An example of using astyanax, a Java client for Cassandra (excerpt from http://slidesha.re/wkf57g)

AstyanaxSample.java

public class AstyanaxSample {
    /** entry point for the cluster; read the docs at https://github.com/Netflix/astyanax/wiki/Getting-Started */
    private static final Keyspace keyspace = null; //null used for compilation; don't try this at home                                                                               
    /** declare/define the column family object */
    private static final ColumnFamily<String, MyCompositeColumn> ALLOCS_COLUMN_FAMILY =
            new ColumnFamily<String, MyCompositeColumn>("cust_allocs", StringSerializer.get(),
                    new AnnotatedCompositeSerializer<MyCompositeColumn>(MyCompositeColumn.class));

    /** annotated class to represent the composite column type for an allocation */
    private static class MyCompositeColumn {
        @Component(ordinal = 0)
        private Integer testId;

        @Component(ordinal = 1)
        private String field;

        public MyCompositeColumn() {  }

        public Integer getTestId() { return testId; }
        public void setTestId(Integer testId) { this.testId = testId; }

        public String getField() { return field; }
        public void setField(String field) { this.field = field; }
    }

    /* get all allocations for a customer */
    public List<Allocation> get(Long customerId){
        try{
            /* construct the query and send it to cassandra */
            ColumnList<MyCompositeColumn> columns = keyspace
                    .prepareQuery(ALLOCS_COLUMN_FAMILY)
                    .getKey(custIdToKey(customerId))
                    .execute()
                    .getResult();
            return readColumns(columns);
        } catch (Exception e){
            // don't do this at home                                                                                                                                                 
            return null;

    }

    /* pull data out of the columns and instantiate/populate the Allocation list */
    private List<Allocation> readColumns(ColumnList<MyCompositeColumn> columns){
        List<Allocation> list = new ArrayList<Allocation>();
        Allocation cur = null;
        for(Column<MyCompositeColumn> column : columns){
            Integer testId = column.getName().testId;
            if(cur == null || !cur.getTestID().equals(testId)){
                cur = new Allocation();
                cur.setTestID(testId);
                list.add(cur);
            }
            String field = column.getName().field;
            if(field.equals("cell"))
                cur.setCell(Integer.valueOf(column.getIntegerValue()));
            else if(field.equals("enabled"))
                cur.setEnabled(column.getStringValue());
        }
        return list;
    }
}

Comments intentionally short to not get in the way of the code.