java - 如何在 SpringBoot 中配置 YML 文件？

Question

我正在尝试配置我的 .yml 但我总是得到一个空指针异常......

我有以下.yml：

search_files:
  csv:
    path: ./
    name: export_files_
    extension: .csv

我有以下pom配置：

<build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-surefire-plugin</artifactId>
                <configuration>
                    <argLine>-Dspring.config.location=file:${home}/config/application.yml</argLine>
                </configuration>
            </plugin>
        </plugins>
        
        <resources>
            <resource>
                <directory>src/resources</directory>
                <filtering>true</filtering>
                <excludes>
                    <exclude>**/application.yml</exclude>
                </excludes>
            </resource>
        </resources>
    </build>

而我的实现：

import java.io.FileWriter;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;

import org.apache.commons.csv.CSVFormat;
import org.apache.commons.csv.CSVPrinter;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

import com.victorprojects.utils.searchFiles.entity.bean.Result;

@Component
public class CSVUtils {

    @Value("${search_files.csv.path}")
    private static String PATH;
    
    @Value("${search_files.csv.name}")
    private static String NAME;
    
    @Value("${search_files.csv.extension}")
    private static String EXTENSION;

    public void createCsv(ArrayList<Result> results) {
       try {
            String fullPath = PATH.concat(NAME.concat(getCurrentDateTime().concat(EXTENSION)));
            FileWriter fileWriter = new FileWriter(fullPath, true);
            CSVPrinter csvPrinter = new CSVPrinter(fileWriter, CSVFormat.RFC4180);

            // HEADER
            csvPrinter.printRecord("Name", "Extension", "Size (Kb)", "Path");

            for (Result result : results) {
                // DATA
                csvPrinter.printRecord(result.getName(), result.getExtension(), result.getSize(), result.getPath());
            }

            csvPrinter.flush();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

当我执行它时，我收到以下消息：

Exception in thread "main" java.lang.NullPointerException: Cannot invoke "org.springframework.core.env.Environment.getProperty(String)" because "this.env" is null
    at com.victorprojects.utils.searchFiles.utils.CSVUtils.createCsv(CSVUtils.java:28)

我在互联网上搜索了很多信息，但我总是得到同样的错误......

我该如何解决这个问题？

编辑

我添加了一张关于我的项目结构的照片：

你可以在这里下载项目：

• https://toffeesha.re/c/KELg3CB5

标签： javaspringspring-bootyaml

Answer 1

I have solved my problem... I was initializing the CSVUtils constructor like this:

Utils utils = new Utils();

But I needed to initialize it this way:

@Autowired
Utils utils;

With the first way, I was initializing explicity the constructor, but I needed to do that with the Spring annotation to be able to use @Value.