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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
Java中List根据对象的属性值进行数据库group by功能的操作
时间：2021-07-01 10:21:17
帮助过：2人阅读
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 }
View Code
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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