JAVA处理字符串压缩以及文件压缩

置顶 于 2017-08-19 18:31:20 发布
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分类专栏： java web开发 文章标签： java 压缩 GZIPInputStream CheckedInputStream
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本文链接：https://blog.youkuaiyun.com/zhangmingziliao/article/details/77414760
本文介绍了如何使用Java进行字符串和文件的压缩与解压，特别是利用GZIPOutputStream和GZIPInputStream进行GZIP压缩。通过示例代码展示了字符串压缩和解压的过程，以及文件的压缩和解压，包括使用ZipTools解决中文路径压缩解压乱码问题。

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字符串压缩：

之前在做Android客户端开发的时候，需要请求一个字典类型的http请求接口，由于接口json数据过大，达到6M，当时建议后端对接口返回的json数据逻辑进行处理，在服务端将json串压缩，然后在客户端进行解压，最后在将数据显示在客户端。

Java实现字符串压缩API：

压缩算法有多种，我说知道和接触有java I/O自带的zip和gzip两种方式，此次的压缩和解压用到的主要就是GZIPOutputStream和GZIPInputStream类，看一下例子:

字符串压缩代码：

public static String compress(String source) {
        ByteArrayOutputStream bos = new ByteArrayOutputStream();

        try {
            GZIPOutputStream gos = new GZIPOutputStream(bos);
            gos.write(source.getBytes("ISO-8859-1"));
            gos.close();
            return bos.toString("ISO-8859-1");
        } catch (IOException var3) {
            System.out.println(var3.getStackTrace().toString());
            return source;
        }
}

字符串解压代码：

/****
	 * @Method compress  字符串解压方法
	 * @author source 需要传入待解压的字符串
	 * 返回值   返回解压后的字符串
	 ****/
    public static String uncompress(String source) {
        if (source != null && source.length() != 0) {
            try {
                ByteArrayOutputStream bos = new ByteArrayOutputStream();
                ByteArrayInputStream bis = new ByteArrayInputStream(source.getBytes("ISO-8859-1"));
                GZIPInputStream gis = new GZIPInputStream(bis);
                byte[] data = new byte[1024];

                for(int len = gis.read(data); len != -1; len = gis.read(data)) {
                    bos.write(data, 0, len);
                }

                return bos.toString();
            } catch (IOException var6) {
            	System.out.println(var6.getStackTrace().toString());
                return source;
            }
        } else {
            return source;
        }
    }

测试代码：

public static void main(String[] args) {
		// 字符串超过一定的长度  
        String str = "ggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggfdgfdgf"
        		+ "ggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggg"
        		+ "gggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggABCdef123中文~!@#$%^&*()_+{fd}"
        		+ ";/1111111111111111111111111AAAAAAAAAAAJDLFJDLFJDLFJLDFFFFJEIIIIIIIIIIFJJJJJJJJJJJJALLLLLLLLLLLLLLLLLLLLLLdddddddddddddddddfdfdfdfdfdfdd"
        		+ "dddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddessdfrdfdfd"
        		+ "ddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd"
        		+ "ddddddddddddddddddddddddddddddddddddddddddddddddddddddgfgggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggf"
        		+ "ddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd"
        		+ "ddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd"
        		+ "ddddddddddddddddddddddddddddddddddddddddddddggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggg" +  
                "LLppppppppppppppppppppppppppppppppppppppppp===========================------------------------------iiiiiiiiiiiiiiiiiiiiiiiggggggggggggg";
        
        
        //字符串原始长度处理
        String originalStr = str;
        System.out.println("原始的字符串长度:" + originalStr.length());
        
        //字符串压缩状态处理
        String compressStr = compress(originalStr);
        System.out.println("压缩的字符串长度:" + compressStr.length());
        
        //字符串解压方法以及测试解压后字符串长度
        String uncompress = uncompress(compressStr);
        System.out.println("解压后的字符串长度:" + uncompress.length());
        
        //字符串压缩率
        float rate = (float)compressStr.length() / uncompress.length();
        System.out.println("字符串压缩率：" + rate);
        
        if(originalStr.equals(uncompress)){
        	System.out.println("解压后的字符串和原始的字符串长度一样");
        }
        
	}

控制台打印输出结果：

原始的字符串长度:1474

压缩的字符串长度:136

解压后的字符串长度:1474

字符串压缩率：0.09226594

如图通过调研compress压缩方法将原始字符串压缩，原始字符串的长度为1474个字节，压缩后字符串大小变为136个字节，字符串的压缩率达到91%。

 

Java代码实现文件压缩与解压：

api说明：

1：添加ZipTools包(主要解决中文路径压缩解压乱码问题)

2：文件压缩需要用到的类 ZipOutputStream(zip文件压缩需要用到的类)

3：ZipEntry 压缩文件的子文件对象，用于保存压缩文件中文件及其文件夹的一个实列

4：ZipFile 压缩文件的实列，用于zip的解压操作

 

文件压缩相关代码：

	/****
	 * 
	 * @Method createZipStream 创建ZIP输出流实例
	 * @param filePath 需要压缩的文件以及路径
	 * @param fileOutPath 生成压缩的文件以及路径
	 * 
	 ****/
	public static void createZipStream(String filePath, String fileOutPath) throws IOException{
		OutputStream os = new FileOutputStream(fileOutPath);//根据压缩的文件路径创建要输出的文件
		CheckedOutputStream cos = new CheckedOutputStream(os, new CRC32());//检查输出流，采用crc算法，保证文件的一致性
		ZipOutputStream zos = new ZipOutputStream(cos);//定义zip文件输出流
		zos.setEncoding("GBK");//设置编码格式，防止中文乱码
		File file = new File(filePath);//需要压缩的文件以及文件夹对象
		compressFile(zos,file);
		zos.close();
		cos.close();
		os.close();
		System.out.println("压缩文件完成");
	}



	/****
	 * @Method compressFile
	 * @param ZipOutputStream zip文件输出流
	 * @param File 要压缩的文件对象
	 ****/
	public static void compressFile(ZipOutputStream zos, File file) throws IOException{
		String fp = file.getPath().substring(3,file.getPath().length());//去掉盘符
		if(file.isDirectory()){//如果是文件目录，添加当前文件夹到zip文件流中
			zos.putNextEntry(new ZipEntry(fp + File.separator));
			for(File f: file.listFiles()){
				compressFile(zos, f);
			}
		}else{//如果是文件目录，添加当前文件到zip文件流中
			System.out.println("正在压缩文件:"+file.getPath());
			zos.putNextEntry(new ZipEntry(fp));
			InputStream is = new FileInputStream(file.getPath());//用字节方式读取文件
			BufferedInputStream bis = new BufferedInputStream(is);//创建一个缓存区
			byte [] b = new byte[1024];
			//将读取的字节写到zip文件流中
			while (bis.read(b) != -1) {
				zos.write(b);
			}
			bis.close();
			is.close();
		}
	}


测试函数以及返回示例：
	public static void main(String[] args) throws IOException {
		
		createZipStream(filePath,fileOutPath);
		
//		unCompressFile(fileOutPath);
		
	}

打印压缩文件过程：

正在压缩文件:D:\MyDrivers\backup\dgsetup.exe

正在压缩文件:D:\MyDrivers\backup\driverlist.mf

正在压缩文件:D:\MyDrivers\backup\Realtek PCIe GBE Family Controller\rt640x64.inf_amd64_98de0ddb0966f29b\rt640x64.inf

正在压缩文件:D:\MyDrivers\backup\Realtek PCIe GBE Family Controller\rt640x64.inf_amd64_98de0ddb0966f29b\rt640x64.PNF

正在压缩文件:D:\MyDrivers\backup\Realtek PCIe GBE Family Controller\rt640x64.inf_amd64_98de0ddb0966f29b\rt640x64.sys

压缩文件完成

文件解压相关函数：

/***
	 * 
	 * @Method unCompressFile
	 * @param filePath 需要解压的文件路径
	 *
	 ***/
	public static  void unCompressFile(String  filePath) throws IOException{
		File file = new File(filePath);
		if(!file.exists()){
			System.out.println("当前压缩文件不存在");
			return;
		}
		ZipFile zipFile = new ZipFile(file.getPath(),"GBK");
		
		for(Enumeration<ZipEntry> enumeration = zipFile.getEntries();enumeration.hasMoreElements();){//循环获取zip文件压缩实例
			
			ZipEntry zipEntry = enumeration.nextElement();//获取元素
			//如果是空文件不解压
			if(!zipEntry.getName().equals(File.separator)){
				String path = "D:\\" + zipEntry.getName();
				System.out.println("文件名:" + path);
				int len = path.length();
				//创建解压目录
				if(path.substring(len - 1, len).equals("\\")){
					File createFile = new File(path);
					if(!createFile.exists()){
						createFile.mkdirs();//如果当前文件不存在，则创建解压目录
					}
				}else{
					//创建解压后的文件
					OutputStream os = new FileOutputStream(new File(path));
					BufferedOutputStream bos = new BufferedOutputStream(os);//带缓冲的写出流
					InputStream is = zipFile.getInputStream(zipEntry);//读取元素
					BufferedInputStream bis = new BufferedInputStream(is);
					CheckedInputStream cis = new CheckedInputStream(bis, new CRC32());//检查读取流，用CRC算法检查文件是否一致性
					byte[] b = new byte[1024];//字节数组，每次读取1024个字节
					//循环读取解压文件的值,将zip流写入新文件中
					while (cis.read(b) != -1) {
						bos.write(b);
					}
					cis.close();
					bis.close();
					is.close();
					bos.close();
					os.close();
				}
			}else{
				System.out.println("目录名:" + zipEntry.getName());
			}
		}
		System.out.println("文件解压结束");
		
	}

测试解压方法：
public static void main(String[] args) throws IOException {
		
//		createZipStream(filePath,fileOutPath);
		
		unCompressFile(fileOutPath);
		
	}

打印解压文件结果：

文件名:D:\MyDrivers\backup\

文件名:D:\MyDrivers\update\

文件名:D:\MyDrivers\backup\dgsetup.exe

文件名:D:\MyDrivers\backup\Realtek PCIe GBE Family Controller\rt640x64.inf_amd64_98de0ddb0966f29b\

文件名:D:\MyDrivers\software\disapp\

文件名:D:\MyDrivers\backup\Realtek PCIe GBE Family Controller\rt640x64.inf_amd64_98de0ddb0966f29b\rt640x64.inf

文件名:D:\MyDrivers\backup\Realtek PCIe GBE Family Controller\

文件名:D:\MyDrivers\backup\Realtek PCIe GBE Family Controller\rt640x64.inf_amd64_98de0ddb0966f29b\rt640x64.PNF

文件名:D:\MyDrivers\backup\driverlist.mf

文件名:D:\MyDrivers\

文件名:D:\MyDrivers\backup\Realtek PCIe GBE Family Controller\rt640x64.inf_amd64_98de0ddb0966f29b\rt640x64.sys

文件名:D:\MyDrivers\hotfix\

文件名:D:\MyDrivers\software\

文件解压结束

自己封装的字符串压缩和文件压缩库：

项目目录结构截图如下：

java_zip.jar包是我封装的字符串和文件压缩jar，slf4j-api-1.7.21.jar，slf4j-nop-1.7.2.jar为代码依赖的日志包，ziptools.jar为JavaApi  zip防止中文乱码开发的包。

Api演示代码如下：

public static String filePath = "D:/MyDrivers/";
	public static String fileOutPath = "D:/MyDrivers.zip";
	
	//在lib文件中有一个Java_zip.jar
	public static void main(String[] args) {
		// 字符串超过一定的长度  
        String str = "ggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggfdgfdgf"
        		+ "ggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggg"
        		+ "gggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggABCdef123中文~!@#$%^&*()_+{fd}"
        		+ ";/1111111111111111111111111AAAAAAAAAAAJDLFJDLFJDLFJLDFFFFJEIIIIIIIIIIFJJJJJJJJJJJJALLLLLLLLLLLLLLLLLLLLLLdddddddddddddddddfdfdfdfdfdfdd"
        		+ "dddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddessdfrdfdfd"
        		+ "ddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd"
        		+ "ddddddddddddddddddddddddddddddddddddddddddddddddddddddgfgggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggf"
        		+ "ddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd"
        		+ "ddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd"
        		+ "ddddddddddddddddddddddddddddddddddddddddddddggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggg" +  
                "LLppppppppppppppppppppppppppppppppppppppppp===========================------------------------------iiiiiiiiiiiiiiiiiiiiiiiggggggggggggg";
        System.out.println("字符串初始长度:" + str.length());
		String compressstr = GzipUtils.compress(str);
		System.out.println("压缩后字符串长度:" + compressstr.length());
		String uncompress = GzipUtils.uncompress(compressstr);
		System.out.println("解压后字符串长度:" + uncompress.length());
		
		//压缩文件
//		ZipUtil.pack(new File(filePath), new File(fileOutPath));
		
		//解压文件
		ZipUtil.unpack(new File(fileOutPath), new File(filePath));

项目Demo地址下载：

https://download.youkuaiyun.com/download/zhangmingziliao/10969290

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