[模版]Java 文件读入（字符流） GZip压缩、解压缩String

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#java #gzip

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本文介绍如何使用Java的字符流读取文件，并进行GZip的压缩和解压缩操作，专注于字符串处理技术。

读文件为字符串也可以采用

BufferedReader br= new BufferedReader(
                    new InputStreamReader(
                        new FileInputStream(
                            new File(""))));

import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;
public class Main
{

    public static void main(String argv[]){
        try {
            String src=FileHelper.fileToString("/home/martin/la.txt");
            String s=ZipUtil.compress(src);

            String ret=ZipUtil.uncompress(s);
            System.out.print(src.length()+ " "+ s.length()+" "+ret.length()+
                    " "+src.equals(ret)+'\n');

        //  System.out.print(ret);
        } catch (IOException e) {
            e.printStackTrace();
        }

    }

    static class ZipUtil{
        public static String compress(String str) throws IOException {
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            GZIPOutputStream gzip = new GZIPOutputStream(out);
            gzip.write(str.getBytes());
            gzip.close();
            return out.toString("ISO-8859-1");
          }

          public static String uncompress(String str) throws IOException {
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            ByteArrayInputStream in = new ByteArrayInputStream(str
                .getBytes("ISO-8859-1"));
            GZIPInputStream gunzip = new GZIPInputStream(in);
            byte[] buffer = new byte[256];
            int n;
            while ((n = gunzip.read(buffer)) >= 0) {
              out.write(buffer, 0, n);
            }
            return out.toString();
          }
    }

    static class FileHelper{
        public static String fileToString(String path) {
            StringBuilder sb=new StringBuilder();
            File file=new File(path);
            try{
                FileReader fr=new FileReader(file);
                BufferedReader br = new BufferedReader(fr);
                String str;
                while((str=br.readLine())!=null){
                    sb.append(str+'\n');
                }
            }catch(Exception e){
                e.printStackTrace();
            }
            return sb.toString();
        }
    }
}