Java generated CSV file example details
- 2020-04-01 03:25:23
- OfStack
The example of this paper mainly describes the method of Java to generate CSV file, the specific implementation steps are as follows:
1. New csvutils.java file:
package com.saicfc.pmpf.internal.manage.utils;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.beanutils.BeanUtils;
public class CSVUtils {
@SuppressWarnings("rawtypes")
public static File createCSVFile(List exportData, LinkedHashMap map, String outPutPath,
String fileName) {
File csvFile = null;
BufferedWriter csvFileOutputStream = null;
try {
File file = new File(outPutPath);
if (!file.exists()) {
file.mkdir();
}
//Define the file name format and create it
csvFile = File.createTempFile(fileName, ".csv", new File(outPutPath));
System.out.println("csvFile : " + csvFile);
//Utf-8 causes the delimiter "," to be read correctly
csvFileOutputStream = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(
csvFile), "UTF-8"), 1024);
System.out.println("csvFileOutputStream : " + csvFileOutputStream);
//Write file header
for (Iterator propertyIterator = map.entrySet().iterator(); propertyIterator.hasNext();) {
java.util.Map.Entry propertyEntry = (java.util.Map.Entry) propertyIterator.next();
csvFileOutputStream
.write(""" + (String) propertyEntry.getValue() != null ? (String) propertyEntry
.getValue() : "" + """);
if (propertyIterator.hasNext()) {
csvFileOutputStream.write(",");
}
}
csvFileOutputStream.newLine();
//Write file contents
for (Iterator iterator = exportData.iterator(); iterator.hasNext();) {
Object row = (Object) iterator.next();
for (Iterator propertyIterator = map.entrySet().iterator(); propertyIterator
.hasNext();) {
java.util.Map.Entry propertyEntry = (java.util.Map.Entry) propertyIterator
.next();
csvFileOutputStream.write((String) BeanUtils.getProperty(row,
(String) propertyEntry.getKey()));
if (propertyIterator.hasNext()) {
csvFileOutputStream.write(",");
}
}
if (iterator.hasNext()) {
csvFileOutputStream.newLine();
}
}
csvFileOutputStream.flush();
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
csvFileOutputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return csvFile;
}
public static void exportFile(HttpServletResponse response, String csvFilePath, String fileName)
throws IOException {
response.setContentType("application/csv;charset=UTF-8");
response.setHeader("Content-Disposition",
"attachment; filename=" + URLEncoder.encode(fileName, "UTF-8"));
InputStream in = null;
try {
in = new FileInputStream(csvFilePath);
int len = 0;
byte[] buffer = new byte[1024];
response.setCharacterEncoding("UTF-8");
OutputStream out = response.getOutputStream();
while ((len = in.read(buffer)) > 0) {
out.write(new byte[] { (byte) 0xEF, (byte) 0xBB, (byte) 0xBF });
out.write(buffer, 0, len);
}
} catch (FileNotFoundException e) {
System.out.println(e);
} finally {
if (in != null) {
try {
in.close();
} catch (Exception e) {
throw new RuntimeException(e);
}
}
}
}
public static void deleteFiles(String filePath) {
File file = new File(filePath);
if (file.exists()) {
File[] files = file.listFiles();
for (int i = 0; i < files.length; i++) {
if (files[i].isFile()) {
files[i].delete();
}
}
}
}
public static void deleteFile(String filePath, String fileName) {
File file = new File(filePath);
if (file.exists()) {
File[] files = file.listFiles();
for (int i = 0; i < files.length; i++) {
if (files[i].isFile()) {
if (files[i].getName().equals(fileName)) {
files[i].delete();
return;
}
}
}
}
}
@SuppressWarnings({ "rawtypes", "unchecked" })
public static void main(String[] args) {
List exportData = new ArrayList<Map>();
Map row1 = new LinkedHashMap<String, String>();
row1.put("1", "11");
row1.put("2", "12");
row1.put("3", "13");
row1.put("4", "14");
exportData.add(row1);
row1 = new LinkedHashMap<String, String>();
row1.put("1", "21");
row1.put("2", "22");
row1.put("3", "23");
row1.put("4", "24");
exportData.add(row1);
LinkedHashMap map = new LinkedHashMap();
map.put("1", " The first column ");
map.put("2", " The second column ");
map.put("3", " The third column ");
map.put("4", " The fourth column ");
String path = "c:/export/";
String fileName = " File export ";
File file = CSVUtils.createCSVFile(exportData, map, path, fileName);
String fileName2 = file.getName();
System.out.println(" File name: " + fileName2);
}
}
2. Call the createCSVFile method to generate CSV file
String name = " Bank refund data ";
List exportData = new ArrayList();
LinkedHashMap datamMap = null;
for (Iterator iterator = refundList.iterator(); iterator.hasNext();) {
HashMap map = (HashMap) iterator.next();
datamMap = new LinkedHashMap();
datamMap.put("1", map.get("merOrderId"));
datamMap.put("2",DateUtil.convertDateToString("yyyyMMdd", (Date) map.get("orderTime")));
BigDecimal amount = (BigDecimal) map.get("amount");
String amountString = amount.divide(new BigDecimal(10)).toPlainString();
datamMap.put("3", amountString);
datamMap.put("4", map.get("remark") != null ? map.get("remark") : "");
exportData.add(datamMap);
}
LinkedHashMap map = new LinkedHashMap();
map.put("1", " The order number ");
map.put("2", " Date of payment ");
map.put("3", " Return cash amount (round amount) Unit: points) ");
map.put("4", " The return reason ");
File file = CSVUtils.createCSVFile(exportData, map, filePath, name);//Generate CSV file
fileName = file.getName();
CSVUtils.exportFile(response, filePath + fileName, fileName);//Download the generated CSV file