瀛︾敓淇℃伅绠＄悊绯荤粺鐧诲綍鐣岄潰(瀛︾敓宸ヤ綔绠＄悊绯荤粺鐧诲綍)

主要操作登陆，增删查改

public class Student {
    private int id;
    private String sId;//学号
    private String name;
    private String password;
    private int classId;//班级号
    private String sex;
    private String mobile;
    private String qq;
    private InputStream photo;//头像
    //get set
}

介于业务逻辑层和数据库之间，进行数据的访问和操作。

DbUtil(下面dao需要用到)

private String dbUrl= "jdbc:mysql://localhost:3306/student_manager?useUnicode=true&characterEncoding=utf8";
    private String jdbcName="com.mysql.jdbc.Driver";
    private String dbUser="用户名";
    private String dbPassword="密码";
    private Connection connection = null;
    public Connection getConnection() {
        try {
            Class.forName(jdbcName);
            connection=DriverManager.getConnection(dbUrl, dbUser, dbPassword);
            System.out.println("数据库连接成功!!");
        } catch(Exception e) {
            System.out.println("数据库连接失败！！！");
            e.printStackTrace();//在命令行打印异常信息在程序中出错的位置及原因。
        }
        return connection;
    }
    public void closeCon() {
        if(connection !=null) {
            try {
                connection.close();
                System.out.println("数据库连接已经关闭!!!");
            }catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        
    }
    
    public static void main(String[] args) {
        DbUtil dbUtil = new DbUtil();
        dbUtil.getConnection();
    }

package com.util;
​
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.util.Random;
​

public class CpachaUtil {
    
    
    final private char[] code = {
        '2', '3', '4', '5', '6', '7', '8', '9',
        'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j',
        'k', 'm', 'n', 'p', 'q', 'r', 's', 't', 'u', 'v', 
        'w', 'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F',
        'G', 'H', 'J', 'K', 'L', 'M', 'N', 'P', 'Q', 'R',
        'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'
    };
    
    final private String[] fontNames = new String[]{
            "黑体", "宋体", "Courier", "Arial", 
            "Verdana", "Times", "Tahoma", "Georgia"};
    
    final private int[] fontStyles = new int[]{
            Font.BOLD, Font.ITALIC|Font.BOLD
    };
    
    
    private int vcodeLen = 4;
    
    private int fontsize = 21;
    
    private int width = (fontsize+1)*vcodeLen+10;
    
    private int height = fontsize+12;
    
    private int disturbline = 3;
    
    
    public CpachaUtil(){}
    
    
    public CpachaUtil(int vcodeLen) {
        this.vcodeLen = vcodeLen;
        this.width = (fontsize+1)*vcodeLen+10;
    }
    
    
    public BufferedImage generatorVCodeImage(String vcode, boolean drawline){
        //创建验证码图片
        BufferedImage vcodeImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        Graphics g = vcodeImage.getGraphics();
        //填充背景色
        g.setColor(new Color(246, 240, 250));
        g.fillRect(0, 0, width, height);
        if(drawline){
            drawDisturbLine(g);
        }
        //用于生成伪随机数
        Random ran = new Random();
        //在图片上画验证码
        for(int i = 0;i < vcode.length();i++){
            //设置字体
            g.setFont(new Font(fontNames[ran.nextInt(fontNames.length)], fontStyles[ran.nextInt(fontStyles.length)], fontsize));
            //随机生成颜色
            g.setColor(getRandomColor());
            //画验证码
            g.drawString(vcode.charAt(i)+"", i*fontsize+10, fontsize+5);
        }
        //释放此图形的上下文以及它使用的所有系统资源
        g.dispose();
        
        return vcodeImage;
    }
    
    public BufferedImage generatorRotateVCodeImage(String vcode, boolean drawline){
        //创建验证码图片
        BufferedImage rotateVcodeImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        Graphics2D g2d = rotateVcodeImage.createGraphics();
        //填充背景色
        g2d.setColor(new Color(246, 240, 250));
        g2d.fillRect(0, 0, width, height);
        if(drawline){
            drawDisturbLine(g2d);
        }
        //在图片上画验证码
        for(int i = 0;i < vcode.length();i++){
            BufferedImage rotateImage = getRotateImage(vcode.charAt(i));
            g2d.drawImage(rotateImage, null, (int) (this.height * 0.7) * i, 0);
        }
        g2d.dispose();
        return rotateVcodeImage;
    }
    
    public String generatorVCode(){
        int len = code.length;
        Random ran = new Random();
        StringBuffer sb = new StringBuffer();
        for(int i = 0;i < vcodeLen;i++){
            int index = ran.nextInt(len);
            sb.append(code[index]);
        }
        return sb.toString();
    }
    
    private void drawDisturbLine(Graphics g){
        Random ran = new Random();
        for(int i = 0;i < disturbline;i++){
            int x1 = ran.nextInt(width);
            int y1 = ran.nextInt(height);
            int x2 = ran.nextInt(width);
            int y2 = ran.nextInt(height);
            g.setColor(getRandomColor());
            //画干扰线
            g.drawLine(x1, y1, x2, y2);
        }
    }
    
    private BufferedImage getRotateImage(char c){
        BufferedImage rotateImage = new BufferedImage(height, height, BufferedImage.TYPE_INT_ARGB);
        Graphics2D g2d = rotateImage.createGraphics();
        //设置透明度为0
        g2d.setColor(new Color(255, 255, 255, 0));
        g2d.fillRect(0, 0, height, height);
        Random ran = new Random();
        g2d.setFont(new Font(fontNames[ran.nextInt(fontNames.length)], fontStyles[ran.nextInt(fontStyles.length)], fontsize));
        g2d.setColor(getRandomColor());
        double theta = getTheta();
        //旋转图片
        g2d.rotate(theta, height/2, height/2);
        g2d.drawString(Character.toString(c), (height-fontsize)/2, fontsize+5);
        g2d.dispose();
        
        return rotateImage;
    }
    
    private Color getRandomColor(){
        Random ran = new Random();
        return new Color(ran.nextInt(220), ran.nextInt(220), ran.nextInt(220)); 
    }
    
    private double getTheta(){
        return ((int) (Math.random()*1000) % 2 == 0 ? -1 : 1)*Math.random();
    }
​
    
    public int getVcodeLen() {
        return vcodeLen;
    }
    
    public void setVcodeLen(int vcodeLen) {
        this.width = (fontsize+3)*vcodeLen+10;
        this.vcodeLen = vcodeLen;
    }
    
    public int getFontsize() {
        return fontsize;
    }
    
    public void setFontsize(int fontsize) {
        this.width = (fontsize+3)*vcodeLen+10;
        this.height = fontsize+15;
        this.fontsize = fontsize;
    }
    
    public int getWidth() {
        return width;
    }
    
    public void setWidth(int width) {
        this.width = width;
    }
    
    public int getHeight() {
        return height;
    }
    
    public void setHeight(int height) {
        this.height = height;
    }
    
    public int getDisturbline() {
        return disturbline;
    }
    
    public void setDisturbline(int disturbline) {
        this.disturbline = disturbline;
    }
    
}

package com.dao;
​
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
​
import com.util.DbUtil;

public class baseDao {
    private DbUtil dbUtil = new DbUtil();
    
    
    public void closeCon() {
        dbUtil.closeCon();//DbUtil里面已经写好方法了
    }
    
    //java.sql.ResultSet接口表示一个数据库查询的结果集
    public ResultSet query(String sql) {
        
        try {
            //Statement是将完整的需要执行的SQL语句通过执行平台传输过去
            PreparedStatement prepareStatement =dbUtil.getConnection().prepareStatement(sql);
            return prepareStatement.executeQuery();//executeQuery方法被用来执行 SELECt 语句
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();//输出错误信息
        }
        
        return null;
    }
    
    public boolean update(String sql) {
        try {
            return dbUtil.getConnection().prepareStatement(sql).executeUpdate() > 0;
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return false;
    }
    
    
    public Connection getConnection(){
        return dbUtil.getConnection();
    }
}

package com.dao;
​
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
​
import com.entity.Student;
import com.entity.Page;
import com.util.StringUtil;
​
​
//这里要继承我们之前写基础类
public class StudentDao extends baseDao {
    
    public boolean addStudent(Student student) {
        String sql="insert into student values(null,'"+student.getsId()+"','"+student.getName()+"'";
        sql += ",'" + student.getPassword() + "'," + student.getClassId();
        sql += ",'" + student.getSex() + "','" + student.getMobile() + "'";
        sql += ",'" + student.getQq() + "',null)";
        return update(sql);
    }
    
    
    public boolean deleteStudent(String id) {
        String sql="delete form student where id in("+id+")";
        return update(sql);
    }
    
    public boolean editPassword(Student student,String newPassword) {
        String sql = "update student set password = '"+newPassword+"' where id = " + student.getId();
        return update(sql);
    }
    
    public boolean setStudentPhoto(Student student) {
        String sql = "update student set photo = ? where id = ?";
        Connection connection = getConnection();
        try {
            PreparedStatement prepareStatement = connection.prepareStatement(sql);
            prepareStatement.setBinaryStream(1, student.getPhoto());
            prepareStatement.setInt(2, student.getId());
            return prepareStatement.executeUpdate() > 0;
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return update(sql);
    }
    
    public Student getStudent(int id){
        String sql = "select * from student where id = " + id;
        Student student = null;
        ResultSet resultSet = query(sql);
        try {
            if(resultSet.next()){
                student = new Student();
                student.setId(resultSet.getInt("id"));
                student.setClassId(resultSet.getInt("class_id"));
                student.setMobile(resultSet.getString("mobile"));
                student.setName(resultSet.getString("name"));
                student.setPassword(resultSet.getString("password"));
                student.setPhoto(resultSet.getBinaryStream("photo"));
                student.setQq(resultSet.getString("qq"));
                student.setSex(resultSet.getString("sex"));
                student.setsId(resultSet.getString("sid"));
                return student;
            }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return student;
    }
    
    public List getStudentList(Student student,Page page){
        List ret = new ArrayList();
        String sql = "select * from student ";
        if(!StringUtil.isEmpty(student.getName())){
            sql += "and name like '%" + student.getName() + "%'";
        }
        if(student.getClassId() != 0){
            sql += " and class_id = " + student.getClassId();
        }
        if(student.getId() != 0){
            sql += " and id = " + student.getId();
        }
        sql += " limit " + page.getStart() + "," + page.getPageSize();
        ResultSet resultSet = query(sql.replaceFirst("and", "where"));
        try {
            while(resultSet.next()){
                Student s = new Student();
                s.setId(resultSet.getInt("id"));
                s.setClassId(resultSet.getInt("class_id"));
                s.setMobile(resultSet.getString("mobile"));
                s.setName(resultSet.getString("name"));
                s.setPassword(resultSet.getString("password"));
                s.setPhoto(resultSet.getBinaryStream("photo"));
                s.setQq(resultSet.getString("qq"));
                s.setSex(resultSet.getString("sex"));
                s.setsId(resultSet.getString("sid"));
                ret.add(s);
            }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return ret;
    }
    
    public int getStudentListTotal(Student student){
        int total = 0;
        String sql = "select count(*)as total from student ";
        if(!StringUtil.isEmpty(student.getName())){
            sql += "and name like '%" + student.getName() + "%'";
        }
        if(student.getClassId() != 0){
            sql += " and class_id = " + student.getClassId();
        }
        if(student.getId() != 0){
            sql += " and id = " + student.getId();
        }
        ResultSet resultSet = query(sql.replaceFirst("and", "where"));
        try {
            while(resultSet.next()){
                total = resultSet.getInt("total");
            }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return total;
    }
    
    public Student login(String name ,String password){
        String sql = "select * from student where name = '" + name + "' and password = '" + password + "'";
        ResultSet resultSet = query(sql);
        try {
            if(resultSet.next()){
                Student student = new Student();
                student.setId(resultSet.getInt("id"));
                student.setName(resultSet.getString("name"));
                student.setPassword(resultSet.getString("password"));
                student.setClassId(resultSet.getInt("class_id"));
                student.setMobile(resultSet.getString("mobile"));
                student.setPhoto(resultSet.getBinaryStream("photo"));
                student.setQq(resultSet.getString("qq"));
                student.setSex(resultSet.getString("sex"));
                student.setsId(resultSet.getString("sid"));
                return student;
            }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return null;
    }
}

LoginServlet

package com.servlet;
​
import java.io.IOException;
​
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
​
import com.dao.StudentDao;
import com.entity.Student;
import com.util.StringUtil;
​

public class LoginServlet extends HttpServlet {
    private static final long serialVersionUID = -5870852067427524781L;
    
    
    public void doGet(HttpServletRequest request,HttpServletResponse response)throws IOException{
        doPost(request, response);
    }
    
    public void doPost(HttpServletRequest request,HttpServletResponse response) throws IOException{
        String mehod=request.getParameter("method");//选择的角色
        if("logout".equals(mehod)) {
            logout(request,response);
            return;
        }
        
        String vcode=request.getParameter("vcode");//验证码
        String name=request.getParameter("account");//账户
        String password=request.getParameter("password");
        int type=Integer.parseInt(request.getParameter("type"));//账户类型 整型数据Integer转换为基本数据类型int
        String loginCache=request.getSession().getAttribute("loginCache").toString();//Session缓存
        //判断验证码为空
        if(StringUtil.isEmpty(vcode)) {
            response.getWriter().write("vcodeError");
            return;
        }
        //判断验证码大写的是否相等
        if(!vcode.toUpperCase().equals(loginCache.toUpperCase())){
            response.getWriter().write("vcodeError");
            return;
        }
        //验证码通过，判断用户名密码
        String loginStatus="loginFaild";//登陆状态(用户类型)
        switch(type) {
        //这里还有 1 2是管理员和老师后面再写
        case 2:{
            StudentDao studentDao=new StudentDao();
            Student student=studentDao.login(name, password);
            studentDao.closeCon();//关闭数据库连接释放资源
            if(student == null) {
                response.getWriter().write("loginError");
                return;
            }
            HttpSession session=request.getSession();
            session.setAttribute("user",student);
            session.setAttribute("userType", type);
            loginStatus="loginSuccess";
            break;
        }
        default:
            break;
        }
        response.getWriter().write(loginStatus);    
        }
    
    
    private void logout(HttpServletRequest request,HttpServletResponse response) throws IOException{
        request.getSession().removeAttribute("user");
        request.getSession().removeAttribute("userType");
        response.sendRedirect("index.jsp");//返回到主界面也就是登陆界面
        }
}

package com.servlet;
​
import java.awt.image.BufferedImage;
import java.io.IOException;
​
import javax.imageio.ImageIO;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
​
import com.util.CpachaUtil;

public class CpachaServlet extends HttpServlet {
​
    
    private static final long serialVersionUID = 4919529414762301338L;
    public void doGet(HttpServletRequest request,HttpServletResponse reponse) throws IOException{
        doPost(request, reponse);
    }
    public void doPost(HttpServletRequest request,HttpServletResponse reponse) throws IOException{
        String method = request.getParameter("method");
        if("loginCapcha".equals(method)){
            generateLoginCpacha(request, reponse);
            return;
        }
        reponse.getWriter().write("error method");
    }
    private void generateLoginCpacha(HttpServletRequest request,HttpServletResponse reponse) throws IOException{
        CpachaUtil cpachaUtil = new CpachaUtil();
        String generatorVCode = cpachaUtil.generatorVCode();
        request.getSession().setAttribute("loginCapcha", generatorVCode);
        BufferedImage generatorRotateVCodeImage = cpachaUtil.generatorRotateVCodeImage(generatorVCode, true);
        ImageIO.write(generatorRotateVCodeImage, "gif", reponse.getOutputStream());
    }
}

package com.servlet;
​
import java.io.IOException;
​
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
​
​
import com.dao.StudentDao;
import com.entity.Student;
 
//记着要写继承类 不然报错 java.lang.ClassCastException: com.servlet.SystemServlet cannot be cast to javax.servlet.Servlet
public class SystemServlet extends HttpServlet {
private static final long serialVersionUID = -7258264317769166483L;
    
    public void doGet(HttpServletRequest request,HttpServletResponse response) throws IOException{
        doPost(request, response);
    }
    public void doPost(HttpServletRequest request,HttpServletResponse response) throws IOException{
        String method = request.getParameter("method");
        if("toPersonalView".equals(method)){
            personalView(request,response);
            return;
        }else if("EditPasswod".equals(method)){
            editPassword(request,response);
            return;
        }
        try {
            request.getRequestDispatcher("view/system.jsp").forward(request, response);
        } catch (ServletException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

    
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