com.xxx.common.excel.filereader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.text.NumberFormat;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.Iterator;
import java.util.List;
import org.apache.poi.xssf.usermodel.XSSFCell;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
public class CreateFileUtil {
public static void main(String[] args) {
//Generating 1 million pieces of data takes a very short time
List<Object[]> rows=new ArrayList<Object[]>();
Long start=System.currentTimeMillis();
for(int i=0;i<1000000;i + + ){
rows.add(new Object[]{1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1 ,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1});
}
Long end=System.currentTimeMillis();
System.out.println("Time consuming ----- " + (end-start)/1000);
String filePath="/Users/wangyonglin/Desktop";
String fileName="test1.txt";
CreateFileUtil.createTxtFile(rows,filePath,fileName);
Long kend=System.currentTimeMillis();
System.out.println("The final end takes time, inserting 1 million data, --- end");
System.out.println((kend-end)/1000);
}
/**
* Generate .TXT format files with almost unlimited number of lines
*/
public static boolean createTxtFile(List<Object[]> rows, String filePath, String fileName) {
// Whether the mark file generation is successful
boolean flag = true;
try {
// Full path including file name
String fullPath = filePath + File.separator + fileName + ".txt";
File file = new File(fullPath);
if (file.exists()) { // If it already exists, delete the old file
file.delete();
}
file = new File(fullPath);
file.createNewFile();
//Format floating point data
NumberFormat formatter = NumberFormat.getNumberInstance();
formatter.setMaximumFractionDigits(10); //Set the maximum decimal place to 10
//Format date data
SimpleDateFormat sdf = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
//Loop through each line of output
PrintWriter pfp = new PrintWriter(file, "UTF-8"); //Set the encoding of the output file to utf-8
for (Object[] rowData : rows) {
StringBuffer thisLine = new StringBuffer("");
for (int i = 0; i < rowData.length; i + + ) {
Object obj = rowData[i]; // current field
//Format data
String field = "";
if (null != obj) {
if (obj.getClass() == String.class) { // if it is a string
field = (String) obj;
} else if (obj.getClass() == Double.class || obj.getClass() == Float.class) { // If it is floating point type
field = formatter.format(obj); // Format floating point numbers so that they are not output in scientific notation
} else if (obj.getClass() == Integer.class || obj.getClass() == Long.class
|| obj.getClass() == Short.class || obj.getClass() == Byte.class) { // If it is an integer
field + = obj;
} else if (obj.getClass() == Date.class) { // If it is date type
field = sdf.format(obj);
}
} else {
field = " "; // Give a space as a placeholder when null
}
// Splice all fields into one row of data, separated by tab key
if (i < rowData.length - 1) { // Not the last element
thisLine.append(field).append("\t");
} else { // is the last element
thisLine.append(field);
}
}
pfp.print(thisLine.toString() + "\
");
}
pfp.close();
} catch (Exception e) {
flag = false;
e.printStackTrace();
}
return flag;
}
/**
* Generate .csv format files with almost unlimited number of lines
*/
public static boolean createCsvFile(List<Object[]> rows, String filePath, String fileName) {
// Whether the mark file generation is successful
boolean flag = true;
//File output stream
BufferedWriter fileOutputStream = null;
try {
// Full path including file name
String fullPath = filePath + File.separator + fileName + ".csv";
File file = new File(fullPath);
if (!file.getParentFile().exists()) { // If the parent directory does not exist, create the parent directory
file.getParentFile().mkdirs();
}
if (file.exists()) { // If it already exists, delete the old file
file.delete();
}
file = new File(fullPath);
file.createNewFile();
//Format floating point data
NumberFormat formatter = NumberFormat.getNumberInstance();
formatter.setMaximumFractionDigits(10); //Set the maximum decimal place to 10
//Format date data
SimpleDateFormat sdf = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
// Instantiate the file output stream
fileOutputStream = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file), "GB2312"), 1024);
//Loop through each line of output
Iterator<Object[]> iterator = rows.iterator();
while (ite.hasNext()) {
Object[] rowData = (Object[]) ite.next();
for (int i = 0; i < rowData.length; i + + ) {
Object obj = rowData[i]; // current field
//Format data
String field = "";
if (null != obj) {
if (obj.getClass() == String.class) { // if it is a string
field = (String) obj;
} else if (obj.getClass() == Double.class || obj.getClass() == Float.class) { // If it is floating point type
field = formatter.format(obj); // Format floating point numbers so that they are not output in scientific notation
} else if (obj.getClass() == Integer.class || obj.getClass() == Long.class
|| obj.getClass() == Short.class || obj.getClass() == Byte.class) { // If it is an integer
field + = obj;
} else if (obj.getClass() == Date.class) { // If it is date type
field = sdf.format(obj);
}
} else {
field = " "; // Give a space as a placeholder when null
}
// Splice all fields into one row of data
if (i < rowData.length - 1) { // Not the last element
fileOutputStream.write(""" + field + """ + ",");
} else { // is the last element
fileOutputStream.write(""" + field + """);
}
}
// Create a new row
if (ite.hasNext()) {
fileOutputStream.newLine();
}
}
fileOutputStream.flush();
} catch (Exception e) {
flag = false;
e.printStackTrace();
} finally {
try {
fileOutputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return flag;
}
/**
* Generate .xls format file, the upper limit of a single page: version 03 is 65536 lines, version 07 is 1048576 lines, version 10 is unknown
*/
public static boolean createXlsFile(List<Object[]> rows, String filePath, String fileName) {
// Whether the mark file generation is successful
boolean flag = true;
try {
//Create a webbook corresponding to an Excel file
XSSFWorkbook wb = new XSSFWorkbook();
//Add a sheet in the webbook, corresponding to the sheet in the Excel file
XSSFSheet sheet = wb.createSheet(fileName);
//Loop through each line of output
for (int i = 0; i < rows.size(); i + + ) {
Object[] rowData = rows.get(i); //Data for each row
XSSFRow row = sheet.createRow(i);
for (int j = 0; j < rowData.length; j + + ) {
XSSFCell cell = row.createCell(j);
// Assume there are only three types of data
if (rowData[j].getClass() == String.class) { // String type value
cell.setCellValue((String) rowData[j]);
} else if (rowData[j].getClass() == double.class) { // double type value
cell.setCellValue((Double) rowData[j]);
} else if (rowData[j].getClass() == int.class) { // int type value
cell.setCellValue((Integer) rowData[j]);
}
}
}
String fullPath = filePath + File.separator + fileName + ".xls"; // Full path including file name File file = new File(fullPath);
File file = new File(fullPath);
if (!file.getParentFile().exists()) { // If the parent directory does not exist, create the parent directory
file.getParentFile().mkdirs();
}
if (file.exists()) { // If it already exists, delete the old file
file.delete();
}
file.createNewFile();
FileOutputStream fileOut = new FileOutputStream(file); // Write data to file
wb.write(fileOut);
fileOut.close();
} catch (Exception e) {
flag = false;
e.printStackTrace();
}
return flag;