HttpServlet练习查

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HttpServlet练习查代码

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package com.xiaoguan.oa.index;

import com.xiaoguan.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 DeptListServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String contextPath=request.getContextPath();
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out=response.getWriter();
        out.print("<!DOCTYPE html>");
        out.print("<html lang='ch'>");
        out.print("  <head>");
        out.print("      <meta charset='UTF-8'>");
        out.print("      <title>部门列表</title>");
        out.print("  </head>");
        out.print("  <body>");
        out.print("       <h1 align='center'>部门列表</h1>");
        out.print("       <hr>");
        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>");
        Connection conn=null;
        PreparedStatement ps=null;
        ResultSet rs=null;
        try {
            conn=DBUtil.getConnection();
            String sql="select deptno,dname,loc from dept ";
            ps=conn.prepareStatement(sql);
            rs=ps.executeQuery();
            int i=0;
            while (rs.next()){
                int deptno=rs.getInt("deptno");
                String dname=rs.getString("dname");
                String loc=rs.getString("loc");
                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=''>删除</a>");
                out.print("                    <a href='edit.html'>修改</a>");
                out.print("                    <a href='"+contextPath+"/detail?deptno="+deptno+"'>详情</a>");
                out.print("                </td>");
                out.print("            </tr>");
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }finally {
            DBUtil.close(conn,ps,rs);
        }
        out.print("        </table>");
        out.print("        <hr>");
        out.print("        <a href='add.html'>新增部门</a><br>");
        out.print("  </body>");
        out.print("</html>");
    }
}

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package com.xiaoguan.oa.index;

import com.xiaoguan.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 DetailServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("text/html;charset=UTF-8");
        PrintWriter out=resp.getWriter();
        String deptno = req.getParameter("deptno");
        Connection conn=null;
        PreparedStatement ps=null;
        ResultSet rs=null;
        out.print("<!DOCTYPE html>");
        out.print("<html lang='ch'>");
        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>");


        try {
            conn= DBUtil.getConnection();
            String sql="select deptno,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' value='"+deptno+"' readonly/><br>");
                out.print("        部门名称<input type='text' value='"+dname+"' readonly/><br>");
                out.print("        部门位置<input type='text' value='"+loc+"' readonly/><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>");
    }
}

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package com.xiaoguan.oa.utils;


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

public class DBUtil {
    private static ResourceBundle bundle=ResourceBundle.getBundle("resources.jdbc");
    private static String driver=bundle.getString("driver");
    private static String url=bundle.getString("url");
    private static String username=bundle.getString("username");
    private static String password=bundle.getString("password");
    static {
        try {
            Class.forName(driver);
        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        }
    }
    public static Connection getConnection() throws SQLException {
        return DriverManager.getConnection(url,username,password);
    }
    public static void close(Connection conn, Statement ps,ResultSet rs){
        if (rs != null) {
            try {
                rs.close();
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }
        }
        if(ps!=null){
            try {
                ps.close();
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }
        }
        if (conn != null) {
            try {
                conn.close();
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }
        }
    }
}