本文主要是介绍基于web的学生管理系统（二）java代码阶段，对大家解决编程问题具有一定的参考价值，需要的程序猿们随着小编来一起学习吧！

代码实现

（一）dao包下代码

        1、BaseDao

package com.offcn.dao;

import com.mchange.v2.c3p0.ComboPooledDataSource;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.dbutils.handlers.ScalarHandler;

import java.sql.SQLException;
import java.util.List;

public class BaseDao<T> {
    static ComboPooledDataSource ds = null;
    static QueryRunner qr = null;
    static{
        ds = new ComboPooledDataSource();//创建c3p0的连接池对象
        qr = new QueryRunner(ds);
    }
    //封装增删改方法
    public int update(String sql,Object...params){
        try {
            return qr.update(sql,params);
        } catch (SQLException e) {
            e.printStackTrace();
            throw new RuntimeException();
        }
    }
    //单行查询
    public  T queryOne(String sql,Class<T> clazz,Object... params){
        try {
            return qr.query(sql,new BeanHandler<>(clazz),params);
        } catch (SQLException e) {
            e.printStackTrace();
            throw new RuntimeException();
        }
    }
    //多行查询
    public List<T> queryMore(String sql, Class<T> clazz, Object...params){
        try {
            return qr.query(sql,new BeanListHandler<>(clazz),params);
        } catch (SQLException e) {
            e.printStackTrace();
            throw new RuntimeException();
        }
    }
    //聚合查询
    public Number queryScar(String sql,Object...params){
        try {
            return qr.query(sql,new ScalarHandler<Number>(),params);
        } catch (SQLException e) {
            e.printStackTrace();
            throw new RuntimeException();
        }
    }

}

        2、StudentDao

package com.offcn.dao;

import com.offcn.entity.Page;
import com.offcn.entity.Student;

import java.util.List;

public class StudentDao extends BaseDao<Student> {
    //删除学生信息
    public boolean delete(int id){
        String sql = "delete from stu where sid=?";
        return update(sql,id)>0 ? true : false;
    }

    //添加学生信息
    public boolean insert(Student s){
        String sql = "insert into stu(name,age,tel,bir,sex,spic)values(?,?,?,?,?,?)";
        Object[] param={s.getName(),s.getAge(),s.getTel(),s.getBir(),s.getSex(),s.getSpic()};
        return update(sql,param)>0 ? true : false;
    }

    //根据id查询学生信息
    public Student stuSinSer(int id){
        String sql = "select * from stu where sid=?";
        return queryOne(sql,Student.class,id);
    }

    //修改学生信息
    public boolean updateStu(Student s,int id){
        String sql = "update stu set name=?,age=?,tel=?,bir=?,sex=?,spic=?where sid=?";
        Object[] param={s.getName(),s.getAge(),s.getTel(),s.getBir(),s.getSex(),s.getSpic(),id};
        return update(sql,param)>0 ? true : false;
    }

    //模糊查询
    public List<Student> StuLike(String name,String sex,Page p){
        StringBuffer sql = new StringBuffer("select * from stu where 1=1");
        if(name!=null&&!"".equals(name)){
            sql.append(" and name like '%"+name+"%'");
        }
        if("0".equals(sex)||"1".equals(sex)){
            sql.append(" and sex="+sex);
        }
        sql.append(" limit ?,?");
        return queryMore(sql.toString(),Student.class,p.getStartIndex(),p.getPageSize());
    }

    public int LikeNum(String name,String sex){
        StringBuffer sql = new StringBuffer("select count(*) from stu where 1=1");
        if(name!=null&&!"".equals(name)){
            sql.append(" and name like '%"+name+"%'");
        }
        if("0".equals(sex)||"1".equals(sex)){
            sql.append(" and sex="+sex);
        }
        return queryScar(sql.toString()).intValue();
    }

}

        3、UserDao

package com.offcn.dao;

import com.offcn.entity.User;

public class UserDao extends BaseDao<User> {
    //根据用户名和密码查询用户信息
    public User login(String username,String password){
        String sql = "select * from user where username=? and pwd=?";
        return queryOne(sql,User.class,username,password);
    }
    //添加用户信息
    public Boolean register(User u){
        String sql = "insert into user(username,pwd,name,tel,bir) values(?,?,?,?,?)";
        Object[] param = {u.getUsername(),u.getPwd(),u.getName(),u.getTel(),u.getBir()};
        return update(sql,param)>0 ? true : false;
    }
}

（二）entity包下代码

        1.Student类

package com.offcn.entity;

import java.util.Date;

public class Student {
    private int sid;
    private String name;
    private int age;
    private String tel;
    private Date bir;
    private int sex;
    private String spic;

    public Student() {
    }

    public Student(String name, int age, String tel, Date bir, int sex, String spic) {

        this.name = name;
        this.age = age;
        this.tel = tel;
        this.bir = bir;
        this.sex = sex;
        this.spic = spic;
    }

    public String getSpic() {
        return spic;
    }

    public void setSpic(String spic) {
        this.spic = spic;
    }

    public int getSid() {
        return sid;
    }

    public void setSid(int sid) {
        this.sid = sid;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getTel() {
        return tel;
    }

    public void setTel(String tel) {
        this.tel = tel;
    }

    public Date getBir() {
        return bir;
    }

    public void setBir(Date bir) {
        this.bir = bir;
    }

    public int getSex() {
        return sex;
    }

    public void setSex(int sex) {
        this.sex = sex;
    }
}

        2、User类

package com.offcn.entity;

import java.util.Date;

public class User {
    private String username;
    private String pwd;
    private String name;
    private String tel;
    private Date bir;

    public User() {
    }

    public User(String username, String pwd, String name, String tel, Date bir) {
        this.username = username;
        this.pwd = pwd;
        this.name = name;
        this.tel = tel;
        this.bir = bir;
    }

    @Override
    public String toString() {
        return "User{" +
                "username='" + username + '\'' +
                ", pwd='" + pwd + '\'' +
                ", name='" + name + '\'' +
                ", tel='" + tel + '\'' +
                ", bir=" + bir +
                '}';
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPwd() {
        return pwd;
    }

    public void setPwd(String pwd) {
        this.pwd = pwd;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getTel() {
        return tel;
    }

    public void setTel(String tel) {
        this.tel = tel;
    }

    public Date getBir() {
        return bir;
    }

    public void setBir(Date bir) {
        this.bir = bir;
    }
}

        3、Page类

package com.offcn.entity;

public class Page {
    private int curPage;//当前页
    private int pageSize;//页容量
    private int nextPage;//下一页
    private int prevPage;//上一页
    private int rows;//总记录数
    private int endPage;//总页数
    private int startIndex;//每一页的起始行下标
    //总体初始化
    public Page(int rows,String curPage) {
        this.rows = rows;
        this.pageSize=5;
        initCurPage(curPage);
        initPrevPage();
        initEndPage();
        initNextPage();
        initStartIndex();

    }
    //属性初始化
    //初始化当前页
    public void initCurPage(String curPage){
        //当页面不传当前页，或当前页为空字符串默认首页
        if(curPage==null||"".equals(curPage)){
            this.curPage = 1;
        }else {
            this.curPage=Integer.valueOf(curPage);
        }
    }
    //初始化上一页
    public void initPrevPage(){
        if(curPage>1){
            prevPage=curPage-1;
        }else {
            prevPage=1;
        }
    }
    //初始化下一页
    public void initNextPage(){
        if(curPage<endPage){
            nextPage=curPage+1;
        }else {
            nextPage=endPage;
        }
    }
    //初始化总页数
    public void initEndPage(){
        if(rows%pageSize==0){
            endPage=rows/pageSize;
        }else {
            endPage=rows/pageSize+1;
        }
    }
    //初始化起始行
    public void initStartIndex(){
        startIndex=(curPage-1)*pageSize;
    }

    public int getCurPage() {
        return curPage;
    }

    public void setCurPage(int curPage) {
        this.curPage = curPage;
    }

    public int getPageSize() {
        return pageSize;
    }

    public void setPageSize(int pageSize) {
        this.pageSize = pageSize;
    }

    public int getNextPage() {
        return nextPage;
    }

    public void setNextPage(int nextPage) {
        this.nextPage = nextPage;
    }

    public int getPrevPage() {
        return prevPage;
    }

    public void setPrevPage(int prevPage) {
        this.prevPage = prevPage;
    }

    public int getRows() {
        return rows;
    }

    public void setRows(int rows) {
        this.rows = rows;
    }

    public int getEndPage() {
        return endPage;
    }

    public void setEndPage(int endPage) {
        this.endPage = endPage;
    }

    public int getStartIndex() {
        return startIndex;
    }

    public void setStartIndex(int startIndex) {
        this.startIndex = startIndex;
    }
}

（三）filter包下代码

        1、EncodeFilter类

package com.offcn.filter;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import java.io.IOException;
//Filter过滤器，解决乱码
@WebFilter("/*")
public class EncodeFilter implements Filter {
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        servletRequest.setCharacterEncoding("utf-8");
        servletResponse.setContentType("text/html;charset=utf-8");
        filterChain.doFilter(servletRequest,servletResponse);
    }
}

        2、LoginFilter类

package com.offcn.filter;

import com.offcn.entity.User;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;
//登录过滤器
@WebFilter("/*")
public class LoginFilter implements Filter {
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        //向下转型
        HttpServletRequest req = (HttpServletRequest)servletRequest;
        HttpServletResponse resp = (HttpServletResponse)servletResponse;
        //获取uri地址
        String uri = req.getRequestURI();
        //截取出需要的地址
        String uriPath = uri.substring(uri.lastIndexOf("/")+1);
        //判断，所有登录之前的操作直接放行，否则查看是否有用户信息，有就直接放行，没有就回到登录页面去登录
        if("register.jsp".equals(uriPath)||"register".equals(uriPath)||"hello".equals(uriPath)||"index.jsp".equals(uriPath)){
            filterChain.doFilter(req,resp);
        }else {
            HttpSession session = req.getSession();
            Object user = (User)session.getAttribute("user");
            if(user!=null){
                filterChain.doFilter(req,resp);
            }else{
                resp.sendRedirect("index.jsp");
            }
        }
    }
}

（四）login包下代码

        1、Login类

package com.offcn.login;

import com.offcn.dao.UserDao;
import com.offcn.entity.User;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.*;
import java.io.IOException;
@WebServlet("/hello")
public class Login extends HttpServlet{
    //实例化dao对象
    UserDao ud = new UserDao();
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //从网页上获取用户名和用户密码
        String username = req.getParameter("username");
        String password = req.getParameter("password");
        //获取记住密码的勾选状态
        String save = req.getParameter("save");
        //调用userdao的登录方法，用一个User对象接收
        User us = ud.login(username,password);
        //判断us是否有值，有值，则用户存在切密码正确，进行登录操作，没值则进入登录失败页面
        if(us != null){
            //如果记住密码勾选，则进行记住密码操作
            if("checkon".equals(save)){
                //创建Cookie对象，将用户输入的用户名和密码存入Cookie
                //实现记住密码功能
                Cookie c1 = new Cookie("username",us.getUsername());
                Cookie c2 = new Cookie("password",us.getPwd());
                //给Cookie设置过期时间
                c1.setMaxAge(60*60*24*7);
                c2.setMaxAge(60*60*24*7);
                //将Cookie响应到浏览器
                resp.addCookie(c1);
                resp.addCookie(c2);
            }
            //实现用户跟踪校验功能，没有登录没法进入其他页面
            //创建session，将us对象绑定到session
            HttpSession session = req.getSession();
            session.setAttribute("user",us);
            //登录之后转发到主页面
            req.getRequestDispatcher("student").forward(req,resp);
        }else {
            //登录失败进入登录失败页面
            resp.sendRedirect("login_fail.jsp");
        }
    }
}

        2、LoginOut类

package com.offcn.login;

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 javax.servlet.http.HttpSession;
import java.io.IOException;
@WebServlet("/logout")
public class LogOut extends HttpServlet {
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        HttpSession session = req.getSession();
        session.invalidate();
        resp.sendRedirect("index.jsp");
    }
}

        3、Register类

package com.offcn.login;

import com.offcn.dao.UserDao;
import com.offcn.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;
//注册
@WebServlet("/register")
public class Register extends HttpServlet {
    UserDao ud = new UserDao();
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //获取信息
        String username = req.getParameter("username");
        String pwd = req.getParameter("pwd");
        String name = req.getParameter("name");
        String tel = req.getParameter("tel");
        String bir = req.getParameter("bir");
        //存入数据库
        User u = new User(username,pwd,name,tel,DateUtil.dateformat(bir));
        boolean b = ud.register(u);
        if(b){
            resp.sendRedirect("index.jsp");
        }else {
            resp.sendRedirect("register.jsp");
        }

    }
}

        4、InsertServlet类

package com.offcn.login;

import com.offcn.dao.StudentDao;
import com.offcn.entity.Student;

import javax.servlet.ServletException;
import javax.servlet.annotation.MultipartConfig;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.Part;
import java.io.File;
import java.io.IOException;
import java.util.UUID;
//插入学生信息操作
@MultipartConfig
@WebServlet("/insert")
public class InsertServlet extends HttpServlet {
    //实例化StudentDao
    StudentDao sd = new StudentDao();
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //获取页面中输入的学生信息
        String name = req.getParameter("name");
        String age = req.getParameter("age");
        String tel = req.getParameter("tel");
        String bir = req.getParameter("bir");
        String sex = req.getParameter("sex");
        Part part = req.getPart("spic");
        //获取图片信息的名字
        String filename = part.getSubmittedFileName();
        //给图片重新命名
        filename = UUID.randomUUID()+filename;
        //图片的保存路径
        String path = "d:/pic";
        //实例化Student，并将获取的学生信息传入
        Student student = new Student(name,Integer.parseInt(age),tel,DateUtil.dateformat(bir),Integer.parseInt(sex),filename);
        //调用插入学生信息方法，将信息传入数据库
        boolean b = sd.insert(student);
        if(b){
            //如果插入成功，则创建文件夹存储图片，并跳转回主页面
            File f = new File(path);
            if(!f.exists()){
                f.mkdir();
            }
            part.write(path+File.separator+filename);
            resp.sendRedirect("student");
        }
    }
}

        5、DeleteServlet类

package com.offcn.login;

import com.offcn.dao.StudentDao;

import javax.servlet.ServletContext;
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;

//删除操作的servlet
@WebServlet("/delete")
public class deleteServlet extends HttpServlet {
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //获取要删除学生的id
        int id = Integer.parseInt(req.getParameter("id"));
        //实例化StudentDao
        StudentDao sd = new StudentDao();
        //调用删除学生信息方法
        boolean b = sd.delete(id);
        //删除之后跳转回主页面
        resp.sendRedirect("student");
    }
}

        6、StuServlet类

package com.offcn.login;

import com.offcn.dao.StudentDao;
import com.offcn.entity.Page;
import com.offcn.entity.Student;

import javax.servlet.ServletException;
import javax.servlet.annotation.MultipartConfig;
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;
@MultipartConfig
@WebServlet("/student")
public class StuServlet extends HttpServlet {
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String curPage = req.getParameter("curPage");
        String name = req.getParameter("name");
        String sex = req.getParameter("sex");
        StudentDao sd = new StudentDao();
        int rows = sd.LikeNum(name,sex);
        Page p = new Page(rows,curPage);
        List<Student> list = sd.StuLike(name,sex,p);
        req.setAttribute("list",list);
        req.setAttribute("p",p);
        req.setAttribute("name",name);
        req.setAttribute("sex",sex);
        req.getRequestDispatcher("stuservlet.jsp").forward(req,resp);
    }
}

        7、UpdateServlet类

package com.offcn.login;

import com.offcn.dao.StudentDao;
import com.offcn.entity.Student;

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.io.PrintWriter;

@WebServlet("/update")
public class UpdateServlet extends HttpServlet {
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String id = req.getParameter("id");
        StudentDao sd = new StudentDao();
        Student s1 = sd.stuSinSer(Integer.parseInt(id));
        req.setAttribute("s1",s1);
        req.getRequestDispatcher("/update.jsp").forward(req,resp);
    }
}

        8、Update2类

package com.offcn.login;

import com.offcn.dao.StudentDao;
import com.offcn.entity.Student;

import javax.servlet.ServletException;
import javax.servlet.annotation.MultipartConfig;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.Part;
import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.UUID;
@MultipartConfig
@WebServlet("/update2")
public class Update2 extends HttpServlet {
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        StudentDao sd = new StudentDao();
        String id = req.getParameter("id");
        String name = req.getParameter("name");
        String age = req.getParameter("age");
        String tel = req.getParameter("tel");
        String bir = req.getParameter("bir");
        String sex = req.getParameter("sex");
        String spic = req.getParameter("spic");
        Part part = req.getPart("newspic");
        String path = "d:/pic";
        String filename = part.getSubmittedFileName();
        String pic = spic;
        if(!"".equals(filename)){
            filename= UUID.randomUUID()+filename;
            pic = filename;
            part.write(path+File.separator+pic);
            File f = new File(path+File.separator+spic);
            f.delete();
        }

        Student s2 = new Student(name,Integer.parseInt(age),tel,DateUtil.dateformat(bir),Integer.parseInt(sex),pic);
        boolean b = sd.updateStu(s2,Integer.parseInt(id));
        if(b){
            resp.sendRedirect("student");
        }
    }
}

        9、DateUtils类

package com.offcn.login;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
//日期工具类
//做字符串转日期，日期转字符串的操作
public class DateUtil {
    //将字符串转为日期类型
    public static Date dateformat(String s){
        SimpleDateFormat sdf = new SimpleDateFormat("YY-MM-dd");
        try {
            return sdf.parse(s);
        } catch (ParseException e) {
            e.printStackTrace();
            throw new RuntimeException();
        }

    }
    //将日期类型转为字符串
    public static String format(Date d){
        SimpleDateFormat sdf = new SimpleDateFormat("YY-MM-dd");
        try {
            return sdf.format(d);
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException();
        }

    }

}

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