From cce92983fdef344aad77d6ec68720960d7c4dcc1 Mon Sep 17 00:00:00 2001
From: ggg444 <sony11112222@sina.com>
Date: Wed, 15 Sep 2021 08:27:45 +0000
Subject: [PATCH] =?UTF-8?q?=E4=BC=98=E5=8C=96Excel=E5=AF=BC=E5=87=BA?=
 =?UTF-8?q?=E8=AE=A1=E7=AE=97sheet=E6=95=B0=E7=9B=AE=E7=9A=84=E6=96=B9?=
 =?UTF-8?q?=E5=BC=8F=201.=20=E5=AF=BC=E5=87=BA=E6=95=B0=E6=8D=AE=E7=9A=84?=
 =?UTF-8?q?=E6=80=BB=E6=9D=A1=E6=95=B0=E5=88=9A=E5=A5=BD=E7=AD=89=E4=BA=8E?=
 =?UTF-8?q?sheet=E6=9C=80=E5=A4=A7=E8=A1=8C=E6=95=B0=E6=97=B6=EF=BC=8C?=
 =?UTF-8?q?=E4=BC=9A=E5=A4=9A=E4=BA=A7=E7=94=9F=E4=B8=80=E4=B8=AA=E7=A9=BA?=
 =?UTF-8?q?=E7=99=BDsheet=20=E6=B5=8B=E8=AF=95=E4=BB=A3=E7=A0=81=E5=A6=82?=
 =?UTF-8?q?=E4=B8=8B=EF=BC=9A=20=20=20=20=20public=20static=20void=20main(?=
 =?UTF-8?q?String[]=20args)=20{=20=20=20=20=20=20=20=20=20System.out.print?=
 =?UTF-8?q?ln("=E6=97=A0=E6=95=B0=E6=8D=AE=E6=97=B6=EF=BC=8C1=E9=A1=B5?=
 =?UTF-8?q?=EF=BC=9A"=20+=20getTotalPage(sheetSize=20*=200));=20=20=20=20?=
 =?UTF-8?q?=20=20=20=20=20System.out.println("=E5=88=9A=E5=A5=BD1=E9=A1=B5?=
 =?UTF-8?q?=EF=BC=9A"=20+=20getTotalPage(sheetSize=20*=201));=20=20=20=20?=
 =?UTF-8?q?=20=20=20=20=20System.out.println("=E5=88=9A=E5=A5=BD7=E9=A1=B5?=
 =?UTF-8?q?=EF=BC=9A"=20+=20getTotalPage(sheetSize=20*=207));=20=20=20=20?=
 =?UTF-8?q?=20=20=20=20=20System.out.println("1=E9=A1=B5=EF=BC=9A"=20+=20g?=
 =?UTF-8?q?etTotalPage(200));=20=20=20=20=20=20=20=20=20System.out.println?=
 =?UTF-8?q?("2=E9=A1=B5=EF=BC=9A"=20+=20getTotalPage(sheetSize=20*=201=20+?=
 =?UTF-8?q?=20200));=20=20=20=20=20=20=20=20=20System.out.println("8?=
 =?UTF-8?q?=E9=A1=B5=EF=BC=9A"=20+=20getTotalPage(sheetSize=20*=207=20+=20?=
 =?UTF-8?q?200));=20=20=20=20=20=20=20=20=20System.out.println("=3D=3D=3D?=
 =?UTF-8?q?=3D=3D=3D=3D=3D=3D");=20=20=20=20=20=20=20=20=20System.out.prin?=
 =?UTF-8?q?tln("=E6=97=A0=E6=95=B0=E6=8D=AE=E6=97=B6=EF=BC=8C1=E9=A1=B5?=
 =?UTF-8?q?=EF=BC=9A"=20+=20getTotalPage2(sheetSize=20*=200));=20=20=20=20?=
 =?UTF-8?q?=20=20=20=20=20System.out.println("=E5=88=9A=E5=A5=BD1=E9=A1=B5?=
 =?UTF-8?q?=EF=BC=9A"=20+=20getTotalPage2(sheetSize=20*=201));=20=20=20=20?=
 =?UTF-8?q?=20=20=20=20=20System.out.println("=E5=88=9A=E5=A5=BD7=E9=A1=B5?=
 =?UTF-8?q?=EF=BC=9A"=20+=20getTotalPage2(sheetSize=20*=207));=20=20=20=20?=
 =?UTF-8?q?=20=20=20=20=20System.out.println("1=E9=A1=B5=EF=BC=9A"=20+=20g?=
 =?UTF-8?q?etTotalPage2(200));=20=20=20=20=20=20=20=20=20System.out.printl?=
 =?UTF-8?q?n("2=E9=A1=B5=EF=BC=9A"=20+=20getTotalPage2(sheetSize=20*=201?=
 =?UTF-8?q?=20+=20200));=20=20=20=20=20=20=20=20=20System.out.println("8?=
 =?UTF-8?q?=E9=A1=B5=EF=BC=9A"=20+=20getTotalPage2(sheetSize=20*=207=20+?=
 =?UTF-8?q?=20200));=20=20=20=20=20}?=
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    private static double getTotalPage(int size) {
        //原方法。
        //ceil方法中是两个int做除法，结果还是int。ceil实际上没有起到作用。
        return Math.ceil(size / sheetSize);
    }

    private static int getTotalPage2(int size) {
        //修改后的方法。
        //size * 1.0 使int转为double，做除法后还是double。max(1, ...)是为了在size为0时，始终能生成一个sheet。
        //需要修改for循环的判断条件
        return Math.max(1, (int)Math.ceil(size * 1.0 / sheetSize));
    }
测试结果：
    //预期结果：0，0，6，0，1，7
    无数据时，1页：0.0
    刚好1页：1.0
    刚好7页：7.0
    1页：0.0
    2页：1.0
    8页：7.0
    =========
    //预期结果：1，1，7，1，2，8
    无数据时，1页：1
    刚好1页：1
    刚好7页：7
    1页：1
    2页：2
    8页：8

2. 有疑问的地方(本次提交没有做修改)：
    1105行 index是从0开始的，即sheet的后缀名也是从0开始的。如果要使后缀名从1开始，可以考虑 (index + 1)
---
 .../main/java/com/ruoyi/common/utils/poi/ExcelUtil.java   | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/ruoyi-common/src/main/java/com/ruoyi/common/utils/poi/ExcelUtil.java b/ruoyi-common/src/main/java/com/ruoyi/common/utils/poi/ExcelUtil.java
index 54157f353..9b7e0d56f 100644
--- a/ruoyi-common/src/main/java/com/ruoyi/common/utils/poi/ExcelUtil.java
+++ b/ruoyi-common/src/main/java/com/ruoyi/common/utils/poi/ExcelUtil.java
@@ -465,8 +465,8 @@ public class ExcelUtil<T>
     public void writeSheet()
     {
         // 取出一共有多少个sheet.
-        double sheetNo = Math.ceil(list.size() / sheetSize);
-        for (int index = 0; index <= sheetNo; index++)
+        int sheetNo = Math.max(1, (int)Math.ceil(list.size() * 1.0 / sheetSize));
+        for (int index = 0; index < sheetNo; index++)
         {
             createSheet(sheetNo, index);
 
@@ -1091,12 +1091,12 @@ public class ExcelUtil<T>
      * @param sheetNo sheet数量
      * @param index 序号
      */
-    public void createSheet(double sheetNo, int index)
+    public void createSheet(int sheetNo, int index)
     {
         this.sheet = wb.createSheet();
         this.styles = createStyles(wb);
         // 设置工作表的名称.
-        if (sheetNo == 0)
+        if (sheetNo == 1)
         {
             wb.setSheetName(index, sheetName);
         }