IO流练习

3:复制文本文件:有5种方式

import java.io.BufferedInputStream;import java.io.BufferedOutputStream;import java.io.BufferedReader;import java.io.BufferedWriter;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.FileReader;import java.io.FileWriter;import java.io.IOException;public class Copytxt {public static void main(String[] args) throws IOException {    method1();    method2();    method3();    method4();    method5();}private static void method5() throws FileNotFoundException, IOException {    BufferedReader br=new BufferedReader(new FileReader("ArrayListInHashMap.java"));    BufferedWriter bw=new BufferedWriter(new FileWriter("e.txt"));    String line=null;    while((line=br.readLine())!=null) {        bw.write(line);        bw.newLine();    }    br.close();    bw.close();}private static void method4() throws FileNotFoundException, IOException {    BufferedInputStream bis=new BufferedInputStream(new FileInputStream("ArrayListInHashMap.java"));    BufferedOutputStream bos=new BufferedOutputStream(new FileOutputStream("d.txt"));    byte[] bys=new byte[1024];    int len=0;    while((len=bis.read(bys))!=-1) {        bos.write(bys, 0, len);    }    bos.close();    bis.close();}private static void method3() throws FileNotFoundException, IOException {    BufferedInputStream bis=new BufferedInputStream(new FileInputStream("ArrayListInHashMap.java"));    BufferedOutputStream bos=new BufferedOutputStream(new FileOutputStream("c.txt"));    int by=0;    while((by=bis.read())!=-1) {        bos.write(by);    }    bos.close();    bis.close();}private static void method2() throws FileNotFoundException, IOException {    FileInputStream fis=new FileInputStream("ArrayListInHashMap.java");    FileOutputStream fos=new FileOutputStream("a.txt");    byte[] bys=new byte[1024];    int len=0;    while((len=fis.read(bys))!=-1) {        fos.write(bys, 0, len);    }    fos.close();    fis.close();}private static void method1() throws FileNotFoundException, IOException {    FileInputStream fis=new FileInputStream("ArrayListInHashMap.java");    FileOutputStream fos=new FileOutputStream("b.txt");    int by=0;    while((by=fis.read())!=-1) {        fos.write(by);    }    fos.close();    fis.close();}}

4:复制图片:4种方式

public class CopyJpg {public static void main(String[] args) throws IOException {    method1();    method2();    method3();    method4();}private static void method4() throws FileNotFoundException, IOException {    BufferedInputStream bis=new BufferedInputStream(new FileInputStream("timg.jpg"));    BufferedOutputStream bos=new BufferedOutputStream(new FileOutputStream("d.jpg"));    byte[] bys=new byte[1024];    int len=0;    while((len=bis.read(bys))!=-1) {        bos.write(bys, 0, len);    }    bos.close();    bis.close();}private static void method3() throws FileNotFoundException, IOException {    BufferedInputStream bis=new BufferedInputStream(new FileInputStream("timg.jpg"));    BufferedOutputStream bos=new BufferedOutputStream(new FileOutputStream("c.jpg"));    int by=0;    while((by=bis.read())!=-1) {        bos.write(by);    }    bos.close();    bis.close();}private static void method2() throws FileNotFoundException, IOException {    FileInputStream fis=new FileInputStream("timg.jpg");    FileOutputStream fos=new FileOutputStream("b.jpg");    byte[] bys=new byte[1024];    int len=0;    while((len=fis.read(bys))!=-1) {        fos.write(bys, 0, len);    }    fos.close();    fis.close();}private static void method1() throws FileNotFoundException, IOException {    FileInputStream fis=new FileInputStream("timg.jpg");    FileOutputStream fos=new FileOutputStream("a.jpg");    int by=0;    while((by=fis.read())!=-1) {        fos.write(by);    }    fos.close();    fis.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.FileInputStream;import java.io.FileOutputStream;import java.io.IOException;import java.util.ArrayList;import java.util.Collections;public class CopyString {public static void main(String[] args) throws IOException {    FileInputStream fis=new FileInputStream("String.txt");    FileOutputStream fos=new FileOutputStream("StringSort.txt");    ArrayList<Character> al=new ArrayList<Character>();    int by=0;    while((by=fis.read())!=-1) {        al.add((char)by);    }    Collections.sort(al);    for(Character s:al) {        fos.write((int)s);    }}}

String.txt内容:hcexfgijkamdnoqrzstuvwybpl
StringSort.txt内容:abcdefghijklmnopqrstuvwxyz

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

package weekends_10;import java.io.Serializable;public class Student implements Serializable,Comparable<Student>{    String name;public Student(String name, String chinese, String math, String english) {        super();        this.name = name;        Chinese = chinese;        this.math = math;        English = english;    }public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }String Chinese;String math;String English;public String getChinese() {    return Chinese;}public void setChinese(String chinese) {    Chinese = chinese;}public String getMath() {    return math;}public void setMath(String math) {    this.math = math;}public String getEnglish() {    return English;}public void setEnglish(String english) {    English = english;}public int getSum() {    return Integer.parseInt(Chinese)+Integer.parseInt(English)+Integer.parseInt(math);}public Student(String chinese, String math, String english) {    super();    Chinese = chinese;    this.math = math;    English = english;}@Overridepublic int hashCode() {    final int prime = 31;    int result = 1;    result = prime * result + ((Chinese == null) ? 0 : Chinese.hashCode());    result = prime * result + ((English == null) ? 0 : English.hashCode());    result = prime * result + ((math == null) ? 0 : math.hashCode());    result = prime * result + ((name == null) ? 0 : name.hashCode());    return result;}@Overridepublic boolean equals(Object obj) {    if (this == obj)        return true;    if (obj == null)        return false;    if (getClass() != obj.getClass())        return false;    Student other = (Student) obj;    if (Chinese == null) {        if (other.Chinese != null)            return false;    } else if (!Chinese.equals(other.Chinese))        return false;    if (English == null) {        if (other.English != null)            return false;    } else if (!English.equals(other.English))        return false;    if (math == null) {        if (other.math != null)            return false;    } else if (!math.equals(other.math))        return false;    if (name == null) {        if (other.name != null)            return false;    } else if (!name.equals(other.name))        return false;    return true;}public Student() {    super();    // TODO Auto-generated constructor stub}@Overridepublic String toString() {    return "Student [name=" + name + ", Chinese=" + Chinese + ", math=" + math + ", English=" + English + "]";}@Overridepublic int compareTo(Student s) {    int num=s.getSum()-this.getSum();    int num1=num==0?s.getName().compareTo(this.getName()):num;    return num1;}}

import java.io.FileWriter;import java.io.IOException;import java.util.Scanner;import java.util.TreeSet;public class StudentDemo {public static void main(String[] args) throws IOException {TreeSet<Student> ts=new TreeSet<Student>();Scanner sc=new Scanner(System.in);for(int i=0;i<5;i++) {    Student s=new Student();    System.out.println("请输入第"+(i+1)+"个学生的名字");    String name = sc.nextLine();    s.setName(name);    System.out.println("请输入第"+(i+1)+"个学生的数学成绩");    String math = sc.nextLine();    s.setMath(math);    System.out.println("请输入第"+(i+1)+"个学生的英语成绩");    String English = sc.nextLine();    s.setEnglish(English);    System.out.println("请输入第"+(i+1)+"个学生的语文成绩");    String chinese = sc.nextLine();    s.setChinese(chinese);    ts.add(s);}FileWriter fos=new FileWriter("Student.txt");for(Student s:ts) {    fos.write("姓名"+s.getName());    fos.write("  ");    fos.write("总分"+String.valueOf(s.getSum()));    fos.write("  ");    fos.write("语文"+s.getChinese());    fos.write("  ");    fos.write("英语"+s.getEnglish());    fos.write("  ");    fos.write("数学"+s.getMath());    fos.write("\r\n");    fos.flush();}fos.close();}}

运行结果

姓名alice 总分450 语文190 英语140 数学120
姓名bob 总分430 语文130 英语120 数学180
姓名allen 总分320 语文100 英语130 数学90
姓名Tubo 总分320 语文100 英语120 数学100
姓名逝水流 总分257 语文78 英语89 数学90