Java 雙指針項目中的實際應用

背景說明

最近在做財務相關的系統，對賬單核銷預付款
從技術角度來看就是將兩個數組進行合併

對賬單核銷預付款前提條件：

1. 對賬單總金額必須等於未核銷金額

數據示例

對賬單數據

預付款數據

結果數據

通過分析可以使用JAVA雙指針演算法可以實現這個需求
雙指針主要用於遍曆數組，兩個指針指向不同的元素，從而協同完成任務。

代碼實現

public static void main(String[] args) {
    class Info {
        private String formId;
        private BigDecimal amount;
    
        public String getFormId() {
            return formId;
        }
    
        public void setFormId(String formId) {
            this.formId = formId;
        }
    
        public BigDecimal getAmount() {
            return amount;
        }
    
        public void setAmount(BigDecimal amount) {
            this.amount = amount;
        }
    }
    
    List<Info> billBatchlist = new ArrayList<>();
    Info info = new Info();
    info.setFormId("B0001");
    info.setAmount(new BigDecimal(100));
    billBatchlist.add(info);
    info = new Info();
    info.setFormId("B0002");
    info.setAmount(new BigDecimal(80));
    billBatchlist.add(info);
    info = new Info();
    info.setFormId("B0003");
    info.setAmount(new BigDecimal(120));
    billBatchlist.add(info);
    
    List<Info> payVerifyControlList = new ArrayList<>();
    Info info1 = new Info();
    info1.setFormId("PRE0001");
    info1.setAmount(new BigDecimal(110));
    payVerifyControlList.add(info1);
    info1 = new Info();
    info1.setFormId("PRE0002");
    info1.setAmount(new BigDecimal(190));
    payVerifyControlList.add(info1);
    billBatchlist.forEach(a -> {
        System.out.println("BillFormId:" + a.formId + ",Amount:" + a.getAmount());
    });
    payVerifyControlList.forEach(a -> {
        System.out.println("PreFormId:" + a.formId + ",Amount:" + a.getAmount());
    });
    System.out.println("==================================");
    
    int i = 0, j = 0;
    BigDecimal preAmount = new BigDecimal(0);
    BigDecimal billAmount = new BigDecimal(0);
    while (i < billBatchlist.size() && j < payVerifyControlList.size()) {
        if (preAmount.compareTo(BigDecimal.ZERO) == 0) {
            preAmount = billBatchlist.get(i).amount;
        }
        if (billAmount.compareTo(BigDecimal.ZERO) == 0) {
            billAmount = payVerifyControlList.get(j).amount;
        }
    
        //當前核銷金額
        BigDecimal verifyAmount = new BigDecimal(0);
        if (preAmount.compareTo(billAmount) > -1) {
            verifyAmount = billAmount;
            // pre剩餘
            preAmount = preAmount.subtract(verifyAmount);
            billAmount = new BigDecimal(0);
        } else {
            verifyAmount = preAmount;
            // bill剩餘
            billAmount = billAmount.subtract(verifyAmount);
            preAmount = new BigDecimal(0);
        }
    
        System.out.println("當前核銷金額：" + verifyAmount + ",preAmount剩餘:" + preAmount + ",billAmount剩餘:" + billAmount);
        //大於等於0
        if (preAmount.compareTo(BigDecimal.ZERO) == 0) {
            i++;
        }
        if (billAmount.compareTo(BigDecimal.ZERO) == 0) {
            j++;
        }
    }
    }

列印結果：

BillFormId:B0001,Amount:100
BillFormId:B0002,Amount:80
BillFormId:B0003,Amount:120
PreFormId:PRE0001,Amount:110
PreFormId:PRE0002,Amount:190
==================================
當前核銷金額：100,preAmount剩餘:0,billAmount剩餘:10
當前核銷金額：10,preAmount剩餘:70,billAmount剩餘:0
當前核銷金額：70,preAmount剩餘:0,billAmount剩餘:120
當前核銷金額：120,preAmount剩餘:0,billAmount剩餘:0

作者：taoz
出處：www.cnblogs.com/bigbrid
本文版權歸作者和博客園共有，歡迎轉載，但未經作者同意必須保留此段聲明，且在文章頁面明顯位置給出原文連接，否則保留追究法律責任的權利。

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