javaweb搭建的增删改查项目
初学javaweb时搭建的一个小项目，对我来说算是有个里程碑的意义把。
本项目由servlet+jsp搭建而成，实现了单表crud功能，项目虽小，但也用了标准的三层架构
包结构如下：
建库语句：CREATE TABLEstudent` (
id int(11) NOT NULL,
name varchar(255) NOT NULL,
age int(11) NOT NULL,
sex varchar(255) NOT NULL,
PRIMARY KEY (id)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
INSERT INTO student VALUES (‘1’, ‘张三’, ‘10’, ‘男’);
INSERT INTO student VALUES (‘2’, ‘李四’, ‘11’, ‘男’);
INSERT INTO student VALUES (‘3’, ‘王五’, ‘12’, ‘女’);
INSERT INTO student VALUES (‘4’, ‘赵六’, ‘13’, ‘男’);
INSERT INTO student VALUES (‘5’, ‘。。。’, ‘13’, ‘未知’);`
1.实体类
Student.java
package com.cm.entity;
public class Student {
private int id;
private String name;
private int age;
private String sex;
public Student() {
super();
}
public Student(int id, String name, int age, String sex) {
super();
this.id = id;
this.name = name;
this.age = age;
this.sex = sex;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
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 getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
}
PageO.java
(分页用到)
package com.cm.entity;
import java.util.List;
public class PageO {
//当前页
private int currentPage;
//当前页码
private int pageSize;
//总数据条数
private int totalCount;
//总页数
private int totalPage;
private List students;
public int getCurrentPage() {
return currentPage;
}
public void setCurrentPage(int currentPage) {
this.currentPage = currentPage;
}
public int getPageSize() {
return pageSize;
}
public void setPageSize(int pageSize) {
this.pageSize = pageSize;
this.totalPage=this.totalCount%this.pageSize==0?this.totalCount/this.pageSize:this.totalCount/this.pageSize+1;
}
public int getTotalCount() {
return totalCount;
}
public void setTotalCount(int totalCount) {
this.totalCount = totalCount;
}
public int getTotalPage() {
return totalPage;
}
// public void setTotalPage(int totalPage) {
// this.totalPage = totalPage;
// }
public List getStudents() {
return students;
}
public void setStudents(List students) {
this.students = students;
}
public PageO(int currentPage, int pageSize, int totalCount, int totalPage, List students) {
super();
this.currentPage = currentPage;
this.pageSize = pageSize;
this.totalCount = totalCount;
this.totalPage = totalPage;
this.students = students;
}
public PageO() {
super();
}
}
2.jdbc工具类
Dbconn.java
package com.cm.util;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
public class Dbconn {
private static final String URL="jdbc:mysql://localhost:3306/smbms?useunicuee=true& characterEncoding=utf8";
private static final String USERNAME="root";
private static final String PASSWORD="123456";
public static Connection connection=null;
public static PreparedStatement pstm=null;
public static ResultSet rs=null;
public static boolean executeUpdate(String sql,Object[] pstms) {
try {
Class.forName("com.mysql.jdbc.Driver");
connection=DriverManager.getConnection(URL,USERNAME,PASSWORD);
pstm=connection.prepareStatement(sql);
for (int i = 0; i < pstms.length; i++) {
pstm.setObject(i+1, pstms[i]);
}
int count=pstm.executeUpdate();
if(count>0){
return true;
}
else{
return false;
}
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return false;
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return false;
}catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
return false;
}finally{
try{
if(rs!=null)rs.close();
if(pstm!=null)pstm.close();
if(connection!=null)connection.close();
}catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
}
}
public static ResultSet qusery(String sql,Object[] pstms){
try {
Class.forName("com.mysql.jdbc.Driver");
connection=DriverManager.getConnection(URL,USERNAME,PASSWORD);
pstm=connection.prepareStatement(sql);
if(pstms!=null){
for (int i = 0; i < pstms.length; i++) {
pstm.setObject(i+1, pstms[i]);
}
}
rs=pstm.executeQuery();
return rs;
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return null;
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return null;
}catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
return null;
}
}
public static int getTotalCount(String sql) {
int count=-1;
try {
rs = qusery(sql, null);
if (rs.next()) {
count=rs.getInt(1);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
try{
if(rs!=null)rs.close();
if(pstm!=null)pstm.close();
if(connection!=null)connection.close();
}catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
}
return count;
}
}
3.dao层
StudentDao.java
package com.cm.dao;
import java.util.List;
import com.cm.entity.Student;
public interface StudentDao {
public Student quseryOne(int id);
public boolean isExist(int id);
public boolean add(Student student);
public boolean delete(int id);
public List qusery();
public boolean updata(Student student);
public int getTotalCount();
public List queryByPage(int currentPage,int pageSize);
}
StudentDaoImpl.java
package com.cm.dao.Impl;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import com.cm.dao.StudentDao;
import com.cm.entity.Student;
import com.cm.util.Dbconn;
public class StudentDaoImpl implements StudentDao {
public boolean isExist(int id) {
return quseryOne(id) == null ? false : true;
}
public boolean add(Student student) {
String sql = "insert into student values(?,?,?,?)";
Object[] pstms = { student.getId(), student.getName(), student.getAge(), student.getSex() };
return Dbconn.executeUpdate(sql, pstms);
}
public boolean delete(int id) {
String sql = "delete from student where id=?";
Object[] pstms = { id };
return Dbconn.executeUpdate(sql, pstms);
}
public boolean updata(Student student) {
String sql = "UPDATE student SET name=?,age=?,sex=? WHERE id=?";
Object[] pstms = { student.getName(), student.getAge(), student.getSex(), student.getId() };
return Dbconn.executeUpdate(sql, pstms);
}
public Student quseryOne(int id) {
Student student = new Student();
student = null;
ResultSet rs = null;
try {
String sql = "select * from student where id=?";
Object[] pstms = { id };
rs = Dbconn.qusery(sql, pstms);
if (rs.next()) {
String name = rs.getString("name");
int age = rs.getInt("age");
String sex = rs.getString("sex");
student = new Student(id, name, age, sex);
}
return student;
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return null;
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
return null;
} finally {
try{
if(rs!=null)rs.close();
if(Dbconn.pstm!=null)Dbconn.pstm.close();
if(Dbconn.connection!=null)Dbconn.connection.close();
}catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
}
}
public List qusery(){
List students=new ArrayList();
ResultSet rs=null;
String sql="select * from student";
rs=Dbconn.qusery(sql, null);
try {
while(rs.next()) {
Student student=new Student();
student.setId( rs.getInt("id"));
student.setName(rs.getString("name"));
student.setAge(rs.getInt("age"));
student.setSex(rs.getString("sex"));
students.add(student);
}
return students;
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return null;
}finally {
try{
if(rs!=null)rs.close();
if(Dbconn.pstm!=null)Dbconn.pstm.close();
if(Dbconn.connection!=null)Dbconn.connection.close();
}catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
}
}
public int getTotalCount() {
String sql="select count(1) from student";
return Dbconn.getTotalCount(sql);
}
@Override
public List queryByPage(int currentPage,int pageSize) {
List students=new ArrayList();
ResultSet rs=null;
String sql="select * from student limit ? ,?";
int i=(currentPage-1)*pageSize;
Object[] pstms={i,pageSize};
rs=Dbconn.qusery(sql, pstms);
try {
while(rs.next()) {
Student student=new Student();
student.setId( rs.getInt("id"));
student.setName(rs.getString("name"));
student.setAge(rs.getInt("age"));
student.setSex(rs.getString("sex"));
students.add(student);
}
return students;
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return null;
}finally {
try{
if(rs!=null)rs.close();
if(Dbconn.pstm!=null)Dbconn.pstm.close();
if(Dbconn.connection!=null)Dbconn.connection.close();
}catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
}
}
}
4.service层
StudentService.java
package com.cm.service;
import java.util.List;
import com.cm.entity.Student;
public interface StudentService {
public boolean add(Student student);
public List qusery();
public boolean delete(int id);
public Student quseryOne(int id);
public boolean updata(Student student);
public List queryByPage(int currentPage,int pageSize);
public int getTotalCount();
}
StudentServiceImpl.java
package com.cm.service.Impl;
import java.util.List;
import com.cm.dao.StudentDao;
import com.cm.dao.Impl.StudentDaoImpl;
import com.cm.entity.Student;
import com.cm.service.StudentService;
public class StudentServiceImpl implements StudentService {
StudentDao studentDao=new StudentDaoImpl();
public boolean add(Student student){
if (!studentDao.isExist(student.getId())) {
studentDao.add(student);
return true;
}else{
System.out.println("此人已存在！");
return false;
}
}
public List qusery() {
return studentDao.qusery();
}
public boolean delete(int id) {
return studentDao.delete(id);
}
public Student quseryOne(int id) {
return studentDao.quseryOne(id);
}
public boolean updata(Student student){
return studentDao.updata(student);
}
public List queryByPage(int currentPage,int pageSize){
return studentDao.queryByPage(currentPage, pageSize);
}
public int getTotalCount(){
return studentDao.getTotalCount();
}
}
5.视图层
servlet
AddStudentServlet.java
package com.cm.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.cm.entity.Student;
import com.cm.service.StudentService;
import com.cm.service.Impl.StudentServiceImpl;
public class AddStudentServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
int id = Integer.parseInt(request.getParameter("id"));
String name = request.getParameter("name");
System.out.println(name);
int age = Integer.parseInt(request.getParameter("age"));
String sex=request.getParameter("sex");
Student student=new Student(id,name,age,sex);
StudentService studentService=new StudentServiceImpl();
boolean result=studentService.add(student);
response.setContentType("text/html;charset=UTF-8");
response.setCharacterEncoding("utf-8");
PrintWriter out = response.getWriter();
if(result==true){
out.print("增加成功");
}else {
out.print("增加失败");
}
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}
DeleteStudentServlet.java
package com.cm.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.cm.service.StudentService;
import com.cm.service.Impl.StudentServiceImpl;
public class DeleteStudentServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
int id = Integer.parseInt(request.getParameter("id"));
StudentService studentService=new StudentServiceImpl();
boolean result=studentService.delete(id);
response.setContentType("text/html;charset=UTF-8");
response.setCharacterEncoding("utf-8");
PrintWriter out = response.getWriter();
if(result==true){
out.print("删除成功");
}else {
out.print("删除失败");
}
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
QueryStudentByPage.java
package com.cm.servlet;
import java.io.IOException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.cm.entity.PageO;
import com.cm.entity.Student;
import com.cm.service.StudentService;
import com.cm.service.Impl.StudentServiceImpl;
public class QueryStudentByPage extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
PageO pageo=new PageO();
StudentService studentService=new StudentServiceImpl();
int totalCount = studentService.getTotalCount();
pageo.setTotalCount(totalCount);
pageo.setPageSize(3);
int currentPage;
if (request.getParameter("currentPage")==null) {
currentPage=1;
}else {
currentPage=Integer.parseInt(request.getParameter("currentPage"));
}
pageo.setCurrentPage(currentPage);
List students=studentService.queryByPage(pageo.getCurrentPage(), pageo.getPageSize());
pageo.setStudents(students);
request.setAttribute("pageo", pageo);
request.getRequestDispatcher("/paging.jsp").forward(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}
ShowAllStudentServlet.java
package com.cm.servlet;
import java.io.IOException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.cm.entity.Student;
import com.cm.service.StudentService;
import com.cm.service.Impl.StudentServiceImpl;
public class ShowAllStudentServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
StudentService studentService=new StudentServiceImpl();
List students=studentService.qusery();
request.setAttribute("students", students);
request.getRequestDispatcher("/list.jsp").forward(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
ShowOneStudentSevlet.java
package com.cm.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.cm.entity.Student;
import com.cm.service.StudentService;
import com.cm.service.Impl.StudentServiceImpl;
public class ShowOneStudentSevlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
int id = Integer.parseInt(request.getParameter("id"));
StudentService studentService=new StudentServiceImpl();
Student student=new Student();
student = studentService.quseryOne(id);
request.setAttribute("student",student);
request.getRequestDispatcher("/showone.jsp").forward(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
UpdataStudentServlet.java
package com.cm.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.cm.entity.Student;
import com.cm.service.StudentService;
import com.cm.service.Impl.StudentServiceImpl;
public class UpdataStudentServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
int id = Integer.parseInt(request.getParameter("id"));
String name = request.getParameter("name");
int age = Integer.parseInt(request.getParameter("age"));
String sex=request.getParameter("sex");
Student student=new Student(id,name,age,sex);
StudentService studentService=new StudentServiceImpl();
boolean result=studentService.updata(student);
response.setContentType("text/html;charset=UTF-8");
response.setCharacterEncoding("utf-8");
PrintWriter out = response.getWriter();
if(result==true){
out.print("修改成功");
}else {
out.print("修改失败");
}
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
jsp
add.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%
request.setCharacterEncoding("UTF-8");
%>
Insert title here
list.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@page import="com.cm.entity.Student,com.cm.servlet.ShowAllStudentServlet,java.util.*"%>
Insert title here
新增
paging.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@page import="com.cm.entity.Student,com.cm.servlet.ShowAllStudentServlet,java.util.*"%>
Insert title here
新增
showone.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%request.setCharacterEncoding("UTF-8");%>
<%@page import="com.cm.entity.Student"%>
Insert title here
最后还有一个web.xml文件
QueryStudentByPage
AddStudentServlet
com.cm.servlet.AddStudentServlet
ShouAllStudent
com.cm.servlet.ShouAllStudent
DeleteStudentServlet
com.cm.servlet.DeleteStudentServlet
ShowOneStudentSevlet
com.cm.servlet.ShowOneStudentSevlet
UpdataStudentServlet
com.cm.servlet.UpdataStudentServlet
QueryStudentByPage
com.cm.servlet.QueryStudentByPage
AddStudentServlet
/AddStudentServlet
ShouAllStudent
/ShouAllStudent
DeleteStudentServlet
/DeleteStudentServlet
ShowOneStudentSevlet
/ShowOneStudentSevlet
UpdataStudentServlet
/UpdataStudentServlet
QueryStudentByPage
/QueryStudentByPage
运行效果如下：
点击id按键进入操作页：
这是初学时做的第一个比较成功的小项目，代码量较大，但实现的功能却不多，还有很多地方也都没有完善，现在也不太愿意去继续完善它了，但毕竟是个能跑的项目，算是留作一个纪念吧。