java 使用jdbc技术怎样连接同一个数据库,但有多个数据库名?

发布网友 发布时间：2022-04-09 17:47

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共1个回答

热心网友 时间：2022-04-09 19:16

将连接封装起来 一个工厂类
public class ConnectionFactory {

private static String _url = null;

private static String _user = null;

private static String _pwd = null;

private static String _driver = null;

public ConnectionFactory() {
// TODO Auto-generated constructor stub
}

static {
_driver = DBConfig.getDBConfig().getValue("driver");

_user = DBConfig.getDBConfig().getValue("user");

_pwd = DBConfig.getDBConfig().getValue("password");

_url = DBConfig.getDBConfig().getValue("url");

}

public static Connection getConnection() throws SQLException {
try {
Class.forName(_driver);
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
System.out.println("注册驱动失败");
e.printStackTrace();
throw new SQLException("注册驱动失败");
}
return DriverManager.getConnection(_url, _user, _pwd);
}

public static void release(Connection con, Statement stm, ResultSet rs) {
try {
if (con != null) {
con.close();
}
if (stm != null) {
con.close();
}
if (rs != null) {
rs.close();
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
然后再写一个配置文件
public class DBConfig {

private static DBConfig instance;
private static Properties info = new Properties();
private static String path = "dbconfig.properties";

public DBConfig() {
// TODO Auto-generated constructor stub
readDBConfig();
}

private void readDBConfig() {
InputStream inputStream = null;
try {
if (!(new File(path).exists())) {
path = "./bin/" + path;
}
inputStream = new FileInputStream(path);
info.load(inputStream);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
if (inputStream != null) {
try {
inputStream.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}

public synchronized static DBConfig getDBConfig() {
// 注意这里
if (instance == null) {
instance = new DBConfig();
}
return instance;
}

public String getValue(String key) {
return info.getProperty(key);
}

public static void main(String[] args) {
String driver = DBConfig.getDBConfig().getValue("driver");
String user = DBConfig.getDBConfig().getValue("user");
String pwd = DBConfig.getDBConfig().getValue("password");
String url = DBConfig.getDBConfig().getValue("url");
System.out.println(driver + '\n' + user + '\n' + pwd + '\n' + url);
}
}
到时调用的时候
你将DBConfig中放在一个.file文件中 读出来 下面就是DBConfig文件：是sqlserver的
想连接什么数据库 把driver url改一下就OK了 到网上查
driver=com.microsoft.jdbc.sqlserver.SQLServerDriver
url=jdbc:microsoft:sqlserver://localhost:1433;databaseName=pubs
user=sa
password=

ConnectionFactory.getConnection(); 这样一句话就连接上了

ConnectionFactory.release(); 就关闭相关对象了