Java的File对象 朴灿烈づ我的快乐病毒、 2022-06-13 01:22 135阅读 0赞 File对象在Java开发中经常需要碰到,其构造方法大家都比较熟悉了: <table> <tbody> <tr> <td><code><strong><a rel="nofollow">File</a></strong>(<a title="java.io 中的类" rel="nofollow">File</a> dir,<a title="java.lang 中的类" rel="nofollow">String</a> name)</code> <br> 使用File对象路径和文件名进行创建句柄</td> </tr> <tr> <td><code><strong><a rel="nofollow">File</a></strong>(<a title="java.lang 中的类" rel="nofollow">String</a> path)</code><br> 只使用路径创建句柄</td> </tr> <tr> <td><code><strong><a rel="nofollow">File</a></strong>(<a title="java.lang 中的类" rel="nofollow">String</a> dirPath,<a title="java.lang 中的类" rel="nofollow">String</a> name)</code> <br> 使用字符路径和文件名来创建句柄</td> </tr> <tr> <td><code><strong><a rel="nofollow">File</a></strong>(<a title="java.net 中的类" rel="nofollow">URI</a> uri)</code><br> 使用URI路径来创建句柄</td> </tr> </tbody> </table> 在使用构造函数之后,这个File对象就存在了,你可以使用File.exists()来对其进行判断,存在则返回true。 Java使用介乎于UNIX和Windows的路径方法,前斜线“/”可以正确解释,而如果要使用反斜线“\\”则需要进行转义序列“\\\\”,才能被解释器正确解释。 很重要的一点就是,Java的File对象可以是文件也可以是文件夹。所以当你使用 File file=new File("/java");后 你返回的是文件夹,但是你在后面加一句 File fileNext=new File("/java/text.txt"); file使用isFile();的返回值就会变成了false。它变成了文件夹,也就是“目录”。 对于目录属性的File,我们可以使用list()来显示目录下的内容。 其他方法摘要,可以参考以下文档 <table> <tbody> <tr> <th colspan="2" align="left"><span style="">方法摘要</span></th> </tr> <tr> <td align="right"><span style=""><code> boolean</code></span></td> <td><code><strong><a rel="nofollow">canRead</a></strong>()</code> <br> Indicates whether the current context is allowed to read from this file.</td> </tr> <tr> <td align="right"><span style=""><code> boolean</code></span></td> <td><code><strong><a rel="nofollow">canWrite</a></strong>()</code> <br> Indicates whether the current context is allowed to write to this file.</td> </tr> <tr> <td align="right"><span style=""><code> int</code></span></td> <td><code><strong><a rel="nofollow">compareTo</a></strong>(<a title="java.io 中的类" rel="nofollow">File</a> another)</code><br> Returns the relative sort ordering of the paths for this file and the file<code>another</code>.</td> </tr> <tr> <td align="right"><span style=""><code> boolean</code></span></td> <td><code><strong><a rel="nofollow">createNewFile</a></strong>()</code> <br> Creates a new, empty file on the file system according to the path information stored in this file.</td> </tr> <tr> <td align="right"><span style=""><code>static <a title="java.io 中的类" rel="nofollow">File</a></code></span></td> <td><code><strong><a rel="nofollow">createTempFile</a></strong>(<a title="java.lang 中的类" rel="nofollow">String</a> prefix,<a title="java.lang 中的类" rel="nofollow">String</a> suffix)</code> <br> Creates an empty temporary file using the given prefix and suffix as part of the file name.</td> </tr> <tr> <td align="right"><span style=""><code>static <a title="java.io 中的类" rel="nofollow">File</a></code></span></td> <td><code><strong><a rel="nofollow">createTempFile</a></strong>(<a title="java.lang 中的类" rel="nofollow">String</a> prefix,<a title="java.lang 中的类" rel="nofollow">String</a> suffix, <a title="java.io 中的类" rel="nofollow">File</a> directory)</code> <br> Creates an empty temporary file in the given directory using the given prefix and suffix as part of the file name.</td> </tr> <tr> <td align="right"><span style=""><code> boolean</code></span></td> <td><code><strong><a rel="nofollow">delete</a></strong>()</code> <br> Deletes this file.</td> </tr> <tr> <td align="right"><span style=""><code> void</code></span></td> <td><code><strong><a rel="nofollow">deleteOnExit</a></strong>()</code> <br> Schedules this file to be automatically deleted once the virtual machine terminates.</td> </tr> <tr> <td align="right"><span style=""><code> boolean</code></span></td> <td><code><strong><a rel="nofollow">equals</a></strong>(<a title="java.lang 中的类" rel="nofollow">Object</a> obj)</code><br> Compares <code>obj</code> to this file and returns <code>true</code> if they represent the<em>same</em> object using a path specific comparison.</td> </tr> <tr> <td align="right"><span style=""><code> boolean</code></span></td> <td><code><strong><a rel="nofollow">exists</a></strong>()</code> <br> Returns a boolean indicating whether this file can be found on the underlying file system.</td> </tr> <tr> <td align="right"><span style=""><code> <a title="java.io 中的类" rel="nofollow">File</a></code></span></td> <td><code><strong><a rel="nofollow">getAbsoluteFile</a></strong>()</code><br> Returns a new file constructed using the absolute path of this file.</td> </tr> <tr> <td align="right"><span style=""><code> <a title="java.lang 中的类" rel="nofollow">String</a></code></span></td> <td><code><strong><a rel="nofollow">getAbsolutePath</a></strong>()</code><br> Returns the absolute path of this file.</td> </tr> <tr> <td align="right"><span style=""><code> <a title="java.io 中的类" rel="nofollow">File</a></code></span></td> <td><code><strong><a rel="nofollow">getCanonicalFile</a></strong>()</code><br> Returns a new file created using the canonical path of this file.</td> </tr> <tr> <td align="right"><span style=""><code> <a title="java.lang 中的类" rel="nofollow">String</a></code></span></td> <td><code><strong><a rel="nofollow">getCanonicalPath</a></strong>()</code><br> Returns the absolute path of this file with all references resolved.</td> </tr> <tr> <td align="right"><span style=""><code> <a title="java.lang 中的类" rel="nofollow">String</a></code></span></td> <td><code><strong><a rel="nofollow">getName</a></strong>()</code> <br> Returns the name of the file or directory represented by this file.</td> </tr> <tr> <td align="right"><span style=""><code> <a title="java.lang 中的类" rel="nofollow">String</a></code></span></td> <td><code><strong><a rel="nofollow">getParent</a></strong>()</code> <br> Returns the pathname of the parent of this file.</td> </tr> <tr> <td align="right"><span style=""><code> <a title="java.io 中的类" rel="nofollow">File</a></code></span></td> <td><code><strong><a rel="nofollow">getParentFile</a></strong>()</code> <br> Returns a new file made from the pathname of the parent of this file.</td> </tr> <tr> <td align="right"><span style=""><code> <a title="java.lang 中的类" rel="nofollow">String</a></code></span></td> <td><code><strong><a rel="nofollow">getPath</a></strong>()</code> <br> Returns the path of this file.</td> </tr> <tr> <td align="right"><span style=""><code> int</code></span></td> <td><code><strong><a rel="nofollow">hashCode</a></strong>()</code> <br> Returns an integer hash code for the receiver.</td> </tr> <tr> <td align="right"><span style=""><code> boolean</code></span></td> <td><code><strong><a rel="nofollow">isAbsolute</a></strong>()</code> <br> Indicates if this file's pathname is absolute.</td> </tr> <tr> <td align="right"><span style=""><code> boolean</code></span></td> <td><code><strong><a rel="nofollow">isDirectory</a></strong>()</code> <br> Indicates if this file represents a <em>directory</em> on the underlying file system.</td> </tr> <tr> <td align="right"><span style=""><code> boolean</code></span></td> <td><code><strong><a rel="nofollow">isFile</a></strong>()</code> <br> Indicates if this file represents a <em>file</em> on the underlying file system.</td> </tr> <tr> <td align="right"><span style=""><code> boolean</code></span></td> <td><code><strong><a rel="nofollow">isHidden</a></strong>()</code> <br> Returns whether or not this file is a hidden file as defined by the operating system.</td> </tr> <tr> <td align="right"><span style=""><code> long</code></span></td> <td><code><strong><a rel="nofollow">lastModified</a></strong>()</code> <br> Returns the time when this file was last modified, measured in milliseconds since January 1st, 1970, midnight.</td> </tr> <tr> <td align="right"><span style=""><code> long</code></span></td> <td><code><strong><a rel="nofollow">length</a></strong>()</code> <br> Returns the length of this file in bytes.</td> </tr> <tr> <td align="right"><span style=""><code> <a title="java.lang 中的类" rel="nofollow">String</a>[]</code></span></td> <td><code><strong><a rel="nofollow">list</a></strong>()</code> <br> Returns an array of strings with the file names in the directory represented by this file.</td> </tr> <tr> <td align="right"><span style=""><code> <a title="java.lang 中的类" rel="nofollow">String</a>[]</code></span></td> <td><code><strong><a rel="nofollow">list</a></strong>(<a title="java.io 中的接口" rel="nofollow">FilenameFilter</a> filter)</code><br> Gets a list of the files in the directory represented by this file.</td> </tr> <tr> <td align="right"><span style=""><code> <a title="java.io 中的类" rel="nofollow">File</a>[]</code></span></td> <td><code><strong><a rel="nofollow">listFiles</a></strong>()</code> <br> Returns an array of files contained in the directory represented by this file.</td> </tr> <tr> <td align="right"><span style=""><code> <a title="java.io 中的类" rel="nofollow">File</a>[]</code></span></td> <td><code><strong><a rel="nofollow">listFiles</a></strong>(<a title="java.io 中的接口" rel="nofollow">FileFilter</a> filter)</code><br> Gets a list of the files in the directory represented by this file.</td> </tr> <tr> <td align="right"><span style=""><code> <a title="java.io 中的类" rel="nofollow">File</a>[]</code></span></td> <td><code><strong><a rel="nofollow">listFiles</a></strong>(<a title="java.io 中的接口" rel="nofollow">FilenameFilter</a> filter)</code><br> Gets a list of the files in the directory represented by this file.</td> </tr> <tr> <td align="right"><span style=""><code>static <a title="java.io 中的类" rel="nofollow">File</a>[]</code></span></td> <td><code><strong><a rel="nofollow">listRoots</a></strong>()</code> <br> Lists the file system roots.</td> </tr> <tr> <td align="right"><span style=""><code> boolean</code></span></td> <td><code><strong><a rel="nofollow">mkdir</a></strong>()</code> <br> Creates the directory named by the trailing filename of this file.</td> </tr> <tr> <td align="right"><span style=""><code> boolean</code></span></td> <td><code><strong><a rel="nofollow">mkdirs</a></strong>()</code> <br> Creates the directory named by the trailing filename of this file, including the complete directory path required to create this directory.</td> </tr> <tr> <td align="right"><span style=""><code> boolean</code></span></td> <td><code><strong><a rel="nofollow">renameTo</a></strong>(<a title="java.io 中的类" rel="nofollow">File</a> dest)</code><br> Renames this file to the name represented by the <code>dest</code> file.</td> </tr> <tr> <td align="right"><span style=""><code> boolean</code></span></td> <td><code><strong><a rel="nofollow">setLastModified</a></strong>(long time)</code><br> Sets the time this file was last modified, measured in milliseconds since January 1st, 1970, midnight.</td> </tr> <tr> <td align="right"><span style=""><code> boolean</code></span></td> <td><code><strong><a rel="nofollow">setReadOnly</a></strong>()</code> <br> Marks this file or directory to be read-only as defined by the operating system.</td> </tr> <tr> <td align="right"><span style=""><code> <a title="java.lang 中的类" rel="nofollow">String</a></code></span></td> <td><code><strong><a rel="nofollow">toString</a></strong>()</code> <br> Returns a string containing a concise, human-readable description of this file.</td> </tr> <tr> <td align="right"><span style=""><code> <a title="java.net 中的类" rel="nofollow">URI</a></code></span></td> <td><code><strong><a rel="nofollow">toURI</a></strong>()</code> <br> Returns a Uniform Resource Identifier for this file.</td> </tr> <tr> <td align="right"><span style=""><code> <a title="java.net 中的类" rel="nofollow">URL</a></code></span></td> <td><code><strong><a rel="nofollow">toURL</a></strong>()</code> <br> Returns a Uniform Resource Locator for this file.</td> </tr> </tbody> </table>
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