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Java中List根据对象的属性值进行数据库group by功能的操作
1 public class test { 2 public static void main(String[] args) { 3 4 List<Bill> list = new test().setObject(); 5 6 Set<String> set = new HashSet(); 7 8 for (Bill bills : list) { 9 set.add(bills.getTradeTime().substring(0, 8)); 10 } 11 12 List list1 = new ArrayList(); 13 int paySuccess = 0; 14 int dfSuccess = 0; 15 int fee = 0; 16 int count = 0; 17 //遍历set集合中的日期 18 for (String a : set) { 19 for (Bill bill : list) { 20 if (a.equals(bill.getTradeTime().substring(0, 8))) { 21 paySuccess += bill.getMoney(); 22 fee += bill.getFee(); 23 count++; 24 if ("承兑或交易成功".equals(bill.getType())) 25 dfSuccess += bill.getMoney(); 26 } 27 } 28 Object[] objects = new Object[10]; 29 objects[0] = new BigDecimal(paySuccess); 30 objects[1] = new BigDecimal(dfSuccess); 31 objects[2] = new BigDecimal(fee); 32 objects[3] = new BigDecimal(paySuccess-fee); 33 objects[4] = a; 34 list1.add(objects); 35 System.out.println("支付成功金额:" + objects[0] + "\t" + "承兑或交易成功: " + objects[1] + "\t" + objects[4] + "\t" + "手续费:" + objects[2] + "\t" + "商户结算" + 36 "金额:" + objects[3] + "\t" + "交易笔数:" + count + "\t日期:" + a); 37 paySuccess = 0; 38 dfSuccess = 0; 39 fee = 0; 40 count = 0; 41 } 42 String date = null; 43 System.out.println(date == null || date.isEmpty()); 44 } 45 46 public List<Bill> setObject() { 47 List<Bill> list = new ArrayList<Bill>(); 48 Bill bill = new Bill(); 49 bill.setTradeTime("201605050203"); 50 bill.setMoney(2); 51 bill.setPayType("支付成功"); 52 bill.setType("承兑或交易成功"); 53 bill.setFee(1); 54 list.add(bill); 55 56 bill = new Bill(); 57 bill.setTradeTime("201605060203"); 58 bill.setMoney(3); 59 bill.setType(""); 60 bill.setPayType("支付成功"); 61 bill.setFee(1); 62 list.add(bill); 63 64 bill = new Bill(); 65 bill.setMoney(4); 66 bill.setTradeTime("201605050203"); 67 bill.setPayType("支付成功"); 68 bill.setType("承兑或交易成功"); 69 bill.setFee(1); 70 list.add(bill); 71 72 bill = new Bill(); 73 bill.setType(""); 74 bill.setPayType("支付成功"); 75 bill.setTradeTime("201605060203"); 76 bill.setMoney(4); 77 bill.setFee(1); 78 list.add(bill); 79 return list; 80 } 81 } 82 83 class Bill { 84 int money; 85 String type; 86 String tradeTime; 87 String payType; 88 int fee; 89 90 public String getPayType() { 91 return payType; 92 } 93 94 public void setPayType(String payType) { 95 this.payType = payType; 96 } 97 98 public int getMoney() { 99 return money; 100 } 101 102 public void setMoney(int money) { 103 this.money = money; 104 } 105 106 public String getType() { 107 return type; 108 } 109 110 public void setType(String type) { 111 this.type = type; 112 } 113 114 public String getTradeTime() { 115 return tradeTime; 116 } 117 118 public void setTradeTime(String tradeTime) { 119 this.tradeTime = tradeTime; 120 } 121 122 public int getFee() { 123 return fee; 124 } 125 126 public void setFee(int fee) { 127 this.fee = fee; 128 } 129 130 @Override 131 public String toString() { 132 return "Bill{" + 133 "money=" + money + 134 ", type=‘" + type + ‘\‘‘ + 135 ", tradeTime=‘" + tradeTime + ‘\‘‘ + 136 ", payType=‘" + payType + ‘\‘‘ + 137 ‘}‘; 138 } 139 }
我的思路是先用set集合对对象的某个属性中不重复的值进行筛选,然后进行计算
如果有更好的方法请在下面留言!
Java中List根据对象的属性值进行数据库group by功能的操作
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