unzip.md

# 解压流

已知 GZIPInputStream 是 Java 标准库中用于从 gzip 格式文件读取信息的类型，那么从一个gzip文件读取信息并解压的正确实现应该是：

## 答案

```java
        String fileZip = "path_to_file.zip";
        File destDir = new File("path_to_dest");
        byte[] buffer = new byte[1024];
        try (ZipInputStream zis = new ZipInputStream(new FileInputStream(fileZip))) {
            ZipEntry zipEntry = zis.getNextEntry();
            while (zipEntry != null) {
                // ...
            }
            zis.closeEntry();
        }
```

## 选项

### 没有关闭资源

```java
        String fileZip = "path_to_file.zip";
        File destDir = new File("path_to_dest");
        byte[] buffer = new byte[1024];
        ZipInputStream zis = new ZipInputStream(new FileInputStream(fileZip)) 
        ZipEntry zipEntry = zis.getNextEntry();
        while (zipEntry != null) {
            // ...
        }
```

### zip 流需要接到字节输入流上工作

```java
        String fileZip = "path_to_file.zip";
        File destDir = new File("path_to_dest");
        byte[] buffer = new byte[1024];
        try (ZipInputStream zis = new ZipInputStream(fileZip)) {
            ZipEntry zipEntry = zis.getNextEntry();
            while (zipEntry != null) {
                // ...
            }
            zis.closeEntry();
        }
```

### 缓冲区需要分配空间

```java
        String fileZip = "path_to_file.zip";
        File destDir = new File("path_to_dest");
        byte[] buffer = null;
        try (ZipInputStream zis = new ZipInputStream(new FileInputStream(fileZip))) {
            ZipEntry zipEntry = zis.getNextEntry();
            while (zipEntry != null) {
                // ...
            }
            zis.closeEntry();
        }
```