HttpServlet练习增删改及相关html页面

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HttpServlet练习增删改

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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.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;

public class ModifyServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest requst, HttpServletResponse response) throws ServletException, IOException {
        requst.setCharacterEncoding("UTF-8");
        String deptno = requst.getParameter("deptno");
        String dname = requst.getParameter("dname");
        String loc = requst.getParameter("loc");
        Connection conn=null;
        PreparedStatement ps=null;
        int count=0;
        try {
            conn= DBUtil.getConnection();
            String sql="update dept set dname=?,loc=? where deptno=?";
            ps=conn.prepareStatement(sql);
            ps.setString(3,deptno);
            ps.setString(1,dname);
            ps.setString(2,loc);
            count=ps.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        }finally {
            DBUtil.close(conn,ps,null);
        }
        if(count==1){
            response.sendRedirect(requst.getContextPath()+"/list");
        }else{
            response.sendRedirect(requst.getContextPath()+"/error.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.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;

public class SaveServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest requst, HttpServletResponse response) throws ServletException, IOException {
        requst.setCharacterEncoding("UTF-8");
        String deptno = requst.getParameter("deptno");
        String dname = requst.getParameter("dname");
        String loc = requst.getParameter("loc");
        Connection conn=null;
        PreparedStatement ps=null;
        int count=0;
        try {
            conn= DBUtil.getConnection();
            String sql="insert into dept(deptno,dname,loc) values(?,?,?)";
            ps=conn.prepareStatement(sql);
            ps.setString(1,deptno);
            ps.setString(2,dname);
            ps.setString(3,loc);
            count=ps.executeUpdate();
            System.out.println(count);
        } catch (SQLException e) {
            e.printStackTrace();
        }finally {
            DBUtil.close(conn,ps,null);
        }
        if(count==1){
            response.sendRedirect(requst.getContextPath()+"/list");
        }else{
            response.sendRedirect(requst.getContextPath()+"/error.html");
        }
    }
}

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package com.xiaoguan.oa.index;

import com.xiaoguan.oa.utils.DBUtil;
import jakarta.servlet.RequestDispatcher;
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.*;

public class DeleteServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String deptno = request.getParameter("deptno");
        Connection conn = null;
        PreparedStatement ps = null;
        ResultSet rs = null;
        int count = 0;
        try {
            conn = DBUtil.getConnection();
            conn.setAutoCommit(false);
            String sql = "delete from dept where deptno=?";
            ps = conn.prepareStatement(sql);
            ps.setString(1, deptno);
            count = ps.executeUpdate();
            conn.commit();
        } catch (SQLException e) {
            if (conn != null) {
                try {
                    conn.rollback();
                } catch (SQLException ex) {
                    ex.printStackTrace();
                }
            }
            e.printStackTrace();
        } finally {
            DBUtil.close(conn, ps, rs);
        }
        if (count == 1) {
            response.sendRedirect(request.getContextPath()+"/list");
        } else {
            response.sendRedirect(request.getContextPath()+"/error.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 EditServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        request.setCharacterEncoding("UTF-8");
        String contextPath = this.getServletContext().getContextPath();
        response.setContentType("text/html;charset=UTF-8");
        String deptno = request.getParameter("deptno");
        PrintWriter out=response.getWriter();
        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>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+"/modify' method='post'>");
        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'>");
        out.print("      </form>");
        out.print("  </body>");
        out.print("</html>");
    }
}

相关HTML页面

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<!DOCTYPE html>
<html lang="ch">
  <head>
      <meta charset="UTF-8">
      <title>欢迎使用OA系统</title>
  </head>
  <body>
        <a href="/test4/list">查看部门列表</a><br>
  </body>
</html>
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<!DOCTYPE html>
<html lang="ch">
  <head>
      <meta charset="UTF-8">
      <title>删除失败</title>
  </head>
  <body>
    <h1>操作失败<a href="javascript:void(0)" onclick="document.location.href='/oa/list'">返回部门列表</a></h1>

  </body>
</html>
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<!DOCTYPE html>
<html lang="ch">
  <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="post">
          部门编号<input type="text" name="deptno" value="10" readonly/><br>
          部门名称<input type="text" name="dname" value="销售部"/><br>
          部门位置<input type="text" name="loc" value="北京"/><br>
          <input type="submit" value="修改">
      </form>
  </body>
</html>
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<!DOCTYPE html>
<html lang="ch">
    <head>
        <meta charset="UTF-8">
        <title>新增部门</title>
    </head>
    <body>
        <h1>新增部门</h1>
        <hr>
        <form action="/test4/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">
        </form>
    </body>
</html>

在更改HTML页面时浏览器可能会出现刷新也不更改的情况，这时需要清空浏览器的缓存，如清空谷歌浏览器中的缓存的图片和文件，光只清除cookie不行。