java file reading and writing tool class sharing
- 2021-01-18 06:29:23
- OfStack
This article example for everyone to share java file reading and writing tool class specific code, for your reference, the specific content is as follows
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Date;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import javax.servlet.http.HttpServletResponse;
/**
* <p> File manipulation tool class <p>
* @version 1.0
* @author li_hao
* @date 2017 years 1 month 18 day
*/
@SuppressWarnings({"resource","unused"})
public class FileUtils {
/**
* To obtain windows/linux The project root directory of
* @return
*/
public static String getConTextPath(){
String fileUrl = Thread.currentThread().getContextClassLoader().getResource("").getPath();
if("usr".equals(fileUrl.substring(1,4))){
fileUrl = (fileUrl.substring(0,fileUrl.length()-16));//linux
}else{
fileUrl = (fileUrl.substring(1,fileUrl.length()-16));//windows
}
return fileUrl;
}
/**
* String to array
* @param str string
* @param splitStr The separator
* @return
*/
public static String[] StringToArray(String str,String splitStr){
String[] arrayStr = null;
if(!"".equals(str) && str != null){
if(str.indexOf(splitStr)!=-1){
arrayStr = str.split(splitStr);
}else{
arrayStr = new String[1];
arrayStr[0] = str;
}
}
return arrayStr;
}
/**
* Read the file
*
* @param Path
* @return
*/
public static String ReadFile(String Path) {
BufferedReader reader = null;
String laststr = "";
try {
FileInputStream fileInputStream = new FileInputStream(Path);
InputStreamReader inputStreamReader = new InputStreamReader(fileInputStream, "UTF-8");
reader = new BufferedReader(inputStreamReader);
String tempString = null;
while ((tempString = reader.readLine()) != null) {
laststr += tempString;
}
reader.close();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return laststr;
}
/**
* Gets the names of all the files in the folder + Fuzzy queries (When fuzzy queries are not needed, queryStr The empty or null )
* 1. When the path doesn't exist, map return retType A value of 1
* 2. When the path is the file path, map return retType A value of 2 , the file name fileName Value is filename
* 3. When there is a folder under the path, map return retType A value of 3 , list of file names fileNameList , folder names list folderNameList
* @param folderPath The path
* @param queryStr Fuzzy query string
* @return
*/
public static HashMap<String, Object> getFilesName(String folderPath , String queryStr) {
HashMap<String, Object> map = new HashMap<>();
List<String> fileNameList = new ArrayList<>();// List of file names
List<String> folderNameList = new ArrayList<>();// List of folder names
File f = new File(folderPath);
if (!f.exists()) { // Path does not exist
map.put("retType", "1");
}else{
boolean flag = f.isDirectory();
if(flag==false){ // The path is a file
map.put("retType", "2");
map.put("fileName", f.getName());
}else{ // The path is folder
map.put("retType", "3");
File fa[] = f.listFiles();
queryStr = queryStr==null ? "" : queryStr;// if queryStr For the incoming null, Then replace it with empty ( indexOf The match value cannot be null )
for (int i = 0; i < fa.length; i++) {
File fs = fa[i];
if(fs.getName().indexOf(queryStr)!=-1){
if (fs.isDirectory()) {
folderNameList.add(fs.getName());
} else {
fileNameList.add(fs.getName());
}
}
}
map.put("fileNameList", fileNameList);
map.put("folderNameList", folderNameList);
}
}
return map;
}
/**
* Reads the file in action units until the end 1 line
* @param filePath
* @return
*/
public static List<String> readFileContent(String filePath) {
BufferedReader reader = null;
List<String> listContent = new ArrayList<>();
try {
reader = new BufferedReader(new FileReader(filePath));
String tempString = null;
int line = 1;
// 1 Time to read 1 Line until it is read in null End of file
while ((tempString = reader.readLine()) != null) {
listContent.add(tempString);
line++;
}
reader.close();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException e1) {
}
}
}
return listContent;
}
/**
* Reads the specified row data , pay attention to: 0 For the start line
* @param filePath
* @param lineNumber
* @return
*/
public static String readLineContent(String filePath,int lineNumber){
BufferedReader reader = null;
String lineContent="";
try {
reader = new BufferedReader(new FileReader(filePath));
int line=0;
while(line<=lineNumber){
lineContent=reader.readLine();
line++;
}
reader.close();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException e1) {
}
}
}
return lineContent;
}
/**
* Read from the beginLine to endLine Data (including beginLine and endLine ), note: 0 For the start line
* @param filePath
* @param beginLineNumber Start line
* @param endLineNumber End line
* @return
*/
public static List<String> readLinesContent(String filePath,int beginLineNumber,int endLineNumber){
List<String> listContent = new ArrayList<>();
try{
int count = 0;
BufferedReader reader = new BufferedReader(new FileReader(filePath));
String content = reader.readLine();
while(content !=null){
if(count >= beginLineNumber && count <=endLineNumber){
listContent.add(content);
}
content = reader.readLine();
count++;
}
} catch(Exception e){
}
return listContent;
}
/**
* Read all data from several files
* @param listFilePath
* @return
*/
public static List<String> readFileContent_list(List<String> listFilePath) {
List<String> listContent = new ArrayList<>();
for(String filePath : listFilePath){
File file = new File(filePath);
BufferedReader reader = null;
try {
reader = new BufferedReader(new FileReader(file));
String tempString = null;
int line = 1;
// 1 Time to read 1 Line until it is read in null End of file
while ((tempString = reader.readLine()) != null) {
listContent.add(tempString);
line++;
}
reader.close();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException e1) {
}
}
}
}
return listContent;
}
/**
* File data write (if folder and file do not exist, create first, then write)
* @param filePath
* @param content
* @param flag true: If the file exists and the content exists, the content is appended with a newline; false: If the file exists and the content exists, the content is replaced
*/
public static String fileLinesWrite(String filePath,String content,boolean flag){
String filedo = "write";
FileWriter fw = null;
try {
File file=new File(filePath);
// If the folder does not exist, the folder is created
if (!file.getParentFile().exists()){
file.getParentFile().mkdirs();
}
if(!file.exists()){// If the file does not exist, the file is created , Write the first 1 line
file.createNewFile();
fw = new FileWriter(file);
filedo = "create";
}else{// If the file exists , The content is appended or replaced
fw = new FileWriter(file, flag);
}
} catch (IOException e) {
e.printStackTrace();
}
PrintWriter pw = new PrintWriter(fw);
pw.println(content);
pw.flush();
try {
fw.flush();
pw.close();
fw.close();
} catch (IOException e) {
e.printStackTrace();
}
return filedo;
}
/**
* Write files
* @param ins
* @param out
*/
public static void writeIntoOut(InputStream ins, OutputStream out) {
byte[] bb = new byte[10 * 1024];
try {
int cnt = ins.read(bb);
while (cnt > 0) {
out.write(bb, 0, cnt);
cnt = ins.read(bb);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
out.flush();
ins.close();
out.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
/**
* judge list Whether the elements are identical in the true, Otherwise returns false )
* @param list
* @return
*/
private static boolean hasSame(List<? extends Object> list){
if(null == list)
return false;
return 1 == new HashSet<Object>(list).size();
}
/**
* judge list Is there a duplicate element in the true, Otherwise returns false )
* @param list
* @return
*/
private static boolean hasSame2(List<? extends Object> list){
if(null == list)
return false;
return list.size() == new HashSet<Object>(list).size();
}
/**
* increase / Reduce the number of days
* @param date
* @param num
* @return
*/
public static Date DateAddOrSub(Date date, int num) {
Calendar startDT = Calendar.getInstance();
startDT.setTime(date);
startDT.add(Calendar.DAY_OF_MONTH, num);
return startDT.getTime();
}
}