JDBC实现增删改查功能

一、数据库结构

1、在本地 localhost，用户名 root ,密码为空，新建数据库 jdbc_study，新建数据表 users 表

users 表结构如下

有七个字段，分别是 id,name,password,birthday,email,create_date,status

二、代码实现

总共有4个类，分别是 DBUtil.java，Users.java，UsersDAO.java，UsersAction.java

采用 MVC 思想，虽然这里没有 View，测试可以在 UsersAction.java

为了方便管理分别建了四个包（package）,具体可以看代码头部

DBUtil.java

package com.liuyanzhao.db;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
/*
* @author LiuYanzhao
*/
public class DBUtil {
private static final String URL = "jdbc:mysql://127.0.0.1:3306/jdbc_study"
+ "?useUnicode=true&characterEncoding=utf8";//防止中文读取乱码
private static final String USER = "root";
private static final String PASSWORD = "";
public static Connection conn = null;
//静态代码块最先执行，先执行一次
static {
try {
//加载驱动
Class.forName("com.mysql.jdbc.Driver");
//获取连接
conn = DriverManager.getConnection(URL, USER, PASSWORD);
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
}
//单例模式，使对象唯一性
public static Connection getConnection() {
return conn;
}
public static void main(String[] args) {
}
}

Users.java

package com.liuyanzhao.model;
import java.sql.Date;
/*
* @author LiuYanzhao
*/
public class Users {
private int id;
private String name;
private String password;
private Date birthday;
private String Email;
private Date create_date;
private int status;
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 String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
public String getEmail() {
return Email;
}
public void setEmail(String email) {
Email = email;
}
public Date getCreate_date() {
return create_date;
}
public void setCreate_date(Date create_date) {
this.create_date = create_date;
}
public int getStatus() {
return status;
}
public void setStatus(int status) {
this.status = status;
}
}

UsersDAO.java

package com.liuyanzhao.dao;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.text.ParseException;
import java.util.ArrayList;
import java.util.List;
import com.liuyanzhao.db.DBUtil;
import com.liuyanzhao.model.Users;
/*
* @author LiuYanzhao
*/
public class UsersDAO {
//添加用户
public void addUsers(Users u) throws SQLException, ParseException {
Connection conn = DBUtil.getConnection();
String sql = " insert into users "
+ "(name,password,birthday,email,create_date,status)"
+ " value("
+ "?,?,?,?,current_date(),1"
+ ") ";
PreparedStatement ptmt = conn.prepareStatement(sql);
ptmt.setString(1, u.getName());
ptmt.setString(2, u.getPassword());
ptmt.setDate(3, u.getBirthday());
ptmt.setString(4, u.getEmail());
ptmt.executeUpdate();
}
//删除用户
public void deleUser(int id) throws SQLException {
Connection conn = DBUtil.getConnection();
String sql = " delete from users where id=?";
PreparedStatement ptmt = conn.prepareStatement(sql);
ptmt.setInt(1, id);
ptmt.executeUpdate();
}
//修改用户
public void updateUser(Users u) throws SQLException {
Connection conn = DBUtil.getConnection();
String sql = " update users set "
+ " name=?,password=?,birthday=?,email=?,"
+ " status=?"
+ " where id=?";
PreparedStatement ptmt = conn.prepareStatement(sql);
ptmt.setString(1, u.getName());
ptmt.setString(2, u.getPassword());
ptmt.setDate(3, u.getBirthday());
ptmt.setString(4, u.getEmail());
ptmt.setInt(5, u.getStatus());
ptmt.setInt(6, u.getId());
ptmt.executeUpdate();
}
//根据id查询单个用户
public Users get(int id) throws SQLException {
Connection conn = DBUtil.getConnection();
String sql = " select * from users where id=?";
PreparedStatement ptmt = conn.prepareStatement(sql);
ptmt.setInt(1, id);
ResultSet rs = ptmt.executeQuery();
Users u = null;
while(rs.next()) {
u = new Users();
u.setId(rs.getInt("id"));
u.setName(rs.getString("name"));
u.setPassword(rs.getString("password"));
u.setBirthday(rs.getDate("birthday"));
u.setEmail(rs.getString("email"));
u.setCreate_date(rs.getDate("create_date"));
u.setStatus(rs.getInt("status"));
}
return u;
}
//遍历用户信息
public List<Users> query() throws SQLException {
List<Users> result = new ArrayList<Users>();
Connection conn = DBUtil.getConnection();
String sql = " select * from users";
PreparedStatement ptmt = conn.prepareStatement(sql);
ResultSet rs = ptmt.executeQuery();
Users u = null;
while(rs.next()) {
u = new Users();
u.setId(rs.getInt("id"));
u.setName(rs.getString("name"));
u.setPassword(rs.getString("password"));
u.setBirthday(rs.getDate("birthday"));
u.setEmail(rs.getString("email"));
u.setCreate_date(rs.getDate("create_date"));
u.setStatus(rs.getInt("status"));
result.add(u);
}
return result;
}
}

UsersAction.java

package com.liuyanzhao.action;
import java.sql.Date;
import java.sql.SQLException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.List;
import com.liuyanzhao.dao.UsersDAO;
import com.liuyanzhao.model.Users;
/*
* @author LiuYanzhao
*/
public class UsersAction {
//添加用户
public void add(Users u) throws SQLException, ParseException {
UsersDAO dao = new UsersDAO();
dao.addUsers(u);
}
//删除用户
public void dele(int id) throws SQLException {
UsersDAO dao = new UsersDAO();
dao.deleUser(id);
}
//修改用户
public void edit(Users u) throws SQLException {
UsersDAO dao = new UsersDAO();
dao.updateUser(u);
}
//根据id查询单条用户
public Users get(int id) throws SQLException {
UsersDAO dao = new UsersDAO();
return dao.get(id);
}
//遍历查询所有用户
public List<Users> query() throws SQLException {
UsersDAO dao = new UsersDAO();
return dao.query();
}
public static void main(String[] args) throws ParseException, SQLException {
//添加用户测试
/*Users u = new Users();
u.setName("小田");
u.setPassword("123456");
u.setBirthday(new Date((new SimpleDateFormat("yyyy-MM-dd").parse("2006-8-10")).getTime()));
u.setEmail("xiaotian@126.com");
UsersAction action = new UsersAction();
action.add(u);*/
//删除用户测试
/*UsersAction action2 = new UsersAction();
action2.dele(5);*/
//更新用户测试
/*Users u3 = new Users();
u3.setId(7);
u3.setName("小雅");
u3.setPassword("aaaaaa");
u3.setBirthday(new Date((new SimpleDateFormat("yyyy-MM-dd").parse("2014-7-21")).getTime()));
u3.setEmail("xiaoya@126.com");
u3.setStatus(1);
UsersAction action3 = new UsersAction();
action3.edit(u3); */
//查询用户测试,单条数据
/*UsersAction action4 = new UsersAction();
Users u4 = action4.get(7);
System.out.println(u4.getId());
System.out.println(u4.getName());
System.out.println(u4.getPassword());
System.out.println(u4.getBirthday());
System.out.println(u4.getEmail());
System.out.println(u4.getCreate_date());
System.out.println(u4.getStatus());*/
//查询所有用户信息，遍历
UsersAction action5 = new UsersAction();
List<Users> list = action5.query();
for(int i=0;i<list.size();i++) {
System.out.print(list.get(i).getId()+" ");
System.out.print(list.get(i).getName()+" ");
System.out.print(list.get(i).getPassword()+" ");
System.out.print(list.get(i).getBirthday()+" ");
System.out.print(list.get(i).getEmail()+" ");
System.out.print(list.get(i).getCreate_date()+" ");
System.out.print(list.get(i).getStatus()+" ");
System.out.println();
}
}
}

三、知识拓展

1、JDBC常用API和使用

2、MySQL常用语句

3、execute、executeUpdate、executeQuery三者的区别

4、Java中PreparedStatement和Statement区别

5、java中ArrayList实例讲解

6、Java中如何使某个类的对象唯一性，只能创建一个对象

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