如何放心地登录到文本文件中可打印的内容

我正在研究一种方法，尝试使用 log4j 将默认的放心日志（转到控制台）更改为文件。

这是一个 JUnit 项目，其方法最终调用 REST 外观，该外观具有类似这样的方法。

 private ResponseSpecification responseSpecification(RequestSpecification requestSpecification, Matcher matcher, int statusCode) {
        ResponseSpecification responseSpecification = requestSpecification.expect().statusCode(StatusCode).body(".", is(matcher));
        if (log) {
            responseSpecification = responseSpecification.log().all();
        }
        return responseSpecification;
    }

继官方文档，我改变了这样的方法：

private ResponseSpecification responseSpecification(RequestSpecification requestSpecification, Matcher matcher, int statusCode) {
    final StringWriter writer = new StringWriter();
    final PrintStream captor = new PrintStream(new WriterOutputStream(writer), true);
    ResponseSpecification responseSpecification = requestSpecification.filter(logResponseTo(captor)).expect().statusCode(statusCode).body(".", is(matcher));
    System.out.println("writer = " + writer.toString() + " <-");
    return responseSpecification;
}

But writer.toString()始终打印一个空字符串（旧的实现工作正常）。也许我做错了什么，但是什么？ :(

我需要获得可以通过 log4j 以这种或其他方式管理的可打印内容。

谁能帮我？

可能也有用：这里有一个类，它将restAssured log() 调用重定向到提供的记录器：

import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintStream;
import org.slf4j.Logger;

/**
 * A wrapper class which takes a logger as constructor argument and offers a PrintStream whose flush
 * method writes the written content to the supplied logger (debug level).
 * <p>
 * Usage:<br> 
 * initializing in @BeforeClass of the unit test:
 * <pre>
 *          ToLoggerPrintStream loggerPrintStream = new ToLoggerPrintStream( myLog );
 *          RestAssured.config = RestAssured.config().logConfig(
 *                                 new LogConfig( loggerPrintStream.getPrintStream(), true ) );
 * </pre>
 * will redirect all log outputs of a ValidatableResponse to the supplied logger:
 * <pre>
 *             resp.then().log().all( true );
 * </pre>
 *
 * @version 1.0 (28.10.2015)
 * @author  Heri Bender
 */
public class ToLoggerPrintStream
{
    /** Logger for this class */
    private Logger myLog;
    private PrintStream myPrintStream;

/**
 * @return printStream
 */
public PrintStream getPrintStream()
{
    if ( myPrintStream == null )
    {
        OutputStream output = new OutputStream()
        {
            private StringBuilder myStringBuilder = new StringBuilder();

            @Override
            public void write(int b) throws IOException 
            {
                this.myStringBuilder.append((char) b );
            }

            /**
             * @see java.io.OutputStream#flush()
             */
            @Override
            public void flush()
            {
                myLog.debug( this.myStringBuilder.toString() );
                myStringBuilder = new StringBuilder();
            }
        };

        myPrintStream = new PrintStream( output, true );  // true: autoflush must be set!
    }

    return myPrintStream;
}

/**
 * Constructor
 *
 * @param aLogger
 */
public ToLoggerPrintStream( Logger aLogger )
{
    super();
    myLog = aLogger;
}