Java C3P0一台服务器多个数据库
早上好 正如标题所说,我想创建一个解决方案,使用连接池连接到同一Mysql服务器上的不同数据库。我遵循了以下帖子中指出的步骤: 我的解决办法是:Java C3P0一台服务器多个数据库,java,mysql,connection-pooling,c3p0,Java,Mysql,Connection Pooling,C3p0,早上好 正如标题所说,我想创建一个解决方案,使用连接池连接到同一Mysql服务器上的不同数据库。我遵循了以下帖子中指出的步骤: 我的解决办法是: public class DatabaseUtility { public static ComboPooledDataSource getDataSource(String db, String user, String pass) throws PropertyVetoException {
public class DatabaseUtility
{
public static ComboPooledDataSource getDataSource(String db, String user, String pass) throws PropertyVetoException
{
ComboPooledDataSource cpds = new ComboPooledDataSource();
cpds.setJdbcUrl("jdbc:mysql://X.X.X.X:3306/"+db);
cpds.setUser(user);
cpds.setPassword(pass);
// Optional Settings
cpds.setInitialPoolSize(5);
cpds.setMinPoolSize(5);
cpds.setAcquireIncrement(5);
cpds.setMaxPoolSize(20);
cpds.setMaxStatements(100);
return cpds;
}
public static void main(String[] args) throws SQLException
{
Connection connection = null;
PreparedStatement pstmt = null;
ResultSet resultSet = null;
try
{
//QUERY to DATABASE 1
ComboPooledDataSource dataSource = DatabaseUtility.getDataSource("bd1", "user1", "pass1");
connection = dataSource.getConnection();
pstmt = connection.prepareStatement("SELECT * FROM municipio");
System.out.println("The Connection Object is of Class: " + connection.getClass());
resultSet = pstmt.executeQuery();
while (resultSet.next())
{
System.out.println(resultSet.getString(1) + "," + resultSet.getString(2) + "," + resultSet.getString(3));
}
//QUERY to DATABASE 2
dataSource = DatabaseUtility.getDataSource("bd2", "user2", "pass2");
connection = dataSource.getConnection();
pstmt = connection.prepareStatement("SELECT * FROM alojamiento");
System.out.println("The Connection Object is of Class: " + connection.getClass());
resultSet = pstmt.executeQuery();
while (resultSet.next())
{
System.out.println(resultSet.getString(1) + "," + resultSet.getString(2) + "," + resultSet.getString(3));
}
}
catch (Exception e)
{
connection.rollback();
e.printStackTrace();
}
}
}
每次连接到数据库时,我都使用特定的连接字符串调用构造函数
然而,我怀疑这是否是一个有效的解决方案,或者我做错了什么
另外,我正在使用一个没有Spring的项目
谢谢你的建议,提前谢谢
您好。不,这绝对不是一个有效的解决方案。每次您想要获取连接时,都会创建一个新的连接池。试试这样的
private static ComboPooledDataSource createDataSource(String db, String user, String pass) {
ComboPooledDataSource cpds = new ComboPooledDataSource();
cpds.setJdbcUrl("jdbc:mysql://X.X.X.X:3306/"+db);
cpds.setUser(user);
cpds.setPassword(pass);
// Optional Settings
cpds.setInitialPoolSize(5);
cpds.setMinPoolSize(5);
cpds.setAcquireIncrement(5);
cpds.setMaxPoolSize(20);
cpds.setMaxStatements(100);
return cpds;
}
private static final class DbUserPassword {
final String db;
final String user;
final String password;
DbUserPassword( String db, String user, String password ) {
this.db = db;
this.user = user;
this.password = password;
}
@Override
public boolean equals( Object o ) {
if ( o instanceof DbUserPassword ) {
DbUserPassword that = (DbUserPassword) o;
return ( this.db.equals( that.db ) && this.user.equals( that.user ) && this.password.equals( that.password ) );
}
else {
return false;
}
}
@Override
public int hashCode() {
return db.hashCode() ^ user.hashCode() ^ password.hashCode();
}
}
// MT: protected by class' lock
private static HashMap<DbUserPassword,ComboPooledDataSource> poolMap = new HashMap<>();
public static synchronized ComboPooledDataSource getDataSource(String db, String user, String pass) {
DbUserPassword dbup = new DbUserPassword( db, user, pass );
ComboPooledDataSource out = poolMap.get(dbup);
if ( out == null ) {
out = createDataSource( db, user, pass );
poolMap.put( dbup, out );
}
return out;
}
私有静态ComboPooledDataSource createDataSource(字符串数据库、字符串用户、字符串传递){
ComboPooledDataSource cpds=新ComboPooledDataSource();
setJdbcUrl(“jdbc:mysql://X.X.X.X:3306/“+db);
设置用户(用户);
设置密码(pass);
//可选设置
设置初始池大小(5);
设置最小池大小(5);
cpds.setAcquireIncrement(5);
设置最大池大小(20);
cpds.setMaxStatements(100);
返回CPD;
}
私有静态最终类DbUserPassword{
最终字符串db;
最终字符串用户;
最终字符串密码;
DbUserPassword(字符串数据库、字符串用户、字符串密码){
这个.db=db;
this.user=用户;
this.password=密码;
}
@凌驾
公共布尔等于(对象o){
if(o DbUserPassword的instanceof){
DbUserPassword,它=(DbUserPassword)o;
返回(this.db.equals(that.db)&&this.user.equals(that.user)&&this.password.equals(that.password));
}
否则{
返回false;
}
}
@凌驾
公共int hashCode(){
返回db.hashCode()^user.hashCode()^password.hashCode();
}
}
//MT:受类“锁”保护
私有静态HashMap poolMap=新HashMap();
公共静态同步ComboPooledDataSource getDataSource(字符串数据库、字符串用户、字符串传递){
DbUserPassword dbup=新的DbUserPassword(db,user,pass);
ComboPooledDataSource out=poolMap.get(dbup);
if(out==null){
out=createDataSource(数据库、用户、过程);
poolMap.put(dbup,out);
}
返回;
}
这正是我需要的,非常感谢!我试过了,效果很好!MiguelPérezMartínez您能告诉我,现在您在代码中如何调用上面的Steve Waldman解决方案吗,那么调用数据源函数两次?