1 package com.company.Day022; 2 3 import sun.java2d.pipe.BufferedRenderPipe; 4 5 import java.io.*; 6 7 /** 8 * Created by junius on 2016/10/24. 9 */ 10 public class InDemo001 { 11 public static void main(String[] args) throws IOException { 12 // keyread(); 13 // keyread_2(); 14 // System.out.println((int)' '); 15 // System.out.println((int)' '); 16 keyread_3(); 17 18 } 19 20 private static void keyread_3() throws IOException { 21 /* InputStream in = System.in; 22 InputStreamReader isr = new InputStreamReader(in); 23 BufferedReader br = new BufferedReader(isr); 24 25 OutputStream out = System.out; 26 OutputStreamWriter osw = new OutputStreamWriter(out); 27 BufferedWriter bw = new BufferedWriter(osw);*/ 28 29 BufferedReader bufr = new BufferedReader(new InputStreamReader(new FileInputStream("demo.txt"))); 30 BufferedWriter bufw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream("c.txt"))); 31 32 String line = null; 33 while((line=bufr.readLine())!=null){ 34 if("over".equals(line)) 35 break; 36 // System.out.println(line.toUpperCase()); 37 bufw.write(line.toUpperCase()); 38 bufw.newLine(); 39 bufw.flush(); 40 } 41 } 42 43 private static void keyread_2() throws IOException { 44 /* 45 * 获取键盘录入 46 * 1、键盘只读取一个字节，要判断是否是over 47 * 2、那就需要一个容器 48 * 3、在用户回车之前，将字节变成字符串判断 49 * */ 50 //创建容器 51 StringBuilder sb = new StringBuilder(); 52 53 //获取键盘读取流 54 InputStream in = System.in; 55 56 //定义变量记录读取到的字节，并循环 57 int ch = 0; 58 while((ch=in.read())!=-1){ 59 //判断换行标记 60 if(ch==' ') 61 continue; 62 if(ch==' ') { 63 String temp = sb.toString(); 64 if ("over".equals(temp)) 65 break; 66 System.out.println(temp.toUpperCase()); 67 sb.delete(0,sb.length()); 68 }else{ 69 sb.append((char)ch); 70 // System.out.println(ch); 71 72 } 73 74 } 75 76 } 77 78 79 private static void keyread() throws IOException { 80 InputStream in = System.in; 81 int ch = in.read(); 82 System.out.println(ch); 83 int ch1 = in.read(); 84 System.out.println(ch1); 85 int ch2 = in.read(); 86 System.out.println(ch2); 87 //流只有一个，不能关闭 88 // in.close(); 89 } 90 }
转换流
InputStreamReader 解码 字节到字符
OutputStreamWriter 编码 字符到字节
1、明确源和目的
源：InputStream Reader
目的：OutputStream Writer
2、明确数据是否使用纯文本数据
源：是纯文本 Reader
否 InputStream
目的：是纯文本 Writer
否 OutputStream
3、明确具体的设备
源
硬盘：File
键盘：System.in
内存：数组
网络：Socket流
目的设备
硬盘
控制台 System.out
内存
网络
4、是否需要其他额外功能
1、是否需要高效（缓冲区）buffer
2、转换 字节 字符
转换流的编码解码
什么时候使用转换流
1、源或目的对应的设备是字节流，但是操作的却是文本数据，
2、一旦操作文本涉及到具体的指定编码表，必须使用转换流
1 package com.company.Day022; 2 3 import javax.annotation.processing.Filer; 4 import java.io.*; 5 6 /** 7 * Created by junius on 2016/10/25. 8 * 1、字节->字符 9 * InputStream in = System.in; 10 * FileWriter fw = new FileWriter("a.txt"); 11 * 12 * InputStreamReader isr = new InputStreamReader(System.in) 13 * FileWriter fw = new FileWriter("a.txt"); 14 * 15 * 16 * 2、字符->字节 17 * FileRead fr = new FileRead("b.txt"); 18 * OutputStream out = System.out; 19 * 20 * FileRead fr = new FileRead("b.txt"); 21 * OutputStreamWriter osw = new OutputStreamWriter(System.out); 22 * 23 * 3、字符->字符 24 * FileRead fr = new FileRead("c.txt"); 25 * FileWriter fw = new FileWriter("d.txt"); 26 * 27 * BufferedReader bufr = new BufferedReader(new FileRead("c.txt")) 28 * BufferedWriter bufw = new BufferedWriter(new FileWrite("d.txt")) 29 * 30 * 4、字节->字节 31 * InputStream in = System.in; 32 * OutputStream out = System.out; 33 */ 34 public class Demo002 { 35 public static void main(String[] args) throws IOException { 36 // writeText(); 37 // writeText_2(); 38 // writeText_3(); 39 // readText_1(); 40 readText_2(); 41 } 42 43 private static void readText_2() throws IOException { 44 InputStreamReader isr = new InputStreamReader(new FileInputStream("U8_1.txt"),"UTF-8"); 45 char[] buf = new char[10]; 46 int len = isr.read(buf); 47 String str = new String(buf, 0, len); 48 System.out.println(str); 49 isr.close(); 50 } 51 52 53 private static void readText_1() throws IOException { 54 FileReader fr = new FileReader("gbk_1.txt"); 55 56 char[] buf = new char[10]; 57 int len = fr.read(buf); 58 String str = new String(buf, 0, len); 59 System.out.println(str); 60 fr.close(); 61 62 } 63 64 private static void writeText_3() throws IOException { 65 OutputStreamWriter osw = new OutputStreamWriter(new FileOutputStream("U8_1.txt"),"UTF-8"); 66 osw.write("你好"); 67 osw.close(); 68 } 69 70 private static void writeText_2() throws IOException { 71 OutputStreamWriter osw = new OutputStreamWriter(new FileOutputStream("gbk_2.txt"),"GBK"); 72 osw.write("你好"); 73 osw.close(); 74 } 75 76 private static void writeText() throws IOException { 77 FileWriter fw = new FileWriter("gbk_1.txt"); 78 fw.write("你好"); 79 fw.close(); 80 } 81 }
File对象--构造函数和字段
文件和文件夹封装成对象
文件属性
方法--获取、创建、删除
判断
重名名 renameTo 剪切+rename
系统根目录和容量获取
获取目录内容
如果访问的不是目录，会发生异常
1 package com.company.Day022; 2 3 4 import java.io.File; 5 import java.io.FileFilter; 6 import java.io.IOException; 7 import java.text.DateFormat; 8 import java.util.Date; 9 10 /** 11 * Created by junius on 2016/10/26. 12 */ 13 public class FileDemo003 { 14 public static void main(String[] args) throws IOException { 15 // conDemo(); 16 // function_1(); 17 // function_2(); 18 // function_3(); 19 // function_4(); 20 function_5(); 21 } 22 23 private static void function_5() { 24 File f1 = new File("D:\java\JavaSE基础视频22\IO流"); 25 String[] names = f1.list(new Suffix(".avi")); 26 for (String name:names){ 27 System.out.println(name); 28 } 29 30 } 31 32 private static void function_4() { 33 File file = new File("D:\java"); 34 String[] names = file.list(); 35 for(String name:names){ 36 System.out.println(name); 37 } 38 } 39 40 private static void function_3() { 41 File[] files = File.listRoots(); 42 for (File file:files) { 43 System.out.println(file); 44 45 } 46 } 47 48 private static void function_2() throws IOException { 49 File f1 = new File("ab"); 50 f1.mkdir(); 51 // f1.delete(); 52 } 53 54 private static void function_1() { 55 File file = new File("gbk_1.txt"); 56 String name = file.getName(); 57 String path = file.getPath(); 58 String absPath = file.getAbsolutePath(); 59 long len = file.length(); 60 long time = file.lastModified(); 61 Date date = new Date(time); 62 DateFormat datemate = DateFormat.getDateTimeInstance(DateFormat.LONG,DateFormat.LONG) ; 63 String str_time = datemate.format(date); 64 System.out.println("name:"+name); 65 System.out.println("path:"+path); 66 System.out.println("absPath:"+absPath); 67 System.out.println("len:"+len); 68 System.out.println("time:"+time); 69 System.out.println("str_time:"+str_time); 70 71 } 72 73 private static void conDemo() { 74 File file = new File("d:\a.txt"); 75 File file2 = new File("d:\","b.txt"); 76 File file3 = new File("c:\"); 77 File file4 = new File(file3, "c.txt"); 78 79 File f4 = new File("d:"+System.getProperty("file.separator")+"abc"+File.separator+"e.txt"); 80 System.out.print(f4); 81 82 } 83 }
过滤器
1 package com.company.Day022; 2 3 import java.io.File; 4 import java.io.FileFilter; 5 import java.io.FilenameFilter; 6 import java.util.logging.Filter; 7 8 /** 9 * Created by junius on 2016/10/27. 10 */ 11 public class FilterByTxt implements FilenameFilter { 12 @Override 13 public boolean accept(File pathname,String name) { 14 return name.endsWith(".txt"); 15 } 16 } 17 package com.company.Day022; 18 19 import java.io.File; 20 import java.io.FilenameFilter; 21 22 /** 23 * Created by junius on 2016/10/27. 24 */ 25 public class Suffix implements FilenameFilter { 26 private String suffix; 27 28 public Suffix(String suffix) { 29 this.suffix = suffix; 30 } 31 32 @Override 33 public boolean accept(File dir, String name) { 34 return name.endsWith(suffix); 35 } 36 }