Super CSV Dozer Extension's use of usage in the Java class library
Title: Super CSV Dozer Extension in the Java Library
introduction:
Super CSV Dozer Extension is a powerful Java class library. It combines Super CSV and Dozer to provide a simple way to handle the mapping and conversion between CSV files and Java objects.This article will introduce you to how to use Super CSV Dozer Extension, the programming code and related configuration during use.
1. Introduce Super CSV Dozer Extension Library
First, you need to introduce the dependencies of the Super CSV Dozer Extension library in your project.You can add the following coordinates to the Maven configuration file of your project, or download the jar file and add it to the class of your project.
<dependency>
<groupId>net.sf.supercsv</groupId>
<artifactId>super-csv-dozer</artifactId>
<version>2.4.0</version>
</dependency>
2. Create CSV file mapping
To create a mapping between CSV files and Java objects, you need to create a mapping file.The mapping file is a XML file that specifies the mapping relationship between the column of the CSV file and the attributes of the Java object.
The following is the content of an example mapping file (Employee_mapping.xml):
<mappings>
<class-mapping bean-factory="org.dozer.BeanFactory" map-null="true">
<field>
<a>EmployeeId</a>
<b>employeeId</b>
</field>
<field>
<a>Name</a>
<b>name</b>
</field>
<field>
<a>Age</a>
<b>age</b>
</field>
</class-mapping>
</mappings>
In this example, the mapping file specifies the mapping between the three columns of the CSV file and the three attributes of the Employee object.
3. Execute the reading and conversion of CSV files
Using Super CSV Dozer Extension, you can easily read the CSV file and convert it to a Java object.
The following is a simple implementation of a sample code:
import org.supercsv.dozer.CsvDozerBeanReader;
import org.supercsv.io.ICsvBeanReader;
public class CsvReader {
public static void main(String[] args) {
try (ICsvBeanReader beanReader = new CsvDozerBeanReader(new FileReader("employees.csv"),
CsvPreference.STANDARD_PREFERENCE, new DozerMappingBuilder().build())) {
final String[] header = beanReader.getHeader(true);
final CellProcessor[] processors = new CellProcessor[] { new NotNull(), new NotNull(), new Optional() };
Employee employee;
while ((employee = beanReader.read(Employee.class, header, processors)) != null) {
// Perform the operation of the EMPLOYEE object you read
// ...
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
In this example, we use CSVDozerbeanReader to read CSV files, use DozermappingBuilder to build mapping, and use CellProcessor to define how to process the data of each column.
4. Perform the writing and conversion of the Java object to CSV file
Super CSV Dozer Extension also allows you to convert Java objects to CSV files and write.
The following is a simple implementation of a sample code:
import org.supercsv.dozer.CsvDozerBeanWriter;
import org.supercsv.io.ICsvBeanWriter;
public class CsvWriter {
public static void main(String[] args) {
try (ICsvBeanWriter beanWriter = new CsvDozerBeanWriter(new FileWriter("employees.csv"),
CsvPreference.STANDARD_PREFERENCE, new DozerMappingBuilder().build())) {
final String[] header = { "employeeId", "name", "age" };
final CellProcessor[] processors = new CellProcessor[] { null, null, null };
beanWriter.writeHeader(header);
Employee employee1 = new Employee(1, "John Doe", 25);
beanWriter.write(employee1, header, processors);
Employee employee2 = new Employee(2, "Jane Smith", 30);
beanWriter.write(employee2, header, processors);
} catch (IOException e) {
e.printStackTrace();
}
}
}
In this example, we use CSVDOZERBEANWRITER to write the Java object into the CSV file and use the DozerMappingBuilder to build a mapping.
in conclusion:
Using Super CSV Dozer Extension can simplify the mapping and conversion process between the CSV file and the Java object.By creating a mapping file, you can easily define the mapping relationship between the columns of the CSV file and the attributes of the Java object.You can then use CSVDozerBeanReader to read CSV files and convert it to Java objects, or use CSVDozerbeanWriter to convert Java objects into CSV files and write it.
I hope this article can help you understand and use Super CSV Dozer Extension.If necessary, you can refer to the relevant document and example code to further understand the detailed programming code and configuration.
