Java JDBC连接数据库实例
问题描述：向数据库按照一定规则增加记录，显示一条一条记录向数据库中增加不是好的方式，应该由程序去实现。
现在给出实例：
JdbcUtils工具类：
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Properties;
/**
*
* JDBC工具类，回去数据库连接和释放连接
*/
public class JdbcUtils {
private static String driver = null;
private static String url = null;
private static String username = null;
private static String password = null;
// 加载驱动，获取数据库连接信息
static {
try {
// 加载配置文件
InputStream in = JdbcUtils.class.getClassLoader()
.getResourceAsStream("DB.properties");
Properties properties = new Properties();
properties.load(in);
driver = properties.getProperty("driver");
url = properties.getProperty("url");
username = properties.getProperty("username");
password = properties.getProperty("password");
// 加载驱动
Class.forName(driver);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
/**
*
* 获取数据库连接
*
* @throws SQLException
*/
public static Connection getConnection() {
try {
return DriverManager.getConnection(url, username, password);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
/**
* 释放资源
*
* @param connection
* @param preparedStatement
* @param resultSet
*/
public static void releaseDB(Connection connection,
PreparedStatement preparedStatement, ResultSet resultSet) {
if (connection != null) {
try {
connection.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (preparedStatement != null) {
try {
preparedStatement.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (resultSet != null) {
try {
resultSet.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}DB.properties 配置文件
driver=com.mysql.jdbc.Driver
url=jdbc:mysql://目标URL/数据库
username=#your 用户名
password=# your 密码JdbcTest CRUD 操作
import java.sql.Connection;
import java.sql.Date;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
public class JdbcTest {
/*
* 增加
*/
public void create() {
Connection connection = null;
PreparedStatement preparedStatement = null;
try {
// 获取连接
connection = JdbcUtils.getConnection();
String carnumber_head = "甬-K-1F-";
for (int i = 1; i <= 100; i++) {
if (i < 10) {
// System.out.println("value------>>>" + carnumber_head+"000" + i);
// 准备sql语句
String sql = "INSERT INTO cx_carnumberpool(carnumber) VALUES(?)";
// 获取PrepareStatement对象
preparedStatement = connection.prepareStatement(sql);
// 填充占位符
preparedStatement.setString(1, carnumber_head+"000" + i);
int num = preparedStatement.executeUpdate();// 返回影响到的行数
System.out.println("一共影响到" + num + "行");
} else if (i < 100) {
// 准备sql语句
String sql = "INSERT INTO cx_carnumberpool(carnumber) VALUES(?)";
// 获取PrepareStatement对象
preparedStatement = connection.prepareStatement(sql);
// 填充占位符
preparedStatement.setString(1, carnumber_head+"00" + i);
int num = preparedStatement.executeUpdate();// 返回影响到的行数
System.out.println("一共影响到" + num + "行");
} else if (i < 1000) {
// 准备sql语句
String sql = "INSERT INTO cx_carnumberpool(carnumber) VALUES(?)";
// 获取PrepareStatement对象
preparedStatement = connection.prepareStatement(sql);
// 填充占位符
preparedStatement.setString(1, carnumber_head+"0" + i);
int num = preparedStatement.executeUpdate();// 返回影响到的行数
System.out.println("一共影响到" + num + "行");
}
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
JdbcUtils.releaseDB(connection, preparedStatement, null);
}
}
/*
* 读取查询
*/
public void retrieve() {
Connection connection = null;
PreparedStatement preparedStatement = null;
ResultSet resultSet = null;
try {
connection = JdbcUtils.getConnection();
String sql = "SELECT user_name,user_password,user_birth FROM user";
preparedStatement = connection.prepareStatement(sql);
resultSet = preparedStatement.executeQuery();
// 遍历结果集
while (resultSet.next()) {
String username = resultSet.getString(1);
String password = resultSet.getString(2);
Date userbirth = resultSet.getDate(3);
System.out.println(username + ":" + password + ":" + userbirth);
}
} catch (Exception e) {
// TODO: handle exception
} finally {
JdbcUtils.releaseDB(connection, preparedStatement, resultSet);
}
}
/*
* 修改更新
*/
public void update() {
Connection connection = null;
PreparedStatement preparedStatement = null;
try {
connection = JdbcUtils.getConnection();
String sql = "UPDATE USER SET user_password = ? WHERE user_name = ?";
preparedStatement = connection.prepareStatement(sql);
preparedStatement.setString(1, "passwordupdate");
preparedStatement.setString(2, "mary");
int num = preparedStatement.executeUpdate();
System.out.println("一共影响到" + num + "行");
} catch (Exception e) {
// TODO: handle exception
} finally {
JdbcUtils.releaseDB(connection, preparedStatement, null);
}
}
/*
* 删除
*/
public void delete() {
Connection connection = null;
PreparedStatement preparedStatement = null;
try {
connection = JdbcUtils.getConnection();
String sql = "DELETE FROM user WHERE user_id = ?";
preparedStatement = connection.prepareStatement(sql);
preparedStatement.setInt(1, 3);
int num = preparedStatement.executeUpdate();
System.out.println("一共影响到" + num + "行");
} catch (Exception e) {
// TODO: handle exception
} finally {
JdbcUtils.releaseDB(connection, preparedStatement, null);
}
}
public static void main(String[] args) {
JdbcTest test = new JdbcTest();
test.create();
}
}实例会上传至CSDN 资源中