Java高并发及测试代码
公司的妹子不会做并发测试。作为一名程序猿看着有点干捉急。并发测试是多个人同时访问一个服务，这不就是多线程吗！于是灵光一现使用多线程来写并发测试代码。想想心理都有点小激动咧。效果比工具还好，废话不多说贴代码
添加Maven依赖
先封装OKHTTP（使用CallBack思想做的封装），这个很早之前就封装了，公司移动端也是使用OKHTTP做的服务请求调用。经常遇到图片上传不了的问题，报的错是Socket连接超时的问题。解决这个问题so easy，把连接时间（KEEP_ALIVE）时间设置长一点就行了嘛！
OkHttp底层是用socket做的通信，现在很多应该的底层通信都用的Socket，例子不多说，全靠经验。
public abstract class HttpCommon {
/**
* 设置连接超时时间为30000秒
*/
private final static int CONNECT_TIMT_OUT = 30000;
/**
* 设置写超时时间为30000秒
*/
private final static int WRITE_TIME_OUT = 30000;
static {
final OkHttpClient.Builder httpBuilder = new OkHttpClient.Builder();
okHttpClient = httpBuilder.connectTimeout(CONNECT_TIMT_OUT, TimeUnit.SECONDS)
.writeTimeout(WRITE_TIME_OUT, TimeUnit.SECONDS).build();
}
public abstract void callBack(String responseString);
/**
* get请求
*
* @param url url地址
* @param map 请求参数
* @return 返回结果。如果为“”表示失败
*/
public void get(String url, Map<Object, Object> map) {
url = wrapUrl(url, map);
// 创建请求参数
Request request = new Request.Builder().url(url).build();
//创建请求对象
Call call = okHttpClient.newCall(request);
try {
Response response = call.execute();
if (response.isSuccessful()) {
callBack(response.body().string());
}
} catch (IOException e) {
e.printStackTrace();
}
}
/**
* post请求
*
* @param url post请求的url
* @param t post请求的表单实体
* @return 返回结果。如果为“”表示失败
*/
public void post(String url, Map<Object, Object> map, T t) {
url = wrapUrl(url, map);
String json = new Gson().toJson(t);
RequestBody body = RequestBody.create(JSON, json);
Request request = new Request.Builder().url(url).post(body).build();
Response response = null;
try {
response = okHttpClient.newCall(request).execute();
if (response.isSuccessful()) {
callBack(response.body().string());
}
} catch (IOException e) {
e.printStackTrace();
}
}
/**
* post请求
*
* @param url post请求的url
* @param t post请求的表单实体
* @return 返回结果。如果为“”表示失败
*/
public void post(String url, T t) {
String json = new Gson().toJson(t);
RequestBody body = RequestBody.create(JSON, json);
Request request = new Request.Builder().url(url).post(body).build();
Response response = null;
try {
response = okHttpClient.newCall(request).execute();
if (response.isSuccessful()) {
callBack(response.body().string());
}
} catch (IOException e) {
e.printStackTrace();
}
}
/**
* 上传文件请求
*
* @param url 请求url
* @param map 请求参数
* @param filePath 文件路径
* @return 返回结果。结果为""表示失败
*/
private void uploadFile(String url, Map<Object, Object> map, String filePath) {
url = wrapUrl(url, map);
File file = new File(filePath);
RequestBody fileBody = RequestBody.create(OCTET, file);
RequestBody requestBody = new MultipartBody.Builder().setType(MultipartBody.FORM)
.addFormDataPart("image", file.getName(), fileBody).build();
Request request = new Request.Builder().url(url).post(requestBody).build();
execute(request);
}
/**
* 上传多个文件请求
*
* @param url 请求url
* @param map 请求参数
* @param filePaths 文件路径
* @return 返回结果。结果为""表示失败
*/
private void uploadFiles(String url, Map<Object, Object> map, List<String> filePaths) {
url = wrapUrl(url, map);
MultipartBody.Builder builder = new MultipartBody.Builder();
builder.setType(MultipartBody.FORM);
for (String str : filePaths) {
File file = new File(str);
RequestBody fileBody = RequestBody.create(OCTET, file);
builder.addFormDataPart("image", file.getName(), fileBody);
}
RequestBody requestBody = builder.build();
Request request = new Request.Builder().url(url).post(requestBody).build();
execute(request);
}
/**
* 执行文件上传操作
*
* @param request
*/
private void execute(Request request) {
try {
Response response = okHttpClient.newCall(request).execute();
if (response.isSuccessful()) {
callBack(response.body().string());
}
} catch (IOException e) {
e.printStackTrace();
}
}
/**
* 拼接get请求url
*
* @param url 请求url
* @param map 参数
* @return 返回拼接完的url地址
*/
private String wrapUrl(String url, Map<Object, Object> map) {
if (null == map) {
return url;
}
url += "?";
for (Map.Entry entry : map.entrySet()) {
url += entry.getKey() + "=" + entry.getValue() + "&";
}
if (url.endsWith("&")) {
url = url.substring(0, url.length() - 1);
}
return url;
}
/**
* 请求客户端
*/
private static OkHttpClient okHttpClient;
/**
* Json媒体类型
*/
private static final MediaType JSON = MediaType.parse("application/json; charset=utf-8");
/**
* 二进制流的媒体类型
*/
private static final MediaType OCTET = MediaType.parse("application/octet-stream");
}
public class RunThread {
private final String URL;
private HttpCommon httpCommon;
private int num;
private static ThreadPoolExecutor executor = new ThreadPoolExecutor(10, 100, 1000000L, TimeUnit.SECONDS, new LinkedBlockingDeque<>());
private CountDownLatch countDownLatch;
/**
* @param url 服务URL地址，
* @param num 并发访问次数，一般配置50+
*/
public RunThread(String url, int num) {
this.URL = url;
this.num = num;
this.countDownLatch = new CountDownLatch(num);
httpCommon = new HttpCommon() {
@Override
public void callBack(String responseString) {
System.out.println(responseString);
}
};
}
public void testGet(Map<Object, Object> map) {
long startTime = System.currentTimeMillis();
for (int i = 0; i < num; i++) {
executor.execute(new Runnable() {
@Override
public void run() {
httpCommon.get(URL, map);
countDownLatch.countDown();
}
});
}
try {
countDownLatch.await();
long executeTime = System.currentTimeMillis() - startTime;
System.out.println("一共消耗：" + executeTime +"毫秒");
} catch (InterruptedException e) {
e.printStackTrace();
}
}
public void testPost(Map<Object, Object> map, T t) {
long startTime = System.currentTimeMillis();
for (int i = 0; i < num; i++) {
executor.execute(new Runnable() {
@Override
public void run() {
httpCommon.post(URL, map, t);
countDownLatch.countDown();
}
});
}
try {
countDownLatch.wait();
long executeTime = System.currentTimeMillis() - startTime;
System.out.println("一共消耗：" + executeTime +"毫秒");
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
public static void main(String[] args) {
String Url = "http://localhost:8085/test/add";
RunThread testMain = new RunThread(Url, 1000);
// 测试Get请求
testMain.testGet(new HashMap<>());
// // 测试POST请求、PUT请求、DELETE请求
// testMain.testPost(new HashMap<>(), null);
}
上面是并发测试代码，那么如何写高并发测试代码呢！想到两点：一个锁、一个事务。先用Oracle做实验。
insert into testa
(aaaa, bbbb)
values
(#{aaa}, #{aaa})
select max(aaaa) from testa
Service层代码，设置事务的隔离级别为不可重复读
Isolation.REPEATABLE_READ，结果报错“Could not open JDBC Connection for transaction; nested exception is java.sql.SQLException: 仅 READ_COMMITTED 和 SERIALIZABLE 是有效的事务处理级”。卧槽！还能不能一起愉快地玩耍了，Oracle居然只支持可重复读和可系列化两种事务级别，真是让人大跌眼镜。
贴一下高并发代码吧，经过实验，通过1000个并发请求，使用Durid + Lock成功1百个不到（在这里还是得喷一下阿里的技术），使用dbcp2 + Lock成功2百多个，使用dbcp2 + synchronized 竟然成功了940个。
@Autowired
private TestMapper testMapper;
//private Lock lock = new ReentrantLock();
@Transactional(isolation = Isolation.SERIALIZABLE)
public synchronized Integer test(Integer a, Integer b) {
int c = testMapper.select();
c += 1;
testMapper.insert(c);
return c;}
代码有问题，找找错误原因吧。Spring AOP执行事务，会在Service方法执行之前就开始事务，再执行Synchronized同步方法。这样会导致查询数据并没有做同步，修改成如下代码，能完美解决问题。测试得出如下代码的执行效率最高，1000个并发耗时9018毫秒
@Autowired
private TestMapper testMapper;
//private Lock lock = new ReentrantLock();
public synchronized Integer test(Integer a, Integer b) {
int c = testMapper.select();
c += 1;
update(c);
return c;}
@Transactional(isolation = Isolation.SERIALIZABLE)
public void update(int c) {
testMapper.insert(c);}