Playframework 将api调用日志写入文件

这就是我试过的

ApiLogWriter.java

package utils;

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;

public class ApiLogWriter {
    FileWriter fw;
    BufferedWriter bw;
    PrintWriter out;

    public ApiLogWriter() {

        try {
            fw = new FileWriter("apiCallLog.txt", true);
            bw = new BufferedWriter(fw);
            out = new PrintWriter(bw);
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }

    public void writeToFile(String apiString) {
        out.println(apiString);
        out.flush();
    }

    @Override
    protected void finalize() throws Throwable {
        if (out != null)
            out.close();
        if (bw != null)
            bw.close();
        if (fw != null)
            fw.close();
        super.finalize();
    }
}

ExampleFilter.java

package filters;

import akka.stream.Materializer;
import java.util.concurrent.CompletionStage;
import java.util.concurrent.Executor;
import java.util.function.Function;
import javax.inject.*;
import play.mvc.*;
import play.mvc.Http.RequestHeader;
import utils.ApiLogWriter;


/**
 * This is a simple filter that adds a header to all requests. It's
 * added to the application's list of filters by the
 * {@link ExampleFilters} class.
 */
@Singleton
public class ExampleFilter extends Filter {

    private final Executor exec;

    /**
     * @param mat This object is needed to handle streaming of requests
     * and responses.
     * @param exec This class is needed to execute code asynchronously.
     * It is used below by the <code>thenAsyncApply</code> method.
     */
    @Inject
    public ExampleFilter(Materializer mat, Executor exec) {
        super(mat);
        this.exec = exec;
    }

    @Inject
    private ApiLogWriter apiLogWriter;

    @Override
    public CompletionStage<Result> apply(
        Function<RequestHeader, CompletionStage<Result>> next,
        RequestHeader requestHeader) {
        apiLogWriter.writeToFile(requestHeader.path());
        return next.apply(requestHeader).thenApplyAsync(
            result -> result.withHeader("X-ExampleFilter", "foo"),
            exec
        );
    }

}

当我使用sbt Run运行该代码时，该代码工作正常，但在项目根/target/universal/stage/bin目录中的

sbt stage

之后启动时，该文件为空

---

请注意，我在dev模式下运行它时，for

fork in run:=false

，但在stage build中它是true

您确定查看了正确的文件吗？在服务器的当前工作目录中创建文件。。。因此，它可能在

Project\u Root/target/universal/stage/

文件夹中。是的，正在创建文件，但实际上它在Project\u Root/target/universal/stage/bin目录中是空的。您是否在配置中启用了过滤器？例如

play.filters.enabled+=filters.ExampleFilter

。不，这是在

application.conf

中使用的HOCON语法。看见