導讀
RandomAccessFile類：隨機文件訪問類，可以讀取文件任意位置的開始到結束位置結束之間的所有內容。
Properties類：用以配置項目或模塊的配置信息，該類可以讀取以“.properties”文件。
文件壓縮類：ZipInputStream和ZipOutputStream類的使用。
裝飾者模式：對象的組合設計方式，增強業務處理能力。
Path接口與Files類：前者是代表一個路徑的接口，後者是代表對文件或者文件夾的處理工具類。（十分好用）
①、RandomAccessFile類的代碼如下：
import java.io.IOException;
import java.io.RandomAccessFile;
public class TestRandomAccessFile {
public static void main(String[] args) throws IOException {
RandomAccessFile rf = new RandomAccessFile("rtest.dat", "rw");
for (int i = 0; i < 10; i++) {
//寫入基本類型double數據
rf.writeDouble(i * 1.414);
}
rf.close();
rf = new RandomAccessFile("rtest.dat", "rw");
//直接將文件指針移到第5個double數據後面
rf.seek(5 * 8);
//覆蓋第6個double數據
rf.writeDouble(47.0001);
rf.close();
rf = new RandomAccessFile("rtest.dat", "r");
for (int i = 0; i < 10; i++) {
System.out.println("Value " + i + ": " + rf.readDouble());
}
rf.close();
}
}
②、Properties工具類使用的代碼如下：
package com.main.util;
import java.io.IOException;
import java.util.Properties;
/**
* 讀取properties文件的工具類
*/
public class Tools {
private static Properties p = new Properties();
/**
* 讀取properties配置文件信息
*/
static{
try {
p.load(Tools.class.getClassLoader().getResourceAsStream("data.properties"));
} catch (IOException e) {
e.printStackTrace();
}
}
/**
* 根據key得到value的值
*/
public static String getValue(String key)
{
return p.getProperty(key);
}
}
③、文件壓縮的代碼如下：
public class TestFile
{
public static void main ( String [ ] args ) throws IOException
{
// new a file input stream
FileInputStream fis = new FileInputStream (
"/home/liangruihua/ziptest/1.txt" ) ;
BufferedInputStream bis = new BufferedInputStream ( fis ) ;
// new a zipPutputStream
// /home/liangruihua/ziptest/1.zip -- the out put file path and
// name
ZipOutputStream zos = new ZipOutputStream (
new FileOutputStream (
"/home/liangruihua/ziptest/1.zip" ) ) ;
BufferedOutputStream bos = new BufferedOutputStream ( zos ) ;
// set the file name in the .zip file
zos.putNextEntry ( new ZipEntry ( "1.txt" ) ) ;
// set the declear
zos.setComment ( "by liangruihua test!" ) ;
byte [ ] b = new byte [ 100 ] ;
while ( true )
{
int len = bis.read ( b ) ;
if ( len == - 1 )
break ;
bos.write ( b , 0 , len ) ;
}
fis.close ( ) ;
zos.close ( ) ;
}
}
文件解壓的代碼如下：
public class TestZipInputStream
{
public static void main ( String [ ] args ) throws ZipException ,
IOException
{
// get a zip file instance
File file = new File ( "/home/liangruihua/ziptest/test.zip" )
// get a ZipFile instance
ZipFile zipFile = new ZipFile ( file ) ;
// create a ZipInputStream instance
ZipInputStream zis = new ZipInputStream ( new FileInputStream(file ) ) ;
// create a ZipEntry instance , lay the every file from
// decompress file temporarily
ZipEntry entry = null ;
// a circle to get every file
while ( ( entry = zis.getNextEntry ( ) ) != null )
{
System.out.println ( "decompress file :"+ entry.getName ( ) ) ;
// define the path to set the file
File outFile = new File ( "/home/liangruihua/ziptest/"+ entry.getName ( ) ) ;
// if the file's parent directory wasn't exits ,than
// create the directory
if ( ! outFile.getParentFile ( ).exists ( ) )
{
outFile.getParentFile ( ).mkdir ( ) ;
}
// if the file not exits ,than create the file
if ( ! outFile.exists ( ) )
{
outFile.createNewFile ( ) ;
}
// create an input stream
BufferedInputStream bis = new BufferedInputStream (zipFile.getInputStream ( entry ) ) ;
// create an output stream
BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream ( outFile ) ) ;
byte [ ] b = new byte [ 100 ] ;
while ( true )
{
int len = bis.read ( b ) ;
if ( len == - 1 )
break ;
bos.write ( b , 0 , len ) ;
}
// close stream
bis.close ( ) ;
bos.close ( ) ;
}
zis.close ( ) ;
}
}
④、裝飾者模式的代碼如下：
//定義被裝飾者
public interface Human {
public void wearClothes();
public void walkToWhere();
}
//定義裝飾者
public abstract class Decorator implements Human {
private Human human;
public Decorator(Human human) {
this.human = human;
}
public void wearClothes() {
human.wearClothes();
}
public void walkToWhere() {
human.walkToWhere();
}
}
//下面定義三種裝飾，這是第一個，第二個第三個功能依次細化，即裝飾者的功能越來越多
public class Decorator_zero extends Decorator {
public Decorator_zero(Human human) {
super(human);
}
public void goHome() {
System.out.println("進房子。。");
}
public void findMap() {
System.out.println("書房找找Map。。");
}
@Override
public void wearClothes() {
// TODO Auto-generated method stub
super.wearClothes();
goHome();
}
@Override
public void walkToWhere() {
// TODO Auto-generated method stub
super.walkToWhere();
findMap();
}
}
public class Decorator_first extends Decorator {
public Decorator_first(Human human) {
super(human);
}
public void goClothespress() {
System.out.println("去衣櫃找找看。。");
}
public void findPlaceOnMap() {
System.out.println("在Map上找找。。");
}
@Override
public void wearClothes() {
// TODO Auto-generated method stub
super.wearClothes();
goClothespress();
}
@Override
public void walkToWhere() {
// TODO Auto-generated method stub
super.walkToWhere();
findPlaceOnMap();
}
}
public class Decorator_two extends Decorator {
public Decorator_two(Human human) {
super(human);
}
public void findClothes() {
System.out.println("找到一件D&G。。");
}
public void findTheTarget() {
System.out.println("在Map上找到神祕花園和城堡。。");
}
@Override
public void wearClothes() {
// TODO Auto-generated method stub
super.wearClothes();
findClothes();
}
@Override
public void walkToWhere() {
// TODO Auto-generated method stub
super.walkToWhere();
findTheTarget();
}
}
//定義被裝飾者，被裝飾者初始狀態有些自己的裝飾
public class Person implements Human {
@Override
public void wearClothes() {
// TODO Auto-generated method stub
System.out.println("穿什麼呢。。");
}
@Override
public void walkToWhere() {
// TODO Auto-generated method stub
System.out.println("去哪裏呢。。");
}
}
//測試類，看一下你就會發現，跟java的I/O操作有多麼相似
public class Test {
public static void main(String[] args) {
Human person = new Person();
Decorator decorator = new Decorator_two(new Decorator_first(
new Decorator_zero(person)));
decorator.wearClothes();
decorator.walkToWhere();
}
}
關於Path接口與Files類的概述與使用，本質內容是——
【網址：https://www.cnblogs.com/ixenos/p/5851976.html】