收集整理的java常见文件操作，方便平时使用：
//1.创建文件夹
//import java.io.*;
File myFolderPath = new File(str1);
try {
if (!myFolderPath.exists()) {
myFolderPath.mkdir();
}
}
catch (Exception e) {
System.out.println("新建目录操作出错");
e.printStackTrace();
}
//2.创建文件
//import java.io.*;
File myFilePath = new File(str1);
try {
if (!myFilePath.exists()) {
myFilePath.createNewFile();
}
FileWriter resultFile = new FileWriter(myFilePath);
PrintWriter myFile = new PrintWriter(resultFile);
myFile.println(str2);
resultFile.close();
}
catch (Exception e) {
System.out.println("新建文件操作出错");
e.printStackTrace();
}
//3.删除文件
//import java.io.*;
File myDelFile = new File(str1);
try {
myDelFile.delete();
}
catch (Exception e) {
System.out.println("删除文件操作出错");
e.printStackTrace();
}
//4.删除文件夹
//import java.io.*;
File delFolderPath = new File(str1);
try {
delFolderPath.delete(); //删除空文件夹
}
catch (Exception e) {
System.out.println("删除文件夹操作出错");
e.printStackTrace();
}
//5.删除一个文件下夹所有的文件夹
//import java.io.*;
File delfile=new File(str1);
File[] files=delfile.listFiles();
for(int i=0;i<files.length;i++){
if(files[i].isDirectory()){
files[i].delete();
}
}
//6.清空文件夹
//import java.io.*;
File delfilefolder=new File(str1);
try {
if (!delfilefolder.exists()) {
delfilefolder.delete();
}
delfilefolder.mkdir();
}
catch (Exception e) {
System.out.println("清空目录操作出错");
e.printStackTrace();
}
//7.读取文件
//import java.io.*;
// 逐行读取数据
FileReader fr = new FileReader(str1);
BufferedReader br = new BufferedReader(fr);
String str2 = br.readLine();
while (str2 != null) {
str3
str2 = br.readLine();
}
br.close();
fr.close();
//8.写入文件
//import java.io.*;
// 将数据写入文件
try {
FileWriter fw = new FileWriter(str1);
fw.write(str2);
fw.flush();
fw.close();
} catch (IOException e) {
e.printStackTrace();
}
//9.写入随机文件
//import java.io.*;
try {
RandomAcessFile logFile=new RandomAcessFile(str1,"rw");
long lg=logFile.length();
logFile.seek(str2);
logFile.writeByte(str3);
}catch(IOException ioe){
System.out.println("无法写入文件："+ioe.getMessage());
}
//10.读取文件属性
//import java.io.*;
// 文件属性的取得
File f = new File(str1);
if (af.exists()) {
System.out.println(f.getName() + "的属性如下： 文件长度为：" + f.length());
System.out.println(f.isFile() ? "是文件" : "不是文件");
System.out.println(f.isDirectory() ? "是目录" : "不是目录");
System.out.println(f.canRead() ? "可读取" : "不");
System.out.println(f.canWrite() ? "是隐藏文件" : "");
System.out.println("文件夹的最后修改日期为：" + new Date(f.lastModified()));
} else {
System.out.println(f.getName() + "的属性如下：");
System.out.println(f.isFile() ? "是文件" : "不是文件");
System.out.println(f.isDirectory() ? "是目录" : "不是目录");
System.out.println(f.canRead() ? "可读取" : "不");
System.out.println(f.canWrite() ? "是隐藏文件" : "");
System.out.println("文件的最后修改日期为：" + new Date(f.lastModified()));
}
if(f.canRead()){
str2
}
if(f.canWrite()){
str3
}
//11.写入属性
//import java.io.*;
File filereadonly=new File(str1);
try {
boolean b=filereadonly.setReadOnly();
}
catch (Exception e) {
System.out.println("拒绝写访问："+e.printStackTrace());
}
//12.枚举一个文件夹中的所有文件
//import java.io.*;
//import java.util.*;
LinkedList folderList = new LinkedList();
folderList.add(str1);
while (folderList.size() > 0) {
File file = new File(folderList.peek());
folderList.removeLast();
File[] files = file.listFiles();
ArrayList fileList = new ArrayList();
for (int i = 0; i < files.length; i++) {
if (files[i].isDirectory()) {
folderList.add(files[i].getPath());
} else {
fileList.add(files[i]);
}
}
for (File f : fileList) {
str2=f.getAbsoluteFile();
str3
}
}
//13.复制文件夹
//import java.io.*;
//import java.util.*;
LinkedList folderList = new LinkedList();
folderList.add(str1);
LinkedList folderList2 = new LinkedList();
folderList2.add(str2+ str1.substring(str1.lastIndexOf("\\")));
while (folderList.size() > 0) {
(new File(folderList2.peek())).mkdirs(); // 如果文件夹不存在 则建立新文件夹
File folders = new File(folderList.peek());
String[] file = folders.list();
File temp = null;
try {
for (int i = 0; i < file.length; i++) {
if (folderList.peek().endsWith(File.separator)) {
temp = new File(folderList.peek() + File.separator
+ file[i]);
} else {
temp = new File(folderList.peek() + File.separator + file[i]);
}
if (temp.isFile()) {
FileInputStream input = new FileInputStream(temp);
FileOutputStream output = new FileOutputStream(
folderList2.peek() + File.separator + (temp.getName()).toString());
byte[] b = new byte[5120];
int len;
while ((len = input.read(b)) != -1) {
output.write(b, 0, len);
}
output.flush();
output.close();
input.close();
}
if (temp.isDirectory()) {// 如果是子文件夹
for (File f : temp.listFiles()) {
if (f.isDirectory()) {
folderList.add(f.getPath());
folderList2.add(folderList2.peek()
+ File.separator + f.getName());
}
}
}
}
} catch (Exception e) {
//System.out.println("复制整个文件夹内容操作出错");
e.printStackTrace();
}
folderList.removeFirst();
folderList2.removeFirst();
}
//14.复制一个文件夹下所有的文件夹到另一个文件夹下
//import java.io.*;
//import java.util.*;
File copyfolders=new File(str1);
File[] copyfoldersList=copyfolders.listFiles();
for(int k=0;k<copyfoldersList.length;k++){
if(copyfoldersList[k].isDirectory()){
ArrayListfolderList=new ArrayList();
folderList.add(copyfoldersList[k].getPath());
ArrayListfolderList2=new ArrayList();
folderList2.add(str2+"/"+copyfoldersList[k].getName());
for(int j=0;j<folderList.length;j++){
(new File(folderList2.get(j))).mkdirs(); //如果文件夹不存在 则建立新文件夹
File folders=new File(folderList.get(j));
String[] file=folders.list();
File temp=null;
try {
for (int i = 0; i < file.length; i++) {
if(folderList.get(j).endsWith(File.separator)){
temp=new File(folderList.get(j)+"/"+file[i]);
} else {
temp=new File(folderList.get(j)+"/"+File.separator+file[i]);
}
FileInputStream input = new FileInputStream(temp);
if(temp.isFile()){
FileInputStream input = new FileInputStream(temp);
FileOutputStream output = new FileOutputStream(folderList2.get(j) + "/" + (temp.getName()).toString());
byte[] b = new byte[5120];
int len;
while ( (len = input.read(b)) != -1) {
output.write(b, 0, len);
}
output.flush();
output.close();
input.close();
}
if(temp.isDirectory()){//如果是子文件夹
folderList.add(folderList.get(j)+"/"+file[i]);
folderList2.add(folderList2.get(j)+"/"+file[i]);
}
}
}
catch (Exception e) {
System.out.println("复制整个文件夹内容操作出错");
e.printStackTrace();
}
}
}
}
//15.移动文件夹
//import java.io.*;
//import java.util.*;
LinkedList folderList = new LinkedList();
folderList.add(str1);
LinkedList folderList2 = new LinkedList();
folderList2.add(str2 + str1.substring(str1.lastIndexOf("\\")));
while (folderList.size() > 0) {
(new File(folderList2.peek())).mkdirs(); // 如果文件夹不存在 则建立新文件夹
File folders = new File(folderList.peek());
String[] file = folders.list();
File temp = null;
try {
for (int i = 0; i < file.length; i++) {
if (folderList.peek().endsWith(File.separator)) {
temp = new File(folderList.peek() + File.separator + file[i]);
} else {
temp = new File(folderList.peek() + File.separator + file[i]);
}
if (temp.isFile()) {
FileInputStream input = new FileInputStream(temp);
FileOutputStream output = new FileOutputStream(
folderList2.peek() + File.separator + (temp.getName()).toString());
byte[] b = new byte[5120];
int len;
while ((len = input.read(b)) != -1) {
output.write(b, 0, len);
}
output.flush();
output.close();
input.close();
if (!temp.delete())
System.out.println("删除单个文件操作出错!");
}
if (temp.isDirectory()) {// 如果是子文件夹
for (File f : temp.listFiles()) {
if (f.isDirectory()) {
folderList.add(f.getPath());
folderList2.add(folderList2.peek() + File.separator + f.getName());
}
}
}
}
} catch (Exception e) {
// System.out.println("复制整个文件夹内容操作出错");
e.printStackTrace();
}
folderList.removeFirst();
folderList2.removeFirst();
}
File f = new File(str1);
if (!f.delete()) {
for (File file : f.listFiles()) {
if (file.list().length == 0) {
System.out.println(file.getPath());
file.delete();
}
}
}
//16.移动一个文件夹下所有的文件夹到另一个目录下
//import java.io.*;
//import java.util.*;
File movefolders=new File(str1);
File[] movefoldersList=movefolders.listFiles();
for(int k=0;k<movefoldersList.length;k++){
if(movefoldersList[k].isDirectory()){
ArrayListfolderList=new ArrayList();
folderList.add(movefoldersList[k].getPath());
ArrayListfolderList2=new ArrayList();
folderList2.add(str2+"/"+movefoldersList[k].getName());
for(int j=0;j<folderList.length;j++){
(new File(folderList2.get(j))).mkdirs(); //如果文件夹不存在 则建立新文件夹
File folders=new File(folderList.get(j));
String[] file=folders.list();
File temp=null;
try {
for (int i = 0; i < file.length; i++) {
if(folderList.get(j).endsWith(File.separator)){
temp=new File(folderList.get(j)+"/"+file[i]);
}
else{
temp=new File(folderList.get(j)+"/"+File.separator+file[i]);
}
FileInputStream input = new FileInputStream(temp);
if(temp.isFile()){
FileInputStream input = new FileInputStream(temp);
FileOutputStream output = new FileOutputStream(folderList2.get(j) + "/" + (temp.getName()).toString());
byte[] b = new byte[5120];
int len;
while ( (len = input.read(b)) != -1) {
output.write(b, 0, len);
}
output.flush();
output.close();
input.close();
temp.delete();
}
if(temp.isDirectory()){//如果是子文件夹
folderList.add(folderList.get(j)+"/"+file[i]);
folderList2.add(folderList2.get(j)+"/"+file[i]);
}
}
}
catch (Exception e) {
System.out.println("复制整个文件夹内容操作出错");
e.printStackTrace();
}
}
movefoldersList[k].delete();
}
}
//17.以一个文件夹的框架在另一个目录创建文件夹和空文件
//import java.io.*;
//import java.util.*;
boolean b=false;//不创建空文件
ArrayListfolderList=new ArrayList();
folderList.add(str1);
ArrayListfolderList2=new ArrayList();
folderList2.add(str2);
for(int j=0;j<folderList.length;j++){
(new File(folderList2.get(j))).mkdirs(); //如果文件夹不存在 则建立新文件夹
File folders=new File(folderList.get(j));
String[] file=folders.list();
File temp=null;
try {
for (int i = 0; i < file.length; i++) {
if(folderList.get(j).endsWith(File.separator)){
temp=new File(folderList.get(j)+"/"+file[i]);
}
else{
temp=new File(folderList.get(j)+"/"+File.separator+file[i]);
}
FileInputStream input = new FileInputStream(temp);
if(temp.isFile()){
if (b) temp.createNewFile();
}
if(temp.isDirectory()){//如果是子文件夹
folderList.add(folderList.get(j)+"/"+file[i]);
folderList2.add(folderList2.get(j)+"/"+file[i]);
}
}
}
catch (Exception e) {
System.out.println("复制整个文件夹内容操作出错");
e.printStackTrace();
}
}
//18.复制文件
//import java.io.*;
int bytesum = 0;
int byteread = 0;
File oldfile = new File(str1);
try {
if (oldfile.exists()) { //文件存在时
FileInputStream inStream = new FileInputStream(oldfile); //读入原文件
FileOutputStream fs = new FileOutputStream(new File(str2,oldfile.getName()));
byte[] buffer = new byte[5120];
int length;
while ( (byteread = inStream.read(buffer)) != -1) {
bytesum += byteread; //字节数 文件大小
System.out.println(bytesum);
fs.write(buffer, 0, byteread);
}
inStream.close();
}
}
catch (Exception e) {
System.out.println("复制单个文件操作出错");
e.printStackTrace();
}
//19.复制一个文件夹下所有的文件到另一个目录
//import java.io.*;
File copyfiles=new File(str1);
File[] files=copyfiles.listFiles();
for(int i=0;i<files.length;i++){
if(!files[i].isDirectory()){
int bytesum = 0;
int byteread = 0;
try {
InputStream inStream = new FileInputStream(files[i]); //读入原文件
FileOutputStream fs = new FileOutputStream(new File(str2,files[i].getName());
byte[] buffer = new byte[5120];
int length;
while ( (byteread = inStream.read(buffer)) != -1) {
bytesum += byteread; //字节数 文件大小
System.out.println(bytesum);
fs.write(buffer, 0, byteread);
}
inStream.close();
} catch (Exception e) {
System.out.println("复制单个文件操作出错");
e.printStackTrace();
}
}
}
//20.提取扩展名
String str2=str1.substring(str1.lastIndexOf(".")+1);