package com.io;
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
public class BufferedReaderDemo01 {
public static void main(String[] args) throws IOException {
BufferedReader br = new BufferedReader(
new InputStreamReader(
new FileInputStream("./src/main/java/com/io/FISDemo1.java"),
StandardCharsets.UTF_8
)
);
String line = null;
while ((line = br.readLine()) != null){
System.out.println(line);
}
br.close();
}
}
package com.io;
import java.io.File;
import java.io.IOException;
public class CreateNewFileDemo {
public static void main(String[] args) throws IOException {
//在当前目录下新建一个文件:test.txt
File file = new File("./test.txt");
//boolean exists()判断当前File表示的位置是否已经实际存在该文件目录
if(file.exists()){
System.out.println("该文件已存在!");
}else{
file.createNewFile();//将File表示的文件创建出来
System.out.println("文件已创建");
}
}
}
package com.io;
import java.io.File;
/**
* 删除一个目录
*/
public class DeleteDirDemo {
public static void main(String[] args) {
File dir = new File("demo");
if(dir.exists()){
dir.delete();
System.out.println("目录已删除");
}else{
System.out.println("目录不存在");
}
}
}
package com.io;
import java.io.File;
public class DeleteFileDemo {
public static void main(String[] args) {
File file = new File("test.txt");
if(file.exists()){
file.delete();
System.out.println("文件已删除");
}else {
System.out.println("文件不存在");
}
}
}
package com.io;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
public class FileCopyDemo01 {
public static void main(String[] args) throws IOException {
FileInputStream fis =
new FileInputStream("a.jpg");
FileOutputStream fos =
new FileOutputStream("b.jpg");
int n = -1;
while((n=fis.read())!=-1){
fos.write(n);
}
fis.close();
fos.close();
}
}
package com.io;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
public class FileCopyDemo2 {
public static void main(String[] args) throws IOException {
//实现思路
//1读取文件内容
FileInputStream fis = new FileInputStream("a.jpg");
FileOutputStream fos = new FileOutputStream("b.jpg");
//读取数据(复制)
//2.1定义数组用于临时存储读取到数据
byte[] data = new byte[1024];//这里数组的大小是自定义
//2.2循环读取数据
int length = -1;
while((length=fis.read(data))!=-1){
fos.write(data,0,length);//读了多少写多少 ,0表示起始位置,length表示写入的字节数
}
//3.关闭流对象
fis.close();
fos.close();
}
}
package com.io;
import java.io.*;
public class FileCopyDemo3 {
public static void main(String[] args) throws IOException {
//
BufferedInputStream bis =
new BufferedInputStream(
new FileInputStream("./a.jpg"));
BufferedOutputStream bos =
new BufferedOutputStream(
new FileOutputStream("./c.jpg")
);
//2.读写数据(拷贝
byte[] data = new byte[16];
int len;
while ((len = bis.read(data))!= -1){
bos.write(data,0,len);
}
bos.flush();//这里表示刷新缓冲区内容到文件
//3.关闭流对象
bis.close();
bos.close();
}
}
package com.io;
import java.io.File;
public class FileDemo {
public static void main(String[] args) {
File file = new File("./demo.txt");
//获取名字
String name = file.getName();
System.out.println(name);
//获取文件大小(单位是字节)
long len = file.length();
System.out.println(len+"字节");
//是否可读可写
boolean cr = file.canRead();
boolean cw = file.canWrite();
System.out.println("是否可读"+cr);
System.out.println("是否可写"+cw);
//是否隐藏
boolean ih = file.isHidden();
System.out.println("是否隐藏:"+ih);
}
}
package com.io;
import java.io.FileInputStream;
import java.io.IOException;
public class FISDemo1 {
public static void main(String[] args) throws IOException {
//构建文件输入流对象
FileInputStream fis = new FileInputStream("jsd/2406/fos.dat");
int n = 0;
while((n=fis.read())!=-1){
System.out.println(n);
}
//3.关闭流对象(水龙头有打开是不是也会有关闭,否则浪费资源
fis.close();//流对象关闭后会释放内存
}
}
package com.io;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
public class FOSDemo01 {
public static void main(String[] args) throws IOException {
// 构建一个文件输出流对象
//创建文件对象
File file = new File("jsd/2406/fos.dat");
//获取文件对象的目录结构
File parent = file.getParentFile();// jsd/2406/
System.out.println(parent);
//假如目录不存在则创建目录mkdirs()
if(!parent.exists()){//parent.exists()加入返回ture表示存在
parent.mkdirs();//创建多层目录
}
FileOutputStream fos2 = new FileOutputStream(file);
//向文件写入数据
fos2.write(3);
fos2.write(4);
fos2.write(5);
System.out.println("数据写入ok");
//释放资源(关闭流对象)
fos2.close();
}
}
package com.io;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
public class InputStreamReaderDemo01 {
public static void main(String[] args) throws IOException {
InputStreamReader isr
= new InputStreamReader(
new FileInputStream("./osw.txt"),
StandardCharsets.UTF_8
);
int data = 0;
while( (data = isr.read())!=-1){
System.out.println((char)data);
}
isr.close();
}
}
package com.io;
import java.io.File;
/**
* 访问一个目录中的所有子项
*/
public class ListFileDemo1 {
public static void main(String[] args) {
//获取当前目录中的所有子项
File dir = new File(".");
/**
* boolean isFile()
* 判断当前File表示的是否为一个文件
* boolean isDirectory()
* 判断当前File表示的是否一个目录
*/
if(dir.isDirectory()){
File[] subs = dir.listFiles();
System.out.println("当前目录包含"+subs.length+"个子项");
for(int i = 0;i< subs.length;i++){
File sub = subs[i];
System.out.println(sub.getName());
}
}
}
}
package com.io;
import java.io.File;
public class ListFilesDemo2 {
public static void main(String[] args) {
File dir = new File(".");
if(dir.isDirectory()){
File[] subs = dir.listFiles(f->f.getName().endsWith(".txt"));
for(File sub:subs){
System.out.println(sub.getName());
}
}
}
}
package com.io;
import java.io.Serializable;
public class Message implements Serializable {
private static final long serialVersionUID = 7613180213416277986L;
private Integer id;
private transient String title;
private String content;
public Message(){}
public Message(Integer id,String title,String content){
this.id= id;
this.title=title;
this.content=content;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getContent() {
return content;
}
public void setContent(String content) {
this.content = content;
}
//alt+insert
@Override
public String toString() {
return "Message{" +
"id=" + id +
", title='" + title + '\'' +
", content='" + content + '\'' +
'}';
}
}
package com.io;
import java.io.File;
public class MkDirDemo {
public static void main(String[] args) {
File dir = new File("demo");
if(dir.exists()){
System.out.println("该目录已存在");
}else{
dir.mkdirs();// 创建目录时会将路径上所有不存在的目录一同创建
System.out.println("目录已创建");
}
}
}
package com.io;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
public class ObjectInputStreamDemo02 {
public static void main(String[] args) throws IOException,ClassNotFoundException {
ObjectInputStream ois =
new ObjectInputStream(
new FileInputStream("message.txt")
);
Message msg = (Message)ois.readObject();
System.out.println(msg);
ois.close();
}
}
package com.io;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
public class ObjectOutputStreamDemo01 {
public static void main(String[] args) throws IOException {
Message m1 = new Message(1,"传奇老师病了","做了一个小手术");
ObjectOutputStream oos =
new ObjectOutputStream(
new FileOutputStream("message.txt")
);
oos.writeObject(m1);
System.out.println("序列化OK");
oos.close();
}
}
package com.io;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.nio.charset.StandardCharsets;
public class OutputStreamWriteDemo01 {
public static void main(String[] args) throws IOException {
OutputStreamWriter osw =
new OutputStreamWriter(
new FileOutputStream("./osw.txt"),
StandardCharsets.UTF_8
);
//2.写数据
osw.write("你好");
osw.write("子干老师 ");
System.out.println("数据写出完毕");
osw.close();
}
}
package com.io;
import java.io.FileNotFoundException;
import java.io.PrintWriter;
public class PrintWriteDemo01 {
public static void main(String[] args) throws FileNotFoundException {
PrintWriter pw = new PrintWriter("./pw.txt");
pw.println("hello");
pw.println("world");
pw.println("Java");
pw.close();
}
}
package com.io;
import java.io.*;
public class PrintWriteDemo2 {
public static void main(String[] args)throws FileNotFoundException {
PrintWriter printWriter = new PrintWriter(
new BufferedWriter(
new OutputStreamWriter(
new FileOutputStream("./pw.txt",true)
)
),true
);
printWriter.println("hello");
printWriter.println("Java");
printWriter.close();
}
}
package com.io;
import java.io.FileInputStream;
import java.io.IOException;
public class ReadStringDemo01 {
public static void main(String[] args) throws IOException {
FileInputStream fis = new FileInputStream("./f1.txt");
//available获取流中有效字节数
byte[] data = new byte[fis.available()];
int len = fis.read(data);
String str = new String(data,0,len);
System.out.println(str);
fis.close();
}
}
package com.io;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Scanner;
public class SimpleNoteDemo1 {
public static void main(String[] args) throws IOException {
Scanner sc = new Scanner(System.in);
PrintWriter pw = new PrintWriter(
new FileOutputStream("mynote.txt",true),
true
);
while(true){
System.out.println("请输入要存储的数据");
String line = sc.nextLine();
if("exit".equalsIgnoreCase(line)){
break;
}
pw.println(line);
}
sc.close();
pw.close();
}
}
package com.io;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
public class WriteStringDemo01 {
public static void main(String[] args) throws IOException {
String str = "我爱Java";
//构建文件输出流对象
FileOutputStream fos = new FileOutputStream("./f1.txt");
//写字符数据
byte[] data = str.getBytes(StandardCharsets.UTF_8);
fos.write(data);
str="Hello Tedu";
fos.write(str.getBytes(StandardCharsets.UTF_8));
//释放资源
fos.close();
}
}
标签:java,String,io,new,import,public
From: https://blog.csdn.net/m0_68935893/article/details/141070098