return new Color(r, g, b); } }
request也是一个域对象：
方法：
setAttribute(String name, Object o) getAttribute(String name) removeAttribute(String name)
作用范围：一次请求中，请求完就销毁了。
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)
public class Servlet01 extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //向rquest域中存值 request.setAttribute("uname","张三"); //请求转发跳转到Servlet02 request.getRequestDispatcher("/Servlet02").forward(request, response); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }
public class Servlet02 extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //从request域中取值 String name=(String)request.getAttribute("uname"); //解决响应乱码 response.setContentType("text/html;charset=UTF-8"); response.getWriter().write(name); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }
总结：
request获得行的内容
request.getMethod() request.getRequestURI() request.getRequestURL() request.getContextPath() request.getRemoteAddr()
request获得头的内容
request.getHeader(name)
request获得体（请求参数）
String request.getParameter(name)
Map<String,String[]> request.getParameterMap();
String[] request.getParameterValues(name);
注意：客户端发送的参数 到服务器端都是字符串
获得中文乱码的解决：
post:request.setCharacterEncoding(“UTF-8”);
get:
parameter = new String(parameter.getBytes(“iso8859-1”),”UTF-8”);
request转发和域
request.getRequestDispatcher(转发的地址).forward(req,resp);
request.setAttribute(name,value)
request.getAttribute(name)
注意：转发与重定向的区别？
1）重定向两次请求，转发一次请求
2）重定向地址栏的地址变化，转发地址不变
3）重新定向可以访问外部网站 转发只能访问内部资源
4）转发的性能要优于重定向
不带数据用重定向，带数据用请求转发。