网站建设计划方案模板汕头网站制作电话
day17_io02
1.上课代码敲一遍
2.读取一个文件，这个文件中有随机的一些数字字符，统计这些数字有几个偶数，几个奇数，并且追加写入到该文件末尾。
例如：
a.txt文件：
3241256364789629090126581212515
奇数：xx个
偶数：xx个
package com.cskaoyan._17day;import java.io.*;
import java.util.ArrayList;public class Exercise {public static void main(String[] args) throws IOException {try {BufferedReader br=new BufferedReader(new InputStreamReader(new FileInputStream(new File("a.txt"))));String lineTxt="3241256364789629090126581212515";int a = 0;ArrayList<String> oddnumber=new ArrayList<>();ArrayList<Object> evennumber=new ArrayList<>();while ((lineTxt=br.readLine())!=null){a++;if (a % 2 == 0) {oddnumber.add(lineTxt);} else {evennumber.add(lineTxt);}}br.close();}catch (Exception e){System.out.println("read error: " + e);}}
}
3.在一个磁盘的文件里保存26个英文小写字母（乱序），将他们读入内存中，进行排序，把排好顺序的数再重新追加写到磁盘的该文件中。
package com.cskaoyan._17day;
import java.io.*;
public class Exercise02 {public static void main(String[] args) throws IOException {FileInputStream sc = new FileInputStream("a.txt");Reader reader = new InputStreamReader( sc );FileOutputStream s = new FileOutputStream("a.txt", true);Writer writer=new OutputStreamWriter( s );char[] chars = new char[1024];int len;while((len = reader.read(chars)) != -1){bubbleSort(chars,len);writer.write("\n");writer.write(chars,0,len);}reader.close();writer.close();}private static void bubbleSort(char arr[] , int len) {for (int i=0; i < len -1; i++) {for (int j=0; j < len -1; j++) {if (arr[j] > arr[j + 1]){char temp = arr[j];arr[j] = arr[j + 1];arr[j + 1] = temp;}}}}
}4.递归查找指定目录中(包括子目录中)，所有的.java文件，并且，把所有这些找到的java文件，复制(是复制不是移动)到一个指定的目录下
package com.cskaoyan._17day;import java.io.*;
import java.util.ArrayList;public class Exercise03 {public static void main(String[] args) {File sc = new File("D:\\");File file = new File("D:\\ ");file.mkdir();String targetDir = "";eachFile(sc);//复制所有。java文件到目标文件夹for (int i=0; i < file.length(); i++) {FileInputStream input = null;FileOutputStream output = null;try{input = new FileInputStream(file.get(i));InputStream inbuffer = new BufferedInputStream(input);//目标文件由输出流自己创建output = new FileInputStream(targetDir + file.get(i).getName());OutputStream outbuffer=new BufferedOutputStream(output);//利用字节缓冲流复制文件byte[] b = new byte[1024];int len;while ((len = inbuffer.read(b)) != -1){outbuffer.write(b,0,len);}} catch (IOException e) {e.printStackTrace();}finally {closeQuietly(input);closeQuietly(output);}}}public static void closeQuietly(Closeable closeable){try{if (closeable != null){closeable.close();}} catch (IOException e){e.printStackTrace();}}public static ArrayList<File> files = new ArrayList<>();//遍历这个文件夹内的所有子目录和文件public static void eachFile(File file){try{File[] targetFile = file.listFiles();for (int i=0; i < targetFile.length; i++) {if (targetFile[i].isDirectory()){eachFile(targetFile[i]);}else{//找到所有的java文件并且放到集合中if (targetFile[i].getName().endsWith("java")){file.add(targetFile[i]);}}}} catch (Exception e){e.printStackTrace();}}
}