Java/w12/datacollect/persist/JsonExporter.java

package com.example.datacollect.persist;

import com.example.datacollect.model.Article;
import com.example.datacollect.repository.ArticleRepository;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.List;

public class JsonExporter {
    private static final Logger logger = LoggerFactory.getLogger(JsonExporter.class);
    private final ObjectMapper objectMapper;

    public JsonExporter() {
        // 初始化Jackson，支持LocalDateTime序列化
        this.objectMapper = new ObjectMapper();
        objectMapper.registerModule(new JavaTimeModule());
        objectMapper.enable(com.fasterxml.jackson.databind.SerializationFeature.INDENT_OUTPUT); // 美化JSON
    }

    /**
     * 导出文章到JSON文件
     * @param repository 文章仓库
     * @param filePath 导出路径（如：articles.json）
     */
    public void export(ArticleRepository repository, String filePath) throws IOException {
        logger.info("开始导出文章到文件: {}", filePath);
        List<Article> articles = repository.getAll();

        if (articles.isEmpty()) {
            logger.warn("仓库无文章，跳过导出");
            return;
        }

        // try-with-resources 自动关闭FileWriter，避免资源泄漏
        try (FileWriter writer = new FileWriter(new File(filePath))) {
            objectMapper.writeValue(writer, articles);
            logger.info("成功导出 {} 篇文章到: {}", articles.size(), filePath);
        } catch (IOException e) {
            logger.error("导出失败: {}", filePath, e);
            throw e;
        }
    }
}