IO(三) 文件切割合并，Properties的使用

1 Properties

Properties 实现了Map接口， 存放的是键值对数据，而且键同样不能重复（重复会覆盖）；不同的是，Properties的键值数据类型都是字符串类。Properties可以和流操作，快速生成含键值对的配置文件，和快速解析配置文件。

 1.1  生成配置文件

import java.io.FileOutputStream;import java.io.FileWriter;import java.io.IOException;import java.util.Properties;public class PropertiesDemo {public static void main(String[] args) throws IOException {setValue();System.out.println("保存成功");}private static void setValue() throws IOException{Properties pro = new Properties();pro.setProperty("蜀", "刘备");pro.setProperty("魏", "曹操");pro.setProperty("吴", "孙权");pro.setProperty("蜀", "孔明");FileOutputStream out = new FileOutputStream("G:\\myFileOutputStream.properties");FileWriter writer = new FileWriter("G:\\myWriter.properties");pro.store(out, "FileOutputStream");pro.store(writer, "FileWriter");out.close();}}

myFileOutStream.properties内容：

#FileOutputStream
#Tue May 24 11:55:27 CST 2016
\u8700=\u5B54\u660E
\u5434=\u5B59\u6743
\u9B4F=\u66F9\u64CD

myWriter,properties内容：

#FileWriter
#Tue May 24 11:55:27 CST 2016
蜀=孔明
吴=孙权
魏=曹操

说明：以Stream存储的数据是以unicode进行编码的， 不能直接打开。以Writer存储的数据则可以直接用文本工具打开。  

1.2 读取配置文件的信息

import java.io.FileReader;import java.io.IOException;import java.util.Properties;import java.util.Set;public class PropertiesDemo {public static void main(String[] args) throws IOException {getValue();}private static void getValue() throws IOException{Properties pro = new Properties();FileReader inStream = new FileReader("G:\\myFileOutputStream.properties");pro.load(inStream);Set<String> keys = pro.stringPropertyNames();for(String key : keys){System.out.println(key+" : "+pro.getProperty(key));}}}

运行结果：

蜀 : 孔明
吴 : 孙权
魏 : 曹操

2 文件分割合并

当我们在存储文件或传输文件时， 当文件过大时， 我们通常会将一个大文件按多个小文件存储， 发送完毕后，再重新合并成原来文件。合并文件用到流SequenceInputStream 

2.1  文件分割

   文件分割时，我们通常会生成一个配置文件， 用来存储原文件信息（比如文件后缀名）。我们将生成的文件配置信息和切分的文件块存放同一个文件夹

import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.FileWriter;import java.io.FilenameFilter;import java.io.IOException;import java.util.Properties;public class SequenceInputStreamDemo {public static final int SPLIT_SIZE =  1024 * 1024 ;//定义切割1M的大小 public static void main(String[] args) throws IOException {splitFile("G:\\easy_ui\\jquery-easyui-1.3.4.zip");}private static void splitFile(String path) throws IOException{File fileOrg = new File(path);String dirPath = fileOrg.getParent();//获取父目录路径。String fileName = fileOrg.getName(); //获取文件名String prefix=fileName.substring(0, fileName.lastIndexOf("."));//文件名称不含后缀名String suffix=fileName.substring(fileName.lastIndexOf(".")+1);//后缀名 .zip//=============1 校验文件夹信息，将相关配置信息读入配置文件（info.property）============File dir = new File(new File(dirPath), prefix+"_part");if(!dir.exists()){dir.mkdirs();}Properties pros = new Properties();pros.setProperty("dir", dir.getName());  //目录非文件名pros.setProperty("fileName", prefix);pros.setProperty("suffix", suffix);int partcount =(int) Math.ceil((double)fileOrg.length()/SPLIT_SIZE);pros.setProperty("partNumber", partcount + "");pros.setProperty("备注", "拆分配置文件");FileWriter fileInfo = new FileWriter(new File(dir , "info.property"));pros.store(fileInfo, "文件拆分");fileInfo.close();//=============2  拆分文件   ===========================================FileInputStream fileStreamOrg = new FileInputStream(fileOrg);byte[] buf = new byte[SPLIT_SIZE];FileOutputStream fos = null;int len = 0;int count = 1;while ((len = fileStreamOrg.read(buf)) != -1) {fos = new FileOutputStream(new File(dir, (count++) + ".part"));fos.write(buf, 0, len);}fileStreamOrg.close();fos.close();}}

运行结果：

2.1  合并文件

通过SequenceInputStream(Enumeration<? extends InputStream> e) 将多个文件流合并成单个流，再写入到硬盘

import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.FileReader;import java.io.FilenameFilter;import java.io.IOException;import java.io.SequenceInputStream;import java.util.ArrayList;import java.util.Collections;import java.util.Enumeration;import java.util.Properties;public class SequenceInputStreamDemo {public static final int SPLIT_SIZE =  1024 * 1024 ;//定义切割1M的大小 public static void main(String[] args) throws IOException {mergeFile("G:\\easy_ui\\jquery-easyui-1.3.4_part");}private static void mergeFile(String dirPath) throws IOException{File dir = new File(dirPath);File[] files = dir.listFiles(new MyFilter(".part"));Properties pro = new Properties();FileReader fReader = new FileReader(new File(dir,"info.property"));pro.load(fReader);if(!(files.length+"").equals(pro.getProperty("partNumber"))){//文件和配置信息出错throw new RuntimeException("源文件出错！");}ArrayList<FileInputStream> lsInputStream = new ArrayList<FileInputStream>();for(int i=0,len=files.length; i<len; i++){lsInputStream.add(new FileInputStream(files[i]));}Enumeration<FileInputStream> en = Collections.enumeration(lsInputStream);SequenceInputStream sis = new SequenceInputStream(en);FileOutputStream fos = new FileOutputStream(new File(dir,pro.getProperty("fileName")+"."+pro.getProperty("suffix")));byte[] buf = new byte[1024];int len;while((len=sis.read(buf))!=-1){fos.write(buf,0,len);}sis.close();fos.close();}}class MyFilter implements FilenameFilter {private String suffix;public MyFilter(String suffix){this.suffix = suffix;}@Overridepublic boolean accept(File dir, String name) {if(name.endsWith(suffix))return true;return false;}}

运行结果:合并生成文件 jquery-easyui-1.3.4.zip