How to use the IOUtils function for IO operations in Java

In Java, various IO operations can be easily performed using the IOUtils function. IOUtils is a tool class provided in the Apache Commons IO library, which includes many common IO operations.

In this article, we will introduce how to use the IOUtils function to read, write, and copy files, and how to use the IOUtils function to process streams.

1. File reading

It is very simple to use the IOUtils function to read files. The following is a sample program segment that demonstrates how to use the IOUtils function to read a text file in text mode:

File file = new File("file.txt");
String content = IOUtils.toString(new FileInputStream(file), "UTF-8");
System.out.println(content);

In this example, we first create a File object, which represents the file to be read. . Next, we use the toString method of the IOUtils function to read the file content in UTF-8 encoding and store it in a string. Finally, we output the read content to the console.

2. File writing

It is also very simple to use the IOUtils function to write files. The following is a sample program segment that demonstrates how to use the IOUtils function to write content to a text file:

File file = new File("file.txt");
String content = "Hello, world!";
IOUtils.write(content, new FileOutputStream(file), "UTF-8");

In this example, we first create a File object, which represents the file to be written. Then, we define a string variable content to store the content to be written. Next, we use the write method of the IOUtils function to write the content to the file. The last parameter specifies UTF-8 encoding for writing.

3. File copy

It is also very simple to use the IOUtils function to copy files. The following is a sample program segment that demonstrates how to use the IOUtils function to copy one file to another:

File source = new File("source.txt");
File dest = new File("dest.txt");
IOUtils.copy(new FileInputStream(source), new FileOutputStream(dest));

In this example, we first create two File objects, representing the source file and the target file respectively. . Next, we use the copy method of the IOUtils function to copy the contents of the source file to the target file.

4. Processing streams

In addition to reading, writing and copying files, the IOUtils function also provides many methods for processing streams. Here are some common methods:

• toByteArray: Convert the InputStream to a byte array.
• toInputStream: Convert string to InputStream.
• toString: Convert InputStream to string.
• toObject: Convert the InputStream to an object.
• copyLarge: used to copy large files.

The following is a sample program segment that demonstrates how to use the IOUtils function to convert an InputStream to a string:

InputStream input = new ByteArrayInputStream("Hello, world!".getBytes("UTF-8"));
String content = IOUtils.toString(input, "UTF-8");
System.out.println(content);

In this example, we first create a ByteArrayInputStream object, which Represents the data stream to be read. We then use the toString method of the IOUtils function to convert that stream into a string and output it to the console.

Summary

IOUtils is a very convenient IO tool class in Java. It can easily complete operations such as reading, writing and copying files, and supports more complex operations such as processing streams. Using IOUtils can help us simplify IO programming and improve development efficiency. The above introduces several common uses of IOUtils, I hope it will be helpful to you.

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