jmeter添加自定义扩展函数之DoubleSum

1，打开eclipse,新建maven工程，在pom中引用jmeter核心jar包，具体请看---https://www.cnblogs.com/guanyf/p/10863033.html---，这里就不再赘述

2，代码如下：

package com.mytest.functions;
import org.apache.jmeter.engine.util.CompoundVariable;
 
import org.apache.jmeter.functions.AbstractFunction;
 
import org.apache.jmeter.functions.InvalidVariableException;
 
import org.apache.jmeter.samplers.SampleResult;
 
import org.apache.jmeter.samplers.Sampler;
 
import org.apache.jmeter.threads.JMeterVariables;
 
import java.util.Collection;
 
import java.util.LinkedList;
 
import java.util.List;
 
/**
 
 * Provides a DoubleSum function that adds two or more Double values.
 
 * Mostly copied from LongSum
 
 */
 
public class DoubleSum extends AbstractFunction {
 
    private static final List<String> desc = new LinkedList<String>();
 
    private static final String KEY = "__doubleSum";
 
    static {
 
        desc.add("First double to add");
 
        desc.add("Second long to add - further doubles can be summed by adding further arguments");
 
        desc.add("Name of variable in which to store the result (optional),The author is guanyf");
 
    }
 
    private Object[] values;
 
    /**
 
     * No-arg constructor.
 
     */
 
    public DoubleSum() {
 
    }
 
    /**
 
     * {@inheritDoc}
 
     */
 
    @Override
 
    public synchronized String execute(SampleResult previousResult, Sampler currentSampler)
 
            throws InvalidVariableException {
 
        JMeterVariables vars = getVariables();
 
        Double sum = 0D;
 
        String varName = ((CompoundVariable) values[values.length - 1]).execute().trim();
 
        for (int i = 0; i < values.length - 1; i++) {
 
            sum += Double.parseDouble(((CompoundVariable) values[i]).execute());
 
        }
 
        try {
 
            sum += Double.parseDouble(varName);
 
            varName = null; // there is no variable name
 
        } catch (NumberFormatException ignored) {
 
        }
 
        String totalString = Double.toString(sum);
 
        if (vars != null && varName != null && varName.length() > 0) {// vars will be null on TestPlan
 
            vars.put(varName, totalString);
 
        }
 
        return totalString;
 
    }
 
    /**
 
     * {@inheritDoc}
 
     */
 
    @Override
 
    public synchronized void setParameters(Collection<CompoundVariable> parameters) throws InvalidVariableException {
 
        checkMinParameterCount(parameters, 2);
 
        values = parameters.toArray();
 
    }
 
    /**
 
     * {@inheritDoc}
 
     */
 
    @Override
 
    public String getReferenceKey() {
 
        return KEY;
 
    }
 
    /**
 
     * {@inheritDoc}
 
     */
 
    @Override
 
    public List<String> getArgumentDesc() {
 
        return desc;
 
    }
 
}