springboot中EventSourceListener的onEvent方法中, 获取HttpServletResponse对象

在Spring Boot中，可以通过注入HttpServletResponse对象来获取。具体步骤如下：

1. 在EventSourceListener类中定义一个HttpServletResponse类型的成员变量response，并添加一个构造函数，将response作为参数传入。

2. 在onEvent方法中，通过response.getWriter()方法获取PrintWriter对象，然后使用该对象向客户端发送数据

以下是示例代码：

@Component
public class MyEventSourceListener implements EventSourceListener {

    private HttpServletResponse response;

    public MyEventSourceListener(HttpServletResponse response) {
        this.response = response;
    }

    @Override
    public void onOpen() throws IOException {
        // 设置响应头
        response.setContentType("text/event-stream");
        response.setCharacterEncoding("UTF-8");
        response.setHeader("Cache-Control", "no-cache");
        response.setHeader("Connection", "keep-alive");
    }

    @Override
    public void onEvent(String event, String id, String data) throws IOException {
        PrintWriter writer = response.getWriter();
        writer.write("event: " + event + "\n");
        writer.write("id: " + id + "\n");
        writer.write("data: " + data + "\n\n");
        writer.flush();
    }

    @Override
    public void onError(Throwable t) {
        t.printStackTrace();
    }

    @Override
    public void onComplete() {
        try {
            response.getWriter().close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}