详解如何使用SpringBoot实现下载JSON文件

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
 
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
 
@RestController
@RequestMapping("/api")
public class FileDownloadController {
 
    @GetMapping("/download-json")
    public void downloadJsonFile(HttpServletResponse response) throws IOException {
        // 1. 准备 JSON 字符串
        String jsonContent = "{\"name\":\"John\", \"age\":30, \"city\":\"New York\"}";
 
        // 2. 设置响应头
        response.setContentType("application/json"); // 文件类型为 JSON
        response.setHeader("Content-Disposition", "attachment; filename=\"data.json\""); // 设置下载文件名
 
        // 3. 将 JSON 字符串写入响应输出流
        response.getOutputStream().write(jsonContent.getBytes(StandardCharsets.UTF_8));
        response.getOutputStream().flush();
    }
}

{"name":"John", "age":30, "city":"New York"}

String fileName = "data_" + System.currentTimeMillis() + ".json";
response.setHeader("Content-Disposition", "attachment; filename=\"" + fileName + "\"");

@GetMapping("/download-dynamic-json")
public void downloadDynamicJsonFile(HttpServletResponse response) throws IOException {
    // 动态生成 JSON 数据
    Map<String, Object> data = new HashMap<>();
    data.put("timestamp", System.currentTimeMillis());
    data.put("message", "Hello, this is a dynamic JSON file!");
 
    // 将 Map 转换为 JSON 字符串
    String jsonContent = new ObjectMapper().writeValueAsString(data);
 
    // 设置响应头
    response.setContentType("application/json");
    response.setHeader("Content-Disposition", "attachment; filename=\"dynamic_data.json\"");
 
    // 写入响应输出流
    response.getOutputStream().write(jsonContent.getBytes(StandardCharsets.UTF_8));
    response.getOutputStream().flush();
}