JAVAWEB-09：HttpServletRequest对象&会话管理之Cookie

package com.heima.request; import java.beans.PropertyDescriptor; import java.io.IOException; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import java.util.Arrays; import java.util.Enumeration; import java.util.Map; 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 com.heima.bean.User; //演示获取客户端的请求参数 public class ServletReqeust3 extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.setCharacterEncoding("UTF-8"); response.setContentType("text/html;charset=UTF-8"); // tes1(request) ; // tes2(request) ; // tes3(request) ; // tes4(request) ; // tes5(request) ; tes6(request) ; } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } //1.拿到单个表单控件的的值:拿取姓名的值 public void tes1(HttpServletRequest request){ String name = request.getParameter("username") ; System.out.println(name); } //2.拿到表单控件的的值（同名控件的多个值）:拿取密码的值 public void tes2(HttpServletRequest request){ String[] password = request.getParameterValues("password") ; for (String string : password) { System.out.println(string); } } //3.拿到所有控件的名字和值 public void tes3(HttpServletRequest request){ Enumeration<String> names = request.getParameterNames() ; while(names.hasMoreElements()){ String name = names.nextElement() ; String[] values = request.getParameterValues(name) ; System.out.println(name + ":" + Arrays.asList(values)); } } //4.将获取的参数应当封装到javabean中: 采用PropertyDesciptor public void tes4(HttpServletRequest request){ User user = new User() ; System.out.println("封装前： " + user); //获取所有的表单控件的名字 Enumeration<String> names = request.getParameterNames() ; //循环封装 while(names.hasMoreElements()){ //拿取控件的名字 String name = names.nextElement() ; //控件的值 String[] values = request.getParameterValues(name) ; try { PropertyDescriptor pd = new PropertyDescriptor(name, User.class) ; //拿到User对象的属性name的属性描述器 Method m = pd.getWriteMethod() ; //拿到属性的set方法 //为了兼容jdk1.4的版本，虚拟机会将values拆分成一个一个值进行传递 if(values !=null && values.length == 1) m.invoke(user, values) ; else{ //方法一：强转成一个object //m.invoke(user, (Object)values) ; //方法二：创建一个数组 m.invoke(user, new Object[]{values}) ; } } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } } System.out.println("封装后： " + user); } //5.将获取的参数应当封装到javabean中: 采用BeanUtils public void tes5(HttpServletRequest request){ User user = new User() ; System.out.println("封装前： " + user); //获取所有的表单控件的名字 Enumeration<String> names = request.getParameterNames() ; //循环封装 while(names.hasMoreElements()){ //拿取控件的名字 String name = names.nextElement() ; //控件的值 String[] values = request.getParameterValues(name) ; try { BeanUtils.setProperty(user, name, values) ; } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } } System.out.println("封装后： " + user); } //6.将获取的参数应当封装到javabean中: 采用BeanUtils的另一种方式 public void tes6(HttpServletRequest request){ User user = new User() ; System.out.println("封装前： " + user); //拿到键值对的映射 Map<String,String[]> map = request.getParameterMap() ; for (Map.Entry<String, String[]> entry : map.entrySet()) { //entry就是键值对 String name = entry.getKey() ; //拿到键 String[] values = entry.getValue() ; //拿到值 try { BeanUtils.setProperty(user, name, values) ; } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } } System.out.println("封装后： " + user); } //7.终极必杀技 (采用beanUtils类)(推荐) public void tes7(HttpServletRequest request){ User user = new User() ; System.out.println("封装前： " + user); try { BeanUtils.populate(user, request.getParameterMap()) ; } catch (IllegalAccessException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (InvocationTargetException e) { // TODO Auto-generated catch block e.printStackTrace(); } System.out.println("封装后： " + user); } }