서버에서 excel file을 내려받아 workbook으로 변환

ExcelResource의 구현체를 추가했다.
추가된 구현체는 Http 서버에서 excel file을 내려받아 Workbook으로 반환한다.
추가로 ExcelResource의 구현체 모두 테스트 코드를 추가했다.

Author: woniper

src/main/java/io/excel/object/mapper/resource/HttpFileExcelResource.java

@@ -0,0 +1,34 @@
+package io.excel.object.mapper.resource;
+
+import org.apache.poi.ss.usermodel.Workbook;
+import org.apache.poi.ss.usermodel.WorkbookFactory;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.HttpURLConnection;
+import java.net.URL;
+import java.util.Objects;
+
+/**
+ * @author woniper
+ */
+public class HttpFileExcelResource implements ExcelResource {
+
+    @Override
+    public Workbook getResource(String resource) throws IOException {
+        URL url = new URL(resource);
+        HttpURLConnection connection = (HttpURLConnection)url.openConnection();
+        connection.setRequestMethod("GET");
+
+        try (InputStream inputStream = connection.getInputStream()) {
+            if (Objects.nonNull(inputStream)) {
+                return WorkbookFactory.create(inputStream);
+            }
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+
+        return WorkbookFactory.create(true);
+    }
+
+}

src/test/java/io/excel/object/mapper/resource/ExcelResourceTest.java

@@ -0,0 +1,42 @@
+package io.excel.object.mapper.resource;
+
+import org.apache.poi.ss.usermodel.Workbook;
+import org.junit.Test;
+
+import java.io.IOException;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author woniper
+ */
+public class ExcelResourceTest {
+
+    @Test
+    public void excel_파일을_내려받아_Workbook으로_반환() throws IOException {
+        // given
+        String url = "http://download.microsoft.com/download/1/4/E/14EDED28-6C58-4055-A65C-23B4DA81C4DE/Financial%20Sample.xlsx";
+        ExcelResource resource = new HttpFileExcelResource();
+
+        // when
+        Workbook workbook = resource.getResource(url);
+
+        // then
+        assertThat(workbook.getNumberOfSheets()).isEqualTo(1);
+        assertThat(workbook.getSheetAt(0).getPhysicalNumberOfRows()).isEqualTo(701);
+    }
+
+    @Test
+    public void resources에_있는_excel_파일을_Workbook으로_반환() throws IOException {
+        // given
+        String fileName = "company.xlsx";
+        ExcelResource excelResource = new ResourcesExcelResource();
+
+        // when
+        Workbook workbook = excelResource.getResource(fileName);
+
+        // then
+        assertThat(workbook.getNumberOfSheets()).isEqualTo(1);
+        assertThat(workbook.getSheetAt(0).getPhysicalNumberOfRows()).isEqualTo(4);
+    }
+}