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   -> 大数据 -> 纯Servlet实现部门管理系统 -> 正文阅读

[大数据]纯Servlet实现部门管理系统

本次技术只由纯Serlet连接连接数据库进行用户的增删改查

首先创建一个DBUtil (JDBC的工具类，因为此次小项目连接数据库次数比较多)

import java.sql.*;
import java.util.ResourceBundle;

/**
 * JDBC的工具类
 */
public class DBUtil {

    //使用静态变量：类加载时执行
    //并且是有顺序的，自上而下的顺序
    private static ResourceBundle bundle = ResourceBundle.getBundle("resources.jdbc1");
    private static String driver = bundle.getString("driver");
    private static String url = bundle.getString("url");
    private static String user = bundle.getString("user");
    private static String password = bundle.getString("password");

    //注册驱动
    //调用一次JDBC工具类执行一次注册驱动即可，所以直接写到静态代码块中【类加载时执行】
    static {
        try {
            //如果"com.mysql.jdbc.Driver"是连接数据库驱动，不能写死，因为以后可能还会连接Oracle数据库。
            //如果连接Oracle数据库的时候，还需要修改代码，则违背OCP开闭原则
            //OCP开闭原则：对扩展开放，对修改关闭
            //Class.forName("com.mysql.jdbc.Driver");
            Class.forName(driver);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }

    //获取连接
    //返回值为Connection,且为静态方法，工具类最好都用静态方法
    public static Connection getConnection() throws SQLException {
        Connection conn = DriverManager.getConnection(url,user,password);
        return conn;
    }
    //获取数据库操作对象和执行sql语句以及处理结果集都是一行代码，不需要封装

    //释放资源
    public static void close(Connection conn, Statement ps, ResultSet rs){
        if (rs != null) {
            try {
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if (ps != null) {
            try {
                ps.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if (conn != null) {
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}

其次创建几个静态页面

<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<title>欢迎使用OA系统</title>
</head>
<body>
<!--这里需要带项目名-->
<a href="/oa/dept/list">查看部门列表</a>
</body>
</html>
<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>新增部门</title>
	</head>
	<body>
		<h1>新增部门</h1>
		<hr >
		<form action="/oa/dept/save" method="post">
			部门编号<input type="text" name="deptno" /><br>
			部门名称<input type="text" name="dname" /><br>
			部门位置<input type="text" name="loc" /><br>
			<input type="submit" value="保存" /><br>
		</form>
	</body>
</html>
<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>修改部门</title>
	</head>
	<body>
		<h1>修改部门</h1>
		<hr >
		<form action="list.html" method="get">
			部门编号<input type="text" name="deptno" value="20" readonly/><br>
			部门名称<input type="text" name="dname" value="研发部"/><br>
			部门位置<input type="text" name="loc" value="北京"/><br>
			<input type="submit" value="修改" /><br>
		</form>
	</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>error</title>
</head>
<body>
<h1>操作失败，<a href="javascript:void(0)" onclick="window.history.back()">返回</a></h1>
</body>
</html>

然后将连接数据库需要的url、username、password等配置到properties文件中

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/bjpowernode
user=root
password=root

最后用几个类实现功能


import com.bjpowernode.oa.utils.DBUtil;
import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.*;

public class DeptListServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request,response);
    }

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        //获取根路径
        String contextPath = request.getContextPath();
        //输出到浏览器
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        //静态页面
        out.print("<!DOCTYPE html>");
        out.print("<html>");
        out.print("<head>");
        out.print("<meta charset='utf-8'>");
        out.print("<title>部门列表页面</title>");
        out.print("</head>");
        out.print("<body>");
        out.print("<h1 align='center'>部门列表</h1>");
        out.print("<hr /> <!--横线-->");
        out.print("<table border='1px' align='center' width='50%'>");
        out.print("<tr>");
        out.print("<th>序号</th>");
        out.print("<th>部门编号</th>");
        out.print("<th>部门名称</th>");
        out.print("<th>操作</th>");
        out.print("</tr>");


        //连接数据库
        Connection conn = null;
        PreparedStatement ps = null;
        ResultSet rs = null;

        try {
            //注册驱动【静态代码块中】、获取连接
            conn = DBUtil.getConnection();
            //获取数据库操作对象
            String sql = "select deptno,dname,loc from dept";
            ps = conn.prepareStatement(sql);
            //执行SQL
            rs = ps.executeQuery();
            //处理结果集
            int i = 0;
            while(rs.next()){
                i++;
                String deptno = rs.getString("deptno");
                String dname = rs.getString("dname");
                String loc = rs.getString("loc");
                //动态页面
                out.print("<tr>");
                out.print("<td>"+i+"</td>");
                out.print("<td>"+deptno+"</td>");
                out.print("<td>"+dname+"</td>");
                out.print("<td>");
                out.print("<a href='"+contextPath+"/dept/delete?deptno="+deptno+"'>删除</a>");
                out.print("<a href='"+contextPath+"/dept/modify?deptno="+deptno+"'>修改</a>");
                out.print("<a href='"+contextPath+"/dept/detail?abc="+deptno+"'>详情</a>");
                out.print("</td>");
                out.print("</tr>");
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(conn,ps,rs);
        }

        //静态界面
        out.print("</table>");
        out.print("<hr >");
        out.print("<a href='"+contextPath+"/add.html'>新增部门</a>");
        out.print("</body>");
        out.print("</html>");
    }
}

import com.bjpowernode.oa.utils.DBUtil;
import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class DeptSaveServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        //获取部门信息
        //注意乱码问题
        request.setCharacterEncoding("UTF-8");
        String deptno = request.getParameter("deptno");
        String dname = request.getParameter("dname");
        String loc = request.getParameter("loc");
        //连接数据库
        Connection conn =null;
        PreparedStatement ps = null;
        ResultSet rs = null;
        int count = 0;
        try {
            conn = DBUtil.getConnection();
            String sql = "insert into dept (deptno,dname,loc) values (?,?,?)";
            ps = conn.prepareStatement(sql);
            //给?传值
            ps.setString(1,deptno);
            ps.setString(2,dname);
            ps.setString(3,loc);

            count = ps.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(conn,ps,rs);
        }
        if(count == 1){
            //增加成功
            request.getRequestDispatcher("/dept/list").forward(request,response);
        }
        else{
            request.getRequestDispatcher("/error.html").forward(request,response);
        }
    }
}


import com.bjpowernode.oa.utils.DBUtil;
import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class DeptModifyServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        //获取根路径
        String contextPath = request.getContextPath();
        //获取部门信息
        String deptno = request.getParameter("deptno");
        //设置输出方式
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();

        out.print("<!DOCTYPE html>");
        out.print("<html>");
        out.print("	<head>");
        out.print("		<meta charset='utf-8'>");
        out.print("		<title>修改部门</title>");
        out.print("	</head>");
        out.print("	<body>");
        out.print("		<h1>修改部门</h1>");
        out.print("		<hr >");
        out.print("		<form action='"+contextPath+"/dept/realModify' method='post'>");



        //连接数据库
        Connection conn = null;
        PreparedStatement ps = null;
        ResultSet rs = null;
        try {
            conn = DBUtil.getConnection();
            String sql = "select dname,loc from dept where deptno=?";
            ps = conn.prepareStatement(sql);
            ps.setString(1,deptno);
            rs = ps.executeQuery();
            if (rs.next()){
                String dname = rs.getString("dname");
                String loc = rs.getString("loc");
                out.print(" 部门编号<input type='text' name='deptno' value='"+deptno+"' readonly/><br>");
                out.print(" 部门名称<input type='text' name='dname' value='"+dname+"'/><br>");
                out.print(" 部门位置<input type='text' name='loc' value='"+loc+"'/><br>");
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(conn,ps,rs);
        }
        out.print("			<input type='submit' value='修改' /><br>");
        out.print("		</form>");
        out.print("	</body>");
        out.print("</html>");
    }
}

import com.bjpowernode.oa.utils.DBUtil;
import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class DeptRealModifyServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        //防止乱码
        request.setCharacterEncoding("UTF-8");
        //获取部门信息
        String dname = request.getParameter("dname");
        String deptno = request.getParameter("deptno");
        String loc = request.getParameter("loc");
        //连接数据库
        Connection conn = null;
        PreparedStatement ps = null;
        ResultSet rs = null;
        int count = 0;
        try {
            conn = DBUtil.getConnection();
            String sql = "update dept set dname=?,loc=? where deptno=?";
            ps = conn.prepareStatement(sql);
            ps.setString(1,dname);
            ps.setString(2,loc);
            ps.setString(3,deptno);
            count = ps.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(conn,ps,rs);
        }
        if(count == 1){
            //修改成功
            //跳转页面
            request.getRequestDispatcher("/dept/list").forward(request,response);
        }

    }
}
import com.bjpowernode.oa.utils.DBUtil;
import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class DeptDeleteServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        //根据部门编号删除部门
        //获取部门编号
        String deptno = request.getParameter("deptno");
        //连接数据库删除部门
        Connection conn = null;
        PreparedStatement ps = null;
        ResultSet rs = null;
        int count = 0;
        try {
            conn = DBUtil.getConnection();
            //获取数据库操作对象
            String sql = "delete from dept where deptno=?";
            ps = conn.prepareStatement(sql);
            //给?传值
            ps.setString(1,deptno);
            count = ps.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(conn,ps,rs);
        }

        //判断是删除失败了还是删除成功了
        if (count == 1){
            //删除成功了！
            //仍然跳转到部门列表页面
            //部门列表页面的显示需要执行另一个Servlet。怎么办？转发
            request.getRequestDispatcher("/dept/list").forward(request,response);
        }else{
            request.getRequestDispatcher("/error.html").forward(request,response);
        }
    }
}

import com.bjpowernode.oa.utils.DBUtil;
import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class DeptDetailServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        //输出到浏览器
        response.setContentType("text/html");
        PrintWriter out = response.getWriter();

        out.print("<!DOCTYPE html>");
        out.print("<html>");
        out.print("<head>");
        out.print("<meta charset='utf-8'>");
        out.print("<title>部门详情</title>");
        out.print("</head>");
        out.print("<body>");
        out.print("<h1>部门详情</h1>");
        out.print("<hr > ");

        //获取请求里的deptno
        String deptno = request.getParameter("abc");
        //连接数据库
        Connection conn = null;
        PreparedStatement ps = null;
        ResultSet rs = null;

        try {
            conn = DBUtil.getConnection();
            //获取数据库操作对象
            String sql = "select dname,loc from dept where deptno=?";
            ps = conn.prepareStatement(sql);
            ps.setString(1,deptno);

            rs = ps.executeQuery();
            if(rs.next()){
                String dname = rs.getString("dname");
                String loc = rs.getString("loc");



                out.print("部门编号："+deptno+" <br> ");
                out.print("部门名称："+dname+"<br>");
                out.print("部门位置："+loc+"<br>");



            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(conn,ps,rs);
        }
        out.print("<input type='button' value='后退' onclick='window.history.back()'/>");
        out.print("</body>");
        out.print("</html>");
    }
}

记得配置web.xml文件

<?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">
    <!--部门列表页面-->
    <servlet>
        <servlet-name>list</servlet-name>
        <servlet-class>com.bjpowernode.oa.web.action.DeptListServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>list</servlet-name>
        <!--这里不带项目名-->
        <url-pattern>/dept/list</url-pattern>
    </servlet-mapping>

    <!--部门详情-->
    <servlet>
        <servlet-name>detail</servlet-name>
        <servlet-class>com.bjpowernode.oa.web.action.DeptDetailServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>detail</servlet-name>
        <!--这里不带项目名-->
        <url-pattern>/dept/detail</url-pattern>
    </servlet-mapping>

    <!--删除部门-->
    <servlet>
        <servlet-name>delete</servlet-name>
        <servlet-class>com.bjpowernode.oa.web.action.DeptDeleteServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>delete</servlet-name>
        <!--这里不带项目名-->
        <url-pattern>/dept/delete</url-pattern>
    </servlet-mapping>

    <!--保存部门-->
    <servlet>
        <servlet-name>save</servlet-name>
        <servlet-class>com.bjpowernode.oa.web.action.DeptSaveServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>save</servlet-name>
        <!--这里不带项目名-->
        <url-pattern>/dept/save</url-pattern>
    </servlet-mapping>

    <!--修改部门页面-->
    <servlet>
        <servlet-name>modify</servlet-name>
        <servlet-class>com.bjpowernode.oa.web.action.DeptModifyServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>modify</servlet-name>
        <!--这里不带项目名-->
        <url-pattern>/dept/modify</url-pattern>
    </servlet-mapping>


    <!--真正的修改部门操作-->
    <servlet>
        <servlet-name>realmodify</servlet-name>
        <servlet-class>com.bjpowernode.oa.web.action.DeptRealModifyServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>realmodify</servlet-name>
        <!--这里不带项目名-->
        <url-pattern>/dept/realModify</url-pattern>
    </servlet-mapping>

</web-app>
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