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JDBC(通俗易懂)简单的操作(增、删、改、查)_慕课手记

时间:2017-06-27 18:38:46      阅读:197      评论:0      收藏:0      [点我收藏+]

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项目所写的类:
技术分享

 

说明①、DButil 动态加载数据库驱动,以及获取java.sql.Connection的对象。
②、Personmodel 数据库列(栏位)所对应的字段,定义了相应的set和get方法。
③、Persondao 对数据库相应的增删改查方法 。
④、Personaction 对Persondao里面增删改查方法的进一步补充完善。
⑤、Personview 对应的将要展示数据的类
①②③④⑤的代码
package DB;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class DButil {
private static Connection connection;
static {
try {
//动态加载数据库驱动,注意要下载JDBC的jar包
Class.forName("com.mysql.jdbc.Driver");
//获得链接
connection = DriverManager.getConnection("jdbc:mysql://192.168.0.103:3306/testjdbc", "root","15090183397");
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static Connection getConnection() {
return connection;
}
}
先定义静态变量 connection,然后在静态代码段里面动态加载数据库驱动,并获得链接connection对象,然后定义get方法获取到该connection对象,以后需要与数据库建立连接进行相关操作的话,只要调用DButil的getconnection()方法即可。
②代码:
package DBmodel;
import java.util.Date;
public class Personmodel {
private Integer id;
private String name;
private String sex;
private String birthday;
private String phone;
private String email;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public String getBirthday() {
return birthday;
}
public void setBirthday(String birthday) {
this.birthday = birthday;
}
public String getPhone() {
return phone;
}
public void setPhone(String phone) {
this.phone = phone;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
}
没错,就是以下人物信息字段,并且有对应的set和get方法(注意体现封装通过set方法给相应变量赋值,get方法获取相应字段的值,而不是直接操作相应变量,具体封装的好处我不再啰嗦,可自行百度),然后大家可能蒙蔽了,我贴出数据库设计表估计你就明白了,下面上图:
技术分享

 

 看到没,Personmodel这个模型类的作用就是为了对应数据库的相应列(栏位),然后将数据库相应栏位的操作对应到Personmodel类的某个对象中,然后进行操作,这就是Personmodel模型类的作用。下面是③,代码如下:
package Dao;
 
 
import java.sql.Connection;
import java.sql.Date;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
 
 
import DB.DButil;
import DBmodel.Personmodel;
 
 
public class Persondao {
 
private static List<Personmodel> personmodels = new ArrayList<Personmodel>();
 
@SuppressWarnings("unused")
 
private Scanner scanner = new Scanner(System.in);
 
 
public static void addperson(Personmodel personmodel) throws SQLException {
 
Connection connection = DButil.getConnection();
 
String sql = " insert person " + " (name,sex,birthday,phone,email) "
 
+ " values(?,?,?,?,?);";
 
PreparedStatement preparedStatement = connection.prepareStatement(sql);
 
preparedStatement
.setString(1, personmodel.getName());
 
preparedStatement
.setString(2, personmodel.getSex());
 
preparedStatement
.setString(3, personmodel.getBirthday());
 
preparedStatement
.setString(4, personmodel.getEmail());
 
preparedStatement
.setString(5, personmodel.getEmail());
 
preparedStatement
.execute();
 
 
}
 
 
public static void deleteperson(Integer id) throws SQLException {
 
Connection connection = DButil.getConnection();
 
 
String sql = " delete from person " + " where id=?;";
 
PreparedStatement preparedStatement = connection.prepareStatement(sql);
 
preparedStatement
.setInt(1, id);
 
preparedStatement
.execute();
 
System.out.println("指定记录删除成功!");
 
 
}
 
 
public static void updateperson(Personmodel personmodel)
 
throws SQLException {
 
Connection connection = DButil.getConnection();
 
String sql = " update person "
 
+ " set name=?,sex=?,birthday=?,phone=?,email=?"
 
+ " where id=?;";
 
PreparedStatement preparedStatement = connection.prepareStatement(sql);
 
preparedStatement
.setString(1, personmodel.getName());
 
preparedStatement
.setString(2, personmodel.getSex());
 
preparedStatement
.setString(3, personmodel.getBirthday());
 
preparedStatement
.setString(4, personmodel.getPhone());
 
preparedStatement
.setString(5, personmodel.getEmail());
 
preparedStatement
.setInt(6, personmodel.getId());
 
preparedStatement
.execute();
 
 
}
 
 
public static Personmodel queryoneperson(Integer id) throws SQLException {
 
Connection connection = DButil.getConnection();
 
String sql = "select * from person " + " where id=?;";
 
PreparedStatement preparedStatement = connection.prepareStatement(sql);
 
preparedStatement
.setInt(1, id);
 
ResultSet resultSet = preparedStatement.executeQuery();
 
while (resultSet.next()) {
 
Personmodel personmodel = new Personmodel();
 
personmodel
.setId(resultSet.getInt("id"));
 
personmodel
.setName(resultSet.getString("name"));
 
personmodel
.setSex(resultSet.getString("sex"));
 
personmodel
.setBirthday(resultSet.getString("birthday"));
 
personmodel
.setPhone(resultSet.getString("phone"));
 
personmodel
.setEmail(resultSet.getString("email"));
 
return personmodel;
 
}
 
return null;
 
}
 
 
public static List<Personmodel> queryonepersonbyname(String name)
 
throws SQLException {
 
Connection connection = DButil.getConnection();
 
String sql = "select * from person " + " where name=?;";
 
PreparedStatement preparedStatement = connection.prepareStatement(sql);
 
preparedStatement
.setString(1, name);
 
ResultSet resultSet = preparedStatement.executeQuery();
 
Personmodel personmodel = null;
 
List<Personmodel> list = new ArrayList<Personmodel>();
 
while (resultSet.next()) {
 
personmodel
= new Personmodel();
 
personmodel
.setId(resultSet.getInt("id"));
 
personmodel
.setName(resultSet.getString("name"));
 
personmodel
.setSex(resultSet.getString("sex"));
 
personmodel
.setBirthday(resultSet.getString("birthday"));
 
personmodel
.setPhone(resultSet.getString("phone"));
 
personmodel
.setEmail(resultSet.getString("email"));
 
list
.add(personmodel);
 
}
 
return list;
 
 
}
 
 
public static List<Personmodel> queryallperson() throws SQLException {
 
Connection connection = DButil.getConnection();
 
Statement statement = connection.createStatement();
 
ResultSet resultSet = statement.executeQuery("select * from person");
 
while (resultSet.next()) {
 
Personmodel personmodel = new Personmodel();
 
personmodel
.setId(resultSet.getInt("id"));
 
personmodel
.setName(resultSet.getString("name"));
 
personmodel
.setSex(resultSet.getString("sex"));
 
personmodel
.setBirthday(resultSet.getString("birthday"));
 
personmodel
.setPhone(resultSet.getString("phone"));
 
personmodel
.setEmail(resultSet.getString("email"));
 
personmodels
.add(personmodel);
 
}
 
 
return personmodels;
 
}
}
这里面写的是数据库的增删改查操作, 首先看第一个方法是增加方法addperson()大家看方法里面代码,先获得connection对象,然后获得预编译对象 preparedStatement ,注意获得对象时调用方法的sql字符串参数,那个是将来要执行的SQL语句,下面preparedStatement的setxxx方法,里面第一个参数值对应sql字符串里面的相应?,第二个参数用了Personmodel的get方法( preparedStatement .setxxx参数意义可百度或查阅api),然后你会问了,那是什么时候进行的set赋值呢?问得好,这时候Personaction类的意义就显示出来了,里面有相对应的方法对Persondao的增删改查补充完善的相应方法,采用该方式逻辑更加清晰,我举例了addperson()增加记录方法的解释,其他类似。
下面是④,代码如下:
package Action;
 
 
import java.sql.SQLException;
import java.util.Date;
import java.util.Iterator;
import java.util.List;
import java.util.Scanner;
 
 
import DBmodel.Personmodel;
import Dao.Persondao;
 
 
public class Personaction {
 
// private static Persondao persondao;
 
private static Scanner scanner = new Scanner(System.in);
 
 
public static void addone() throws SQLException {
 
Personmodel personmodel = new Personmodel();
 
System.out.println("请依次输入要新增记录的以下属性值~");
 
System.out.println("姓名:");
 
personmodel
.setName(scanner.next());
 
System.out.println("性别:");
 
personmodel
.setSex(scanner.next());
 
System.out.println("生日(例如:1994-01-01):");
 
personmodel
.setBirthday(scanner.next());
 
System.out.println("电话:");
 
personmodel
.setPhone(scanner.next());
 
System.out.println("邮箱:");
 
personmodel
.setEmail(scanner.next());
 
Persondao.addperson(personmodel);
 
System.out.println("指定记录添加成功!");
 
}
 
 
public static boolean deleteone() throws SQLException {
 
List<Personmodel> personmodels = Persondao.queryallperson();
 
String stringid = null;
 
while (true) {
 
System.out.println("请输入要删除记录的指定id:");
 
stringid
= scanner.next();
 
if (!stringid.matches("\\d+")) {
 
System.out.println("请输入正整数!");
 
continue;
 
}
 
break;
 
}
 
int id = Integer.valueOf(stringid);
 
for (Personmodel personmodel : personmodels) {
 
if (personmodel.getId() == id) {
 
Persondao.deleteperson(id);
 
System.out.println("删除成功,删除id为" + id + "的数据~");
 
return true;
 
}
 
}
 
System.out.println("删除失败,指定id不存在~");
 
return false;
 
}
 
 
public static boolean update() throws SQLException {
 
List<Personmodel> personmodels = Persondao.queryallperson();
 
String stringid = null;
 
 
while (true) {
 
System.out.println("请输入要修改记录的指定id:");
 
stringid
= scanner.next();
 
if (!stringid.matches("\\d+")) {
 
System.out.println("请输入正整数!");
 
continue;
 
}
 
break;
 
}
 
int id = Integer.valueOf(stringid);
 
for (Personmodel personmodel2 : personmodels) {
 
if (personmodel2.getId() == id) {
 
Personmodel personmodel = new Personmodel();
 
personmodel
.setId(id);
 
System.out.println("请依次输入要更改记录的以下属性值~");
 
System.out.println("姓名:");
 
personmodel
.setName(scanner.next());
 
System.out.println("性别:");
 
personmodel
.setSex(scanner.next());
 
System.out.println("生日(例如:1994-01-01):");
 
personmodel
.setBirthday(scanner.next());
 
System.out.println("电话:");
 
personmodel
.setPhone(scanner.next());
 
System.out.println("邮箱:");
 
personmodel
.setEmail(scanner.next());
 
Persondao.updateperson(personmodel);
 
System.out.println("指定记录修改成功!");
 
 
return true;
 
}
 
}
 
 
System.out.println("要修改的id记录不存在!");
 
return false;
 
 
}
 
 
public static boolean selectone() throws SQLException {
 
List<Personmodel> personmodels = Persondao.queryallperson();
 
String stringid = null;
 
while (true) {
 
System.out.println("请输入要查询记录的指定id:");
 
stringid
= scanner.next();
 
if (!stringid.matches("\\d+")) {
 
System.out.println("请输入正整数!");
 
continue;
 
}
 
break;
 
}
 
int id = Integer.valueOf(stringid);
 
for (Personmodel personmodel : personmodels) {
 
if (personmodel.getId() == id) {
 
personmodel
= Persondao.queryoneperson(id);
 
System.out.println("查询成功,id为" + id + "的数据:");
 
System.out.print("|");
 
System.out.print("学生编号:" + personmodel.getId() + " ");
 
System.out.print("姓名:" + personmodel.getName() + " ");
 
System.out.print("性别:" + personmodel.getSex() + " ");
 
System.out.print("生日:" + personmodel.getBirthday() + " ");
 
System.out.print("电话:" + personmodel.getPhone() + " ");
 
System.out.print("邮件:" + personmodel.getEmail() + " ");
 
System.out.println();
 
return true;
 
}
 
}
 
System.out.println("查询失败,指定id不存在~");
 
return false;
 
}
 
 
public static boolean selectonebyname() throws SQLException {
 
List<Personmodel> personmodels = Persondao.queryallperson();
 
System.out.println("请输入要查询记录的指定姓名:");
 
String name = scanner.next();
 
for (Personmodel personmodel2 : personmodels) {
 
if (personmodel2.getName().equals(name)) {
 
List<Personmodel> list = Persondao.queryonepersonbyname(name);
 
for (int i = 0; i < list.size(); i++) {
 
Personmodel personmodel = list.get(i);
 
System.out.println("查询成功,姓名为" + name + "的数据:");
 
System.out.print("|");
 
System.out.print("学生编号:" + personmodel.getId() + " ");
 
System.out.print("姓名:" + personmodel.getName() + " ");
 
System.out.print("性别:" + personmodel.getSex() + " ");
 
System.out.print("生日:" + personmodel.getBirthday() + " ");
 
System.out.print("电话:" + personmodel.getPhone() + " ");
 
System.out.print("邮件:" + personmodel.getEmail() + " ");
 
System.out.println();
 
}
 
return true;
 
}
 
}
 
System.out.println("查询失败,指定id不存在~");
 
return false;
 
}
 
 
public static void selectall() throws SQLException {
 
List<Personmodel> personmodels = Persondao.queryallperson();
 
for (Personmodel personmodel : personmodels) {
 
System.out.print("|");
 
System.out.print("学生编号:" + personmodel.getId() + " ");
 
System.out.print("姓名:" + personmodel.getName() + " ");
 
System.out.print("性别:" + personmodel.getSex() + " ");
 
System.out.print("生日:" + personmodel.getBirthday() + " ");
 
System.out.print("电话:" + personmodel.getPhone() + " ");
 
System.out.print("邮件:" + personmodel.getEmail() + " ");
 
System.out.println();
 
}
 
}
}
刚才讲③的时候,为了大家的方便理解我顺带解释了④,大家看代码即可,我不再赘述啦。需要注意的一点是,我进行了控制台输入语句的判断,判断是否是合法类型。
最后是⑤,代码如下:
package View;
 
 
import java.sql.SQLException;
import java.util.Scanner;
 
 
import Action.Personaction;
import Dao.Persondao;
 
 
public class Personview {
 
public static Scanner scanner = new Scanner(System.in);
 
 
public static void main(String[] args) throws SQLException {
 
while (true) {
 
System.out.println("以下是数据库的各种操作:(标号为对应操作)");
 
System.out.println("0、退出数据库操作:");
 
System.out.println("1、查询全部记录:");
 
System.out.println("2、新增单条记录:");
 
System.out.println("3、更新单条记录:");
 
System.out.println("4、查询单条记录(通过id查询):");
 
System.out.println("5、查询部分记录(通过name查询):");
 
System.out.println("6、删除单条记录(通过id删除):");
 
 
String actionid = scanner.next();
// ("\\d+")是正则表达是,判断是否是数字
 
if (!actionid.matches("\\d+")) {
 
System.out.println("请输入正整数!");
 
continue;
 
}
 
int idchose = Integer.valueOf(actionid);
 
if (idchose == 0) {
 
break;
 
}
 
switch (idchose) {
 
 
case 1:
 
Personaction.selectall();
 
break;
 
case 2:
 
Personaction.addone();
 
break;
 
case 3:
 
Personaction.update();
 
break;
 
case 4:
 
Personaction.selectone();
 
break;
 
case 5:
 
Personaction.selectonebyname();
 
break;
 
case 6:
 
Personaction.deleteone();
 
break;
 
case 7:
 
 
break;
 
 
default:
 
System.out.println("请选择0-7之间操作~");
 
break;
 
}
 
}
 
 
// persondao = new Persondao();
 
// Personaction.addone();
 
// Personaction.deleteone();
 
// Personaction.selectall();
 
// Personaction.selectone();
 
// Personaction.update();
 
// Personaction.selectonebyname();
 
}
 
 
}
注意看我的Personview的逻辑设计,主要采用了while循环的方式,不过也有相应的退出操作以及判断是否合法代码,感觉这种方式的设计还是相当容易看懂的。
以上要分享的代码都贴了,该说的也说了,相信大家也都看得明白吧,如果你觉得我的文章对你有帮助的话,还希望你点赞、分享、转发,让更多的人看到,互相学习,交流! 好了,大家下篇文章见~~

JDBC(通俗易懂)简单的操作(增、删、改、查)_慕课手记

标签:let   his   建立   pack   cas   list   整数   img   修改   

原文地址:http://www.cnblogs.com/zsqfightyourway/p/7086414.html

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