Servlet学习入门的第一个例子
环境 MyEclipse10.0+Tomcat7.0+Postgresql9.1
效果
代码：
LoginServlet.java
<pre name="code" class="java">import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.sql.*;
/*
* Servlet for Login
* @zm 2014-7-31
*/
@SuppressWarnings("serial")
public class LoginServlet extends HttpServlet{
private String url;
private String user;
private String password;
public void init()throws ServletException{
String driverClass = "org.postgresql.Driver";
url = "jdbc:postgresql://localhost:5432/student";
user = "postgres"; //默认用户名
password = "******"; //数据库密码
try{
Class.forName(driverClass);
}
catch(ClassNotFoundException ce){
throw new UnavailableException("加载数据库驱动失败！");
}
}
public void doGet(HttpServletRequest req,HttpServletResponse resp){
resp.setContentType("text/html;charset=gb2312");
String name = req.getParameter("name");
String id = req.getParameter("id");
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
try{
conn = DriverManager.getConnection(url, user, password);
stmt = conn.createStatement();
String sql = "select * from students where id = "+"'"+id+"'"+"and name ="+"'"+name+"'";
rs = stmt.executeQuery(sql);
if(rs.next()){
PrintWriter out = resp.getWriter();
out.println("Welcome : "+name);
}else{PrintWriter out = resp.getWriter();
out.println("姓名或id输入错误！");}
}catch (Exception e) {
e.printStackTrace();
}
finally{
if(stmt!=null){
try{stmt.close();}
catch(SQLException se){se.printStackTrace();}
stmt = null;
}
if(conn!=null){
try{conn.close();}
catch(SQLException se){se.printStackTrace();}
conn = null;
}
}
}
public void doPost(HttpServletRequest req,HttpServletResponse resp){
doGet(req,resp);
}
}
SignUp.java
import javax.servlet.*;
import javax.servlet.http.*;
import java.sql.*;
/*
* Servlet for 用户注册
* @zm 2014-7-31
*/
@SuppressWarnings("serial")
public class SignUpServlet extends HttpServlet{
private String url;
private String user;
private String password;
//加载数据库
public void init()throws ServletException{
String driverClass = "org.postgresql.Driver";
url = "jdbc:postgresql://localhost:5432/student";
user = "postgres";
password = "*******";
try{
Class.forName(driverClass);
}
catch(ClassNotFoundException ce){
throw new UnavailableException("加载数据库驱动失败！");
}
}
public void doGet(HttpServletRequest req,HttpServletResponse resp){
resp.setContentType("text/html;charset=gb2312");
String name = req.getParameter("name");
String id = req.getParameter("id");
Connection conn = null;
Statement stmt = null;
try{
conn = DriverManager.getConnection(url, user, password);
stmt = conn.createStatement();
String sql = "insert into students (id,name) values ('"+id+"','"+name+"')";
stmt.executeUpdate(sql);
resp.sendRedirect("Login.html");
}catch (Exception e) {
e.printStackTrace();
}
finally{
if(stmt!=null){
try{stmt.close();}
catch(SQLException se){se.printStackTrace();}
stmt = null;
}
if(conn!=null){
try{conn.close();}
catch(SQLException se){se.printStackTrace();}
conn = null;
}
}
}
public void doPost(HttpServletRequest req,HttpServletResponse resp){
doGet(req,resp);
}
}
登陆界面Login.html
<html>
<head>
<title>ZM的登陆网页！</title>
</head>
<body>
<form action="Login" method="post">
<table>
<tr>
<td>请输入id： </td>
<td><input type="password" name="id"></td>
</tr>
<tr>
<td>请输入用户名： </td>
<td><input type="text" name="name"></td>
</tr>
<tr>
<td><input type="reset" name="重填"> </td>
<td><input type="submit" name="登录"></td>
<td><input type="button" value="注册" onclick="javascrtpt:window.location.href='SignUp.html'"><td>
</tr>
</table>
</form>
</body>
</html>
注册界面SignUp.html
<html>
<head>
<title>用户注册</title>
</head>
<body>
<form action="SignUp" method="post">
<table>
<tr>
<td>请输入id： </td>
<td><input type="password" name="id"></td>
</tr>
<tr>
<td>请输入用户名： </td>
<td><input type="text" name="name"></td>
</tr>
<tr>
<td><input type="reset" name="重填"> </td>
<td><input type="submit" name="注册"></td>
</tr>
</table>
</form>
</body>
</html>
部署文件web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<display-name></display-name>
<servlet>
<servlet-name>ZM</servlet-name>
<servlet-class>LoginServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ZM</servlet-name>
<url-pattern>/Login</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>ZM1</servlet-name>
<servlet-class>SignUpServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ZM1</servlet-name>
<url-pattern>/SignUp</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
1.访问数据库注意加载JDBC驱动程序 postgresql-9.1-901-1.jdbc4.jar
2.数据库创建连接Connection conn = DriverManager.getConnection(url, user, password);
URL=协议名+IP地址（域名）+端口+数据库的名称
jdbc:postgresql://localhost:5432/student
用户名和密码是指登陆数据库时所使用的用户名和密码。
3.数据库注意打开服务。
4.入门不宜直接使用myEclipse部署,自己手动部署了解过程才好。
Servlet实战（一）---账户登录,布布扣,bubuko.com
时间： 2024-08-24 17:06:55