If the amount of data need to refer to large, and require or need not repeat increment, it can be implemented using a counter.
Counter (counter): allows users to create a counter within the thread group can be cited.
Counter allows users to configure a starting point, a maximum number of increments, circulated to the maximum, then start again, continue to do so until the end of the test. Long using the stored value of the counter, the range is taken 63--2 ^ 2 ^ 63-1.
1, start JMeter, add thread group, adding configure the right element - a counter
Counter interface is as follows:
Start (start): to a predetermined start value of the counter, the initial value, the first iteration, the counter will assign that value
PS: The English version is Start, Jmeter the Chinese language will be translated into Start "Start", some ambiguity
Increment (Increment): After each iteration, to counter the increased value
Maximum value (Maximum): the maximum counter value, and if it exceeds the maximum value, resets to the initial value (the Start), the default maximum value of Long.MAX_VALUE, 2 ^ 63-1 (continued if the measured pressure, best not provided maximum)
Number format: alternative formats, such as 000, 001, 002, formatted as; default format is Long.toString (), but the default format, or can be used as numbers
Reference name (Reference Name): used to control the reference value in the other elements in the form: $ (reference_name}
To each separate user tracking counters (Track Counter Independently for each User) : global counter, if not checked, i.e. global, user # 1 acquires such a value of 1, the user # 2 to obtain the value of 1 or;
如果勾选，即独立的，则每个用户有自己的值：比如用户#1 获取值为1，用户#2获取值为2。
每次迭代复原计数器（Reset counter on each Thread Group Iteration）：可选，仅勾选与每用户独立的跟踪计数器时可用；
如果勾选，则每次线程组迭代，都会重置计数器的值，当线程组是在一个循环控制器内时比较有用。
2、具体过程
①计数器设置（不勾选）
②计数器设置（勾选）
