exportando excel con la libreria apache-poi

pom.xml

@@ -27,13 +27,6 @@
             <artifactId>json</artifactId>
             <version>20180130</version>
         </dependency>
-
-        <dependency>
-            <groupId>com.microsoft.sqlserver</groupId>
-            <artifactId>sqljdbc4</artifactId>
-            <version>4.0</version>
-            <scope>test</scope>
-        </dependency>
         
         <dependency>
             <groupId>io.github.cdimascio</groupId>
@@ -41,6 +34,12 @@
             <version>3.1.1</version>
         </dependency>
         
+        <dependency>
+            <groupId>org.apache.poi</groupId>
+            <artifactId>poi</artifactId>
+            <version>3.16</version>
+        </dependency>
+        
     </dependencies>
 
     <build>

src/main/java/asistencia/filters/RequestsFilter.java

@@ -76,7 +76,7 @@ public class RequestsFilter implements Filter {
                                 for (int i = 0; i < urls.length(); i++) {
                                     vistas.add(urls.get(i));
                                 }
-                                
+                                vistas.add("main.jsp");
                                 String ruta = request.getRequestURI();
                                 int indice = GeneralUtils.obtenerIndex(ruta);
                                 String rutaJsp = ruta.substring(indice, ruta.length());

src/main/java/asistencia/servlets/CrearExcel.java

+/*
+ * To change this license header, choose License Headers in Project Properties.
+ * To change this template file, choose Tools | Templates
+ * and open the template in the editor.
+ */
+package asistencia.servlets;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.util.Map;
+import java.util.Set;
+import java.util.TreeMap;
+import org.apache.poi.hssf.usermodel.HSSFWorkbook;
+import org.apache.poi.ss.usermodel.Cell;
+import org.apache.poi.ss.usermodel.CellStyle;
+import org.apache.poi.ss.usermodel.IndexedColors;
+import org.apache.poi.ss.usermodel.Row;
+import org.apache.poi.ss.usermodel.Sheet;
+import org.apache.poi.ss.usermodel.Workbook;
+
+/**
+ *
+ * @author sistem19user
+ */
+public class CrearExcel {
+
+    public static void main(String args[]) {
+        //Crear libro de trabajo en blanco
+        Workbook workbook = new HSSFWorkbook();
+        //Crea hoja nueva
+        Sheet sheet = workbook.createSheet("Reporte de montos");
+
+        CellStyle headerStyle = workbook.createCellStyle();
+        headerStyle.setFillForegroundColor(IndexedColors.AQUA.getIndex());
+        headerStyle.setFillPattern(CellStyle.SOLID_FOREGROUND);
+
+        String[] headers = {"Identificador", "Nombre", "Apellidos"};
+
+        Row headerRow = sheet.createRow(0);
+        for (int i = 0; i < headers.length; ++i) {
+            String header = headers[i];
+            Cell cell = headerRow.createCell(i);
+            cell.setCellStyle(headerStyle);
+            cell.setCellValue(header);
+        }
+        
+        
+        Object[][] data = new Object[][]{
+          new Object[]{1, "María", "Remen"},  
+          new Object[]{2, "David", "Allos"},  
+          new Object[]{3, "Carlos", "Caritas"}  
+        };
+        
+        int i = 0;
+        for(String header: headers){
+            Cell cell = headerRow.createCell(i++);
+            cell.setCellStyle(headerStyle);
+            cell.setCellValue(header);
+        }
+        
+        i = 1;
+        Row row;
+        for(Object[] array: data){
+            row = sheet.createRow(i++);
+            
+            Cell cell;
+            int j = 0;
+            for(Object value: array){
+                cell = row.createCell(j++);
+                
+                if(value instanceof Integer){
+                    cell.setCellValue(Integer.parseInt(value.toString()));
+                }else if(value instanceof String){
+                    cell.setCellValue(value.toString());
+                }else if(value instanceof Double){
+                    cell.setCellValue(Double.parseDouble(value.toString()));
+                }else if(value instanceof Boolean){
+                    cell.setCellValue((boolean)value);
+                }else{
+                    cell.setCellValue(value.toString());
+                }
+            }
+        }
+        
+        sheet.createFreezePane(0, 1);
+
+        try {
+            //Se genera el documento
+            FileOutputStream out = new FileOutputStream(new File("D:/ejemplo.xls"));
+            workbook.write(out);
+            out.close();
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+}

src/main/java/asistencia/servlets/PoliciasServlet.java

+/*
+ * To change this license header, choose License Headers in Project Properties.
+ * To change this template file, choose Tools | Templates
+ * and open the template in the editor.
+ */
+package asistencia.servlets;
+
+import asistencia.utilities.ExcelHelper;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.PrintWriter;
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+public class PoliciasServlet extends HttpServlet {
+
+    @Override
+    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        response.setContentType("application/vnd.ms-excel");
+        response.setHeader("Content-Disposition", "attachment; filename=sample.xls");
+        OutputStream output = response.getOutputStream();
+        ExcelHelper excel = new ExcelHelper(output);
+        String[] headers = {"id", "nombres", "apellidos", "edad"};
+        Object[][] data = new Object[][]{
+            new Object[]{"1", "Felipe", "Escala", "22"},
+            new Object[]{"2", "Luis", "Gangas", "23"},
+        };
+        
+        excel.setHeaders(headers);
+        excel.setSheetName("Pruebas");
+        excel.setData(data);
+        excel.generate();
+    }
+
+}

src/main/java/asistencia/utilities/ExcelHelper.java

+/*
+ * To change this license header, choose License Headers in Project Properties.
+ * To change this template file, choose Tools | Templates
+ * and open the template in the editor.
+ */
+package asistencia.utilities;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import org.apache.poi.hssf.usermodel.HSSFWorkbook;
+import org.apache.poi.ss.usermodel.Cell;
+import org.apache.poi.ss.usermodel.CellStyle;
+import org.apache.poi.ss.usermodel.IndexedColors;
+import org.apache.poi.ss.usermodel.Row;
+import org.apache.poi.ss.usermodel.Sheet;
+import org.apache.poi.ss.usermodel.Workbook;
+
+/**
+ *
+ * @author sistem19user
+ */
+public class ExcelHelper {
+
+    private String[] headers;
+    private Object[][] data;
+    private OutputStream output;
+    private String sheetName;
+
+    public ExcelHelper(OutputStream output) {
+        this.output = output;
+    }
+
+    public void setHeaders(String[] headers) {
+        this.headers = headers;
+    }
+
+    public void setSheetName(String sheetName) {
+        this.sheetName = sheetName;
+    }
+    
+    public void setData(Object[][] data){
+        this.data = data;
+    }
+    
+    public void generate() throws IOException {
+        Workbook workbook = new HSSFWorkbook();
+        //Crea hoja nueva
+        Sheet sheet = workbook.createSheet(sheetName);
+
+        CellStyle headerStyle = workbook.createCellStyle();
+        headerStyle.setFillForegroundColor(IndexedColors.AQUA.getIndex());
+        headerStyle.setFillPattern(CellStyle.SOLID_FOREGROUND);
+
+        Row headerRow = sheet.createRow(0);
+
+
+        int i = 0;
+        for (String header : headers) {
+            Cell cell = headerRow.createCell(i++);
+            cell.setCellStyle(headerStyle);
+            cell.setCellValue(header);
+        }
+
+        i = 1;
+        Row row;
+        for (Object[] array : data) {
+            row = sheet.createRow(i++);
+
+            Cell cell;
+            int j = 0;
+            for (Object value : array) {
+                cell = row.createCell(j++);
+
+                if (value instanceof Integer) {
+                    cell.setCellValue(Integer.parseInt(value.toString()));
+                } else if (value instanceof String) {
+                    cell.setCellValue(value.toString());
+                } else if (value instanceof Double) {
+                    cell.setCellValue(Double.parseDouble(value.toString()));
+                } else if (value instanceof Boolean) {
+                    cell.setCellValue((boolean) value);
+                } else {
+                    cell.setCellValue(value.toString());
+                }
+            }
+        }
+
+        sheet.createFreezePane(0, 1);
+        workbook.write(output);
+    }
+
+}

src/main/webapp/WEB-INF/web.xml

@@ -25,6 +25,10 @@
         <servlet-name>RedireccionarServlet</servlet-name>
         <servlet-class>asistencia.servlets.RedireccionarServlet</servlet-class>
     </servlet>
+    <servlet>
+        <servlet-name>PoliciasServlet</servlet-name>
+        <servlet-class>asistencia.servlets.PoliciasServlet</servlet-class>
+    </servlet>
     <servlet-mapping>
         <servlet-name>InterceptarRedireccionServlet</servlet-name>
         <url-pattern>/vistas/interceptar</url-pattern>
@@ -45,6 +49,10 @@
         <error-code>404</error-code>
         <location>/vistas/error/error.jsp</location>
     </error-page>
+    <servlet-mapping>
+        <servlet-name>PoliciasServlet</servlet-name>
+        <url-pattern>/servlet/PoliciasServlet</url-pattern>
+    </servlet-mapping>
     <session-config>
         <session-timeout>
             30