How to quickly develop the CSV file operation function in the Java class library through the OpenCSV framework
How to quickly develop the CSV file operation function in the Java class library through the OpenCSV framework
introduce:
CSV (comma separation value) is a common file format for storing and exchange data, which is especially suitable for table data.OpenCSV is a Java class library used to handle CSV files, which can be easily read and write into CSV files.This article will introduce how to use the OpenCSV framework to quickly develop the CSV file operation function in the Java class library.
step:
1. Introduce OpenCSV dependencies:
First, the dependencies of OpenCSV are introduced in the Java project.You can introduce it by maven or directly download the jar file.
<dependency>
<groupId>com.opencsv</groupId>
<artifactId>opencsv</artifactId>
<version>5.5.2</version>
</dependency>
2. Read CSV file:
It is very simple to read the CSV file using OpenCSV.Just use the constructor of the CSVReader class to create a CSVReader object, and then read the entire file by using its Readall () method.
try (CSVReader reader = new CSVReader(new FileReader("data.csv"))) {
List<String[]> data = reader.readAll();
for (String[] record : data) {
System.out.println(Arrays.toString(record));
}
} catch (IOException e) {
e.printStackTrace();
}
3. Write into CSV file:
Similarly, it is also simple to write the CSV file with OpenCSV.Create a CSVWRiter object and write data to write data with its WRITEALL () or WRITENEXT () method.
try (CSVWriter writer = new CSVWriter(new FileWriter("data.csv"))) {
List<String[]> data = new ArrayList<>();
data.add(new String[]{"Name", "Age", "City"});
data.add(new String[]{"John", "25", "New York"});
data.add(new String[]{"Jane", "30", "London"});
writer.writeAll(data);
} catch (IOException e) {
e.printStackTrace();
}
4. Customized separators and quotes characters:
OpenCSV uses the comma as a separator and dual quotation as a quotation character.If you need to use other characters, you can set up when creating a CSVReader or CSVWriter object.
try (CSVReader reader = new CSVReaderBuilder(new FileReader("data.csv"))
.withSeparator(';').withQuoteChar('\'').build()) {
// Read the CSV file ...
} catch (IOException e) {
e.printStackTrace();
}
Summarize:
Through the OpenCSV framework, we can easily read and write CSV files to improve development efficiency.This article introduces how to introduce OpenCSV dependencies and provides example code reading and writing to CSV files.In addition, how to customize separators and quotes characters.Using OpenCSV, you can quickly develop the CSV file operation function in the Java class library.
I hope this article will help you use the OpenCSV framework in the Java library for CSV file operations.
