Analysis of the technical principles of the "Simple CSV" framework in the Java class library
Analysis of the technical principle of "Simple CSV" framework
Brief introduction
"Simple CSV" is a Java class library for processing the CSV (comma division value) file.It provides a simple and efficient way to read, write, and operates CSV files so that developers can easily process CSV data in their Java applications.
Technical principle
1. Read the CSV file: Simple CSV framework uses InputStream or Reader object to read the CSV file.It identifies the separators and reference symbols of the field by analyzing the comma, replacement and quotation characters in the file.Through the content of the file by line, and using the appropriate separators to split each row of data into fields, the Simple CSV can convert the content of the CSV file into a Java object or data structure.
2. Write CSV file: Simple CSV framework uses OutputStream or Writer objects to write CSV files.By converting the Java object or data structure into a CSV format string, Simple CSV can write data into the CSV file.It can automatically add quotes to fields containing commas or quotes, and use the comma to separate the field.
3. Analysis of CSV data: The Simple CSV framework provides a simple way to parse the CSV data and convert it into a Java object or data structure.It can map the CSV file to the corresponding class attributes according to the field name of the Java class.Developers can configure field mapping relationships by commentary or programming.
4. Generate CSV data: The Simple CSV framework can also generate data in CSV format according to the Java object or data structure.After configured the field mapping relationship with annotations or programming, the developer can convert the Java object into a CSV format string to facilitate the export of data or interact with other systems.
Example code and related configuration
Here are examples of reading and writing with the Simple CSV framework to the CSV file.
Read the CSV file:
import com.simplecsv.*;
import java.io.*;
import java.util.List;
public class CSVReaderExample {
public static void main(String[] args) {
try {
CSVReader csvReader = new CSVReaderBuilder(new FileReader("data.csv")).build();
List<CSVRecord> csvRecords = csvReader.readAll();
for (CSVRecord record : csvRecords) {
System.out.println("Name: " + record.get("Name"));
System.out.println("Age: " + record.get("Age"));
System.out.println("City: " + record.get("City"));
System.out.println("
");
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
The above code uses the csv file named "data.csv" in the CSVREADER class of the Simple CSV framework and print its content to the console.
Write to CSV file:
import com.simplecsv.*;
import java.io.*;
public class CSVWriterExample {
public static void main(String[] args) {
try {
CSVWriter csvWriter = new CSVWriterBuilder(new FileWriter("data.csv"))
.setSeparator(',')
.setQuoteChar('"')
.setEscapeChar('\\')
.setLineEnd("\r
")
.build();
String[] headers = {"Name", "Age", "City"};
csvWriter.writeNext(headers);
String[] row1 = {"John Doe", "25", "New York"};
String[] row2 = {"Jane Smith", "30", "Los Angeles"};
csvWriter.writeNext(row1);
csvWriter.writeNext(row2);
csvWriter.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
The above code uses the CSVWriter class of the Simple CSV framework to create a CSV file called "Data.CSV", and write the content containing the title lines and two lines of data.
Finally, you need to add the dependency information of the Simple CSV library in the construction and configuration file of the project.According to the project construction tool, you can use Maven, Gradle or manually importing JAR files to add dependencies.
Use maven to add dependencies (pom.xml):
<dependencies>
<dependency>
<groupId>com.simplecsv</groupId>
<artifactId>simplecsv</artifactId>
<version>1.0.0</version>
</dependency>
</dependencies>
By understanding the technical principles and example code of the Simple CSV framework, developers can easily process CSV files and operate data in their Java applications.
