一，什么是jmeter Sampler

jmeterSampler

二，准备工作

需要一些java基础及java开发环境（推荐IDEA）

三，实施阶段

以jemeter自带的示例ExampleSampler为范：

1.编写Sampler

package org.apache.jmeter.examples.sampler;

import java.util.concurrent.atomic.AtomicInteger;

import org.apache.jmeter.samplers.AbstractSampler;
import org.apache.jmeter.samplers.Entry;
import org.apache.jmeter.samplers.SampleResult;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class ExampleSampler extends AbstractSampler {
    //每个Sampler都是AbstractSampler 的子类
    private static final long serialVersionUID = 240L;
    private static final Logger log = LoggerFactory.getLogger(ExampleSampler.class);
    //以常量方式定义需要输入的参数
    public static final String DATA = "ExampleSampler.data";
    
    // keep track of classes created
    private static AtomicInteger classCount = new AtomicInteger(0); 

    // 计数与日志跟踪，可以忽略
    public ExampleSampler() {
        classCount.incrementAndGet();
        trace("ExampleSampler()");
    }

    //Sampler的测试过程，测试结果设置  
    @Override
    public SampleResult sample(Entry e) {
        trace("sample()");
        SampleResult res = new SampleResult();
        boolean isOK = false; // Did sample succeed?
        String data = getData(); // Sampler data
        String response = null;

        res.setSampleLabel(getTitle());
        /*
         * Perform the sampling
         */
        res.sampleStart(); // Start timing
        try {

            // Do something here ...

            response = Thread.currentThread().getName();

            /*
             * Set up the sample result details
             */
            res.setSamplerData(data);
            res.setResponseData(response, null);
            res.setDataType(SampleResult.TEXT);

            res.setResponseCodeOK();
            res.setResponseMessage("OK");// $NON-NLS-1$
            isOK = true;
        } catch (Exception ex) {
            log.debug("", ex);
            res.setResponseCode("500");// $NON-NLS-1$
            res.setResponseMessage(ex.toString());
        }
        res.sampleEnd(); // End timimg

        res.setSuccessful(isOK);

        return res;
    }

    //测试结果标题
    private String getTitle() {
        return this.getName();
    }

    //从JMeterProperty中获取GUI中得到的参数值
    public String getData() {
        return getPropertyAsString(DATA);
    }

    //跟踪日志，可以忽略
    private void trace(String s) {
        String tl = getTitle();
        String tn = Thread.currentThread().getName();
        String th = this.toString();
        log.debug(tn + " (" + classCount.get() + ") " + tl + " " + s + " " + th);
    }
}

2，编写SamplerGUI

package org.apache.jmeter.examples.sampler.gui;

import java.awt.BorderLayout;
import java.awt.Component;

import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import org.apache.jmeter.examples.sampler.ExampleSampler;
import org.apache.jmeter.samplers.gui.AbstractSamplerGui;
import org.apache.jmeter.testelement.TestElement;
import org.apache.jmeter.util.JMeterUtils;

public class ExampleSamplerGui extends AbstractSamplerGui {

    private static final long serialVersionUID = 240L;
    //定义界面元素，用于获取参数输入
    private JTextArea data;

    public ExampleSamplerGui() {
        init();
    }

    //设置Sampler标题，但由于国际化，需要在core的message.propertis文件中定义，所以getStaticLabel()方法直接设置标题
    @Override
    public String getLabelResource() {
        return "example_title"; // $NON-NLS-1$
    }

    //从界面获取参数
    @Override
    public void configure(TestElement element) {
        data.setText(element.getPropertyAsString(ExampleSampler.DATA));
        super.configure(element);
    }

    //调用ExampleSampler
    @Override
    public TestElement createTestElement() {
        ExampleSampler sampler = new ExampleSampler();
        modifyTestElement(sampler);
        return sampler;
    }

    //将从页面获取到的参数值加入JMeterProperty中，供Sampler中获取
    @Override
    public void modifyTestElement(TestElement te) {
        te.clear();
        configureTestElement(te);
        te.setProperty(ExampleSampler.DATA, data.getText());
    }

    //设置GUI界面
    private void init() { 
        // Standard setup
        setLayout(new BorderLayout(0, 5));
        setBorder(makeBorder());
        add(makeTitlePanel(), BorderLayout.NORTH); // Add the standard title

        // Specific setup
        add(createDataPanel(), BorderLayout.CENTER);
    }

    //自定义的参数输入单元
    private Component createDataPanel() {
        JLabel label = new JLabel(JMeterUtils.getResString("example_data")); //$NON-NLS-1$

        data = new JTextArea();
        data.setName(ExampleSampler.DATA);
        label.setLabelFor(data);

        JPanel dataPanel = new JPanel(new BorderLayout(5, 0));
        dataPanel.add(label, BorderLayout.WEST);
        dataPanel.add(data, BorderLayout.CENTER);

        return dataPanel;
    }

    //设置参数的默认值
    @Override
    public void clearGui() {
        super.clearGui();
        data.setText(""); // $NON-NLS-1$

    }
}