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  1. import org.junit.Test;
  3. import java.io.File;
  4. import java.io.IOException;
  6. public class iofile {
  7.     public static void main(String[] args) {
  9.     }
  10.     @Test
  11.    public void creat01(){
  12.        File parentFile=new File("d:\\");
  13.        String fileName="news1.text";
  14.        File file = new File(parentFile,fileName);
  16.        try {
  17.            file.createNewFile();
  18.            System.out.println("创建成功");
  19.        } catch (IOException e) {
  20.            e.printStackTrace();
  21.        }
  22.    }
  23.    @Test
  24.    public void creat02(){
  25.         String filePath="d:\\new2.txt";
  26.        File file = new File(filePath);
  28.        try {
  29.            file.createNewFile();
  30.            System.out.println("文件创建成功");
  31.        } catch (IOException e) {
  32.            e.printStackTrace();
  33.        }
  34.    }
  35.    @Test
  36.    public void creat03(){
  37.         String parentFile="d:\\";
  38.         String fileName="text03.txt";
  39.        File file = new File(parentFile,fileName);
  40.        try {
  41.            file.createNewFile();
  42.            System.out.println("文件创建成功！");
  43.        } catch (IOException e) {
  44.            e.printStackTrace();
  45.        }
  46.    }
  47. }

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csdn上面的讲解

链接
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  2. import java.io.File;
  3. import java.io.FileInputStream;
  4. import java.io.FileOutputStream;
  5. import java.io.IOException;
  7. public class IoTest {
  8.     //字节流
  9.     public static void main(String[] args) throws IOException {
  10.         File file1 = new File("D:/test1.txt");
  11.         write(file1);
  12.         System.out.println(read(file1));
  13.     }
  14.     public static void write(File file)throws IOException {
  15.         FileOutputStream os = new FileOutputStream(file,true);
  16.         String s="人家最喜欢惠祁啦！";
  17.         os.write(s.getBytes());
  18.         os.close();
  19.     }
  20.     public static String read(File file)throws IOException{
  21.         FileInputStream fs = new FileInputStream(file);
  22.         byte[]bytes=new byte[1024];
  23.         StringBuilder sb = new StringBuilder();
  24.         int length;
  25.         while ((length=fs.read(bytes))!=-1){
  26.             sb.append(new String(bytes,0,length));
  27.         }
  28.         fs.close();
  30.         return sb.toString();
  31.     }
  32. }
  2. //缓冲字节流
  3. public class IOTest01 {
  4.     public static void main(String[] args) throws IOException {
  5.         File file = new File("D:/test2.txt");
  6.         write(file);
  7.         System.out.println(read(file));
  8.     }
  9.     public static void write(File file)throws IOException {
  10.         BufferedOutputStream bs = new BufferedOutputStream(new FileOutputStream(file,true));
  11.         String s="垃圾惠祁垃圾惠祁！";
  12.         bs.write(s.getBytes());
  13.         bs.close();
  15.     }
  16.     public static String read(File file)throws IOException{
  17.         BufferedInputStream fs = new BufferedInputStream(new FileInputStream(file));
  18.         byte [] bytes=new byte[1024];
  19.         //用来接收读取的字节数组
  20.         StringBuilder sb=new StringBuilder();
  21.         //读取到字节数组的长度
  22.         int length;
  23.         while ((length=fs.read(bytes))!= -1){
  24.             //将读取到的内容转化为字符串
  25.             sb.append(new String(bytes,0,length));
  26.         }
  27.         fs.close();
  28.         return sb.toString();
  29.     }
  31. }
  2. //字符流
  3. public class IOTest03 {
  4.     public static void main(String[] args)throws IOException {
  5.         File file = new File("D:/test03.txt");
  6.         write(file);
  7.         System.out.println(read(file));
  8.     }
  10.     public static void write(File file) throws IOException {
  11.         OutputStreamWriter ow = new OutputStreamWriter(new FileOutputStream(file, true));
  12.         String s = "io流好麻烦呀1";
  13.         ow.write(s);
  14.         ow.close();
  16.     }
  18.     public static String read(File file)throws IOException{
  19.         InputStreamReader ir = new InputStreamReader(new FileInputStream(file), "UTF-8");
  20.         //一起读取多少给字符
  21.         char[]chars=new char[1024];
  22.         //读取的字符数组先append到StringBuilder里面
  23.         StringBuilder sb=new StringBuilder();
  24.         int length;
  25.         while ((length= ir.read(chars))!= -1){
  26.             sb.append(new String(chars,0,length));
  27.         }
  28.         ir.close();
  29.         return sb.toString();
  30.     }
  31. }
  39. import java.io.*;
  40. import java.nio.charset.StandardCharsets;
  42. //字符流
  43. public class IOTest03 {
  44.     public static void main(String[] args)throws IOException {
  45.         File file = new File("D:/test03.txt");
  46.         write(file);
  47.         System.out.println(read(file));
  48.     }
  50.     public static void write(File file) throws IOException {
  51.         OutputStreamWriter ow = new OutputStreamWriter(new FileOutputStream(file, true));
  52.         String s = "io流好麻烦呀1";
  53.         ow.write(s);
  54.         ow.close();
  56.     }
  58.     public static String read(File file)throws IOException{
  59.         InputStreamReader ir = new InputStreamReader(new FileInputStream(file), "UTF-8");
  60.         //一起读取多少给字符
  61.         char[]chars=new char[1024];
  62.         //读取的字符数组先append到StringBuilder里面
  63.         int length;
  64.         while ((length= ir.read(chars))!= -1){
  65.             System.out.println(new String(chars,0,length));
  66.         }
  67.         ir.close();
  68.         return new String();
  69.     }
  2. ///字符流便捷类
  3. public class IOTest02 {
  4.     public static void main(String[] args)throws IOException {
  5.         File file = new File("D:/test04.txt");
  6.         write(file);
  7.         System.out.println(read(file));
  9.     }
  10.     public static void write(File file)throws IOException {
  11.         FileWriter fw = new FileWriter(file, true);
  12.         String s="慢慢学一定可以的！";
  13.         fw.write(s);
  14.         fw.close();
  15.     }
  16.     public static String read(File file)throws IOException{
  17.         FileReader fileReader = new FileReader(file);
  18.         char [] chars= new char[1024];
  19.         StringBuilder sb=new StringBuilder();
  20.         int length;
  21.         while ((length=fileReader.read(chars)) != -1){
  22.             sb.append(new String(chars,0,length));
  24.         }
  25.         fileReader.close();
  26.         return sb.toString();
  27.     }
  28. }

文件的拷贝

  2. import com.sun.xml.internal.ws.policy.privateutil.PolicyUtils;
  4. import java.io.*;
  5. //文件拷贝
  6. public class IOTest04 {
  7.     public static void main(String[] args) throws IOException {
  9.         {
  10.             try {
  11.                 FileInputStream fi = new FileInputStream("D:/test2.txt");
  12.                 FileOutputStream fo = new FileOutputStream("D:/test03.txt",true);
  13.                 byte[] bytes = new byte[1024];
  14.                 StringBuilder stringBuilder = new StringBuilder();
  15.                 int length;
  16.                 while ((length = fi.read(bytes)) != -1) {
  17.                     fo.write(bytes, 0, length);
  18.                 }
  20. fi.close();
  21. fo.close();
  23.             } catch (IOException e) {
  24.                 e.printStackTrace();
  25.             }
  28.         }
  31.     }
  32. }

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