Quick Demo

Java API uses DBConnection to execute scripts and functions on the DolphinDB server and facilitates data transfer between clients and servers.

The following example connects to a DolphinDB server as a guest user and executes a simple script. Make sure the DolphinDB server is started before establishing a connection.

Note: The variables YourHost and YourPort in the following TestDemo class should be specified as your actual host and port.

public class TestDBConnection {
    private static final String HOST = "localhost"; 
    private static final int PORT = 8848; 

    DBConnection dbConnection = new DBConnection();

    @Test
    public void testDBConnectAndRun() throws IOException {
        dbConnection.connect(HOST, PORT);
        Entity entity = dbConnection.run("x = 1+1; x;");
        dbConnection.close();
        
        System.out.println(entity.getString());
    }
}

Expected output:

Connect to localhost:8848.
2

Some functions (such as getFunctionViews) can only be executed with appropriate privileges. The following example connects to a DolphinDB server as an admin and executes a simple script.

public class TestDBConnection {
    private static final String HOST = "localhost"; 
    private static final int PORT = 8848; 
    private static final String USER = "admin"; 
    private static final String PASSWORD = "123456"; 

    DBConnection dbConnection = new DBConnection();

    @Test
    public void testAdminUserConnectAndRun() throws IOException {
        dbConnection.connect(HOST, PORT, USER, PASSWORD);
        Entity entity = dbConnection.run("getFunctionViews()");
        System.out.println(entity.getString());
    }
}

The output is expected to contain the function views saved on the DolphinDB server.

name    body                                                   
------- -------------------------------------------------------------
CONCAT1 def CONCAT1(X, Y){
  return string(X) + string(Y)
}    
instr   def instr(string1, string2, start_position = NULL, n...
nvl2    def nvl2(col, result1, result2){
  return iif(! isNu...

For a non-admin user, the following exception will be thrown:

java.io.IOException: 192.168.0.68:8848 Server response: 'getFunctionViews() => Only administrators can use function getFunctionViews.' script: 'getFunctionViews()'