Introduction to the functions and uses of OpenCSV framework in the Java library

OpenCSV is a Java class library for reading and writing CSV files.CSV (comma separation value) is a commonly used file format for storing table data.OpenCSV provides some simple and easy -to -use methods for us to read and write CSV files. Function: 1. Read CSV file: OpenCSV can read data from the CSV file and convert it to Java object.It provides a variety of options to configure the reading process, such as customized separators, skipping the empty line, etc.CSV files containing different types of data including string, numbers, and dates can be read. 2. Write to CSV file: Through OpenCSV, we can write the Java object into the CSV file.It provides a simple way to convert the Java object into a CSV format and write it into the file.Similarly, you can also customize separators, date formats, etc. 3. Process quotes and rotary characters: OpenCSV supports processing quotes and rotary characters to ensure correctly analyzing and generating field values in CSV files.It can correctly analyze the data containing quotes and comma, and ensure that these special characters are appropriately transferred when writing. 4. Support custom mapping: OpenCSV allows us to define custom field mapping to better control the reading and writing process.We can specify the mapping relationship between the field and the CSV column by annotating or programming to make the read and write operation more flexible. use: 1. Data import and export: OpenCSV can be used to import data from CSV files to database or other data storage systems.It provides efficient reading methods and data type conversion, which can be used to load CSV data to the Java object or database table.At the same time, you can also use OpenCSV to export database query results as CSV files. 2. Data conversion and cleaning: Sometimes we need to convert, filter or clean the original data.OpenCSV provides a simple way that can read CSV files, transform and process data as needed, and write the results into new CSV files. 3. Report generation: Through OpenCSV, we can export the data of the Java object as a CSV file.These CSV files can be used to generate reports or exchange data with other systems. Here are some examples of Java code read and write to CSV files using OpenCSV: // Read the CSV file CSVReader reader = new CSVReader(new FileReader("data.csv")); String[] nextLine; while ((nextLine = reader.readNext()) != null) { // Process each row of data for (String value : nextLine) { System.out.print(value + " | "); } System.out.println(); } reader.close(); // Write into CSV files CSVWriter writer = new CSVWriter(new FileWriter("output.csv")); String[] record = {"John Doe", "john.doe@example.com", "28"}; writer.writeNext(record); writer.close(); Through the above example, we can see the simple usage of OpenCSV.When reading the CSV file, we can read the data with CSVReader row, and then process the values of each row on demand.When writing the CSV file, we use CSVWriter to write the data to the file. Summarize: OpenCSV is a powerful and easy -to -use Java class library for reading and writing to CSV files.It provides rich functions and options, enabling us to easily process CSV data.Whether it is data import and export, data conversion cleaning or reporting, OpenCSV is a practical tool.