Use Commons CSV (Sandbox) for data import and export instance tutorial
Use Commons CSV (Sandbox) for data import and export instance tutorial
Commons CSV is a popular Java library that is used to process the values (CSV) file with a comma.It provides a simple and flexible way to read and write into the CSV file.This tutorial will show you how to use the Commons CSV (Sandbox) to implement data introduction and export.
1. Introduce dependencies
First, you need to introduce the Commons CSV (Sandbox) library in your Java project.You can add the following dependencies to Maven or Gradle:
Maven:
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-csv</artifactId>
<version>1.9.0-SNAPSHOT</version>
</dependency>
Gradle:
implementation 'org.apache.commons:commons-csv:1.9.0-SNAPSHOT'
2. Data Export Example
Let's start with a simple dataset and export it to a CSV file.Suppose we have the following data:
List<List<String>> data = new ArrayList<>();
data.add (Arrays.aslist ("Name", "Age", "City");
data.add (Arrays.aslist ("Zhang San", "25", "Beijing");
data.add (Arrays.aslist ("Li Si", "30", "Shanghai");
data.add (Arrays.aslist ("Wang Wu", "28", "Shenzhen");
Now, we will use Commons CSV to export the data to the CSV file:
try (CSVPrinter csvPrinter = new CSVPrinter(new FileWriter("data.csv"), CSVFormat.DEFAULT)) {
for (List<String> rowData : data) {
csvPrinter.printRecord(rowData);
}
} catch (IOException e) {
e.printStackTrace();
}
In the above code block, we create a CSVPrinter object and specify the target files and CSV formats to be written.Then, we traversed the data list and wrote each line of data into the CSV file with the `PrintRecord` method.
After executing the above code, you will see a CSV file called `data.csv`, which contains the exported data.
3. Data import example
Next, we will show how to use the Commons CSV (Sandbox) to import CSV files and read data.Suppose our CSV file is shown below:
Name, age, city
Zhang San, 25, Beijing
Li Si, 30, Shanghai
Wang Wu, 28, Shenzhen
To import and read the data, you can use the following code:
try (CSVParser csvParser = CSVParser.parse(new File("data.csv"), Charset.defaultCharset(), CSVFormat.DEFAULT)) {
for (CSVRecord record : csvParser) {
String name = record.get(0);
String age = record.get(1);
String city = record.get(2);
// Print data
System.out.println ("Name:" + Name + ", age:" + Age + ", City:" + City);
}
} catch (IOException e) {
e.printStackTrace();
}
In the above code, we use the `CSVPARSER` object to analyze the CSV file and use the` CSVRecord` object to access the data of each line.By calling the `Get` method, we can obtain the value of each column according to the index.We can then further process the data as needed.
After executing the above code, you will print the imported data on the console.
This is a simple example tutorial that uses Commons CSV (Sandbox) for data import and export.You can further expand and adjust these examples according to your needs.I hope this tutorial can help you quickly get started with CSV CSV and easily handle the introduction and export of CSV files.
