1 前言

现有的sample已基本能满足日常使用，但如果有些特殊要求，比如远程连接服务器，或者操作新型NoSQL库，就得专门定制

Java Request采样器要求实现org.apache.jmeter.protocol.java.sampler.JavaSamplerClient接口，或者继承AbstractJavaSamplerClient抽象类

系统自带JavaTest、SleepTest 2个Java Request采样器

2 JavaSamplerClient

每个线程，JMeter都会创建一个JavaSamplerClient的实例

JavaSamplerClient运行过程：

• 先执行setupTest()，完成初始化
• 然后是runTest()，每次迭代都会执行
• 最后是teardownTest()，可能存在的资源释放

接口方法如下：

• getDefaultParameters : Arguments，在GUI模式下显示参数及默认值
• runTest(JavaSampleContext ctx) : SampleResult
• setupTest(JavaSampleContext ctx) : void
• teardownTest(JavaSampleContext ctx) : void

3 SampleResult

SampleResult携带一系列属性，可以提供给pre/post processor，或者交由Assertion校验

SampleResult(boolean nanoTime, long nanoThreadSleep) {
    this.responseData = EMPTY_BA;
    this.responseCode = "";
    this.label = "";
    this.resultFileName = "";
    this.threadName = "";
    this.responseMessage = "";
    this.responseHeaders = "";
    this.requestHeaders = "";
    this.timeStamp = 0L;
    this.startTime = 0L;
    this.endTime = 0L;
    this.idleTime = 0L;
    this.pauseTime = 0L;
    this.dataType = "";
    this.files = new HashSet(3);
    this.contentType = "";
    this.elapsedTime = 0L;
    this.latency = 0L;
    this.connectTime = 0L;
    this.testLogicalAction = TestLogicalAction.CONTINUE;
    this.stopThread = false;
    this.stopTest = false;
    this.stopTestNow = false;
    this.sampleCount = 1;
    this.bytes = 0L;
    this.headersSize = 0;
    this.bodySize = 0L;
    this.groupThreads = 0;
    this.allThreads = 0;
    this.elapsedTime = 0L;
    this.useNanoTime = nanoTime;
    this.nanoThreadSleep = nanoThreadSleep;
    this.nanoTimeOffset = this.initOffset();
}

4 实例：图片下载

public class DownloadPicSample extends AbstractJavaSamplerClient {
    private DataInputStream dataInputStream;
    private String localFoldStr;

    @Override
    public Arguments getDefaultParameters() {
        Arguments arguments = new Arguments();
        arguments.addArgument("PicLink", "");
        arguments.addArgument("Local_Directory", "");
        return arguments;
    }

    @Override
    public void setupTest(JavaSamplerContext context) {
        String picLink = context.getParameter("PicLink", "").trim();
        try {
            URL url = new URL(picLink);
            dataInputStream = new DataInputStream(url.openStream());
        } catch (java.io.IOException e) {
            dataInputStream = null;
        }

        localFoldStr = context.getParameter("Local_Directory").trim();
        File localFold = new File(localFoldStr);
        if (! localFold.exists() || ! localFold.isDirectory()) {
            localFoldStr = null;
        }
    }

    @Override
    public SampleResult runTest(JavaSamplerContext javaSamplerContext) {
        SampleResult sampleResult = new SampleResult();
        if(dataInputStream == null || localFoldStr == null) {
            sampleResult.setResponseData("参数配置错误", "UTF-8");
            return sampleResult;
        }

        if(localFoldStr.endsWith(File.separator))
            localFoldStr.substring(0, localFoldStr.length()-1);
        String localPicFile = localFoldStr + File.separator + System.currentTimeMillis() + ".jpg";

        FileOutputStream outputStream = null;
        try {
            outputStream = new FileOutputStream(new File(localPicFile), false);

            byte[] buffer = new byte[1024];
            int length;
            while((length = dataInputStream.read(buffer)) > 0) {
                outputStream.write(buffer, 0, length);
            }
            sampleResult.setResponseOK();
            sampleResult.setResponseData(localPicFile, "UTF-8");
        } catch (java.io.IOException e) {
            sampleResult.setResponseData("IO读写失败", "UTF-8");
        } finally {
            try {
                outputStream.close();
                dataInputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return sampleResult;
    }
}