2017.11.25作业

1:需求：递归删除带内容的目录

import java.io.File;public class Homework1 {public static void main(String[] args) {File Folder = new File ("RNG6");Delete(Folder);}private static void Delete(File Folder) {File[] fileArray=Folder.listFiles();if (fileArray!=null){for(File file:f6ileArray){if(file.isDirectory()){Delete(file);}else{System.out.println(file.getName()+file.delete());}}}}}

2:需求：请大家把E:\JavaSE目录下所有的java结尾的文件的绝对路径给输出在控制台。

import java.io.File;public class HomeWork2 {public static void main(String[] args) {File file = new File("C:\\KSWJJ\\src");File[]lists= file.listFiles();for(File f: lists){if(f.isFile()){if(f.toString().endsWith(".java")){System.out.println(f);}}}}}

3. 复制文本文件:有5种方式

package qx.work_02;import java.io.BufferedInputStream;import java.io.BufferedOutputStream;import java.io.BufferedReader;import java.io.BufferedWriter;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.FileReader;import java.io.FileWriter;import java.io.IOException;public class HomeWork1 {private static String srcString;public static void main(String[] args) throws IOException {long startTime = System.currentTimeMillis();method1("E:\\abc.mp4","Copy.mp4") ;method2("E:\\abc.mp4","Copy.mp4") ;method3("E:\\abc.mp4","Copy.mp4") ;method4("E:\\abc.mp4","Copy.mp4") ;method5("E:\\abc.mp4","Copy.mp4") ;long endTime = System.currentTimeMillis();System.out.println("共耗时:"+(endTime - startTime)+"毫秒");}//高效字节流一次读取一个字节数组private static void method4(String srcString , String destString) throws IOException{//封装数据源和目的地BufferedInputStream bis = new BufferedInputStream(new FileInputStream(srcString));BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(destString));//一次读取一个字节数组byte [] bys = new byte[1024];int len = 0;while((len = bis.read(bys))!=-1){bos.write(bys,0,len);bos.flush();}bis.close();bos.close();}//字节缓冲输入流一次读取一个字节private static void method3(String SrcString, String destString) throws IOException {//创建字节缓冲输入对象BufferedInputStream bis = new BufferedInputStream(new FileInputStream(srcString));BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(destString));//一次读取一个字节int by = 0;while((by = bis.read())!=-1){bos.write(by);bos.flush();}bis.close();bos.close();}//基本字节流一次读取一个字节数组private static void method2(String SrcString, String destString) throws IOException {FileInputStream fis = new FileInputStream(srcString);FileOutputStream fos = new FileOutputStream(destString);//一次读取一个字节数组byte [] bys = new byte[1024];int len = 0;while((len = fis.read())!=-1){fos.write(bys,0,len);}fis.close();fos.close();}//基本字节流一次读取一个字节private static void method1(String StrString, String destString) throws IOException{FileInputStream fis = new FileInputStream(srcString);FileOutputStream fos = new FileOutputStream(destString);//一次读取一个字节//并且一次写一个字节int by = 0;while((by = fis.read())!=-1){fos.write(by);}fis.close();fos.close();}//字符缓冲流一次读取一个字符串private static void method5(String srcString, String destString) throws IOException{BufferedReader br = new BufferedReader(new FileReader(srcString));BufferedWriter bw = new BufferedWriter(new FileWriter(destString));String line = null;while((line = br.readLine())!=null){bw.write(line);bw.newLine();bw.flush();}br.close();bw.close();}}

4. 复制图片:4种方式

import java.io.BufferedInputStream;import java.io.BufferedOutputStream;import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;public class HomeWork4 {public static void main(String[] args) throws IOException {File s1 = new File("a.jpg");File s2 = new File ("b.jpg");method1(s1,s2);method2(s1,s2);method3(s1,s2);method4(s1,s2);}//高效字节流一个读写一个字节数组private static void method4(File s1, File s2) throws IOException {BufferedInputStream bis = new BufferedInputStream(new FileInputStream(s1));        BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(s2));        byte[] bys = new byte[1024];         int len = 0;         while ((len = bis.read(bys)) != -1) {            bos.write(bys, 0, len);             bos.flush();         }        bos.close();        bis.close();    }  //高效字节流一次读写一个字节private static void method3(File s1, File s2) throws IOException {BufferedInputStream bis = new BufferedInputStream(new FileInputStream(s1));        BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(s2));          int by = 0;    while ((by=bis.read())!=-1){    bos.write(by);    }    bis.close();    bos.close();}//基本字节流一次读写一个字节 数组private static void method2(File s1, File s2) throws IOException {FileInputStream fis = new FileInputStream(s1);FileOutputStream fos = new FileOutputStream(s2);byte [] bys = new byte [1024];int by = 0;while((by=fis.read(bys))!=-1){fos.write(bys,0,by);fos.flush();}fis.close();    fos.close();}//基本字节流一次读写一个字节private static void method1(File s1, File s2)throws IOException  {FileInputStream fis = new FileInputStream(s1);FileOutputStream fos = new FileOutputStream(s2); int by = 0;    while ((by=fis.read())!=-1){    fos.write(by);    }    fis.close();    fos.close();}}

5:已知s.txt文件中有这样的一个字符串：“hcexfgijkamdnoqrzstuvwybpl”

          请编写程序读取数据内容，把数据排序后写入ss.txt中。

import java.io.BufferedReader;import java.io.BufferedWriter;import java.io.FileReader;import java.io.FileWriter;import java.io.IOException;import java.util.Arrays;public class HomeWork5 {public static void main(String[] args) throws IOException {BufferedReader br = new BufferedReader(new FileReader("s.txt"));String line = br.readLine();br.close();//把字符串转换为字符数组Char[] chs = line.toCharArray();//对字符数组进行排序Arrays.sort(chs);//把排序后的字符数组转换为字符串String s = new String(chs);//把字符串再次写入ss.txtBufferedWriter bw = new BufferedWriter(new FileWriter("ss.txt"));bw.write(s);bw.newLine();bw.flush();bw.close();}  }

6:键盘录入5个学生信息(姓名,语文成绩,数学成绩,英语成绩),按照总分从高到低存入文本文件

import java.io.BufferedWriter;import java.io.IOException;import java.util.Scanner;import java.util.TreeSet;public class HomeWork6 {    public static void main(String[] args) throws IOException {          // 创建集合对象          TreeSet<Student> ts = new TreeSet<Student> (new Comparator<Student>() {              public int compare(Student s1, Student s2) {                  int num = s2.getSum() - s1.getSum();                int num2 = num == 0 ? s1.getChinese() - s2.getChinese() : num;                 int num3 = num2 == 0 ? s1.getMath() - s2.getMath() : num2;                  int num4 = num3 == 0 ? s1.getEnglish() - s2.getEnglish() : num3;                  int num5 = num4 == 0 ? s1.getName().compareTo(s2.getName()) : num4;                  return num5;             }          });            // 键盘录入学生信息存储到集合          for (int x = 1; x <= 5; x++) {            Scanner sc = new Scanner(System.in);             System.out.println("请录入第" + x + "个的学习信息");             System.out.println("姓名：");            String name = sc.nextLine();             System.out.println("语文成绩：");              int chinese = sc.nextInt();             System.out.println("数学成绩：");              int math = sc.nextInt();             System.out.println("英语成绩：");              int english = sc.nextInt();               Student s = new Student();             s.setName(name);            s.setChinese(chinese);                 s.setMath(math);             s.setEnglish(english);              // 把学生信息添加到集合              ts.add(s);         }         // 遍历集合，把数据写到文本文件          BufferedWriter bw = new BufferedWriter(new FileWriter("students.txt"));         bw.write("学生信息如下：");         bw.newLine();         bw.flush();         bw.write("姓名,语文成绩,数学成绩,英语成绩");          bw.newLine();          bw.flush();          for (Student s : ts) {             StringBuilder sb = new StringBuilder();              sb.append(s.getName()).append(",").append(s.getChinese())                     .append(",").append(s.getMath()).append(",")                     .append(s.getEnglish());              bw.write(sb.toString());              bw.newLine();              bw.flush();        }         // 释放资源         bw.close();     }  }  

public class Student {private String name;private int Chinese;private int English;private int math;public Student() {super();// TODO Auto-generated constructor stub}public Student(String name, int chinese, int english, int math) {super();this.name = name;Chinese = chinese;English = english;this.math = math;}public String getName() {return name;}public void setName(String name) {this.name = name;}public int getChinese() {return Chinese;}public void setChinese(int chinese) {Chinese = chinese;}public int getEnglish() {return English;}public void setEnglish(int english) {English = english;}public int getMath() {return math;}public void setMath(int math) {this.math = math;}public String toString() {return "Student [name=" + name + ", Chinese=" + Chinese + ", English="+ English + ", math=" + math + "]";}public int getSum(){return this.Chinese+this.English+this.math;}}