【JSP基础】JSP实现登录注册界面
初学者，很多迷惑，把自己写的东西记录下来，希望帮到各位以外，也希望自己有迷惑的时候再回来看一看，解除迷惑。
首先是JAVAbeen：
public class User {
protected int username;
protected String password;
protected String code;
public int getUsername() {
return username;
}
public void setUsername(int username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getCode() {
return code;
}
public void setCode(String tell) {
this.code = code;
}
之后，我们需要建立一个与之对应的数据库表，这里用的是mysql数据库， 
所以我们要在WEB-INT/lib路径下导入与数据库连接的jre包,这里用的是：
做好准备工作之后，就开始我们的工程了。
写一个与数据库连接的class。
public class DBOperator {
protected final static String driver = "com.mysql.jdbc.Driver";
protected final static String url = "jdbc:mysql://localhost:3306/当前所要使用的数据库名";
static {
try {
Class.forName(driver);
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
}
public static Connection getconnection( ){
Connection conn = null;
try {
conn= (Connection) DriverManager.getConnection(url,"root","root");//只是mysql进入的用户名和密码。
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
return conn;
}
public static void close (Statement st, ResultSet rs, Connection conn ){
try {
if(st!=null){
st.close();
}
if (rs!=null){
rs.close();
}
if(conn!=null){
conn.close();
}
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
}
public static void close(PreparedStatement pst, Connection conn){
try {
if(pst!=null){
pst.close();
}
if(conn!=null){
conn.close();
}
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
}
}接着，需要建立我们完成登录所用的两个方法，首先写一个接口，这样会让代码更规范，执行效率更高。
public interface UserManager {
public boolean add( User u);
public boolean addm( int username ,String password);
}
然后就是实现这个接口的类：（登录和注册需要的两个方法）
public class UserManagerImpl implements UserManager{
@Override
public boolean add(User u) {
// TODO Auto-generated method stub
boolean flag = false;
Connection conn = null;
PreparedStatement pst = null;
try {
conn = DBOperator.getconnection();
String sql = "insert into t_users (username,password,code) value(?,?,?)";
pst = (PreparedStatement) conn.prepareStatement(sql);
pst.setInt(1, u.getUsername());
pst.setString(2, u.getPassword());
pst.setString(3, u.getCode());
int rows = pst.executeUpdate();
if(rows>0){
flag= true;
}
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}finally{
DBOperator.close(pst, conn);
}
return flag;
}
@Override
public boolean addm(int username, String password) {
// TODO Auto-generated method stub
boolean flag = false;
Connection conn = null;
Statement st = null;
ResultSet rs = null;
try {
conn = DBOperator.getconnection();
String sql = "select * from t_users where username="+username;
st = (Statement) conn.createStatement();
rs = (ResultSet) st.executeQuery(sql);
while(rs.next()){
if (rs.getString("password").equals(password)){
flag = true;
}
}
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}finally{
DBOperator.close(st, rs, conn);
}
return flag;
}
}
完成之后开始写登录的jsp网页：登录这里用到了关于验证码的东西，验证码先不解释，最后解释。
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
My JSP 'index.jsp' starting page
建立jsp后，需要建立一个servlet去接收form表单传来的数据。
public class addm extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request, response);
}
/**
* The doPost method of the servlet.
*
* This method is called when a form has its tag value method equals to post.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
int un = Integer.parseInt(request.getParameter("Username"));
String pswd = request.getParameter("Password");
String checkcode = request.getParameter("Checkcode");
String pickcode = (String) request.getSession().getAttribute("piccode");
UserManager um = new UserManagerImpl();
User u = new User();
boolean flag= false;
try {
flag = um.addm(un, pswd);
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
if(flag&&checkcode.equals(pickcode)){
response.sendRedirect("logchegngong.jsp");
}
}
}
通过post方法接收来自网页的消息。这里post方法与get方法是有区别的，get方法常用语小于2k内容的信息传递。
然后建立注册的jsp：
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
My JSP 'zhuce.jsp' starting page
注册新用户
返回
与登陆一致，需要建立相应的servlet去接收消息，：
public class add extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
int username = Integer.parseInt(request.getParameter("Username"));
String pswd = request.getParameter("Password");
String code = request.getParameter("Code");
UserManager um =new UserManagerImpl();
User u = new User();
u.setUsername(username);
u.setPassword(pswd);
u.setCode(code);
boolean flag= false;
try {
flag = um.add(u);
if(flag==true){
response.sendRedirect("index.jsp");
}
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
}这样登录和注册页面就可以完成了。这里再说一下关于验证码的问题。
验证码用于恶意登录。
刚刚在登录页面我们已经写了它的界面，这里需要建立一个相应的servlet他就可以正常运行了。
public class ImagerServelt extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//1、BufferedImage图像数据缓冲区
BufferedImage bi = new BufferedImage(70, 40, BufferedImage.TYPE_INT_RGB);
//2、Graphics绘制图片
Graphics g = bi.getGraphics();
//3、Color获取颜色
Color c = new Color(80,10,50);
g.setColor(c);
g.fillRect(0, 0, 70, 40);
char ch[] = "ABCDEFGHIJK123456789".toCharArray();
StringBuffer sb = new StringBuffer();
//4、Random生成随机数
Random r = new Random();
for (int i = 0; i < 4; i++) {
int index = r.nextInt(ch.length);
g.setColor(new Color(r.nextInt(255),r.nextInt(255),r.nextInt(255)));
g.drawString(ch[index]+"", i*15+3, 20);
sb.append(ch[index]);
}
request.getSession().setAttribute("piccode", sb.toString());
ImageIO.write(bi, "JGP", response.getOutputStream());
}
}最后把工程截图发上来。