本篇文章为你整理了创建第一个属于自己的JavaWeb小程序吧(创建第一个web项目)的详细内容,包含有创建第一个jsp程序 创建第一个web项目 编写第一个java程序 java第一步怎么创建 创建第一个属于自己的JavaWeb小程序吧,希望能帮助你了解 创建第一个属于自己的JavaWeb小程序吧。
INSERT INTO `user` VALUES (1, 123, 123, 女, 北京, 123);
INSERT INTO `user` VALUES (2, 111, 111, 男, 北京, 123123);
然后打开 idea 创建以下 几个目录:
com.filter //过滤器 解决中文字符集乱码
com.util //数据库连接工具类
com.entity //实体类
com.dao //数据操作类
com.servlet //servlet类
在filter下新建一个EncodingFilter用来解决中文字符集乱码,需要实现Filter接口,并且重写doFilter函数
package com.filter;
import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
public class EncodingFilter implements Filter{
public EncodingFilter(){
System.out.println("过滤器构造");
public void destroy() {
System.out.println("过滤器销毁");
public void doFilter(ServletRequest request, ServletResponse response,FilterChain chain) throws IOException, ServletException {
request.setCharacterEncoding("utf-8"); //将编码改为utf-8
response.setContentType("text/html;charset=utf-8");
chain.doFilter(request, response);
public void init(FilterConfig arg0) throws ServletException {
System.out.println("过滤器初始化");
}
然后到web.xml下进行对EncodingFilter相应的 xml配置
?xml version="1.0" encoding="UTF-8"?
web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0"
!-- 设置编码格式 --
filter
filter-name EncodingFilter /filter-name
filter-class com.filter.EncodingFilter /filter-class !--全路径 从根包开始一直到类名--
/filter
filter-mapping
filter-name EncodingFilter /filter-name
url-pattern /* /url-pattern !--* 为过滤所有--
/filter-mapping
!-- 设置首页为登录页 首页从默认的 index.jsp 换成 login.jsp --
welcome-file-list
welcome-file login.jsp /welcome-file
/welcome-file-list
/web-app
在util下新建一个DBconn类用来处理对数据库的连接操作(用户名和密码需要对照自己的数据库进行更改)
package com.util;
import java.sql.*;
public class DBConnection {
//定义连接数据库的属性
private static String JDBC_DRIVER = "com.mysql.jdbc.Driver";
private static String url = "jdbc:mysql://localhost:3306/demo";
// 用户 密码
private static String username = "root";
private static String pwd = "123456";
private static Connection conn = null;
static ResultSet rs = null;
static PreparedStatement ps =null;
public static void init(){
try {
Class.forName(JDBC_DRIVER);
conn = DriverManager.getConnection(url,username,pwd);
} catch (Exception e) {
System.out.println("init [SQL驱动程序初始化失败!]");
e.printStackTrace();
public static int addUpdDel(String sql){
int i = 0;
try {
PreparedStatement ps = conn.prepareStatement(sql);
i = ps.executeUpdate();
} catch (SQLException e) {
System.out.println("数据库增删改异常");
e.printStackTrace();
return i;
public static ResultSet selectSql(String sql){
try {
ps = conn.prepareStatement(sql);
rs = ps.executeQuery(sql);
} catch (SQLException e) {
System.out.println("数据库查询异常");
e.printStackTrace();
return rs;
public static void closeConn(){
try {
conn.close();
} catch (SQLException e) {
System.out.println("数据库关闭异常");
e.printStackTrace();
}
在entity下新建一个User实体类对应数据库中的每个字段
package com.entity;
public class User {
private int id;
private String name;
private String pwd;
private String sex;
private String address;
private String info;
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 getPwd() {
return pwd;
public void setPwd(String pwd) {
this.pwd = pwd;
public String getSex() {
return sex;
public void setSex(String sex) {
this.sex = sex;
public String getAddress() {
return address;
public void setAddress(String address) {
this.address = address;
public String getInfo() {
return info;
public void setInfo(String info) {
this.info = info;
}
在dao下新建一个UserDao接口 以及对应的方法实现类 规范开发 需要使用 接口及实现类
UserDao.java
package com.dao;
import com.entity.User;
import java.util.List;
public interface UserDao {
public boolean login(String name,String pwd);//登录
public boolean register(User user);//注册
public List User getUserAll();//返回用户信息集合
public boolean delete(int id) ;//根据id删除用户
public boolean update(int id,String name, String pwd,String sex, String home,String info) ;//更新用户信息
}
在写一个 UserDaoImpl.java 实现UserDao接口,及未实现的方法
package com.dao;
import com.entity.User;
import com.util.DBConnection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
public class UserDaoImpl implements UserDao {
DBConnection DBconn = new DBConnection();
// 注册用户
@Override
public boolean register(User user) {
boolean flag = false;
DBconn.init();
int i =DBconn.addUpdDel("insert into user(name,pwd,sex,address,info) " +
"values("+user.getName()+","+user.getPwd()+","+user.getSex()+","+user.getAddress()+","+user.getInfo()+")");
if(i 0){
flag = true;
DBconn.closeConn();
return flag;
// 查询 登录用户是否存在
@Override
public boolean login(String name, String pwd) {
boolean flag = false;
try {
DBconn.init();
ResultSet rs = DBconn.selectSql("select * from user where name="+name+" and pwd="+pwd+"");
while(rs.next()){
if(rs.getString("name").equals(name) rs.getString("pwd").equals(pwd)){
flag = true;
DBconn.closeConn();
} catch (SQLException e) {
e.printStackTrace();
return flag;
// 获取用户
@Override
public List User getUserAll() {
List User list = new ArrayList User ();
try {
DBconn.init();
ResultSet rs = DBconn.selectSql("select * from user");
while(rs.next()){
User user = new User();
user.setId(rs.getInt("id"));
user.setName(rs.getString("name"));
user.setPwd(rs.getString("pwd"));
user.setSex(rs.getString("sex"));
user.setAddress(rs.getString("address"));
user.setInfo(rs.getString("info"));
list.add(user);
DBconn.closeConn();
return list;
} catch (SQLException e) {
e.printStackTrace();
return null;
// 更新用户数据
@Override
public boolean update(int id, String name, String pwd, String sex, String home, String info) {
boolean flag = false;
DBconn.init();
String sql ="update user set name ="+name
+" , pwd ="+pwd
+" , sex ="+sex
+" , home ="+home
+" , info ="+info+" where id = "+id;
int i =DBconn.addUpdDel(sql);
if(i 0){
flag = true;
DBconn.closeConn();
return flag;
// 删除用户
@Override
public boolean delete(int id) {
boolean flag = false;
DBconn.init();
String sql = "delete from user where id="+id;
int i =DBconn.addUpdDel(sql);
if(i 0){
flag = true;
DBconn.closeConn();
return flag;
在servlet下创建DengluServlet用来实现对用户登录的操作 ,实现Servlet具体内容,然后需要去WEB_INF下的web.xml去配置servlet
package com.servlet;
import com.dao.UserDao;
import com.dao.UserDaoImpl;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.IOException;
@WebServlet(name = "signinServlet", value = "/signinServlet")
public class Signin extends HttpServlet { // serverlet 需要继承 HttpServerlet 并重写doGet和doPost方法
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request, response); //将信息使用doPost方法执行 对应jsp页面中的form表单中的method
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String name = request.getParameter("name"); //得到jsp页面传过来的参数
String pwd = request.getParameter("pwd");
UserDao ud = new UserDaoImpl();
if(ud.login(name, pwd)){
request.setAttribute("xiaoxi", "欢迎用户"+name); //向request域中放置信息
request.getRequestDispatcher("/success.jsp").forward(request, response);//转发到成功页面
}else{
response.sendRedirect("index.jsp"); //重定向到首页
}
两点要注意的地方:
一:getParameter与getAttribute两者的区别
request.setAttribute("xiaoxi", "欢迎用户"+name);//向request域中放置信息 ( 键值对的形式) 名字为xiaoxi 内容为"欢迎用户"+name
request.getAttribute("xiaoxi");//得到request域中放置名字为xiaoxi的信息
request.getParameter("name");//得到request域的参数信息(得到jsp页面传过来的参数)
getAttribute表示从request范围取得设置的属性,必须要先setAttribute设置属性,才能通过getAttribute来取得,设置与取得的为Object对象类型 。
getParameter表示接收参数,参数为页面提交的参数,包括:表单提交的参数、URL重写(就是xxx?id=1中的id)传的参数等,因此这个并没有设置参数的方法(没有setParameter),而且接收参数返回的不是Object,而是String类型
二:转发与重定向的区别
(1).重定向的执行过程:Web服务器向浏览器发送一个http响应--》浏览器接受此响应后再发送一个新的http请求到服务器--》服务器根据此请求寻找资源并发送给浏览器。它可以重定向到任意URL,不能共享request范围内的数据。
(2).重定向是在客户端发挥作用,通过新的地址实现页面转向。
(3).重定向是通过浏览器重新请求地址,在地址栏中可以显示转向后的地址。
(4).转发过程:Web服务器调用内部方法在容器内部完成请求和转发动作--》将目标资源发送给浏览器,它只能在同一个Web应用中使用,可以共享request范围内的数据。
(5).转发是在服务器端发挥作用,通过forward()方法将提交信息在多个页面间进行传递。
(6).转发是在服务器内部控制权的转移,客户端浏览器的地址栏不会显示出转向后的地址。
在servlet下创建一个ZhuceServlet用来实现用户注册的操作
package com.servlet;
import com.dao.UserDao;
import com.dao.UserDaoImpl;
import com.entity.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(name = "LogonServlet", value = "/LogonServlet")
public class Logon extends HttpServlet{
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
super.doGet(req, resp);
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String name = req.getParameter("name"); //获取jsp页面传过来的参数
String pwd = req.getParameter("pwd");
String sex = req.getParameter("sex");
String address = req.getParameter("address");
String info = req.getParameter("info");
User user = new User(); //实例化一个对象,组装属性
user.setName(name);
user.setPwd(pwd);
user.setSex(sex);
user.setAddress(address);
user.setInfo(info);
UserDao ud = new UserDaoImpl();
if( ud.register(user) ){
req.setAttribute("username", name); //向req域中放置参数
req.setAttribute("xiaoxi", "注册成功");
req.getRequestDispatcher("/login.jsp").forward(req, resp); //转发到登录页面
}else{
resp.sendRedirect("login.jsp");//重定向到首页
}
在servlet下创建SearchallServlet用来返回数据库中所有用户信息Searchall.java
package com.servlet;
import com.dao.UserDao;
import com.dao.UserDaoImpl;
import com.entity.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;
import java.util.List;
@WebServlet(name = "SearchallServlet", value = "/SearchallServlet")
public class Searchall extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
super.doGet(req, resp);
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
UserDao ud = new UserDaoImpl();
List User userAll = ud.getUserAll();
req.setAttribute("userAll", userAll);
req.getRequestDispatcher("/showall.jsp").forward(req, resp);
}
在servlet下创建DeleteServlet用来删除用户操作DeleteServlet.java
package com.servlet;
import com.dao.UserDao;
import com.dao.UserDaoImpl;
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(name = "DeleteServlet", value = "/DeleteServlet")
public class Delete extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
super.doGet(req, resp);
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String id = req.getParameter("id");
int userId = Integer.parseInt(id);
UserDao ud = new UserDaoImpl();
if(ud.delete(userId)){
req.setAttribute("xiaoxi", "删除成功");
req.getRequestDispatcher("/Searchall").forward(req, resp);
}else{
resp.sendRedirect("index.jsp");
}
在servlet下创建UpdateServlet操作用来更新用户信息UpdateServlet.java
package com.servlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
@WebServlet(name = "UpdateServlet", value = "/UpdateServlet")
public class Update extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
super.doGet(req, resp);
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String id = req.getParameter("id");
int userId = Integer.parseInt(id);
String name = req.getParameter("name");
String pwd = req.getParameter("pwd");
String sex = req.getParameter("sex");
String home = req.getParameter("home");
String info = req.getParameter("info");
System.out.println("------------------------------------"+userId);
UserDao ud = new UserDaoImpl();
if(ud.update(userId, name, pwd, sex, home, info)){
req.setAttribute("xiaoxi", "更新成功");
req.getRequestDispatcher("/Searchall").forward(req, resp);
}else{
resp.sendRedirect("index.jsp");
}
配置servlet
?xml version="1.0" encoding="UTF-8"?
web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0"
!-- 设置编码格式 --
filter
filter-name EncodingFilter /filter-name
filter-class com.filter.EncodingFilter /filter-class !--全路径 从根包开始一直到类名--
/filter
filter-mapping
filter-name EncodingFilter /filter-name
url-pattern /* /url-pattern !--* 为过滤所有--
/filter-mapping
servlet-name LogonServlet /servlet-name
servlet-class com.servlet.Logon /servlet-class
/servlet
servlet
servlet-name SigninServlet /servlet-name
servlet-class com.servlet.Signin /servlet-class
/servlet
servlet
servlet-name SearchallServlet /servlet-name
servlet-class com.servlet.Searchall /servlet-class
/servlet
servlet
servlet-name DeleteServlet /servlet-name
servlet-class com.servlet.Delete /servlet-class
/servlet
servlet
servlet-name UpdateServlet /servlet-name
servlet-class com.servlet.Update /servlet-class
/servlet
!--配置Servlet 类--
servlet-mapping
servlet-name LogonServlet /servlet-name
url-pattern /LogonServlet /url-pattern
/servlet-mapping
servlet-mapping
servlet-name SigninServlet /servlet-name
url-pattern /SigninServlet /url-pattern
/servlet-mapping
servlet-mapping
servlet-name SearchallServlet /servlet-name
url-pattern /SearchallServlet /url-pattern
/servlet-mapping
servlet-mapping
servlet-name DeleteServlet /servlet-name
url-pattern /DeleteServlet /url-pattern
/servlet-mapping
servlet-mapping
servlet-name UpdateServlet /servlet-name
url-pattern /UpdateServlet /url-pattern
/servlet-mapping
!-- 设置首页为登录页 --
welcome-file-list
welcome-file login.jsp /welcome-file
/welcome-file-list
/web-app
新建jsp页面 login
%@ page contentType="text/html;charset=UTF-8" language="java" %
html
head
title 登录页 /title
/head
body
form action="SigninServlet" method="post"
用户名: input type="text" name="name"value="" br br
密码: input type="password" name="pwd"value="" br br
input type="submit"value="登录"name="denglu" input type="reset"value="重置" br
/form
form action="zhuce.jsp"
input type="submit"value="新用户注册"
/form
/body
/html
zhuce.jsp 用户注册页面
%@ page contentType="text/html;charset=UTF-8" language="java" %
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
html
head
title My JSP BB.jsp starting page /title
/head
body
form action="LogonServlet"method="post"
输入用户名: input name="name" type="text" br br
输入密码: input name="pwd" type="password" br br
选择性别: input type="radio"name="sex"value="男"checked 男
input type="radio"name="sex"value="女" 女 br br
选择家乡:
select name="address"
option value="上海" 上海 /option
option value="北京" selected 北京 /option
option value="纽约" 纽约 /option
/select br
填写个人信息: br
textarea name="info" row="5"cols="30" /textarea br
input type="reset"value="重置" input type="submit"value="注册"
/form
/body
/html
失败页面 index.jsp
%@ page contentType="text/html;charset=UTF-8" language="java" %
html
head
title /title
/head
body
p 失败 /p
/body
/html
success.jsp 成功页面
%@ page contentType="text/html;charset=UTF-8" language="java" %
html
head
title My JSP success.jsp starting page /title
/head
body
${xiaoxi} br
a href="showall.jsp" 查看所有用户 /a
/body
/html
完成以上工作就可以 运行 Tomcat服务,然后运行啦
本博文参考大佬http://blog.csdn.net/qq_23994787/article/details/73612870
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