How to integrate SOLR Specific Commons CSV frameworks in the Java class library
How to integrate SOLR Specific Commons CSV frameworks in the Java class library
During the development of Java, when we need to handle CSV files, we can use a third -party library to simplify this process.SOLR Specific Commons CSV is a powerful and easy -to -use Java library that can easily read and write data from CSV files.
Below is the step of integrated SOLR Specific Commons CSV framework and Java code example:
Step 1: Add dependencies
First, add the dependencies of Solr Specific Commons CSV to your project.You can add the following dependencies in Maven or Gradle configuration files:
Maven dependencies:
<dependency>
<groupId>org.apache.solr</groupId>
<artifactId>solr-commons-csv</artifactId>
<vision> 6.6.6 </version> <!-Replace it with the version you want->
</dependency>
Gradle dependencies:
groovy
compile 'org.apache.solr: solr-commons-csv: 6.6.6' // replace it with the version you want
Step 2: Read the CSV file
Next, we will understand how to read data in CSV files using Solr Specific Commons CSV.
import org.apache.solr.common.util.NamedList;
import org.apache.solr.common.util.SimpleOrderedMap;
import org.apache.solr.handler.dataimport.CSVLoader;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;
public class CSVReaderExample {
public static void main(String[] args) {
CSVLoader csvLoader = new CSVLoader();
String csvFilePath = "path/to/your/csv/file.csv";
try {
NamedList<Object> csvData = csvLoader.loadFile(Files.newInputStream(Paths.get(csvFilePath)), "UTF-8", null, null);
for (int i = 0; i < csvData.size(); i++) {
SimpleOrderedMap<Object> rowData = (SimpleOrderedMap<Object>) csvData.getVal(i);
for (int j = 0; j < rowData.size(); j++) {
String columnName = (String) rowData.getName(j);
Object columnValue = rowData.getVal(j);
System.out.println(columnName + ": " + columnValue);
}
System.out.println();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
In the above example, a CSVloader instance is first created.Then, we specify the path of the CSV file to be read, and use the Files.NewinPutStream method to convert the file to input stream.Finally, call the loadfile method to load the data of the CSV file.
Step 3: Write into CSV files
Solr Specific Commons CSV also provides a simple API to write data into CSV files.The following is an example:
import org.apache.solr.common.util.SimpleOrderedMap;
import org.apache.solr.handler.dataimport.CSVWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
public class CSVWriterExample {
public static void main(String[] args) {
CSVWriter csvWriter = new CSVWriter();
try (PrintWriter writer = new PrintWriter(new FileWriter("path/to/your/csv/file.csv"))) {
csvWriter.init(writer, ",", true);
SimpleOrderedMap<Object> rowData1 = new SimpleOrderedMap<>();
rowData1.add("Name", "John Smith");
rowData1.add("Age", 30);
SimpleOrderedMap<Object> rowData2 = new SimpleOrderedMap<>();
rowData2.add("Name", "Jane Doe");
rowData2.add("Age", 25);
csvWriter.write(rowData1);
csvWriter.write(rowData2);
} catch (IOException e) {
e.printStackTrace();
}
}
}
In the above example, we first create a CSVWriter instance.We then create a PRINTWRITER object to write the CSV file.Next, initialize the CSVWriter and set the separators to comma.We then create two SimpleserDeredMap objects to save the data to be written.Finally, we use the WRITE method to write the data into the CSV file.
In summary, by integrating Solr Specific Commons CSV framework and using the API provided by it, we can easily read and write data in the CSV file.This makes processing CSV files in the Java class library simple and efficient.
