javaio流编程题

1. java Io流练习题大佬帮忙做一下啊/* * 使用扫描器接收键盘输入模拟用户登陆注册 * 要

importjava.io.BufferedReader;
importjava.io.BufferedWriter;
importjava.io.File;
importjava.io.FileInputStream;
importjava.io.FileOutputStream;
importjava.io.IOException;
importjava.io.InputStreamReader;
importjava.io.OutputStreamWriter;
importjava.util.Map.Entry;
importjava.util.Iterator;
importjava.util.Properties;
importjava.util.Scanner;

publicclassIoTest{
	staticScannersc=newScanner(System.in);
	staticPropertiespro=newProperties();
	staticFilefile=newFile("K:\IO测试\Bai\登陆.properties");
	staticStringid=null,pass=null,num=null;
	staticBufferedReaderbr;
	staticBufferedWriterbw;

	publicstaticvoidmain(String[]args)throwsIOException{
		if(!file.exists()){
			bw=newBufferedWriter(newOutputStreamWriter(newFileOutputStream(file)));
			pro.store(bw,"ID/Pass");
		}else{
			br=newBufferedReader(newInputStreamReader(newFileInputStream(file)));
			pro.load(br);
		}
		while(true){
			System.out.println("1.注册
2.登陆
请选择...");
			num=sc.nextLine();
			System.out.println("输入ID:");
			id=sc.nextLine();
			System.out.println("输入密码:");
			pass=sc.nextLine();
			if(num.equals("1"))
				reg(id,pass);
			else
				sig(id,pass);
		}
	}

	privatestaticvoidreg(Stringd,Stringp)throwsIOException{//注册
		if(pro.getProperty(d)!=null){
			System.out.println("用户存在不能注册,请直接登陆");
			return;
		}
		pro.setProperty(d,p);
		bw=newBufferedWriter(newOutputStreamWriter(newFileOutputStream(file)));
		pro.store(bw,"ID/Pass");
		System.out.println("-->注册成功");
	}

	privatestaticvoidsig(Stringd,Stringp)throwsIOException{//登陆
		booleanb=false;
		for(Iterator<Entry<Object,Object>>it=pro.entrySet().iterator();it.hasNext();){
			Stringkey=(String)it.next().getKey();
			if(key.equals(d)){
				b=true;
				break;
			}
		}
		if(b){
			if(!pro.getProperty(d).equals(p))
				System.out.println("密码错误");
			else
				System.out.println("登陆成功<----");
		}else{
			System.out.println("用户不存在,请去注册");
		}
	}
}

2. 请教两道java编程题，关于IO包的。

nio不能实现一行一行读，只能一块一块读或者一个字符一个字符读。
代码如下：

import java.io.*;
import java.nio.*;
import java.nio.channels.FileChannel;
public class Main
{
public static void main(String[] args)
{
Main t = new Main();
t.ReadFlieByLine_IO("E:\\123.txt");
t.ReadFileByLine_NIO("E:\\123.txt");
}

public void ReadFlieByLine_IO(String Filename)
{
File file = new File(Filename);
BufferedReader reader = null;
try
{
System.out.println("以行为单位读取文件内容，一次读一整行：");
reader = new BufferedReader(new FileReader(file));
String tempString = null;
int line = 1;
//一次读入一行，直到读入null为文件结束
while ((tempString = reader.readLine()) != null)
{ //显示行号
System.out.println("line " + line + ": " + tempString);
line++;
}
reader.close();
}
catch (IOException e) {
e.printStackTrace();
}
/** finally {
if (reader != null){
try {
reader.close();
}
catch (IOException e1) {
}
}
}
*/
}

private void ReadFileByLine_NIO(String Filename)
{
FileInputStream file = null;
FileChannel reader = null;
try
{
file = new FileInputStream(Filename);
reader = file.getChannel();
String tempString = null;
ByteBuffer bb = ByteBuffer.allocate((int)reader.size());
reader.read(bb);
bb.flip();
String fileContent= new String(bb.array());
System.out.println(fileContent);
reader.close();
}
catch (IOException e) {
e.printStackTrace();
}
/** finally {
if (reader != null){
try {
reader.close();
}
catch (IOException e1) {
}
}
}
*/
}
}

3. java中Io流问题

importjava.io.*;
publicclassUpTest{
	publicstaticvoidmain(String[]args){
		Filetxt=newFile("K:\IO测试\大小写转换\Test.txt");//目标源!
		BufferedReaderbr=null;//读!
		BufferedWriterbw=null;//写!
		StringBuilderstb=newStringBuilder();//缓存!
		try{
			br=newBufferedReader(newFileReader(txt));
			try{
				for(Stringstr=br.readLine();str!=null;str=br.readLine()){
					char[]chs=str.toCharArray();//临时数组!
					for(inti=0;i<chs.length;i++){//遍历!
						if(Character.isUpperCase(chs[i])){//大小写转换!
							chs[i]=Character.toLowerCase(chs[i]);
							stb.append(chs[i]);
						}else{
							chs[i]=Character.toUpperCase(chs[i]);
							stb.append(chs[i]);
						}
					}
					stb.append(System.getProperty("line.separator"));//跨平台换行!
				}
				bw=newBufferedWriter(newFileWriter("K:\IO测试\大小写转换\Test1.txt"));//目标目的地!
				bw.write(stb.toString());//写!
				bw.flush();//刷新流!
			}catch(IOExceptione){
				e.printStackTrace();
			}
		}catch(FileNotFoundExceptione){
			e.printStackTrace();
		}finally{//关流!
			if(br!=null){
				try{
					br.close();
				}catch(IOExceptione){
					e.printStackTrace();
				}finally{
					if(bw!=null){
						try{
							bw.close();
						}catch(IOExceptione){
							e.printStackTrace();
						}
					}
				}
			}
		}
	}
}

4. java 实现写文件功能 io流题

importjava.io.Console;
importjava.io.File;
importjava.io.IOException;
importjava.io.PrintWriter;
importjava.util.ArrayList;
importjava.util.List;
importjava.util.Scanner;

publicclassUser{
	privateStringuserName;
	privateStringuserPass;

	publicUser(StringuserName,StringuserPass){
		super();
		this.userName=userName;
		this.userPass=userPass;
	}

	publicStringgetUserName(){
		returnuserName;
	}

	publicvoidsetUserName(StringuserName){
		this.userName=userName;
	}

	publicStringgetUserPass(){
		returnuserPass;
	}

	publicvoidsetUserPass(StringuserPass){
		this.userPass=userPass;
	}

	publicstaticvoidmain(String[]args)throwsIOException{
		StringuserName=null;
		StringuserPass=null;

		List<User>userList=newArrayList<User>();

//		Consoleconsole=System.console();
//		for(inti=0;i<5;i++){
//			userName=console.readLine("用户名:");
//			userPass=console.readLine("密码:");
//			Useruser=newUser(userName,userPass);
//			userList.add(user);
//		}
		Scannerconsole=newScanner(System.in);
		for(inti=0;i<5;i++){
			System.out.print("用户名:");
			userName=console.nextLine();
			System.out.print("密码:");
			userPass=console.nextLine();
			Useruser=newUser(userName,userPass);
			userList.add(user);
		}
		console.close();

		Filefile=newFile("users.txt");
		PrintWriterout=newPrintWriter(file,"UTF-8");
		for(Useruser:userList){
			out.println(String.format("用户名:%s,密码:%s",user.getUserName(),user.getUserPass()));
		}
		out.close();
	}
}

用户名:123,密码:333
用户名:213,密码:333
用户名:asds,密码:123
用户名:sadas,密码:123
用户名:dasdas,密码:123

5. Java 编程基础题:io流和集合综合相关的题目不会做,哪位大神来看一下

此需求的关键点主要是两个：

1、IO读取文本信息；

2、TreeSet的排序问题。

解决过程如下：

首先通过TreeSet(Comparator<? super E>comparator) 构造方法指定TreeSet的比较器进行排序，而创建自己的实现比较器。

packagetest.treeset;
importjava.util.Comparator;
<Student>{
@Override
publicintcompare(Studentstu1,Studentstu2){
if(stu1.getScore()>stu2.getScore()){
return-1;
}elseif(stu1.getScore()==stu2.getScore()){
if(stu1.getAge()>stu2.getAge()){
return-1;
}elseif(stu1.getAge()==stu2.getAge()){
return0;
}else{
return1;
}
}else{
return1;
}
}
}

创建学生Bean类

packagetest.treeset;
importjava.io.Serializable;
{
privateStringname;
privateintage;
privateintscore;
publicStudent(Stringname,intage,intscore){
this.name=name;
this.age=age;
this.score=score;
}
publicStringgetName(){
returnname;
}
publicvoidsetName(Stringname){
this.name=name;
}
publicintgetAge(){
returnage;
}
publicvoidsetAge(intage){
this.age=age;
}
publicintgetScore(){
returnscore;
}
publicvoidsetScore(intscore){
this.score=score;
}
@Override
publicStringtoString(){
returnname+"-"+age+"-"+score;
}
}

创建实现类，实现对文件的读取已经将读取内容实例化入Student中，添加入TreeSet中排序，之后顺序打印TreeSet数据。

packagetest.treeset;
importjava.io.BufferedReader;
importjava.io.File;
importjava.io.FileInputStream;
importjava.io.FileNotFoundException;
importjava.io.IOException;
importjava.io.InputStreamReader;
importjava.io.UnsupportedEncodingException;
importjava.util.TreeSet;
/**
*已知项目根目录下student_info.txt文件中有如下数据：（姓名-年龄-总分)
*lucy-28-98
*lily-23-97
*robt-25-100
*wili-15-100
*klin-29-93搜索
*运用IO技术获取将该文件中的数据分别封装成5个Student(姓名为String类型,年龄为int类型,总分为int类型)对象存入TreeSet集合中（需要自己定义Student类）
*要求：
*根据学生的总分进行排序（降序），如果分数相同则比较年龄，年龄较大的排在前面。
*按照排序完的顺序将所有信息打印到控制台上:
*打印格式如下：
*robt-25-100
*wili-15-100
*lucy-28-98
*lily-23-97
*klin-29-93
*/
publicclassIoReadTest{
publicstaticvoidmain(String[]args){
TreeSet<Student>set=newTreeSet<Student>(newMyComparator());
try{
FileInputStreamfis=newFileInputStream(newFile("D:\student_info.txt"));
InputStreamReaderisr=newInputStreamReader(fis,"UTF-8");
BufferedReaderbr=newBufferedReader(isr);
Stringstr="";
while((str=br.readLine())!=null){
String[]info=str.split("-");
Stringname=info[0];
intage=Integer.parseInt(info[1]);
intscore=Integer.parseInt(info[2]);
Studentstudent=newStudent(name,age,score);
set.add(student);
}
}catch(FileNotFoundExceptione){
e.printStackTrace();
}catch(UnsupportedEncodingExceptione){
e.printStackTrace();
}catch(IOExceptione){
e.printStackTrace();
}
for(Studentstudent:set){
System.out.println(student);
}
}
}

运行后输出结果

robt-25-100
wili-15-100
lucy-28-98
lily-23-97
klin-29-93