1. 概述

在上一篇文章中，我们向你展示了如何将文件压缩成zip文件格式。在这篇文章中，我们将向你展示如何解压它。本文的例子使用try-with-resources语句来自动关闭资源，并在JDK 8及以后的版本中编译和执行。

2. 从ZIP文件解压文件 示例

1. 用 "ZipInputStream "读取ZIP文件

ZipInputStream zis = new ZipInputStream(new FileInputStream(zipFile))

1. 获取文件到 "ZipEntry "并将其输出到 "FileOutputStream"。

FileOutputStream fos = new FileOutputStream(newFile)

在这个例子中，它将从 "C:\Project_Work\samples\dest_sample.zip "中读取一个ZIP文件，并将所有的压缩文件解压到 "C:\Project_Work\samples\outputzip "文件夹。

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.List;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

/**
* This Java program demonstartes that how to decompress files from zip.
* @author javaguides.net
*
*/
public class DecompressZipExample {
 List<String> fileList;
 private static final String INPUT_ZIP_FILE = "C:\\Project_Work\\samples\\dest_sample.zip";
 private static final String OUTPUT_FOLDER = "C:\\Project_Work\\samples\\outputzip";

 public static void main(String[] args) {
  DecompressZipExample unZip = new DecompressZipExample();
  unZip.unZipIt(INPUT_ZIP_FILE, OUTPUT_FOLDER);
 }

 /**
* Unzip it
* 
* @param zipFile
*            input zip file
* @param output
*            zip file output folder
*/
 public void unZipIt(String zipFile, String outputFolder) {

  byte[] buffer = new byte[1024];

  File folder = new File(OUTPUT_FOLDER);
  if (!folder.exists()) {
   folder.mkdir();
  }

  try (ZipInputStream zis = new ZipInputStream(new FileInputStream(zipFile))) {
   // get the zipped file list entry
   ZipEntry ze = zis.getNextEntry();

   while (ze != null) {

    String fileName = ze.getName();
    File newFile = new File(outputFolder + File.separator + fileName);

    System.out.println("file unzip : " + newFile.getAbsoluteFile());

    // create all non exists folders
    // else you will hit FileNotFoundException for compressed folder
    new File(newFile.getParent()).mkdirs();

    try (FileOutputStream fos = new FileOutputStream(newFile)) {
     int len;
     while ((len = zis.read(buffer)) > 0) {
      fos.write(buffer, 0, len);
     }
    }
    ze = zis.getNextEntry();
   }

   zis.closeEntry();
   zis.close();

   System.out.println("Done");

  } catch (IOException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
 }
}

输出

file unzip : C:\Project_Work\samples\outputzip\sample.txt
file unzip : C:\Project_Work\samples\outputzip\sample1.txt
file unzip : C:\Project_Work\samples\outputzip\sample2.txt
Done