1. 响应对象 Response（重点：HTTP协议响应部分）
查看 HttpServletResponse
set是 有这个头 修改 没有添加一个新的 和 add 有点小区别
案例：
1.1 字节流向客户端输出中文数据 ServletOutputStream
//字节流向客户端输出中文数据
public class ResponseDemo1 extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
test2(response);
}
//解决方案一：更改浏览器的码表（不建议）
//解决方案二(不建议)：向客户端输出一个<meta>标签,模拟了响应消息头：<meta http-equiv='Content-Type' content='text/html;charset=UTF-8'>
//out.write("<meta http-equiv='Content-Type' content='text/html;charset=UTF-8'>".getBytes());
//解决方案三（建议）:向客户端输出响应消息头：response.setHeader("Content-Type", "text/html;charset=UTF-8");
//解决方案四（建议）：向客户端输出响应消息头response.setContentType("text/html;charset=UTF-8");
//字节流输出数据查UTF-8
private void test2(HttpServletResponse response) throws IOException {
String data = "不见了远处的青山";
response.setContentType("text/html;charset=UTF-8");
ServletOutputStream out = response.getOutputStream();
out.write(data.getBytes("UTF-8"));//默认情况下：浏览器是乱码的（他默认查GBK）
}
//字节流输出数据查本地码表
private void test1(HttpServletResponse response) throws IOException {
String data = "不见了远处的青山";
ServletOutputStream out = response.getOutputStream();
out.write(data.getBytes());//String: getBytes()查本地默认的码表GBK getBytes(String charset)查指定码表
}
1.2 字符流输出中文数据 PrintWriter
//字符流输出中文数据
public class ResponseDemo2 extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String data = "幸福是什么呢";
//改变字符流查的码表，还能告知客户端用UTF-8进行解码
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
//HttpServletResponse的实例由Tomcat服务器提供，默认查ISO-8859-1的。
//Tomcat8.X ,默认编码就变为了UTF-8
out.write(data);
}
private void test1(HttpServletResponse response) throws IOException {
String data = "幸福是什么";
//改变字符流查的码表
response.setCharacterEncoding("UTF-8");
//告知客户端用UTF-8进行解码
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();//HttpServletResponse的实例由Tomcat服务器提供，默认查ISO-8859-1的。
//Tomcat8.X ,默认编码就变为了UTF-8
out.write(data);
}
1.3 输出随机验证码图片：CAPTCHA图像
//输出随机验证码图片：CAPTCHA图像
public class ResponseDemo3 extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
int width = 120;
int height = 25;
//创建一副内存图像
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
//得到画笔
Graphics g = image.getGraphics();
//开始画
//边线
g.setColor(Color.BLUE);
g.drawRect(0, 0, width, height);
//填充背景色
g.setColor(Color.YELLOW);
g.fillRect(1, 1, width-2, height-2);
//话干扰线
g.setColor(Color.GRAY);
Random r = new Random();
for(int i=0;i<9;i++)
g.drawLine(r.nextInt(width), r.nextInt(height), r.nextInt(width), r.nextInt(height));
//验证码
g.setColor(Color.RED);
g.setFont(new Font("宋体", Font.ITALIC|Font.BOLD, 19));
// String base = "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";
int x = 20;
for(int i=0;i<4;i++){
g.drawString(r.nextInt(10)+"", x,20 );
// g.drawString(base.charAt(r.nextInt(base.length()))+"", x, 20);
x+=18;
}
//输出
response.setHeader("Expires", "-1");
response.setHeader("Cache-Control", "no-cache");
response.setHeader("Pragma", "no-cache");
ImageIO.write(image, "jpg", response.getOutputStream());
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}
html
<body>
<form action="" method="post">
用户名：<input type="text" name="username"/><br/>
密码：<input type="password" name="password"/><br/>
<input type="text" size="3" name="code"/><img id="img1" src="/day08_00_response/servlet/ResponseDemo3"/><a href="javascript:change()">看不清</a><br/>
<input type="submit" value="登录"/>
</form>
<script type="text/javascript">
function change(){
var imgObj = document.getElementById("img1");
imgObj.src="/day08_00_response/servlet/ResponseDemo3?time="+new Date().getTime();//浏览器发现地址没有变化，根本不发请求
}
</script>
</body>
1.4 定时刷新 登陆跳转等待
//控制客户端定时刷新
public class ResponseDemo4 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
test2(response);
}
//定时刷新到别处
private void test2(HttpServletResponse response) throws IOException {
response.setContentType("text/htm;charset=UTF-8");
response.setHeader("Refresh", "2;URL=http://www.huyifan.cn");
response.getWriter().write("登录成功，2秒后跳转到主页");
}
//定时刷新自己
private void test1(HttpServletResponse response) throws IOException {
Random r = new Random();
// response.setHeader("Refresh", "1");
response.setIntHeader("Refresh", 1);
response.getWriter().write(r.nextInt()+"");
}
1.5 控制缓存时间
//控制缓存的时间
//静态资源需要控制缓存时间
//动态资源一般不要缓存
public class ResponseDemo5 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String data = "不见了远处的青山";
//让他缓存1个小时
response.setDateHeader("Expires", System.currentTimeMillis()+1*60*60*1000);
response.setContentType("text/html;charset=UTF-8");
response.getWriter().write(data);
}
1.6 请求重定向
//演示请求重定向:可以重定向到任何地址上
//发出2次请求
//地址栏会发生变化
public class ResponseDemo6 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.sendRedirect("http://www.huyifan.com");
}
//重定向到应用内的资源
private void test1(HttpServletResponse response) throws IOException {
// response.setStatus(302);
// response.setHeader("Location", "/day08_00_response/servlet/ResponseDemo7");
response.sendRedirect("/day08_00_response/servlet/ResponseDemo7");
}
public class ResponseDemo7 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.getWriter().write("I am yif");
// response.getOutputStream().write("a".getBytes());
}
细节：
1、字节流和字符流互斥，只能用其中一个。
2、response的流用完之后自动关（服务器关）
2. 请求对象 Request（重点：HTTP协议请求部分）
2.1 HttpServletRequest对象的生命周期
诞生：请求来了
死亡：响应结束
2.2 也是一个域（范围）对象：请求范围
request
Map
setAttribute
getAttribute
removeAttribute‘
2.2 开发中尽量用绝对路径
绝对路径：要不要加应用名称
地址给服务器用的：/就代表当前应用
地址给客户端用的：/应用名demo
2.3 HttpServletRequest中的常用方法
public class RequestDemo1 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String method = request.getMethod();//请求方式
String uri = request.getRequestURI();// /day08_01_request/servlet/RequestDemo1
String url = request.getRequestURL().toString();// http://localhost:8080/day08_01_request/servlet/RequestDemo1
String protocal = request.getProtocol();//客户端使用的协议
String remoteIp = request.getRemoteAddr();//来访者的ip
int port = request.getRemotePort();// 随机的
String queryString = request.getQueryString();//GET方式：/day08_01_request/servlet/RequestDemo1?username=abc&password=123
//username=abc&password=123
System.out.println(method);
System.out.println(uri);
System.out.println(url);
System.out.println(protocal);
System.out.println(remoteIp);
System.out.println(port);
System.out.println(queryString);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
2.4 获取请求消息头
public class RequestDemo2 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
test3(request);
}
//得到所有的消息头
private void test3(HttpServletRequest request) {
Enumeration<String> e = request.getHeaderNames();
while(e.hasMoreElements()){
String headerName = e.nextElement();//透明称
Enumeration<String> headerValues = request.getHeaders(headerName);
while(headerValues.hasMoreElements()){
System.out.println(headerName+":"+headerValues.nextElement());
}
}
}
//http协议是允许头有重复的情况，多个重名的头
private void test2(HttpServletRequest request) {
Enumeration<String> e = request.getHeaders("Accept-Encoding");//得到的头值
while(e.hasMoreElements()){
String headerValue = e.nextElement();
System.out.println(headerValue);
}
}
//得到指定请求消息头的值。如果没有该头，返回null
private void test1(HttpServletRequest request) {
String supportEncoding = request.getHeader("Accept-Encoding");
if(supportEncoding.contains("gzip")){
System.out.println("支持gzip压缩");
}else{
System.out.println("不支持gzip压缩");
}
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
2.5 获取请求参数
public class RequestDemo3 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
test8(request, response);
}
//终极解决方案：借助BeanUtil框架 jar包直接放在 web-inf 的 ；lib 文件夹里就ok
private void test8(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
User user = new User();
System.out.println("封装前："+user);
try {
BeanUtils.populate(user, request.getParameterMap());
} catch (Exception e) {
e.printStackTrace();
}
System.out.println("封装后："+user);
}
//getParameterMap获取参数:封装到JavaBean中
private void test7(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//key:请求参数名 value:请求参数值数组
Map<String,String[]> map = request.getParameterMap();
User user = new User();
System.out.println("封装前："+user);
for(Map.Entry<String, String[]> me:map.entrySet()){
String paramName = me.getKey();//参数名称
String paramValues[] = me.getValue();//参数值
try {
PropertyDescriptor pd = new PropertyDescriptor(paramName, User.class);
Method m = pd.getWriteMethod();//setter方法
if(paramValues.length>1){
m.invoke(user, (Object)paramValues);//参考补充视频：反射main方法
}else{
m.invoke(user, paramValues);
}
} catch (Exception e1) {
e1.printStackTrace();
}
}
System.out.println("封装后："+user);
}
//getParameterMap获取参数
private void test6(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//key:请求参数名 value:请求参数值数组
Map<String,String[]> map = request.getParameterMap();
for(Map.Entry<String, String[]> me:map.entrySet()){
System.out.println(me.getKey()+"="+Arrays.asList(me.getValue()));
}
}
//把请求参数的值封装到JavaBean中
//约定优于编码：表单的输入域的name取值和JavaBean中的属性（getter和setter方法）保持一致
private void test5(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
Enumeration<String> e = request.getParameterNames();//参数名
User user = new User();
System.out.println("封装前："+user);
while(e.hasMoreElements()){
String paramName = e.nextElement();//即是JavaBean中的属性名称
String paramValue = request.getParameter(paramName);
// setUsername(paramValue); setPassword(paramValue);
//JavaBean的内省
try {
PropertyDescriptor pd = new PropertyDescriptor(paramName, User.class);
Method m = pd.getWriteMethod();//setter方法
m.invoke(user, paramValue);
} catch (Exception e1) {
e1.printStackTrace();
}
}
System.out.println("封装后："+user);
}
// private void test4(HttpServletRequest request, HttpServletResponse response)
// throws ServletException, IOException {
// User user = new User();
// System.out.println("封装前："+user);
// String username = request.getParameter("username");
// String password = request.getParameter("password");
// String gender = request.getParameter("gender");
// user.setUsername(username);
// user.setPassword(password);
// user.setGender(gender);
// System.out.println("封装后："+user);
// }
//以下内容只用简单的程序开发
//获取所有的请求参数名和值
private void test3(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
Enumeration<String> e = request.getParameterNames();//参数名
while(e.hasMoreElements()){
String paramName = e.nextElement();
String values [] = request.getParameterValues(paramName);
System.out.println(paramName+"="+Arrays.asList(values));
}
}
//获取重名请求参数的值
private void test2(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String username = request.getParameter("username");//不区分get还是post的
String passwords[] = request.getParameterValues("password");//获取重名的请求参数值
System.out.println(username+":"+Arrays.asList(passwords));
}
//获取单一的请求参数的值(用户所有的输入都是String)
private void test1(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String username = request.getParameter("username");//不区分get还是post的
String password = request.getParameter("password");
System.out.println(username+":"+password);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
domain
public class User {
private String username;
private String password[];
private String gender;
public String getUsername() {//读属性，属性名称username
return username;
}
public void setUsername(String username) {//写属性，属性名username
this.username = username;
}
public String[] getPassword() {
return password;
}
public void setPassword(String[] password) {
this.password = password;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
@Override
public String toString() {
return "User [username=" + username + ", password="
+ Arrays.toString(password) + ", gender=" + gender + "]";
}
}
public class Student {
private int id;//BeanUtil对于基本类型自动转换
private String name;
private String password;
private String gender;
private boolean married;
private String[] hobby;
private String province;
private String description;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
public boolean isMarried() {
return married;
}
public void setMarried(boolean married) {
this.married = married;
}
public String[] getHobby() {
return hobby;
}
public void setHobby(String[] hobby) {
this.hobby = hobby;
}
public String getProvince() {
return province;
}
public void setProvince(String province) {
this.province = province;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
@Override
public String toString() {
return "Student [id=" + id + ", name=" + name + ", password="
+ password + ", gender=" + gender + ", married=" + married
+ ", hobby=" + Arrays.toString(hobby) + ", province="
+ province + ", description=" + description + "]";
}
}
<form action="/day08_01_request/servlet/RequestDemo4" method="post">
用户名：<input type="text" name="username"/><br/>
密码：<input type="password" name="password"/><br/>
确认密码：<input type="password" name="password"/><br/>
性别：<input type="text" name="gender" value="male"/>
<input type="submit" value="注册"/>
</form>
2.4 以输入流的形式接收请求正文：POST
一般情况下用不着，文件上传时使用。
public class RequestDemo4 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
ServletInputStream in = request.getInputStream();
int len = -1;
byte b[] = new byte[1024];
while((len=in.read(b))!=-1){
System.out.println(new String(b,0,len));
}
in.close();
}
2.5 获取常用表单输入域的值
type:radio checkbox ,如果用户一个都没有选，客户端是根本不会传参数到服务器的。
public class RequestDemo5 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
test3(request,response);
}
//请求编码和响应编码没有关系
private void test3(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");//设置请求正文的编码。只对POST有效
Student s = new Student();
System.out.println("封装前："+s);
try {
BeanUtils.populate(s, request.getParameterMap());
} catch (Exception e) {
e.printStackTrace();
}
response.setContentType("text/html;charset=UTF-8");
response.getWriter().write(s.toString());
}
//get请求方式的编码问题
private void test2(HttpServletRequest request)
throws UnsupportedEncodingException {
String username = request.getParameter("name");//是二进制数据 %E6%9D%8E%E5%9B%9B
byte b[] = username.getBytes("ISO-8859-1");
username = new String(b,"UTF-8");
System.out.println(username);//二进制转为字符，用ISO-8859-1的
}
//获取请求正文的参数乱码问题
private void test1(HttpServletRequest request)
throws UnsupportedEncodingException {
request.setCharacterEncoding("UTF-8");//设置请求正文的编码。只对POST有效
Student s = new Student();
System.out.println("封装前："+s);
try {
BeanUtils.populate(s, request.getParameterMap());
} catch (Exception e) {
e.printStackTrace();
}
System.out.println("封装后："+s);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
<form action="/day08_01_request/servlet/RequestDemo5" method="post">
<input type="hidden" value="438" name="id"/>
<table border="1" width="438">
<tr>
<td>姓名</td>
<td>
<input type="text" name="name"/>
</td>
</tr>
<tr>
<td>密码</td>
<td>
<input type="password" name="password"/>
</td>
</tr>
<tr>
<td>性别</td>
<td>
<input type="radio" name="gender" value="male" checked="checked"/>男性
<input type="radio" name="gender" value="female"/>女性
</td>
</tr>
<tr>
<td>婚否</td>
<td>
<input type="checkbox" name="married"/>
</td>
</tr>
<tr>
<td>爱好</td>
<td>
<input type="checkbox" name="hobby" value="eat"/>吃饭
<input type="checkbox" name="hobby" value="sleep"/>睡觉
<input type="checkbox" name="hobby" value="java"/>学Java
</td>
</tr>
<tr>
<td>籍贯</td>
<td>
<select name="province">
<option value="BJ">北京</option>
<option value="SD">山东</option>
<option value="HB">湖北</option>
</select>
</td>
</tr>
<!--
<tr>
<td>靓照</td>
<td>
<input type="file" name="image"/>
</td>
</tr>
-->
<tr>
<td>简介</td>
<td>
<textarea rows="3" cols="38" name="description"></textarea>
</td>
</tr>
<tr>
<td colspan="2">
<!-- <input type="submit" value="注册"/> -->
<!-- <input type="image" src="an-0333.gif"/> -->
<input type="button" value="注册" onclick="toSubmit()"/>
</td>
</tr>
</table>
<script type="text/javascript">
function toSubmit(){
//验证用户的输入
document.forms[0].submit();
}
</script>
</form>
编码：
2.6 请求转发
//转发：源
//源和目标：共享请求范围中的数据
public class RequestDemo6 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setAttribute("p", "ppp");
//ServletContext:地址的写法。必须以"/"，代表当前应用。（应用开头的绝对路径）
// RequestDispatcher rd = getServletContext().getRequestDispatcher("/servlet/RequestDemo7");
//绝对路径
// RequestDispatcher rd = request.getRequestDispatcher("/servlet/RequestDemo7");
//相对路径
RequestDispatcher rd = request.getRequestDispatcher("RequestDemo7");
rd.forward(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
//转发：目标
public class RequestDemo7 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String s = (String)request.getAttribute("p");//注意和getParameter没有关系
response.getWriter().write(s);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
请求与重定向区别
2.7 包含：源 服务器端行为
public class RequestDemo8 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
response.getWriter().write("我喜欢");
RequestDispatcher rd = request.getRequestDispatcher("/servlet/RequestDemo9");
rd.include(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
public class RequestDemo9 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
response.getWriter().write("成都");
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
2.8 请求 和 包含 的小细节
//转发前后，源输出的任何响应正文无效
public class Forward1 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setHeader("Refresh", "1");
System.out.println("转发前");
response.getWriter().write("forward before");//转发前会清空响应对象中的正文内容
request.getRequestDispatcher("/servlet/Forward2").forward(request, response);//转发
System.out.println("转发后");
response.getWriter().write("forward after");
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
//转发：目标
public class Forward2 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.getWriter().write("222222");//响应结束
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
//包含：源
//只会包含目标的正文，头部信息包含前清空
public class IncludeDemo1 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.getWriter().write("11111");
request.getRequestDispatcher("/servlet/IncludeDemo2").include(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
//包含：目标
public class IncludeDemo2 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setIntHeader("Refresh", 1);
response.getWriter().write("22222");
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}