Spring Boot 内嵌容器Undertow参数设置
配置项：
# 设置IO线程数, 它主要执行非阻塞的任务,它们会负责多个连接, 默认设置每个CPU核心一个线程
# 不要设置过大，如果过大，启动项目会报错：打开文件数过多
server.undertow.io-threads=16# 阻塞任务线程池, 当执行类似servlet请求阻塞IO操作, undertow会从这个线程池中取得线程
# 它的值设置取决于系统线程执行任务的阻塞系数，默认值是IO线程数*8server.undertow.worker-threads=256# 以下的配置会影响buffer,这些buffer会用于服务器连接的IO操作,有点类似netty的池化内存管理
# 每块buffer的空间大小,越小的空间被利用越充分，不要设置太大，以免影响其他应用，合适即可
server.undertow.buffer-size=1024# 每个区分配的buffer数量 , 所以pool的大小是buffer-size * buffers-per-region
server.undertow.buffers-per-region=1024# 是否分配的直接内存(NIO直接分配的堆外内存)
server.undertow.direct-buffers=true来看看源代码：
ioThreads = Math.max(Runtime.getRuntime().availableProcessors(), 2);
workerThreads= ioThreads * 8;//smaller than 64mb of ram we use 512b buffers
if (maxMemory < 64 * 1024 * 1024) {//use 512b buffers
directBuffers = false;
bufferSize= 512;
}else if (maxMemory < 128 * 1024 * 1024) {//use 1k buffers
directBuffers = true;
bufferSize= 1024;
}else{//use 16k buffers for best performance//as 16k is generally the max amount of data that can be sent in a single write() call
directBuffers = true;
bufferSize= 1024 * 16 - 20; //the 20 is to allow some space for protocol headers, see UNDERTOW-1209
}很显然，Undertow认为它的运用场景是在IO密集型的系统应用中，并且认为多核机器是一个比较容易满足的点，Undertow初始化假想应用的阻塞系数在0.8~0.9之间，所以阻塞线程数直接乘了个8，当然，如果对应用较精确的估测阻塞系数，可以配置上去。
Spring Boot内嵌容器支持Tomcat、Jetty、Undertow。为什么选择Undertow？
1. Setup Spring Boot Application
We will use Maven to setup a new project in Eclipse with the appropriate dependencies. We will use the starter parent for this example but the dependencies in a production application will likely be altered to streamline, optimize or customize.
1.1 Setup Spring Boot Dependencies
The default embedded servlet is Tomcat. This version of Spring Web 1.4.3 brings in Tomcat version 8.5.6.
pom.xml
org.springframework.boot
spring-boot-starter-parent
1.4.3.RELEASE
org.springframework.boot
spring-boot-starter-web
1.2 Setup Spring Boot Main Application and Controllers
To setup the Spring Boot application you include the @SpringBootApplication annotation in your Main class. The @SpringBootApplication annotation brings in @SpringBootConfiguration, @EnableAutoConfiguration and @ComponentScanannotations.
Application.java
@SpringBootApplication
@ConfigurationPropertiespublic classApplication {public static voidmain(String[] args) {
SpringApplication.run(Application.class, args);
}
You may choose to eliminate this annotation and add the @SpringBootConfiguration alone or to another class that allows you to customize the configuration. The @ComponentScan will scan your application for items like the @Controller you will need to setup a RESTful service. The following controller will return a simple “Hello World” string from a HTTP GET request. We have also included in the bundled example another endpoint mapping that returns a complex object type.
SampleController.java
@Controllerpublic classSampleController {
@AutowiredprivateResourceLoader resourceLoader;
@RequestMapping("/")
@ResponseBodypublicString home() {return "Hello World!";
}
1.3 Key Configuration Parameters
The default properties for all the embedded servlets are the same. Some of the most important properties to consider are the properties for configuring startup information like ports and application name, TSL, access logs, compression and many more.
For example, to configure SSL add the following to key value pairs to the application.properties.
application.properties
server.port=8443server.ssl.key-store=classpath:keystore.jks
server.ssl.key-store-password=secret
server.ssl.key-password=another-secret
1.4 How to Find Additional Parameters
To explore the parameters for Spring boot applications you can add the Spring actuator dependency and the @ConfigurationProperties annotation to your Main class. You then visit the /configprops endpoint on your application to get a list of the available properties.
Application.java
@SpringBootApplication
@ConfigurationPropertiespublic class Application {
pom.xml
org.springframework.boot
spring-boot-starter-actuator
1.5 Change version of Embedded Servlet Containers
The embedded servlet versions are defined in the following parent dependency from the pom. You can change the version of the embedded servlet by explicitly including the dependency and identifying a new version in the pom. We will show you how in the examples below.
pom.xml
org.springframework.boot
spring-boot-dependencies
1.3.7.RELEASE
2. Tomcat
As Tomcat is the default embedded servlet there is nothing you need to do to the default implementation to use Tomcat. You can change the version of Tomcat you are using or change properties in the pom.xml or application.properties files.
2.2 Change Version of Tomcat
pom.xml
8.5.6
org.apache.tomcat.embed
tomcat-embed-core
${tomcat.version}
org.apache.tomcat.embed
tomcat-embed-el
${tomcat.version}
org.apache.tomcat.embed
tomcat-embed-websocket
${tomcat.version}
3. Jetty
To change the embedded servlet to Jetty you need to edit the pom file to remove the Tomcat dependency and add Jetty.
3.1 Change to Jetty (version 9.3.14)
pom.xml
org.springframework.boot
spring-boot-starter-web
org.springframework.boot
spring-boot-starter-tomcat
org.springframework.boot
spring-boot-starter-jetty
4. Undertow
To change the embedded servlet to Undertow you need to edit the pom file to remove the Tomcat dependency and add Undertow.
4.1 Change to Undertow (version 1.3.24 final)
Notice the undertow version included in the spring boot starter is incorrect, referring to 1.3.25. You’ll need to change it to 1.3.24.Final for this to work at the time of this article.
pom.xml
org.springframework.boot
spring-boot-starter-web
org.springframework.boot
spring-boot-starter-tomcat
org.springframework.boot
spring-boot-starter-undertow
io.undertow
undertow-core
1.3.24.Final
io.undertow
undertow-servlet
1.3.24.Final
5. Performance and Load
In this example, we will analyze both the peformance of HTTP requests and the memory footprint at startup of all three embedded servlets. We used JMeter to measure performance by simulating load and JVisualVM to look at the memory footprint.
5.1 Measure Performance
In this example, we will analyze both the peformance of simple RESTFul GET requests that return a string and more complex GET requests that return complex JSON objects. JMeter is the tool used to measure the performance of the the three different types ofs. The key to setting up this test was establishing thread groups with the appropriate load, a counter to dynamically update the input to the API and report viewers to display or aggregate the results. For the simple string examples, we used a thread group with 1000 threads that would loop 3 times through the sequence. It also used a ramp up time of 10 seconds. For the complex object examples, we used the same parameters but did not loop.
JMeter Tomcat Thread Group
JMeter Tomcat Summary Report
5.1.1 Tomcat
5.1.1.1 Simple String
Label# SamplesAverageMinMaxStd. Dev.Error %ThroughputReceived KB/secSent KB/secAvg. Bytes
Startup
3000
7
1
549
35.78374361
0
293.8583603
55.95935572
55.67238466
195
Others
3000
1
0
45
1.359661682
0
287.8802418
54.82094449
54.53981144
195
Others
3000
1
0
24
1.155032275
0
292.1129503
55.62697785
55.3417113
195
5.1.1.2 Complex Object with Dynamic Data
Label# SamplesAverageMinMaxStd. Dev.Error %ThroughputReceived KB/secSent KB/secAvg. Bytes
Startup
1000
114
3
1601
322.8671905
0
97.68486861
202.3335999
19.93763432
2121
Others
1000
3
2
17
1.328216473
0
97.88566954
202.7495167
19.9786181
2121
Others
1000
2
1
16
1.110529603
0
98.52216749
204.0678879
20.10852833
2121
Others
1000
2
1
21
1.344498419
0
98.53187506
204.0879951
20.11050966
2121
5.1.2 Jetty
5.1.2.1 Simple Object
Label# SamplesAverageMinMaxStd. Dev.Error %ThroughputReceived KB/secSent KB/secAvg. Bytes
Startup
3000
7
0
561
40.13705065
0
291.5168594
56.0828333
55.22878
197
Others
3000
1
0
21
1.058925031
0
293.5995302
56.48350338
55.6233485
197
Others
3000
1
0
21
0.926034317
0
294.3485086
56.62759395
55.7652448
197
5.1.2.2 Complex Object with Dynamic Data
Label# SamplesAverageMinMaxStd. Dev.Error %ThroughputReceived KB/secSent KB/secAvg. Bytes
Startup
1000
110
3
1397
278.7961107
0
98.13542689
203.3626717
19.93375859
2122
Others
1000
3
2
20
1.500210319
0
98.48335631
204.0836739
20.00443175
2122
Others
1000
3
2
45
2.729377218
0
98.29942003
203.7025091
19.96706969
2122
5.1.3 Undertow
5.1.3.1 Simple Object
Label# SamplesAverageMinMaxStd. Dev.Error %ThroughputReceived KB/secSent KB/secAvg. Bytes
Startup
3000
6
0
451
31.6188702
0
295.6830278
63.81440346
56.01807363
221
Others
3000
1
0
22
1.255447862
0
292.7400468
63.17924839
55.46051669
221
Others
3000
1
0
18
1.559477975
0
294.3773918
63.53262069
55.77071681
221
5.1.3.2 Complex Object with Dynamic Data
Label# SamplesAverageMinMaxStd. Dev.Error %ThroughputReceived KB/secSent KB/secAvg. Bytes
Startup
1000
70
3
1114
197.1333241
0
97.059109
203.3969361
19.62044201
2145.893
Startup
1000
42
3
852
132.6443576
0
98.02960494
205.6324135
20.00799554
2148
Others
1000
3
2
19
1.293570253
0
98.55129595
206.6305004
20.01823199
2147
Others
1000
2
2
27
1.659250132
0
98.74592673
207.0385788
20.05776637
2147
Others
1000
2
1
17
1.260904041
0
98.28975821
206.0821395
19.96510714
2147
5.2 Measure Memory
To measure the memory of each embedded servlet we looked at the memory usage on startup. JVisualVM is a tool provided with the Java Development Kit for visualizing the memory and footprint of java applications. We used this tool to show the initial startup impact of each of the three embedded servlets. The heap size and thread counts are key in analyzing this initial footprint. The ten threads that are common to all threes include: JMX server connection timeout, RMI Scheduler, RMI TCP Connection (2), RMI TCP Accept, Attach Listener, DestroyJavaVM, Signal Dispatcher, Finalizer and Reference Handler.
JVisualVM Report
5.2.2 Tomcat
Heap Size: 697,827,328 B
Used: 124,260,976 B
Max: 2,147,483,648 B
Threads: 17 Live, 22 Started
5.2.3 Jetty
Heap Size: 628,621,312 B
Used: 311,476,776 B
Max: 2,147,483,648 B
Threads: 19 Live, 22 Started
5.2.4 Undertow
Heap Size: 630,718,464 B
Used: 114,599,536 B
Max: 2,147,483,648 B
Threads: 17 Live, 20 Started6. 对比
6.1 性能
压测结果：从上面的6张压力测试报告中，可以看到3个容器在相同的用例及并发请求下，Undertow稍微比Tomcat和Jetty好一点。
资源消耗：JETY启动时内存占用最大，使用311 MB。Tomcat和Undertow的初始脚印相似，在120 MB左右，Undertow出现在114 MB的最低水平。响应头中的关键差异在于默认情况下默认情况下包括HTTP持久连接。该头将在支持持久连接的客户端中使用，以通过重用连接细节来优化性能。
6.1.1 Tomcat Response Headers
Content-Type →application/json;charset=UTF-8
Date →Mon, 09 Jan 2017 02:23:26 GMT
Transfer-Encoding →chunked
X-Application-Context →JcgSpringBootContainers:# Application index.
6.1.2 Jetty Response Headers
Content-Type →application/json;charset=UTF-8
Date →Mon, 09 Jan 2017 02:29:21 GMT
Transfer-Encoding →chunked
X-Application-Context →JcgSpringBootContainers:# Application index.
6.1.3 Undertow Response Headers
Connection →keep-alive
Content-Type →application/json;charset=UTF-8
Date →Mon, 09 Jan 2017 02:20:25 GMT
Transfer-Encoding →chunked
X-Application-Context →JcgSpringBootContainers:# Application index.7. 结论
这些数字表明Undertow在性能和内存使用方面是最好的。令人鼓舞的是，Undertow 正在接受最新的能力，并默认为持久的连接。这些数字并不表示在这个例子中使用的负载有显著的性能差异，但我想它们会缩放，如果性能是最重要的因素，则Undertow 是应用程序的正确匹配。认为一个组织可能因为熟悉它的能力而喜欢嵌入的servlet容器也是合理的。很多时候默认设置将不得不改变，因为应用程序要求包括性能、内存使用和功能。
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在Spring Boot中使用 Undertow 而不是 Tomcat
1、Maven示例：
org.springframework.boot
spring-boot-starter-web
org.springframework.boot
spring-boot-starter-tomcat
org.springframework.boot
spring-boot-starter-undertow
2、配置Undertow，application.yml示例：
server.undertow.accesslog.dir= # Undertow access log directory.
server.undertow.accesslog.enabled=false # Enable access log.
server.undertow.accesslog.pattern=common # Format pattern for access logs.
server.undertow.accesslog.prefix=access_log. # Log file name prefix.
server.undertow.accesslog.rotate=true # Enable access log rotation.
server.undertow.accesslog.suffix=log # Log file name suffix.
server.undertow.buffer-size= # Size of each buffer in bytes.
server.undertow.buffers-per-region= # Number of buffer per region.
server.undertow.direct-buffers= # Allocate buffers outside the Java heap.
server.undertow.io-threads= # Number of I/O threads to create for the worker.
server.undertow.max-http-post-size=0 # Maximum size in bytes of the HTTP post content.
server.undertow.worker-threads= # Number of worker threads.
3、使用 Undertow 监听多个端口示例：
@BeanpublicUndertowEmbeddedServletContainerFactory embeddedServletContainerFactory() {
UndertowEmbeddedServletContainerFactory factory= newUndertowEmbeddedServletContainerFactory();
factory.addBuilderCustomizers(newUndertowBuilderCustomizer() {
@Overridepublic voidcustomize(Builder builder) {
builder.addHttpListener(8080, "0.0.0.0");
}
});returnfactory;
}