你有一个简单的数据库的源代码吗？最好用Java实现的...

Question

如题所述

Answer 1

class ConnectionProvider{
private static String JDBC_DRIVER;
private static String DB_URL;
private static String DB_USER;
private static String DB_PASSWORD;

public ConnectionProvider()
{
JDBC_DRIVER = "com.mysql.jdbc.Driver"
DB_URL = "jdbc:mysql://localhost:3306/u-disk";
DB_USER = "root";
DB_PASSWORD = "root"
};
public Connection getConnection()
{
try {
Class.forName(JDBC_DRIVER);
} catch (Exception e) {
System.out.println("驱动文件路径有误！");
}
}
Connection con = null;
try {
con = DriverManager.getConnection(DB_URL, DB_USER,
DB_PASSWORD);
} catch (SQLException e) {
System.out.println("数据库连接建立异常！\n@shy2850@" + e.getMessage() +
e.getCause());
}
System.out.println("得到连接:Connection " + ConnectionPool.connections.size() + 1);
return new ConnectionImpl(con);
}
}

可以使用这个包装的数据库连接数据源在DAO工具类中使用：

package com.jdbc;

import java.sql.*;

/**课题：封装数据库的增删改查的工具类的实现。
*
* 假设相关数据库的表结构如下：
* 表名：user
* 列名及属性：id(int 自增)，name(varchar(20))，tele(char(12))，birthday(date)
* @author shy2850
*/
public class UserDAO {

Connection conn;

public UserDAO(Connection conn) {
this.conn = conn;
}

public int save(User user) throws SQLException {
String sql = "insert into user values(0,?,?,?)";
PreparedStatement pstmt = conn.prepareStatement(sql);
pstmt.setString(1, user.getName());
pstmt.setString(2, user.getTele());
pstmt.setDate(3, user.getBirthday());
int n = pstmt.executeUpdate();
pstmt.close();
return n;
}

public int delete(User user) throws SQLException{
String sql = "delete from user where id = "+user.getId();
Statement stmt = conn.createStatement();
int n = stmt.executeUpdate(sql);
stmt.close();
return n;
}

public int update(User user) throws SQLException{
String sql = "update user set name=?, tele=?, birthday=? where id = "+user.getId();
PreparedStatement pstmt = conn.prepareStatement(sql);
pstmt.setString(2, user.getName());
pstmt.setString(3, user.getTele());
pstmt.setDate(4, user.getBirthday());
int n = pstmt.executeUpdate(sql);
pstmt.close();
return n;
}

public User getUser(Integer id) throws SQLException{
String sql = "select * from user where id = " + id;
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery(sql);
User user = getUserFromResultSet(rs);
rs.close();
stmt.close();
return user;
}

static User getUserFromResultSet(ResultSet rs) throws SQLException{
Integer id = rs.getInt("id");
String name= rs.getString("name");
String tele= rs.getString("tele");
Date birthday = rs.getDate("birthday");
return new User(id, name, tele, birthday);
}
}
/**
* 构建数据库表的java类映射
*/
class User{
private Integer id;
private String name;
private String tele;
private Date birthday;

public User() {
}
public User(Integer id, String name, String tele, Date birthday) {
super();
this.id = id;
this.name = name;
this.tele = tele;
this.birthday = birthday;
}

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 getTele() {
return tele;
}

public void setTele(String tele) {
this.tele = tele;
}

public Date getBirthday() {
return birthday;
}

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