Vaadin Web应用开发教程(50): SQLContainer-使用FreeformQuery

jerry VaadinWeb 2015年11月25日收藏

在大部分情况下使用TableQuery就可以满足应用要求，如果需要使用复杂查询，比如多表查询，则可以使用FreeformQuery。缺省情况下FreeformQuery为只读，如果需要支持写操作，可以自行实现FreeformQueryDelegate接口。

// Read-only queries
public StatementHelper getCountStatement()
public StatementHelper getQueryStatement(int offset, int limit)
public StatementHelper getContainsRowQueryStatement(Object... keys)

// Filtering and sorting
public void setFilters(List<Filter> filters)
public void setFilters(List<Filter> filters,
                       FilteringMode filteringMode)
public void setOrderBy(List<OrderBy> orderBys)
 
// Write support
public int storeRow(Connection conn, RowItem row)
public boolean removeRow(Connection conn, RowItem row)

使用多表查询，查询语句如下：

SELECT C.FIRSTNAME , C.LASTNAME , INV.ID,INV.TOTAL 
FROM CUSTOMER C 
INNER JOIN INVOICE INV
ON C.ID=INV.CUSTOMERID;

void openTable(VerticalLayout layout){
	try {
		JDBCConnectionPool pool = new SimpleJDBCConnectionPool(
				"org.hsqldb.jdbc.JDBCDriver",
				"jdbc:hsqldb:file:/hsqldb/data/sample", "SA", "", 2, 5);
		FreeformQuery query = new FreeformQuery(
				"SELECT C.FIRSTNAME , " +
				"C.LASTNAME , INV.ID,INV.TOTAL " +
				"FROM CUSTOMER C " +
				"INNER JOIN INVOICE INV " +
				"ON C.ID=INV.CUSTOMERID;", pool, "ID");
		SQLContainer container = new SQLContainer(query);
		Table table = new Table("All Invoices", container);
		table.setSelectable(true);

		layout.addComponent(table);
		
	} catch (SQLException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	}
	}