java信息解压缩编程题
㈠ 问一道java程序题,如图所示。
new Son();这扰虚个会调用没猜Son类的无参构造方法
public Son(){
this("dd");//这缓察燃个会调用自己的方法 Son(String name);//这个方法会调用super("dd")//父类的有参构造方法
}
打印顺序等一个方法执行完之后一步一步的执行,也就是你那个打印的东西
㈡ 请教两道java编程题,关于IO包的。
nio不能实现一行一行读,只能一块一块姿或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("以行为局册咐单位读取文件内容,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)
{ //显示行桐纯号
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) {
}
}
}
*/
}
}
㈢ 简单java解压缩问题
既然目录的尘渗悄问题那你可喊改以在输出流输出之前创建目录派渣撒,
你先创建一个File对象
然后测试他是否为一个目录,不是就创建目录
如你hello.zip
File f=new File("E:\\hello");
if(!f.isDirectory()){
f.mkdirs();
}
㈣ 5道简单的JAVA编程题(高分悬赏)
很详细的帮你写下,呵呵,所以要给分哦!
1、
(1)源程序如下:
public class One {
public static void main(String[] args) {
String name = "张三";
int age = 23;
char sex = '男';
String myclass = "某某专业2班";
System.out.println("姓名:" + name);
System.out.println("姓名:" + age);
System.out.println("姓名:" + sex);
System.out.println("姓名:" + myclass);
}
}
(2)
编写完程序的后缀名是.java,如本题,文件名就是One.java。
开始\运行\cmd,进入“命令提示符窗口”,然后用javac编译器编译.java文件,语句:javac One.java。
(3)
编译成功后,生成的文件名后缀是.class,叫做字节码文件。再用java解释器来运行改程序,语句:java One
2、编写程序,输出1到100间的所有偶数
(1)for语句
public class Two1 {
public static void main(String[] args) {
for(int i=2;i<=100;i+=2)
System.out.println(i);
}
}
(2)while语句
public class Two2 {
public static void main(String[] args) {
int i = 2;
while (i <= 100) {
System.out.println(i);
i += 2;
}
}
}
(3)do…while语句
public class Two3 {
public static void main(String[] args) {
int i = 2;
do {
System.out.println(i);
i += 2;
}while(i<=100);
}
}
3、编写程序,从10个数当中找出最大值。
(1)for循环
import java.util.*;
public class Three1 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
int number;
int max = 0;
for (int i = 0; i < 10; i++) {
System.out.print("输入第" + (i + 1) + "个数:");
number = input.nextInt();
if (max < number)
max = number;
}
System.out.println("最大值:" + max);
}
}
(2)while语句
import java.util.*;
public class Three2 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
int number;
int max = 0;
int i = 0;
while (i < 10) {
System.out.print("输入第" + (i + 1) + "个数:");
number = input.nextInt();
if (max < number)
max = number;
i++;
}
System.out.println("最大值:" + max);
}
}
(3)do…while语句
import java.util.*;
public class Three3 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
int number;
int max = 0;
int i = 0;
do {
System.out.print("输入第" + (i + 1) + "个数:");
number = input.nextInt();
if (max < number)
max = number;
i++;
}while(i<10);
System.out.println("最大值:" + max);
}
}
4、编写程序,计算从1到100之间的奇数之和。
(1)for循环
public class Four1 {
public static void main(String[] args) {
int sum=0;
for(int i = 1;i<=100;i+=2){
sum+=i;
}
System.out.println("1~100间奇数和:" + sum);
}
}
(2)while语句
public class Four2 {
public static void main(String[] args) {
int sum = 0;
int i = 1;
while (i <= 100) {
sum += i;
i += 2;
}
System.out.println("1~100间奇数和:" + sum);
}
}
(3)do…while语句
public class Four3 {
public static void main(String[] args) {
int sum = 0;
int i = 1;
do {
sum += i;
i += 2;
} while (i <= 100);
System.out.println("1~100间奇数和:" + sum);
}
}
5、
(1)什么是类的继承?什么是父类?什么是子类?举例说明。
继承:是面向对象软件技术当中的一个概念。如果一个类A继承自另一个类B,就把这个A称为"B的子类",而把B称为"A的父类"。继承可以使得子类具有父类的各种属性和方法,而不需要再次编写相同的代码。在令子类继承父类的同时,可以重新定义某些属性,并重写某些方法,即覆盖父类的原有属性和方法,使其获得与父类不同的功能。另外,为子类追加新的属性和方法也是常见的做法。继承需要关键字extends。举例:
class A{}
class B extends A{}
//成员我就不写了,本例中,A是父类,B是子类。
(2)编写一个继承的程序。
class Person {
public String name;
public int age;
public char sex;
public Person(String n, int a, char s) {
name = n;
age = a;
sex = s;
}
public void output1() {
System.out.println("姓名:" + name + "\n年龄:" + age + "\n性别:" + sex);
}
}
class StudentPerson extends Person {
String school, department, subject, myclass;
public StudentPerson(String sc, String d, String su, String m, String n,
int a, char s) {
super(n, a, s);
school = sc;
department = d;
subject = su;
myclass = m;
}
public void output2() {
super.output1();
System.out.println("学校:" + school + "\n系别:" + department + "\n专业:"
+ subject + "\n班级:" + myclass);
}
}
public class Five2 {
public static void main(String[] args) {
StudentPerson StudentPersonDemo = new StudentPerson("某某大学", "某某系别",
" 某专业", "某某班级", " 张三", 23, '男');
StudentPersonDemo.output2();
}
}
㈤ java压缩文件的问题
有三种方式实现java压缩:
1、jdk自带的包java.util.zip.ZipOutputStream,不足之处,文件(夹)名称带中文时,出现乱码问题,实现代码如下:
/**
* 功能:把 sourceDir 目录下的所有文件进行 zip 格式的压缩,保存为指定 zip 文件
* @param sourceDir 如果是目录,eg:D:\\MyEclipse\\first\\testFile,则压缩目录下所有文件;
* 如果是文件,eg:D:\\MyEclipse\\first\\testFile\\aa.zip,则只压缩本文件
* @param zipFile 最后压缩的文件路径和名称,eg:D:\\MyEclipse\\first\\testFile\\aa.zip
*/
public File doZip(String sourceDir, String zipFilePath) throws IOException {
File file = new File(sourceDir);
File zipFile = new File(zipFilePath);
ZipOutputStream zos = null;
try {
// 创建写出流操作
OutputStream os = new FileOutputStream(zipFile);
BufferedOutputStream bos = new BufferedOutputStream(os);
zos = new ZipOutputStream(bos);
String basePath = null;
// 获取目录
if(file.isDirectory()) {
basePath = file.getPath();
}else {
basePath = file.getParent();
}
zipFile(file, basePath, zos);
}finally {
if(zos != null) {
zos.closeEntry();
zos.close();
}
}
return zipFile;
}
/**
* @param source 源文件
* @param basePath
* @param zos
*/
private void zipFile(File source, String basePath, ZipOutputStream zos)
throws IOException {
File[] files = null;
if (source.isDirectory()) {
files = source.listFiles();
} else {
files = new File[1];
files[0] = source;
}
InputStream is = null;
String pathName;
byte[] buf = new byte[1024];
int length = 0;
try{
for(File file : files) {
if(file.isDirectory()) {
pathName = file.getPath().substring(basePath.length() + 1) + "/";
zos.putNextEntry(new ZipEntry(pathName));
zipFile(file, basePath, zos);
}else {
pathName = file.getPath().substring(basePath.length() + 1);
is = new FileInputStream(file);
BufferedInputStream bis = new BufferedInputStream(is);
zos.putNextEntry(new ZipEntry(pathName));
while ((length = bis.read(buf)) > 0) {
zos.write(buf, 0, length);
}
}
}
}finally {
if(is != null) {
is.close();
}
}
}
2、使用org.apache.tools.zip.ZipOutputStream,代码如下,
package net.szh.zip;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.zip.CRC32;
import java.util.zip.CheckedOutputStream;
import org.apache.tools.zip.ZipEntry;
import org.apache.tools.zip.ZipOutputStream;
public class ZipCompressor {
static final int BUFFER = 8192;
private File zipFile;
public ZipCompressor(String pathName) {
zipFile = new File(pathName);
}
public void compress(String srcPathName) {
File file = new File(srcPathName);
if (!file.exists())
throw new RuntimeException(srcPathName + "不存在!");
try {
FileOutputStream fileOutputStream = new FileOutputStream(zipFile);
CheckedOutputStream cos = new CheckedOutputStream(fileOutputStream,
new CRC32());
ZipOutputStream out = new ZipOutputStream(cos);
String basedir = "";
compress(file, out, basedir);
out.close();
} catch (Exception e) {
throw new RuntimeException(e);
}
}
private void compress(File file, ZipOutputStream out, String basedir) {
/* 判断是目录还是文件 */
if (file.isDirectory()) {
System.out.println("压缩:" + basedir + file.getName());
this.compressDirectory(file, out, basedir);
} else {
System.out.println("压缩:" + basedir + file.getName());
this.compressFile(file, out, basedir);
}
}
/** 压缩一个目录 */
private void compressDirectory(File dir, ZipOutputStream out, String basedir) {
if (!dir.exists())
return;
File[] files = dir.listFiles();
for (int i = 0; i < files.length; i++) {
/* 递归 */
compress(files[i], out, basedir + dir.getName() + "/");
}
}
/** 压缩一个文件 */
private void compressFile(File file, ZipOutputStream out, String basedir) {
if (!file.exists()) {
return;
}
try {
BufferedInputStream bis = new BufferedInputStream(
new FileInputStream(file));
ZipEntry entry = new ZipEntry(basedir + file.getName());
out.putNextEntry(entry);
int count;
byte data[] = new byte[BUFFER];
while ((count = bis.read(data, 0, BUFFER)) != -1) {
out.write(data, 0, count);
}
bis.close();
} catch (Exception e) {
throw new RuntimeException(e);
}
}
}
3、可以用ant中的org.apache.tools.ant.taskdefs.Zip来实现,更加简单。
package net.szh.zip;
import java.io.File;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.taskdefs.Zip;
import org.apache.tools.ant.types.FileSet;
public class ZipCompressorByAnt {
private File zipFile;
public ZipCompressorByAnt(String pathName) {
zipFile = new File(pathName);
}
public void compress(String srcPathName) {
File srcdir = new File(srcPathName);
if (!srcdir.exists())
throw new RuntimeException(srcPathName + "不存在!");
Project prj = new Project();
Zip zip = new Zip();
zip.setProject(prj);
zip.setDestFile(zipFile);
FileSet fileSet = new FileSet();
fileSet.setProject(prj);
fileSet.setDir(srcdir);
//fileSet.setIncludes("**/*.java"); 包括哪些文件或文件夹 eg:zip.setIncludes("*.java");
//fileSet.setExcludes(...); 排除哪些文件或文件夹
zip.addFileset(fileSet);
zip.execute();
}
}
测试一下
package net.szh.zip;
public class TestZip {
public static void main(String[] args) {
ZipCompressor zc = new ZipCompressor("E:\\szhzip.zip");
zc.compress("E:\\test");
ZipCompressorByAnt zca = new ZipCompressorByAnt("E:\\szhzipant.zip");
zca.compress("E:\\test");
}
}
㈥ 有关java编程题目
按照题目要求源晌编写的圆,圆锥和测试类的Java程序如下
Test.java文件内容如下
class Circle{
private double r;
private String color;
public Circle(double r){
this.r=r;
}
public double area(){
return Math.PI*r*r;
}
public double perimeter(){
return Math.PI*2*r;
}
public double getR(){
return this.r;
}
public void setR(double r){
this.r=r;
}
public String getColor(){
return this.color;
}
public void setColor(String color){
this.color=color;
}
public String toString(){
return "圆的半径为"+r+",颜色为"+color;
}
}
class Cone{
private Circle c;
private double h;
private String color;
public Cone(Circle c,double h){
this.c=c;
this.h=h;
}
public double volume(){
return 1.0/3*c.area()*h;
}
public Circle getCircle(){
return this.c;
}
public void setCircle(Circle c){
this.c=c;
}
public double getH(){
return this.h;
}
public void setH(double h){
this.h=h;
}
public String getColor(){
return this.color;
}
public void setColor(String color){
this.color=color;
}
public String toString(){
return "圆锥的底面积为"燃悔+c.area()+",高为"+h+",颜色为"+color;
}
}
public class Test{
public static void main(String[] args){
Circle circle1=new Circle(2.5);
circle1.setColor("红色");
System.out.println(circle1.toString());
System.out.println("圆的面积为"+circle1.area());
System.out.println("圆的周雹段锋长为"+circle1.perimeter());
Cone circlar1=new Cone(circle1,2.7);
circlar1.setColor("蓝色");
System.out.println(circlar1.toString());
System.out.println("圆锥的体积为"+circlar1.volume());
}
}