request对象继承体系结构
获取请求消息数据
使用IDEA提供的Servlet模板新建类文件
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>注册页面</title>
</head>
<body>
<form action="/code6_war_exploded/requestDemo1" method="post">
<input type="text" placeholder="请输入用户名" name="username"><br>
<input type="text" placeholder="请输入密码" name="password"><br>
<input type="submit" value="注册">
</form>
</body>
</html>
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.BufferedReader;
import java.io.IOException;
import java.util.Enumeration;
@WebServlet("/requestDemo1")
public class RequestDemo1 extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//获取请求消息体
BufferedReader br = request.getReader();
String line = null;
while((line = br.readLine())!=null){
System.out.println(line);
}
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException {
// 获取请求行数据
String method = request.getMethod();
System.out.println(method);
String contextPath = request.getContextPath();
System.out.println(contextPath);
String servletPath = request.getServletPath();
System.out.println(servletPath);
String queryString = request.getQueryString();
System.out.println(queryString);
String requestURI = request.getRequestURI();
System.out.println(requestURI);
StringBuffer RequestURL = request.getRequestURL();
System.out.println(RequestURL);
String protocol = request.getProtocol();
System.out.println(protocol);
String remoteAddr = request.getRemoteAddr();
System.out.println(remoteAddr);
// 获取请求头数据
Enumeration<String> headerNames = request.getHeaderNames();
while(headerNames.hasMoreElements()){
String name = headerNames.nextElement();
String value = request.getHeader(name);
System.out.println(name+"---"+value);
}
}
}
请求转发和数据共享
案例
druid.properties文件导入：将druid的配置文件改写后放入项目的src文件夹中
对于库文件的导入：在web目录下创建WEB-INFO目录，在WEB-INF目录下创建lib目录，将相应的库文件假如该lib目录，并导入项目。
package cn.itcast.domain;
public class User {
private int id;
private String username;
private String password;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
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;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", username='" + username + '\'' +
", password='" + password + '\'' +
'}';
}
}
4.创建cn.itcast.dao包，并在包中创建UserDao类，用于操作数据库中User表的类
5.实现操作数据库连接池的工具类，实现UserDao类对数据库进行查询操作
package cn.itcast.util;
import com.alibaba.druid.pool.DruidDataSourceFactory;
import javax.sql.DataSource;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;
public class JDBCUtils {
private static DataSource ds;
static{
try{
Properties pro = new Properties();
InputStream is = JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties");
pro.load(is);
ds = DruidDataSourceFactory.createDataSource(pro);
}catch(IOException e){
e.printStackTrace();
}catch (Exception e){
e.printStackTrace();
}
}
public static DataSource getDataSource(){ return ds; }
public static Connection getConnection() throws SQLException { return ds.getConnection(); }
}
6.编写cn.itcast.web.servlet.LoginServlet类
import cn.itcast.dao.UserDao;
import cn.itcast.domain.User;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
@WebServlet("/loginServlet")
public class LoginServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//设置编码
req.setCharacterEncoding("utf-8");
String username = req.getParameter("username");
String password = req.getParameter("password");
User loginuser = new User();
loginuser.setUsername(username);
loginuser.setPassword(username);
UserDao dao = new UserDao();
User user = dao.login(loginuser);
if(user == null){
req.getRequestDispatcher("/failServlet").forward(req,resp);
}else{
req.setAttribute("user",user);
req.getRequestDispatcher("/successServlet").forward(req,resp);
}
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
this.doGet(req,resp);
}
}
@WebServlet("/successServlet")
public class successServlet extends HttpServlet {
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
User user = (User)req.getAttribute("user");
if(user != null) {
resp.setContentType("text/html;charset=utf-8");
resp.getWriter().write("登陆成功，欢迎您" + user.getUsername());
}
}
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
this.doPost(req, resp);
}
}
@WebServlet("/failServlet")
public class failServlet extends HttpServlet {
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
resp.setContentType("text/html;charset=utf-8");
resp.getWriter().write("登陆失败，用户名或密码错误");
}
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
this.doPost(req,resp);
}
}
使用BeanUtils
使用BeanUtils封装请求参数并赋值给对象的代码
