DBUtil 封装数据库工具类

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

/*
* 数据库工具类
*/
public class DBUtil {

// 获取数据库连接
public static Connection getConnection() {
String driverClassName = "com.mysql.jdbc.Driver";
String url = "jdbc:mysql://localhost:3306/test";
String user = "root";
String password = "123456";
Connection conn = null;
try {
Class.forName(driverClassName);
conn = DriverManager.getConnection(url, user, password);
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
return conn;
}

// 关闭所有
public static void closeAll(ResultSet rs, Statement stmt, Connection conn) {
try {
if (rs != null)
rs.close();
if (st
4000
mt != null)
stmt.close();
if (conn != null) {
conn.close();
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
rs = null;
stmt = null;
conn = null;
}
}
}

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JDBC 数据库连接实例

登录

import java.awt.BorderLayout;
import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import javax.swing.JTextField;
import javax.swing.JLabel;
import java.awt.FlowLayout;
import javax.swing.JButton;

public class Login extends JFrame {

private JPanel contentPane;
private JTextField textField;

/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
Login frame = new Login();
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}

/**
* Create the frame.
*/
public Login() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 450, 300);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
contentPane.setLayout(new BorderLayout(0, 0));
setContentPane(contentPane);

JPanel panel = new JPanel();
contentPane.add(panel, BorderLayout.CENTER);
panel.setLayout(new FlowLayout(FlowLayout.CENTER, 5, 5));

JLabel label = new JLabel("用户名");
panel.add(label);

textField = new JTextField();
panel.add(textField);
textField.setColumns(20);

JButton btnNewButton = new JButton("登陆");
panel.add(btnNewButton);
}

}

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查询相关信息

import java.sql.Connection;
import java.sql.Date;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.List;

public class Test04 {
Connection conn = null;
PreparedStatement pstmt = null;
ResultSet rs = null;

// 根据编号查询用户信息
public User getUserById(int id) {
User user = null;
try {
Class.forName("com.mysql.jdbc.Driver");
conn = DriverManager.getConnection(
"jdbc:mysql://localhost:3306/test", "root", "123456");
/*
* stmt = conn.createStatement(); String sql =
* "select * from user where id=" + id;
*/
String sql = "select * from user where id=?";
pstmt = conn.prepareStatement(sql);
pstmt.setInt(1, id);
rs = pstmt.executeQuery();
if (rs.next()) {
user = new User(rs.getInt("id"), rs.getString("name"),
rs.getString("password"), rs.getInt("age"),
rs.getDate("birthday"));
}
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
} finally {
try {
rs.close();
pstmt.close();
conn.close();
} catch (SQLException e) {
e.printStackTrace();
} finally {
rs = null;
pstmt = null;
conn = null;
}
}
return user;
}

// 检查用户登陆，即判断用户名或密码是否正确
public boolean checkLogin(User user) {
boolean flag = false;
/*String sql = "select *  from user where name='" + user.getName()
+ "' and password='" + user.getPassword() + "'";*/
String sql="select * from user where name=? and password=?";

try {
Class.forName("com.mysql.jdbc.Driver");
conn = DriverManager.getConnection(
"jdbc:mysql://localhost:3306/test", "root", "123456");
pstmt=conn.prepareStatement(sql);
pstmt.setString(1, user.getName());
pstmt.setString(2, user.getPassword());
rs=pstmt.executeQuery();
if(rs.next()){
flag=true;
}
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}finally{
try {
rs.close();
pstmt.close();
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
return flag;
}

//查询所有用户信息
public List<User> getAllUser(){
List<User> users=new ArrayList<User>();
try {
Class.forName("com.mysql.jdbc.Driver");
conn = DriverManager.getConnection(
"jdbc:mysql://localhost:3306/test", "root", "123456");
String sql = "select * from user";
pstmt = conn.prepareStatement(sql);
rs = pstmt.executeQuery();
while(rs.next()) {
users.add(new User(rs.getInt("id"), rs.getString("name"),
rs.getString("password"), rs.getInt("age"),
rs.getDate("birthday")));
}
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
} finally {
try {
rs.close();
pstmt.close();
conn.close();
} catch (SQLException e) {
e.printStackTrace();
} finally {
rs = null;
pstmt = null;
conn = null;
}
}
return users;
}

//用户注册，即添加用户
public void addUser(User user){
String sql="insert into user values (null,?,?,?,?)";

//调用工具类，获取连接Connection
conn=DBUtil.getConnection();
try {
pstmt=conn.prepareStatement(sql);
pstmt.setString(1, user.getName());
pstmt.setString(2,user.getPassword());
pstmt.setInt(3, user.getAge());
pstmt.setDate(4, new Date(user.getBirthday().getTime()));//将java.util.Date转换为java.sql.Date
pstmt.executeUpdate();
System.out.println("添加用户成功！");
} catch (SQLException e) {
e.printStackTrace();
}finally{
DBUtil.closeAll(rs, pstmt, conn);
}
}

//根据编号删除用户信息
public void deleteUserById(int id){

}

//更新用户信息
public void updateUser(User user){

}

//根据编号范围和姓名模糊查询
public List<User> getUserByCondition(int sid,int eid,String name){

return null;
}

public static void main(String[] args) {
Test04 test = new Test04();
User user = test.getUserById(2);
System.out.println(user);

User user=new User("赵超","222222");
boolean flag=test.checkLogin(user);
System.out.println("是否登陆成功？"+flag);

List<User> users=test.getAllUser();
System.out.println(users);
SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");
java.util.Date birthday=null;
try {
birthday = sdf.parse("2014-2-14");
} catch (ParseException e) {
e.printStackTrace();
}
test.addUser(new User("余书石", "123456", 18, birthday));
}
}

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用户类,实体类

import java.util.Date;

/*
* 用户类,实体类
*/
public class User {
private int id;
private String name;
private String password;
private int age;
private Date birthday;

public User(int id, String name, String password, int age, Date birthday) {
super();
this.id = id;
this.name = name;
this.password = password;
this.age = age;
this.birthday = birthday;
}

public User() {
}

public User(String name, String password, int age, Date birthday) {
super();
this.name = name;
this.password = password;
this.age = age;
this.birthday = birthday;
}

public User(String name, String password) {
super();
this.name = name;
this.password = password;
}

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 int getAge() {
return age;
}

public void setAge(int age) {
this.age = age;
}

public Date getBirthday() {
return birthday;
}

public void setBirthday(Date birthday) {
this.birthday = birthday;
}

public String toString() {
return "User[id=" + id + ",name=" + name + ",age=" + age + ",birthday="
+ birthday + "]";
}

}

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创建数据库语句

create table user
(
id int primary key auto_increment,
name varchar(20) not null,
password varchar(20),
age int,
birthday date
);