Notes, a complete collection of tools for operating files, all code function directories are marked, if you need to find the directory; this article is continuously updated!
Article Directory
IO
JDK native
Txt
Get Txt content (read string by line)
/**
txtPath: 文件路径
return : 行内容列表
*/
public static List<String> getTxt(String txtPath){
File file = new File(txtPath);
BufferedReader reader = null;
String temp = null;
List<String> resList = new ArrayList<>();
try {
reader = new BufferedReader(new FileReader(file));
while ((temp = reader.readLine()) != null) {
System.out.println(temp);
resList.add(temp);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
if (reader != null) {
try {
reader.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
return resList;
}
Excel
//maven
<!-- poi -->
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi-ooxml</artifactId>
<version>3.9</version>
</dependency>
Create Excel write content
//生成文件位置
private static final String PATH="D:\\3\\";
public static void testWrite() throws Exception {
Workbook workbook = new HSSFWorkbook();
//创建一个工作表sheet
Sheet sheet = workbook.createSheet("第一个sheet");
//创建一行(0表示创建的是第一行)
Row row1 = sheet.createRow(0);
//创建一个单元格(这个单元格表示的是第一行第一列的单元格，即坐标（1，1）)
Cell cell11 = row1.createCell(0);
//赋值
cell11.setCellValue("坐标（1，1）");
//在创建一个 坐标 1，2
Cell cell = row1.createCell(1);
cell.setCellValue("坐标 1，2");
//生成Excel文件（使用io流）,注：文件后缀要与excel版本对应
FileOutputStream fileOutputStream = new FileOutputStream(PATH + "test.xls");
//写入
workbook.write(fileOutputStream);
//文件写完后关闭流
fileOutputStream.close();
}
Read Excel content
/**
* 读取Excel 某列数据
* @param filePath excel文件路径
* @param cellNum 获取的列数 1开始
* @return
*/
public static List<String> readExcel(String filePath,int cellNum) {
List<String> resList =new ArrayList<>();
String path = filePath;
Workbook workbook = ExcelUtil.getWorkbook(path);
Sheet sheetAt = workbook.getSheetAt(cellNum-1);
//获取最大行数
int rowNum = sheetAt.getPhysicalNumberOfRows();
for (int i = 1; i < rowNum; i++) {
Row row1 = sheetAt.getRow(i);
String s1 = row1.getCell(0).toString();
resList.add(s1);
}
return resList;
}
//获取读取excel对象
public static Workbook getWorkbook(String filePath) {
Workbook wb = null;
if (filePath == null) {
return null;
}
String extString = filePath.substring(filePath.indexOf('.'));
InputStream is = null;
try {
is = new FileInputStream(filePath);
if (".xls".equals(extString)) {
return wb = new HSSFWorkbook(is);
} else if (".xlsx".equals(extString)) {
return wb = new XSSFWorkbook(is);
} else {
return wb = null;
}
} catch (IOException e) {
e.printStackTrace();
}
return wb;
}
/**
* 测试
* @param args
*/
public static void main(String[] args) {
List<String> list = ExcelUtil.readExcel("D:\\3\\其它\\military.xlsx", 1);
for (String s : list) {
System.out.println(s);
}
}
Modify Excel content
public static void main(String[] args) {
Workbook workbook = getWorkbook("D:/3/其它/military.xlsx");
Sheet sheetAt = workbook.getSheetAt(0);
//System.out.println(sheetAt);
Row row = sheetAt.getRow(1);
//System.out.println(row);
Cell cell = row.getCell(2);
System.out.println(cell);
cell.setCellValue("中中");
try {
FileOutputStream fos = new FileOutputStream("D:/3/其它/military.xlsx");
workbook.write(fos);
} catch (IOException e) {
e.printStackTrace();
}
}
Excel to csv
<dependencies>
<dependency>
<groupId>e-iceblue</groupId>
<artifactId>spire.xls</artifactId>
<version>12.11.8</version>
</dependency>
</dependencies>
<repositories>
<repository>
<id>com.e-iceblue</id>
<name>e-iceblue</name>
<url>https://repo.e-iceblue.cn/repository/maven-public/</url>
</repository>
</repositories>
// excel 转csv
public static void excelToCsv(String excelPath,String csvPath){
//创建Workbook类的对象
com.spire.xls.Workbook workbook = new com.spire.xls.Workbook();
//加载Excel
workbook.loadFromFile(excelPath);
//获取第一张工作表sheet
Worksheet sheet = workbook.getWorksheets().get(0);
//保存为CSV
sheet.saveToFile(csvPath, ",", Charset.forName("UTF-8"));
}
commons-io toolkit
// maven
<dependency>
<groupId>commons-io</groupId>
<artifactId>commons-io</artifactId>
<version>2.11.0</version>
</dependency>
read txt text
private static String txtPath = "D:\\3\\test.txt";
public static void main(String[] args) throws IOException {
File file = new File(txtPath);
byte[] bytes = FileUtils.readFileToByteArray(file);
System.out.println(new String(bytes));
}
hutooltoolkit
// maven
<dependency>
<groupId>cn.hutool</groupId>
<artifactId>hutool-core</artifactId>
<version>5.7.20</version>
</dependency>
Read local file to get byte stream
// 本地文件路径
String filePath = "D:\\3\\后台开发项目\\entity.json";
File file = new File(filePath);
byte[] bytes = FileUtil.readBytes(file);