如何检查Java中是否存在文件

红太狼 2023-02-28 08:43 15阅读 0赞

**java.io.File** class *exists()* method can be used to check if file exists or not in java. If file exists, it returns true else this method returns false.

**java.io.File**类*exist（）*方法可用于检查java中文件是否存在。 如果文件存在，则返回true，否则此方法返回false。

## Java检查文件是否存在 **(**Java Check if File Exists**)** ##

Let’s look at a simple program to check if a file exists or not in Java.

让我们看一个简单的程序，检查Java中文件是否存在。

package com.journaldev.files;
    
    import java.io.File;
    import java.io.IOException;
    
    public class FileExists {
    
        public static void main(String[] args) {
            File file = new File("/Users/pankaj/source.txt");
            File notExist = new File("xyz.txt");
            
            try {
                System.out.println(file.getCanonicalPath() + " exists? "+file.exists());
                System.out.println(notExist.getCanonicalPath() + " exists? "+notExist.exists());
            } catch (IOException e) {
                e.printStackTrace();
            }
            
        }
    
    }

Output of the above program is:

上面程序的输出是：

/Users/pankaj/source.txt exists? true
    /Users/pankaj/JavaPrograms/xyz.txt exists? false

**Note**: When we provide a relative path to create a file object, Eclipse uses project root as the base directory. If you are running the program from the command line, then the current directory is used as the base directory.

**注意** ：当我们提供创建文件对象的相对路径时，Eclipse使用项目根目录作为基本目录。 如果从命令行运行程序，则将当前目录用作基本目录。

Read following post to know about [java file path, canonical path and absolute path][java file path_ canonical path and absolute path].

阅读以下文章，以了解[Java文件路径，规范路径和绝对路径][java file path_ canonical path and absolute path] 。

[GitHub Repository][]. [GitHub存储库中][GitHub Repository]签出更多Java IO示例。

> 翻译自: [https://www.journaldev.com/912/java-check-if-file-exists][https_www.journaldev.com_912_java-check-if-file-exists]

[java file path_ canonical path and absolute path]: https://www.journaldev.com/848/java-file-path-absolute-canonical
[GitHub Repository]: https://github.com/journaldev/journaldev/tree/master/CoreJavaProjects/CoreJavaExamples
[https_www.journaldev.com_912_java-check-if-file-exists]: https://www.journaldev.com/912/java-check-if-file-exists