Web作业02
流程图
1.先获取需要解析的源文件
InputStream is=Resources.getResourceAsStream("mybatis-config.xml");执行流程
- 使用工具类的Rescources 源调用getResources(String resources)将配置文件加载进来
- Rescources 工具类的getResourceAsStream(classLoader loader,String resources)方法将源文件的加载进类构造器
- 在调用类加载器的过程中发现调用的是classLoaderWrapper中getResourceAsStream(String rescource,ClassLoader classLoader)里面的数组getResourceAsStream(String resource,ClassLoader[] classLoader)
- 数组中还有ClassLoaderWrappper中成员变量默认的类加载器，当前对象的类加载器以及系统类加载器，五个类加载器
- 最后通过对该数组进行判断，看类加载器中所读的流是否为null，如果不为null，则返回InputStream对象
2.获取SqlSessionFactory对象
SqlSessionFactory factory=new SqlSessionFactoryBuilder().build(is);
- 进入到build 传递reader有参数构造函数
- SqlSessionFactoryBuilder使用XMLConfigBuilder解析配置文件，封装成Configuration对象。
- configuration是全局的所以只能被解析一次
- 执行environmentsElement() 方法
- 解析的文件内容套接到configuration中 而这个configuration 相当于 mybatis-config.xml 中的配置文件所对应的类返回DefaultSqlSessionFactory对象
3.获取sqlsession对象
SqlSession session=factory.openSession();
- 先使用DefaultSqlSessionFactory对象的opensession方法返回DefaultSQLSession对象
- 然后调用openSessionFromDataSource(ExecutorType execType, TransactionIsolationLevel level, boolean autoCommit)方法
- 接下来声明事务对象，读取配置文件中的相关属性，通过envirnment对象去获得工厂对象
- 创建实体类执行器newExcutor()
- 返回 DefaultSqlSession对象。
4.获得classmapper对象
ClassMapper mapper=session.getMapper(ClassMapper.class);
- 先执行configuration的getMapper（Class
type,Sqlsession sqlSession）方法返回相关对象 - MapperRegistry中的getMapper(Class
type,Sqlsession sqlSession)方法返回 T泛型对象 - MapperProxy.newMapperProxy(type, sqlSession);这句是创建接口的代理的
- 通过mapperProxyFactory.newInstance(sqlSession)，进入MapperProxyFactory的newInstance方法中
- 找到MapperProxyFactory的newIntance方法，通过参数类型SqlSession可以得知，上面的调用先进入第二个newInstance方法中并创建我们所需要重点关注的MapperProxy对象，
mybaits实现分页
分页sql映射
pojo层抽象方法
public List findListBypage(); 测试程序
String resource = "Mybatis-config.xml";
InputStream is =Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
SqlSession session = sqlSessionFactory.openSession();
Map map = new HashMap();
map.put("index", 0);
map.put("size", 5);
List list = session.selectList("com.openlab.mapper.TB7Mapper.findListBypage", map);
System.out.println("姓名"+"---"+"年龄"+"---"+"薪水");
for(TB7 r:list){
System.out.println(r.getUsername()+"---"+r.getAge()+"---"+r.getSalary());
} 结果
在线人数
监听器配置
com.hand.pac1.SessionCounter
监听器类
package com.hand.pac1;
import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;
public class SessionCounter implements HttpSessionListener{
private static int activeSessions = 0;
@Override
public void sessionCreated(HttpSessionEvent arg0) {
// TODO Auto-generated method stub
activeSessions++;
}
@Override
public void sessionDestroyed(HttpSessionEvent arg0) {
// TODO Auto-generated method stub
if (activeSessions > 0)
activeSessions--;
}
public static int getActiveSessions() {
return activeSessions;
}
}
注册和登录功能的实现
数据库
登录功能的Servlet
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class login extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("GBK");
String username= request.getParameter("username") ;
String password= request.getParameter("password");
String checkcode= request.getParameter("checkcode");
String checkcode1=(String) request.getSession().getAttribute("chrr");
System.out.print(checkcode1);
try {
Class.forName("com.mysql.jdbc.Driver");
Connection con= DriverManager.getConnection("jdbc:mysql:///ks","root","123456");
Statement st=con.createStatement();
String sql="select * from zcuser where username='"+username+"'";
ResultSet rs=st.executeQuery(sql);
if(rs.next()){
System.out.println(rs.getString(3));
if(password.equals( rs.getString(3))){
if(checkcode.toLowerCase().equals(checkcode1.toLowerCase())){
request.getSession().setAttribute("username", username);
response.sendRedirect("index.jsp");
}
else {
response.getWriter().write("" );
response.setHeader("refresh","0;url=/index.jsp");
}
}
else {
response.getWriter().write("" );
response.setHeader("refresh","0;url=/index.jsp");
}
}
else {
response.getWriter().write("" );
response.setHeader("refresh","0;url=index.jsp");
}
}
catch (ClassNotFoundException e) {
e.printStackTrace();
}
catch (SQLException e) {
e.printStackTrace();
}
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request,response);
}
}
注册页面的Servlet
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import util.myutil;
public class zhuce extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
Connection con=null;
PreparedStatement st=null;
response.setCharacterEncoding("utf-8");
String username=myutil.getNewString(request.getParameter("username"));
String password =request.getParameter("password");
String email=request.getParameter("email");
String telephone =request.getParameter("telephone");
String gender=myutil.getNewString(request.getParameter("gender"));
try {
Class.forName("com.mysql.jdbc.Driver");
con = DriverManager.getConnection("jdbc:mysql://localhost:3306/ks","root","123456");
String sql="insert into zcuser values(?,?,?,?,?)";
st = con.prepareStatement(sql);
st.setString(1,email);
st.setString(2, username);
st.setString(3,password);
st.setString(4,gender);
st.setString(5,telephone);
st.executeUpdate();
}catch (ClassNotFoundException e) {
e.printStackTrace();
}
catch (SQLException e) {
e.printStackTrace();
}
System.out.println("插入成功。。。");
System.out.println(username);
response.sendRedirect("index.jsp");
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}验证码
package yzjs;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class checkcode extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//1.在内存中生成图片
int width=120;
int height=30;
BufferedImage img=new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
//2.获取画笔
Graphics2D g=(Graphics2D) img.getGraphics();
//设置颜色
g.setColor(Color.yellow);
g.fillRect(0, 0, width, height);
//画边框
g.setColor(Color.blue);
g.drawRect(0, 0, width-1, height-1);
//3.随机生成验证码的字母和数字
String words="ABCDEFGHIJKLMNOPQRSTUVWZXYZ123";
//设置字体
g.setFont(new Font("隶书",Font.BOLD,20));
Random random=new Random();
int x=20,y=20;
//Graphics2D
/*
* abstract void rotate(double theta,double x,double y)
* 将当前的Graphics2D Transfrom 于平移后的旋转转换连接
* theta:hudu
* hudu:jiaodu*math.PI/100
* */
//创建 randomCode 对象, 用于保存随机产生的验证码, 以便用户登录后进行验证
StringBuffer randomCode;
randomCode = new StringBuffer();
for(int i=0;i<4;i++){
int jiaodu=random.nextInt(60)-30;
double hudu=jiaodu*Math.PI/180;
g.rotate(hudu,x,y);
int index=random.nextInt(words.length());//随即下标
char chr=words.charAt(index);
g.drawString(""+chr, x, y);
g.rotate(-hudu,x,y);
x+=20;
randomCode.append(chr);
System.out.println("........"+chr);
}
String st=randomCode.toString();
request.getSession().setAttribute("chrr", st);
System.out.println(st);
//5。画4条干扰线
g.setColor(Color.green);
int x1,y1,x2,y2;
for(int i=0;i<4;i++){
x1=random.nextInt(width);
y1=random.nextInt(height);
x2=random.nextInt(width);
y2=random.nextInt(height);
g.drawLine(x1, y1, x2, y2);
}
//6.把内存中的图片输入到客户端
ImageIO.write(img, "jpg", response.getOutputStream());
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request,response);
}
}
结果：
