The technical principle of the CSV verification device framework in the realization of the Java class library
The technical principle of the CSV verification device framework in the realization of the Java class library
CSV (comma separation value) is a common data format that stores simple table data with simple storage structure.When processing CSV data, verifying the accuracy and integrity of the input is very important.The CSV validator framework is a tool implemented in the Java library to verify the effectiveness of the CSV file and ensure the consistency and correctness of the data.This article will introduce the technical principles of the CSV verification device framework and provide some Java code examples.
Technical principle:
1. Data structure definition:
First, the CSV verification device framework needs to define the structure of CSV data.You can use the Java class to define the attributes of each line of data, and define the type, length, format and other verification rules of the data.By using annotations, metadata of verification rules can be added to the Java class.
Example code:
public class CsvData {
@CsvField(columnIndex = 1, dataType = DataType.STRING, maxLength = 10)
private String name;
@CsvField(columnIndex = 2, dataType = DataType.INTEGER, minValue = 1, maxValue = 100)
private int age;
// getter and setter methods
}
2. Analyze CSV data:
The CSV verification device framework needs to analyze the CSV file and convert it to the Java object.You can use Java files to read and segmentation such as string to read CSV files, and analyze the data as a Java object.During the analysis process, basic lexical and grammar verification can also be performed.
Example code:
public class CsvParser {
public List<CsvData> parseCsv(File csvFile) {
List<CsvData> dataList = new ArrayList<>();
try (Scanner scanner = new Scanner(csvFile)) {
while (scanner.hasNextLine()) {
String line = scanner.nextLine();
String[] fields = line.split(",");
if (fields.length < 2) {
// Treatment of CSV data format errors
continue;
}
CsvData data = new CsvData();
data.setName(fields[0]);
data.setAge(Integer.parseInt(fields[1]));
dataList.add(data);
}
} catch (FileNotFoundException e) {
e.printStackTrace();
}
return dataList;
}
}
3. Verification rules verification:
The validator framework is based on Java's reflection mechanism and obtain metadata of the verification rules by reading the annotations of the Java class.When parsing CSV data, each field can be verified according to the rules.If the data does not meet the verification rules, you can record an error message or throw an exception.
Example code:
public class CsvValidator {
public void validateCsvData(CsvData data) {
Field[] fields = CsvData.class.getDeclaredFields();
for (Field field : fields) {
if (field.isAnnotationPresent(CsvField.class)) {
CsvField csvField = field.getAnnotation(CsvField.class);
// Verify data type
if (csvField.dataType() == DataType.STRING && field.getType() != String.class) {
// Error treatment
}
if (csvField.dataType() == DataType.INTEGER && field.getType() != int.class) {
// Error treatment
}
// Verify data length
if (csvField.maxLength() > 0 && csvField.maxLength() < ((String) field.get(data)).length()) {
// Error treatment
}
// Verification data range
if (csvField.minValue() > 0 && (int) field.get(data) < csvField.minValue()) {
// Error treatment
}
if (csvField.maxValue() > 0 && (int) field.get(data) > csvField.maxValue()) {
// Error treatment
}
// Execute other custom verification rules
// ...
}
}
}
}
4. Integrated application:
Finally, the process of analysis and verification can be integrated into an application to achieve complete verification of CSV data.By calling the CSV parser and the verification device, you can read and verify the entire CSV file.
Example code:
public class CsvValidatorApp {
public static void main(String[] args) {
CsvParser csvParser = new CsvParser();
CsvValidator csvValidator = new CsvValidator();
File csvFile = new File("data.csv");
List<CsvData> dataList = csvParser.parseCsv(csvFile);
for (CsvData data : dataList) {
csvValidator.validateCsvData(data);
}
}
}
Through the CSV verification device framework, we can easily analyze and verify CSV data to ensure the effectiveness and consistency of the data and quickly identify errors in the data.The technical principle of this framework is based on the Java's reflection mechanism and annotation, simplifying the process of CSV data verification and providing flexible verification rules customization functions.Through the implementation and use of the CSV validator framework, the accuracy and efficiency of CSV data processing can be improved.
