jmeter函数开发实现返回随机字符串

实现功能：对给定的用逗号分隔的字符串，随机返回其中一个。

 

代码如下：

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * 
 */

package org.apache.jmeter.functions;


import org.apache.jmeter.engine.util.CompoundVariable;
import org.apache.jmeter.samplers.SampleResult;
import org.apache.jmeter.samplers.Sampler;
import org.apache.jmeter.util.JMeterUtils;

import java.util.*;
import java.util.Random;

/**
 * Function to return a random string you given
 * Pass parameters split by comma
 * 
 * @since 2.10
 */
public class GetRandomStr extends AbstractFunction {
    
    private static final List<String> desc = new LinkedList<>();

    private static final String KEY = "__getrandomstr"; //$NON-NLS-1$

    static {
        desc.add(JMeterUtils.getResString("getrandomstr_string")); //$NON-NLS-1$
    }

    private Object[] values;
    Random ra;
    int rannum;

    public GetRandomStr() {
    }

    /** {@inheritDoc} */
    @Override
    public String execute(SampleResult previousResult, Sampler currentSampler)
            throws InvalidVariableException {
        String randomString = ""; //$NON-NLS-1$
        ra =new Random();
        rannum = ra.nextInt(values.length);
        try {
            randomString = ((CompoundVariable) values[rannum]).execute();
        } catch (Exception uee) {
            return null;
        }
        return randomString;
    }

    /** {@inheritDoc} */
    @Override
    public void setParameters(Collection<CompoundVariable> parameters) throws InvalidVariableException {
        //checkParameterCount(parameters, 1);
        values = parameters.toArray();
    }

    /** {@inheritDoc} */
    @Override
    public String getReferenceKey() {
        return KEY;
    }

    /** {@inheritDoc} */
    @Override
    public List<String> getArgumentDesc() {
        return desc;
    }
}

 在messages.properties中增加对应的属性：

urlencode_string=String to encode in URL encoded chars
getrandomstr_string=return a random you given,split by comma
use_custom_dns_resolver=Use custom DNS resolver

 使用截图：