java简单增删改查_无框架JavaWeb简单增删改查,纯jsp小练习

刚入门javaweb,自己做个jsp小练习供以后参考,本文纯jsp与后台JDBC增删改查的操作,还有一些瑕疵需要修复(当然大佬就不要挑我这个小白的毛病了,小白正在不断学习中....).

写这篇文章的目的是为了记录 怎样把数据从前台传输到后端数据库,也是对自己学习的一次小总结, 不足之处多多见谅~~~

好啦,开始整吧

(1) 数据库(mysql)只有一张表 emp

(2) eclipse建立web项目(不使用maven)   具体结构如下:

(3)上代码

后台代码 :

(3.1) 先写好连接数据库的配置文件,配置文件的作用就是方便更改我们数据库的账户密码,数据库驱动等

1 jdbc.name &＃61;root2 jdbc.password &＃61;root3 jdbc.url &＃61; jdbc:mysql://localhost:3306/cust?useSSL&＃61;false

4 jdbc.driver &＃61; com.mysql.jdbc.Driver

jdbc.properties

(3.2) util包下的工具类

1 packagecn.ssq.util;2

3 importjava.io.IOException;4 importjava.io.InputStream;5 importjava.util.Properties;6

7 public classProsutil {8

9 private staticProperties properties;10

11 static{12 properties &＃61; newProperties();13 //引入配置文件

14 InputStream is &＃61; Thread.currentThread().getContextClassLoader().getResourceAsStream("jdbc.properties");15

16 try{17 properties.load(is);18 } catch(IOException e) {19 //TODO Auto-generated catch block

20 e.printStackTrace();21 }22

23 }24 public staticString getStringByKey(String key){25 return properties.getProperty(key,"");26 }27 }

Prosutil.java(调用配置文件)

1 packagecn.ssq.util;2

3 importjava.sql.Connection;4 importjava.sql.DriverManager;5 importjava.sql.PreparedStatement;6 importjava.sql.ResultSet;7 importjava.sql.SQLException;8

9 public classDButil {10 //通过配置文件读取数据库的相关配置

11 private static final String URL &＃61; Prosutil.getStringByKey("jdbc.url");12 private static final String DRIVER &＃61; Prosutil.getStringByKey("jdbc.driver");13 private static final String USERNAME &＃61; Prosutil.getStringByKey("jdbc.name");14 private static final String PASSWORD &＃61; Prosutil.getStringByKey("jdbc.password");15 //建立数据库连接

16 public staticConnection getConn(){17 Connection conn &＃61; null;18

19 try{20 Class.forName(DRIVER);21 conn &＃61;DriverManager.getConnection(URL,USERNAME,PASSWORD);22 } catch(ClassNotFoundException e) {23

24 e.printStackTrace();25 } catch(SQLException e) {26

27 e.printStackTrace();28 }29 returnconn;30 }31

32 //关闭数据库连接

33 public static voidCloseAll(ResultSet rs,PreparedStatement ps, Connection conn){34

35 try{36 if(rs !&＃61; null){37 rs.close();38 rs &＃61; null;39 }40 if(ps !&＃61;null){41 ps.close();42 ps &＃61; null;43 }44 if(conn!&＃61;null){45 conn.close();46 conn &＃61; null;47 }48 } catch(SQLException e) {49

50 e.printStackTrace();51 }52

53 }54

55 //private static ResultSet rs;

56 private staticPreparedStatement ps;57 private staticConnection conn;58 /**

59 * 增删改60 *&＃64;return

61 */

62 public static intexecuUpdate(String sql ,Object...param){63 int num &＃61; 0;64 conn &＃61;getConn();65 try{66 PreparedStatement ps &＃61;conn.prepareStatement(sql);67 for (int i &＃61; 0; i

74 e.printStackTrace();75 }finally{76 CloseAll(null,ps,conn);77 }78 returnnum;79 }80 /**

81 * 通用查询82 */

83 public staticResultSet execuQuery(String sql,Object...param){84 ResultSet rs &＃61; null;85 conn &＃61;getConn();86 try{87 PreparedStatement ps &＃61;conn.prepareStatement(sql);88 for (int i &＃61; 0; i

95 e.printStackTrace();96 }97 returnrs;98

99 }100 }

DButil.java(数据库工具类)

(3.3)entity包下的实体类

1 packagecn.ssq.entity;2

3 public classEmp {4

5 private intid;6 privateString name;7 privateString gender;8 privateString tel;9 privateString username;10 privateString password;11 public intgetId() {12 returnid;13 }14 public void setId(intid) {15 this.id &＃61;id;16 }17 publicString getName() {18 returnname;19 }20 public voidsetName(String name) {21 this.name &＃61;name;22 }23 publicString getGender() {24 returngender;25 }26 public voidsetGender(String gender) {27 this.gender &＃61;gender;28 }29 publicString getTel() {30 returntel;31 }32 public voidsetTel(String tel) {33 this.tel &＃61;tel;34 }35 publicString getUsername() {36 returnusername;37 }38 public voidsetUsername(String username) {39 this.username &＃61;username;40 }41 publicString getPassword() {42 returnpassword;43 }44 public voidsetPassword(String password) {45 this.password &＃61;password;46 }47 publicEmp() {48 super();49

50 }51 public Emp(intid, String name, String gender, String tel, String username,52 String password) {53 super();54 this.id &＃61;id;55 this.name &＃61;name;56 this.gender &＃61;gender;57 this.tel &＃61;tel;58 this.username &＃61;username;59 this.password &＃61;password;60 }61

62 }

Emp.java

(3.4)dao包下的接口和接口实现类

1 packagecn.ssq.dao;2

3 importjava.util.List;4

5 importcn.ssq.entity.Emp;6

7 public interfaceEmpDao {8

9 intsave(Emp emp);10 int delete(intid);11 intupdate(Emp emp);12 ListfindAll();13 Emp getEmpById(intid);14

15 }

EmpDao.java

1 packagecn.ssq.dao.impl;2

3 importjava.sql.ResultSet;4 importjava.sql.SQLException;5 importjava.util.ArrayList;6 importjava.util.List;7

8 importcn.ssq.dao.EmpDao;9 importcn.ssq.entity.Emp;10 importcn.ssq.util.DButil;11

12 public class EmpDaoImpl implementsEmpDao {13

14 Emp emp &＃61; null;15 /**

16 * 添加17 */

18 &＃64;Override19 public intsave(Emp emp) {20 String sql &＃61; "insert into customer(id,name,gender,tel,username,password)values(?,?,?,?,?,?)";21 returnDButil.execuUpdate(sql, emp.getId(),emp.getName(),emp.getGender(),emp.getTel(),emp.getUsername(),emp.getPassword());22 }23

24 /**

25 * 删除26 */

27 &＃64;Override28 public int delete(intid) {29 String sql &＃61; "delete from customer where id &＃61; ?";30 returnDButil.execuUpdate(sql, id);31 }32

33 /**

34 * 修改35 */

36 &＃64;Override37 public intupdate(Emp emp) {38 String sql &＃61; "update customer set name &＃61; ?,gender&＃61;?,tel&＃61;?,username&＃61;?,password&＃61;? where id&＃61;?";39 returnDButil.execuUpdate(sql, emp.getName(),emp.getGender(),emp.getTel(),emp.getUsername(),emp.getPassword(),emp.getId());40 }41

42 /**

43 * 查询44 */

45 &＃64;Override46 public ListfindAll() {47 List list &＃61; new ArrayList();48 String sql &＃61; "select * from customer";49 ResultSet rs &＃61;DButil.execuQuery(sql);50 try{51 while(rs.next()){52 emp &＃61; newEmp();53 emp.setId(rs.getInt("id"));54 emp.setGender(rs.getString("gender"));55 emp.setName(rs.getString("name"));56 emp.setTel(rs.getString("tel"));57 emp.setUsername(rs.getString("username"));58 emp.setPassword(rs.getString("password"));59 list.add(emp);60 }61 } catch(SQLException e) {62

63 e.printStackTrace();64 }65

66 returnlist;67 }68

69 //根据id查询

70 &＃64;Override71 public Emp getEmpById(intid) {72 Emp emp&＃61;null;73 String sql &＃61; "select * from customer where id &＃61; ?";74 ResultSet rs &＃61;DButil.execuQuery(sql, id);75 try{76 while(rs.next()){77 emp &＃61; newEmp();78 emp.setGender(rs.getString("gender"));79 emp.setName(rs.getString("name"));80 emp.setPassword(rs.getString("password"));81 emp.setUsername(rs.getString("username"));82 emp.setTel(rs.getString("tel"));83 }84 } catch(SQLException e) {85

86 e.printStackTrace();87 }88

89

90 returnemp;91 }92

93 }

EmpDaoImpl.java

(3.5)service包下的业务层

1 packagecn.ssq.service;2

3 importjava.util.List;4

5 importcn.ssq.entity.Emp;6

7 public interfaceServiceDao {8

9 booleansave(Emp emp);10 boolean delete(intid);11 booleanupdate(Emp emp);12 ListfindAll();13 Emp getEmpById(intid);14 }

ServiceDao.java

1 packagecn.ssq.service.impl;2

3 importjava.util.List;4

5 importcn.ssq.dao.EmpDao;6 importcn.ssq.dao.impl.EmpDaoImpl;7 importcn.ssq.entity.Emp;8 importcn.ssq.service.ServiceDao;9 /**

10 * 业务调用11 *&＃64;author北城墨白12 *13 * 2018年12月13日14 */

15 public class ServiceDaoImpl implementsServiceDao {16

17 EmpDao dao &＃61; newEmpDaoImpl();18 &＃64;Override19 public booleansave(Emp emp) {20

21 return dao.save(emp)>0;22 }23

24 &＃64;Override25 public boolean delete(intid) {26

27 return dao.delete(id)>0;28 }29

30 &＃64;Override31 public booleanupdate(Emp emp) {32 return dao.update(emp)>0;33 }34

35 &＃64;Override36 public ListfindAll() {37 returndao.findAll();38 }39

40 &＃64;Override41 public Emp getEmpById(intid) {42

43 returndao.getEmpById(id);44 }45

46 }

ServiceDaoImpl.java

到这里,基本的底层代码已经结束了,剩下的就是前端jsp的编写了(记得导包,jar包的下载地址问度娘就可以了,在这我就不啰嗦了)

(3.6)WebContent文件夹下的jsp页面代码

前端代码:

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7 pageEncoding&＃61;"UTF-8"%>

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16 request.setCharacterEncoding("UTF-8");17 response.setCharacterEncoding("utf-8");18 ServiceDao service &＃61; newServiceDaoImpl();19 List list &＃61;service.findAll();20 %>

21 添加新员工

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33 for(Emp e:list){34 %>

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index.jsp(首页查询显示界面)

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4 pageEncoding&＃61;"UTF-8"%>

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13 request.setCharacterEncoding("UTF-8");14 response.setCharacterEncoding("utf-8");15 String did &＃61; request.getParameter("did");16 int empid &＃61;Integer.valueOf(did);17 ServiceDao service &＃61; newServiceDaoImpl();18

19 if(service.delete(empid)&＃61;&＃61;true){20 response.sendRedirect("index.jsp");21 }else{22 response.sendRedirect("index.jsp");23 }24 %>

25

26

delete.jsp(删除处理)

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5 pageEncoding&＃61;"UTF-8"%>

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15 String nid &＃61; request.getParameter("nid");16 Emp e &＃61; null;17 ServiceDao service &＃61; newServiceDaoImpl();18 if(nid !&＃61;null){19 int eid &＃61;Integer.valueOf(nid);20 e &＃61;service.getEmpById(eid);21 }22

23 %>

24

25

员工信息

26

27 员工编号: ">(员工编号不可重复)

28 员工姓名: ">

29 员工性别: ">

30 员工电话: ">

31      用户名:">

32 员工密码: ">

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insert_update.jsp(添加和修改共用一个显示页面)

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5 pageEncoding&＃61;"UTF-8"%>

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14 request.setCharacterEncoding("UTF-8");15 response.setCharacterEncoding("utf-8");16 String id &＃61; request.getParameter("nid");17 String name&＃61;request.getParameter("name");18 String gender&＃61;request.getParameter("gender");19 String tel &＃61; request.getParameter("tel");20 String username&＃61;request.getParameter("username");21 String password&＃61;request.getParameter("password");22

23 Emp emp &＃61; newEmp();24

25 int eid &＃61;Integer.valueOf(id);26

27 emp.setId(eid);28 emp.setName(name);29 emp.setGender(gender);30 emp.setTel(tel);31 emp.setUsername(username);32 emp.setPassword(password);33

34 ServiceDao service &＃61; newServiceDaoImpl();35 if(service.save(emp)&＃61;&＃61;true){36 response.sendRedirect("index.jsp");37 }else{38 response.sendRedirect("insert_update.jsp");39 }40 %>

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doadd.jsp(添加处理)

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5 pageEncoding&＃61;"UTF-8"%>

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14 request.setCharacterEncoding("UTF-8");15 response.setCharacterEncoding("utf-8");16 String id &＃61; request.getParameter("nid");17 String name&＃61;request.getParameter("name");18 String gender&＃61;request.getParameter("gender");19 String tel &＃61; request.getParameter("tel");20 String username&＃61;request.getParameter("username");21 String password&＃61;request.getParameter("password");22

23 Emp emp &＃61; newEmp();24

25 int eid &＃61;Integer.valueOf(id);26

27 emp.setId(eid);28 emp.setName(name);29 emp.setGender(gender);30 emp.setTel(tel);31 emp.setUsername(username);32 emp.setPassword(password);33

34 ServiceDao service &＃61; newServiceDaoImpl();35 if(service.update(emp)&＃61;&＃61;true){36 response.sendRedirect("index.jsp");37 }else{38 response.sendRedirect("insert_update.jsp");39 }40 %>

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doupdate.jsp(修改处理)

代码完毕!

(4)运行index.jsp页面就可以正常使用了,当然这个小练习没有实用性,只是对jsp知识点的一次小回顾,效果图如下 :

结束

小白希望能和大家多多交流,互相学习,毕竟学到老活到老嘛,啊不,活到老学到老,编程(码农)就是一步步慢慢来的,一起加油吧!