如何從Java列表中獲取特定列列表

Question

我從某個表中獲取列表，並且我想從該列表中獲取特定列。

列表來自，

List<StockInwordBean> stockInwordList = siDaoImpl.getStockInwordBeans(); 

它獲取的結果，（當控制檯打印）

[StockInwordBean [srno=2, date=2014-01-16, itemName=666, itemCode=1, metal=Silver, seal=21, itemGroup=21, itemSubGroup=21, variety=21, center=21, quantity=2, weight=1000.0, lessWeight=0.000, addWeight=0.0, recivedTunch=75.00, recivedWastage=10.00, fine=850.0, itemSize=21, recivedMakingChargesBy=Kg, recivedMakingRate=100.00, recivedMakingAmount=100, saleMakingChargesBy=Kg, saleMakingRate=150.00, saleWastage=5.00], StockInwordBean [srno=3, date=2014-01-16, itemName=121, itemCode=145, metal=Silver, seal=21, itemGroup=21, itemSubGroup=21, variety=21, center=21, quantity=2, weight=12.0, lessWeight=12.000, addWeight=12.0, recivedTunch=1.00, recivedWastage=21.00, fine=21.0, itemSize=21, recivedMakingChargesBy=Kg, recivedMakingRate=21.00, recivedMakingAmount=2, saleMakingChargesBy=Kg, saleMakingRate=11.00, saleWastage=21.00], StockInwordBean [srno=1, date=2014-01-16, itemName=1, itemCode=188, metal=Fine, seal=21, itemGroup=21, itemSubGroup=212, variety=12, center=1, quantity=21, weight=12.0, lessWeight=21.000, addWeight=21.0, recivedTunch=21.00, recivedWastage=21.00, fine=21.0, itemSize=21, recivedMakingChargesBy=Kg, recivedMakingRate=12.00, recivedMakingAmount=12, saleMakingChargesBy=Kg, saleMakingRate=21.00, saleWastage=21.00], StockInwordBean [srno=9, date=2014-01-17, itemName=111111, itemCode=45, metal=Patala, seal=54, itemGroup=54, itemSubGroup=5, variety=45, center=45, quantity=45, weight=45.0, lessWeight=45.000, addWeight=45.0, recivedTunch=45.00, recivedWastage=45.00, fine=4.0, itemSize=54, recivedMakingChargesBy=Kg, recivedMakingRate=54.00, recivedMakingAmount=54, saleMakingChargesBy=Kg, saleMakingRate=545.00, saleWastage=4.00], StockInwordBean [srno=7, date=2014-01-16, itemName=454, itemCode=5, metal=Silver, seal=54, itemGroup=54, itemSubGroup=54, variety=54, center=54, quantity=54, weight=54.0, lessWeight=54.000, addWeight=54.0, recivedTunch=54.00, recivedWastage=54.00, fine=54.0, itemSize=5, recivedMakingChargesBy=Kg, recivedMakingRate=5.00, recivedMakingAmount=45, saleMakingChargesBy=Kg, saleMakingRate=54.00, saleWastage=45.00], StockInwordBean [srno=4, date=2014-01-16, itemName=54, itemCode=54, metal=Fine, seal=545, itemGroup=4, itemSubGroup=54, variety=54, center=54, quantity=54, weight=54.0, lessWeight=545.000, addWeight=45.0, recivedTunch=45.00, recivedWastage=45.00, fine=4.0, itemSize=545, recivedMakingChargesBy=Kg, recivedMakingRate=54.00, recivedMakingAmount=54, saleMakingChargesBy=Kg, saleMakingRate=54.00, saleWastage=54.00], StockInwordBean [srno=8, date=2014-01-16, itemName=4, itemCode=5454, metal=Silver, seal=54, itemGroup=45, itemSubGroup=54, variety=54, center=54, quantity=54, weight=5.0, lessWeight=45.000, addWeight=45.0, recivedTunch=4.00, recivedWastage=56.00, fine=6.0, itemSize=546, recivedMakingChargesBy=Kg, recivedMakingRate=645.00, recivedMakingAmount=64, saleMakingChargesBy=Kg, saleMakingRate=4645.00, saleWastage=6.00], StockInwordBean [srno=6, date=2014-01-16, itemName=656, itemCode=56, metal=Fine, seal=5, itemGroup=65, itemSubGroup=65, variety=65, center=65, quantity=65, weight=65.0, lessWeight=6.000, addWeight=56.0, recivedTunch=56.00, recivedWastage=56.00, fine=5.0, itemSize=65, recivedMakingChargesBy=Kg, recivedMakingRate=56.00, recivedMakingAmount=5, saleMakingChargesBy=Kg, saleMakingRate=65.00, saleWastage=65.00], StockInwordBean [srno=5, date=2014-01-16, itemName=89, itemCode=8, metal=Fine, seal=98, itemGroup=98, itemSubGroup=98, variety=9, center=89, quantity=89, weight=89.0, lessWeight=89.000, addWeight=8.0, recivedTunch=98.00, recivedWastage=98.00, fine=98.0, itemSize=9, recivedMakingChargesBy=Kg, recivedMakingRate=98.00, recivedMakingAmount=98, saleMakingChargesBy=Kg, saleMakingRate=9.00, saleWastage=89.00], StockInwordBean [srno=10, date=2014-01-17, itemName=7, itemCode=878, metal=Silver, seal=7, itemGroup=87, itemSubGroup=87, variety=87, center=87, quantity=8, weight=787.0, lessWeight=8.000, addWeight=78.0, recivedTunch=7.00, recivedWastage=87.00, fine=87.0, itemSize=87, recivedMakingChargesBy=Nos, recivedMakingRate=78.00, recivedMakingAmount=7, saleMakingChargesBy=Nos, saleMakingRate=87.00, saleWastage=8.00]] 

注：這是類型的簡單數組列表，

這裏我只需要列表中的「itemName」列的特定列表。

我都試過了，

List<String> col = new ArrayList<String>(); 
for(int i=0 ;i< stockInwordList.size();i++) 
{ 
     col.add(stockInwordList.get(i).toString()); 
     System.out.println("col is.."+col.get(i)); 

} 

但它可以讓列表作爲，（當控制檯打印）

col is..StockInwordBean [srno=3, date=2014-01-16, itemName=121, itemCode=145, metal=Silver, seal=21, itemGroup=21, itemSubGroup=21, variety=21, center=21, quantity=2, weight=12.0, lessWeight=12.000, addWeight=12.0, recivedTunch=1.00, recivedWastage=21.00, fine=21.0, itemSize=21, recivedMakingChargesBy=Kg, recivedMakingRate=21.00, recivedMakingAmount=2, saleMakingChargesBy=Kg, saleMakingRate=11.00, saleWastage=21.00] 
col is..StockInwordBean [srno=1, date=2014-01-16, itemName=1, itemCode=188, metal=Fine, seal=21, itemGroup=21, itemSubGroup=212, variety=12, center=1, quantity=21, weight=12.0, lessWeight=21.000, addWeight=21.0, recivedTunch=21.00, recivedWastage=21.00, fine=21.0, itemSize=21, recivedMakingChargesBy=Kg, recivedMakingRate=12.00, recivedMakingAmount=12, saleMakingChargesBy=Kg, saleMakingRate=21.00, saleWastage=21.00] 
col is..StockInwordBean [srno=9, date=2014-01-17, itemName=111111, itemCode=45, metal=Patala, seal=54, itemGroup=54, itemSubGroup=5, variety=45, center=45, quantity=45, weight=45.0, lessWeight=45.000, addWeight=45.0, recivedTunch=45.00, recivedWastage=45.00, fine=4.0, itemSize=54, recivedMakingChargesBy=Kg, recivedMakingRate=54.00, recivedMakingAmount=54, saleMakingChargesBy=Kg, saleMakingRate=545.00, saleWastage=4.00] 
col is..StockInwordBean [srno=7, date=2014-01-16, itemName=454, itemCode=5, metal=Silver, seal=54, itemGroup=54, itemSubGroup=54, variety=54, center=54, quantity=54, weight=54.0, lessWeight=54.000, addWeight=54.0, recivedTunch=54.00, recivedWastage=54.00, fine=54.0, itemSize=5, recivedMakingChargesBy=Kg, recivedMakingRate=5.00, recivedMakingAmount=45, saleMakingChargesBy=Kg, saleMakingRate=54.00, saleWastage=45.00] 
col is..StockInwordBean [srno=4, date=2014-01-16, itemName=54, itemCode=54, metal=Fine, seal=545, itemGroup=4, itemSubGroup=54, variety=54, center=54, quantity=54, weight=54.0, lessWeight=545.000, addWeight=45.0, recivedTunch=45.00, recivedWastage=45.00, fine=4.0, itemSize=545, recivedMakingChargesBy=Kg, recivedMakingRate=54.00, recivedMakingAmount=54, saleMakingChargesBy=Kg, saleMakingRate=54.00, saleWastage=54.00] 
col is..StockInwordBean [srno=8, date=2014-01-16, itemName=4, itemCode=5454, metal=Silver, seal=54, itemGroup=45, itemSubGroup=54, variety=54, center=54, quantity=54, weight=5.0, lessWeight=45.000, addWeight=45.0, recivedTunch=4.00, recivedWastage=56.00, fine=6.0, itemSize=546, recivedMakingChargesBy=Kg, recivedMakingRate=645.00, recivedMakingAmount=64, saleMakingChargesBy=Kg, saleMakingRate=4645.00, saleWastage=6.00] 
col is..StockInwordBean [srno=6, date=2014-01-16, itemName=656, itemCode=56, metal=Fine, seal=5, itemGroup=65, itemSubGroup=65, variety=65, center=65, quantity=65, weight=65.0, lessWeight=6.000, addWeight=56.0, recivedTunch=56.00, recivedWastage=56.00, fine=5.0, itemSize=65, recivedMakingChargesBy=Kg, recivedMakingRate=56.00, recivedMakingAmount=5, saleMakingChargesBy=Kg, saleMakingRate=65.00, saleWastage=65.00] 
col is..StockInwordBean [srno=5, date=2014-01-16, itemName=89, itemCode=8, metal=Fine, seal=98, itemGroup=98, itemSubGroup=98, variety=9, center=89, quantity=89, weight=89.0, lessWeight=89.000, addWeight=8.0, recivedTunch=98.00, recivedWastage=98.00, fine=98.0, itemSize=9, recivedMakingChargesBy=Kg, recivedMakingRate=98.00, recivedMakingAmount=98, saleMakingChargesBy=Kg, saleMakingRate=9.00, saleWastage=89.00] 
col is..StockInwordBean [srno=10, date=2014-01-17, itemName=7, itemCode=878, metal=Silver, seal=7, itemGroup=87, itemSubGroup=87, variety=87, center=87, quantity=8, weight=787.0, lessWeight=8.000, addWeight=78.0, recivedTunch=7.00, recivedWastage=87.00, fine=87.0, itemSize=87, recivedMakingChargesBy=Nos, recivedMakingRate=78.00, recivedMakingAmount=7, saleMakingChargesBy=Nos, saleMakingRate=87.00, saleWastage=8.00] 

所以，請幫我拿到名單爲，

ITEMNAME = 666

itemName = 121

itemName = 1 。 。 。

在此先感謝。

Answer 1

你只是循環包含StockInwordBean的列表並使用toString（）將對象轉換爲String。相反，您必須將每個對象的特定屬性添加到不同的列表中。

請試試這個代碼：

List<String> col = new ArrayList<String>(); 
for(StockInwordBean si : stockInwordList){ 
    col.add(si.getItemName()); 
} 

Answer 2

你存儲對象的toString不是你想要的值。

getItemName是getter方法。

請嘗試以下代碼段。

List<String> col = new ArrayList<String>(); 
for(int i=0 ;i< stockInwordList.size();i++) 
{ 
     col.add(stockInwordList.get(i).getItemName()); 
     System.out.println("col is.."+col.get(i)); 

}