NEO4J CSV read and analytical use guidelines in Java class libraries
NEO4J CSV read and analytical use guidelines in Java class libraries
preface:
Neo4J is a database management system based on graphs, which is widely used in storage and processing connection data.When processing a large amount of data, using CSV files for data import is a common way.In order to simplify this process, Neo4J provides a set of powerful CSV reading and analysis tools to facilitate users to import the structured data into the NEO4J diagram database.
This article will introduce the guidelines for the use of CSV reading and parsing tools in the NEO4J Java class library, and provide the corresponding Java code example.
1. Introduce dependency library
First of all, in your Java project, the Neo4J Java class library dependencies need to be introduced.Add the following to the pom.xml file of your maven project::
<dependencies>
<dependency>
<groupId>org.neo4j.driver</groupId>
<artifactId>neo4j-java-driver</artifactId>
<version>4.3.7</version>
</dependency>
</dependencies>
2. Create CSV Reader object
Neo4J provides a CSV Reader class to read and analyze CSV files.To create a CSV Reader object, you can use the following code:
import org.neo4j.driver.util.Pair;
import org.neo4j.driver.util.Tuples;
CsvParser csvParser = CsvParser.newParser()
.withFieldDelimiter(',')
.withQuoteChar('"')
.withCommentChar('#')
.withEscapeChar('\\')
.build();
In the above example, we used the `newparser` method of the` csvparser` class to create a CSV reader object, and set the field separator as a comma, the reference character is a dual quotation sign, the notes are the well, and the switch is transferred.The righteous character is a back slope.
3. Read the content of CSV files
Using the CSV Reader object, you can read the content of the CSV file.The following code demonstrates how to read the CSV file and print it to the console:
CsvReader csvReader = csvParser.parse(new File("data.csv"));
List<Pair<String, Object>> row;
while ((row = csvReader.nextRecord()) != null) {
for (Pair<String, Object> field : row) {
System.out.println("Field: " + field.key() + ", Value: " + field.value());
}
System.out.println("----------");
}
csvReader.close();
In the above code, we open a CSV file with the `Parse` method of the` CSVPARSER` object, and read the content of the CSV file with the `NextRecord` method.The data of each row is expressed as the `list <string, object >>` object, traversing each field in the cycle, and printing them to the console.
4. Import data to NEO4J
Once you read the content of the CSV file, you can use the NEO4J's Java class library to import the data into the NEO4J diagram database.The following code shows how to import CSV data into nodes and relationships:
Driver driver = GraphDatabase.driver("bolt://localhost:7687", AuthTokens.basic("username", "password"));
Session session = driver.session();
csvReader = csvParser.parse(new File("data.csv"));
while ((row = csvReader.nextRecord()) != null) {
String label = row.get(0).value().toString();
String property = row.get(1).value().toString();
session.run("CREATE (n:" + label + ") SET n.property = " + property);
}
session.close();
driver.close();
In the above example, we use the Neo4J's Driver class and the Session class to establish a connection with the local NEO4J database.Then, we read the contents of the CSV file with the `CSVReader` object, and use the CyPher to query the language to import the data into the NEO4J diagram database.In this example, we assume that the first column of the CSV file is the label of the node, and the second column is the attribute value of the node.You can adjust these logic according to your needs.
in conclusion:
This article introduces the use of CSV reading and parsing tools in CSV in class libraries in class libraries, and provides corresponding Java code examples.By using these tools, you can easily import structured data from CSV files into the NEO4J diagram database, so as to achieve more efficient data management and inquiry.By using these tools flexibly, you can better use the powerful functions of NEO4J to build a complex map database application.
