Tips ： When the article is finished , Directories can be generated automatically , How to generate it, please refer to the help document on the right

Preface

The project is based on jsp Basic small projects , It can realize login function and basic addition, deletion, modification and query .

One 、 Project requirements

1. Will be ready html Change the page to jsp.
2. Realize administrator login function , And apply permission verification .
3. Add, delete, modify and check employees .
4. Query employees using paged queries , And provide the home page , Tail page . page-up key , The next page .

Two 、 Project structures,

Construction of project directory

2. Project resource introduction

Create project import related jar file .

3. Database creation

4. Project development

Show only key code , Other codes poke me .

User logged in controller

The code is as follows （ Example ）：

package com.controller;


import com.entity.EmpManager;
import com.service.EmpManagerService;
import com.service.impl.EmpManagerServiceImpl;

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(name = "EmpManagerLoginController",value = "/manager/loginController")
public class EmpManagerLoginController extends HttpServlet {
    
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
        //1. Collect parameters 
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        String inputVcode = request.getParameter("inputVcode");

        //2. Verification code 
        String codes = (String)request.getSession().getAttribute("codes");
        if(!inputVcode.isEmpty() && inputVcode.equalsIgnoreCase(codes)){
    
            // Call business logic to realize login 
            EmpManagerService empManagerService = new EmpManagerServiceImpl();
            EmpManager empManager = empManagerService.login(username,password);
            if(empManager!=null){
    
                // Login successful 
                // Stored in session Scope 
                HttpSession session = request.getSession();
                session.setAttribute("empManager",empManager);
                // Jump to query all controller
                response.sendRedirect(request.getContextPath()+"/manager/safe/showall");
            }else{
    
                response.sendRedirect(request.getContextPath()+"/login.html");
            }
        }else{
    
            // Error in captcha input , Go to the login page 
            response.sendRedirect(request.getContextPath()+"/login.html");
        }
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
        doPost(request,response);
    }
}

Imported with the above jar Verification code of file creation controller

The code is as follows （ Example ）：

package com.controller;

import cn.dsna.util.images.ValidateCode;

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(name = "CreateCodeController",value = "/createCode")
public class CreateCodeController extends HttpServlet {
    
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
        ValidateCode validateCode = new ValidateCode(200,30,4,10);
        String codes = validateCode.getCode();
        HttpSession session = request.getSession();
        session.setAttribute("codes",codes);

        validateCode.write(response.getOutputStream());
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
        doPost(request, response);
    }
}

Paged query controller

package com.controller;
import com.entity.Emp;
import com.entity.Page;
import com.service.EmpService;
import com.service.impl.EmpServiceImpl;

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.util.List;

@WebServlet(name = "ShowAllEmpController",value = "/manager/safe/showall")
public class ShowAllEmpController extends HttpServlet {
    
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
        String pageIndex = request.getParameter("pageIndex");
        if(pageIndex == null){
    
            pageIndex="1";
        }

        Page page = new Page(Integer.valueOf(pageIndex));

        EmpService empService = new EmpServiceImpl();
        List<Emp> emps = empService.selectAll(page);

        request.setAttribute("emps",emps);
        request.setAttribute("page",page);

        request.getRequestDispatcher("/emplist.jsp").forward(request,response);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
        doPost(request, response);
    }
}

Pagination in jsp The core code in is implemented as follows

    <tr>
                    <td colspan="5" align="center">
                        <a href="<c:url context='${pageContext.request.contextPath}' value='/manager/safe/showall?pageIndex=1'/>"> home page </a>

                        <c:if test="${page.pageIndex > 1}">
                            <a href="<c:url context='${pageContext.request.contextPath}' value='/manager/safe/showall?pageIndex=${page.pageIndex - 1}' />"> The previous page </a>
                        </c:if>
                        <c:if test="${page.pageIndex==1}">
                            <a> The previous page </a>
                        </c:if>

                        <c:if test="${page.pageIndex < page.totalPages}">
                            <a href="<c:url context='${pageContext.request.contextPath}' value='/manager/safe/showall?pageIndex=${page.pageIndex + 1}' />"> The next page </a>
                        </c:if>
                        <c:if test="${page.pageIndex == page.totalPages}">
                            <a> The next page </a>
                        </c:if>

                        <a href="<c:url context='${pageContext.request.contextPath}' value='/manager/safe/showall?pageIndex=${page.totalPages}'/>"> Tail page </a>
                    </td>
                </tr>

page The core configuration information of the page

public class Page {
    
    private Integer pageIndex;// The current page number 

    private Integer pageSize;// Page size 

    private Integer totalCounts;// The total number of data 

    private Integer totalPages;// Total number of pages 

    private Integer startRows;// Start line 

    public Page(Integer pageIndex) {
    
        this(pageIndex,5);
    }

    public Page(Integer pageIndex, Integer pageSize) {
    
        this.pageIndex = pageIndex;
        this.pageSize = pageSize;
        this.setStartRows((pageIndex - 1) * pageSize);
    }

    public Integer getPageIndex() {
    
        return pageIndex;
    }

    public void setPageIndex(Integer pageIndex) {
    
        this.pageIndex = pageIndex;
    }

    public Integer getPageSize() {
    
        return pageSize;
    }

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

    public Integer getTotalCounts() {
    
        return totalCounts;
    }

    public void setTotalCounts(Integer totalCounts) {
    
        this.totalCounts = totalCounts;

        this.setTotalPages(this.totalCounts % this.pageSize ==0? this.totalCounts / this.pageSize : this.totalCounts / this.pageSize + 1);
    }

    public Integer getTotalPages() {
    
        return totalPages;
    }

    public void setTotalPages(Integer totalPages) {
    
        this.totalPages = totalPages;
    }

    public Integer getStartRows() {
    
        return startRows;
    }

    public void setStartRows(Integer startRows) {
    
        this.startRows = startRows;
    }
}

Add employee's insertcontroller

package com.controller;

import com.entity.Emp;
import com.service.EmpService;
import com.service.impl.EmpServiceImpl;

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;

@WebServlet(value = "/manager/safe/insertemp")
public class InsertEmpController  extends HttpServlet {
    

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    

        String name=req.getParameter("name");
        Double salary=Double.valueOf(req.getParameter("salary"));
        Integer age=Integer.valueOf(req.getParameter("age"));

        Emp emp=new Emp(name,salary,age);

        EmpService empService=new EmpServiceImpl();
        empService.insert(emp);

        resp.sendRedirect(req.getContextPath()+"/manager/safe/showall");
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    
      doPost(req, resp);
    }
}

Modify employee information controller

import com.entity.Emp;
import com.service.EmpService;
import com.service.impl.EmpServiceImpl;

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;


@WebServlet(name = "UpdateEmpController",value = "/manager/safe/updateEmp")
public class UpdateEmpController extends HttpServlet {
    
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
        Integer id = Integer.valueOf(request.getParameter("id"));
        String name = request.getParameter("name");
        Double salary = Double.valueOf(request.getParameter("salary"));
        Integer age = Integer.valueOf(request.getParameter("age"));

        Emp emp = new Emp(id,name,salary,age);

        EmpService empService = new EmpServiceImpl();
        empService.update(emp);

        response.sendRedirect(request.getContextPath()+"/manager/safe/showall");
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
        doPost(request, response);
    }
}

Query the information of a single employee controller

package com.controller;

import com.entity.Emp;
import com.service.EmpService;
import com.service.impl.EmpServiceImpl;

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;

@WebServlet(name = "ShowEmpController",value = "/manager/safe/showEmp")
public class ShowEmpController extends HttpServlet {
    
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
        Integer id = Integer.valueOf(request.getParameter("id"));

        EmpService empService = new EmpServiceImpl();
        Emp emp = empService.select(id);


        request.setAttribute("emp",emp);


        request.getRequestDispatcher("/UpdateEmp.jsp").forward(request,response);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
        doPost(request, response);
    }
}

Delete employee information contoller

import com.service.EmpService;
import com.service.impl.EmpServiceImpl;

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;

@WebServlet(value = "/manager/safe/deleteemp")
public class DeleteEmpController  extends HttpServlet {
    
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    

        int id=Integer.valueOf(req.getParameter("id"));

        EmpService empService=new EmpServiceImpl();
        empService.delete(id);

        resp.sendRedirect(req.getContextPath()+"/manager/safe/showall");
    }


    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    
        super.doPost(req, resp);
    }
}

3、 ... and 、 Project renderings

summary

1. This is the chicken after learning web Basic knowledge is a simple web project .
2.page The logic of encapsulation is a little complicated , You need to calculate , Need to spend some time to taste carefully .
3.web The relevant path of the project can be omitted web.x Inside to configure , It's a little bit of a hassle . Can be directly in servlet Use notes inside @webServlet（）.
4. Don't panic when you report an error , Check it slowly , To correct . I'll come across this in the future bug It can be easily solved .
5. The first publication of chicken with vegetables , I hope you can support me more , If there is something wrong , I hope you can point out the exchange , Crab ！