add excel formula

excelformula/.gitignore

@@ -0,0 +1,34 @@
+HELP.md
+mvnw
+mvnw.cmd
+.mvn
+target/
+!.mvn/wrapper/maven-wrapper.jar
+!**/src/main/**
+!**/src/test/**
+
+### STS ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+
+### IntelliJ IDEA ###
+.idea
+*.iws
+*.iml
+*.ipr
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+build/
+
+### VS Code ###
+.vscode/

excelformula/pom.xml

@@ -0,0 +1,57 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <groupId>org.springframework.boot</groupId>
+        <artifactId>spring-boot-starter-parent</artifactId>
+        <version>2.3.1.RELEASE</version>
+        <relativePath/> <!-- lookup parent from repository -->
+    </parent>
+    <groupId>com.bealdung.poi</groupId>
+    <artifactId>excelformula</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <name>excelformula</name>
+    <description>Demo project for Spring Boot</description>
+    <properties>
+        <java.version>11</java.version>
+        <poi-ooxml.version>4.1.2</poi-ooxml.version>
+        <junit.version>4.13</junit.version>
+    </properties>
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+            <exclusions>
+                <exclusion>
+                    <groupId>org.junit.vintage</groupId>
+                    <artifactId>junit-vintage-engine</artifactId>
+                </exclusion>
+            </exclusions>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.poi</groupId>
+            <artifactId>poi-ooxml</artifactId>
+            <version>${poi-ooxml.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>${junit.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+            </plugin>
+        </plugins>
+    </build>
+</project>

excelformula/src/main/java/com/bealdung/poi/excelformula/ExcelFormula.java

@@ -0,0 +1,36 @@
+package com.bealdung.poi.excelformula;
+
+import org.apache.poi.ss.usermodel.CellValue;
+import org.apache.poi.xssf.usermodel.XSSFCell;
+import org.apache.poi.xssf.usermodel.XSSFFormulaEvaluator;
+import org.apache.poi.xssf.usermodel.XSSFSheet;
+import org.apache.poi.xssf.usermodel.XSSFWorkbook;
+import org.springframework.stereotype.Component;
+
+import java.io.IOException;
+import java.util.List;
+
+@Component
+public class ExcelFormula {
+    XSSFWorkbook excel;
+    public XSSFSheet inserData(List<Integer> dataList) {
+        excel = new XSSFWorkbook();
+        XSSFSheet sheet = excel.createSheet();
+        int rowNum =0 ;
+        for (Integer data : dataList){
+            sheet.createRow(rowNum++).createCell(0).setCellValue(data);
+        }
+        return sheet;
+    }
+    public double setFormula(String formula) throws IOException {
+        XSSFSheet sheet = excel.getSheetAt(0);
+        int lastCellNum = sheet.getRow(0).getLastCellNum();
+        XSSFCell formulaCell = sheet.getRow(0).createCell(lastCellNum + 1);
+        formulaCell.setCellFormula(formula);
+        XSSFFormulaEvaluator formulaEvaluator = excel.getCreationHelper().createFormulaEvaluator();
+        CellValue evaluate = formulaEvaluator.evaluate(formulaCell);
+        if(excel != null)
+            excel.close();
+        return evaluate.getNumberValue();
+    }
+}

excelformula/src/main/java/com/bealdung/poi/excelformula/ExcelformulaApplication.java

@@ -0,0 +1,13 @@
+package com.bealdung.poi.excelformula;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class ExcelformulaApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(ExcelformulaApplication.class, args);
+    }
+
+}

excelformula/src/main/resources/application.properties

@@ -0,0 +1 @@
+

excelformula/src/test/java/com/bealdung/poi/excelformula/ExcelformulaApplicationTests.java

@@ -0,0 +1,38 @@
+package com.bealdung.poi.excelformula;
+
+import org.apache.poi.ss.util.CellReference;
+import org.apache.poi.xssf.usermodel.XSSFSheet;
+import org.junit.Assert;
+import org.junit.jupiter.api.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.junit4.SpringRunner;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.List;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest
+class ExcelformulaApplicationTests {
+    @Autowired
+    private ExcelFormula excelFormula;
+
+    @Test
+    void givenExcelData_whenSetAndEvaluateFormula() throws IOException {
+        List<Integer> data = Arrays.asList(2, 5, 10, 15, 7, 9);
+        XSSFSheet sheet = excelFormula.inserData(data);
+        int result = 0;
+        for (int row = 0; row <= sheet.getLastRowNum(); row++) {
+            result += sheet.getRow(row).getCell(0).getNumericCellValue();
+        }
+        String colName = CellReference.convertNumToColString(0);
+        String startCell = colName + 1;
+        String stopCell = colName + (sheet.getLastRowNum() + 1);
+        String sumFormula = String.format("SUM(%s:%s)", startCell, stopCell);
+        int resultValue = (int) excelFormula.setFormula(sumFormula);
+        Assert.assertEquals("The results are the same!", resultValue , result);
+    }
+
+}