二、通过preserve-order="true"
　　在xml添加<suite name="Suite" preserve-order="true">，方法将按照XML中配置的先后顺序由上按下执行（代码无需额外控制）
<?xml version="1.0" encoding="UTF-8"?>
<suite name="Suite" preserve-order="true">
<test name="Test">
<classes>
<class name="test.testng.TestOrder"/>
<methods>
<include name="test2" />
<include name="test3" />
<include name="test1" />
</methods>
</classes>
</test> <!-- Test -->
</suite> <!-- Suite -->
　　执行顺序，打印结果：
　　this is test2
　　this is test3
　　this is test1
　　三、并发执行，Parallel
　　1、如果没有并发执行用例的需要，建议把Parallel=false，如果等于Parallel=true，则会并发执行用例，除非你设置了Dependencies，否则执行的顺序将不受控制
　　如：<suite name="Suite" parallel="true">
　　2、添加Parallel的时候也可以设置线程数，如：
　　<suite name="My suite" parallel="methods" thread-count="5">
　　<suite name="My suite" parallel="tests" thread-count="5">
　　<suite name="My suite" parallel="classes" thread-count="5">
　　<suite name="My suite" parallel="instances" thread-count="5">
　　官方的解释，有兴趣的可以自行翻译：
　　parallel="methods": TestNG will run all your test methods in separate threads. Dependent methods will also run in separate threads but they will respect the order that you specified.
　　parallel="tests": TestNG will run all the methods in the same <test> tag in the same thread， but each <test> tag will be in a separate thread. This allows you to group all your classes that are not thread safe in the same 　　　　　　　　<test> and guarantee they will all run in the same thread while taking advantage of TestNG using as many threads as possible to run your tests.
　　parallel="classes": TestNG will run all the methods in the same class in the same thread， but each class will be run in a separate thread.
　　parallel="instances": TestNG will run all the methods in the same instance in the same thread， but two methods on two different instances will be running in different threads.
　　Additionally， the attribute thread-count allows you to specify how many threads should be allocated for this execution.