Spring Boot内嵌Web容器主要有三种：
- tomcat（默认）
- jetty
- undertow
1. tomcat容器
在spring boot中，有关内嵌tomcat的默认属性配置如下，前缀为 server.tomcat （参考官方文档）：
server.tomcat.accept-count=100 # Maximum queue length for incoming connection requests when all possible request processing threads are in use.
server.tomcat.accesslog.buffered=true # Whether to buffer output such that it is flushed only periodically.
server.tomcat.accesslog.directory=logs # Directory in which log files are created. Can be absolute or relative to the Tomcat base dir.
server.tomcat.accesslog.enabled=false # Enable access log.
server.tomcat.accesslog.file-date-format=.yyyy-MM-dd # Date format to place in the log file name.
server.tomcat.accesslog.pattern=common # Format pattern for access logs.
server.tomcat.accesslog.prefix=access_log # Log file name prefix.
server.tomcat.accesslog.rename-on-rotate=false # Whether to defer inclusion of the date stamp in the file name until rotate time.
server.tomcat.accesslog.request-attributes-enabled=false # Set request attributes for the IP address, Hostname, protocol, and port used for the request.
server.tomcat.accesslog.rotate=true # Whether to enable access log rotation.
server.tomcat.accesslog.suffix=.log # Log file name suffix.
server.tomcat.additional-tld-skip-patterns= # Comma-separated list of additional patterns that match jars to ignore for TLD scanning.
server.tomcat.background-processor-delay=10s # Delay between the invocation of backgroundProcess methods. If a duration suffix is not specified, seconds will be used.
server.tomcat.basedir= # Tomcat base directory. If not specified, a temporary directory is used.
server.tomcat.internal-proxies=10\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}|\\
192\\.168\\.\\d{1,3}\\.\\d{1,3}|\\
169\\.254\\.\\d{1,3}\\.\\d{1,3}|\\
127\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}|\\
172\\.1[6-9]{1}\\.\\d{1,3}\\.\\d{1,3}|\\
172\\.2[0-9]{1}\\.\\d{1,3}\\.\\d{1,3}|\\
172\\.3[0-1]{1}\\.\\d{1,3}\\.\\d{1,3}\\
0:0:0:0:0:0:0:1\\
::1 # Regular expression that matches proxies that are to be trusted.
server.tomcat.max-connections=10000 # Maximum number of connections that the server accepts and processes at any given time.
server.tomcat.max-http-post-size=2MB # Maximum size of the HTTP post content.
server.tomcat.max-swallow-size=2MB # Maximum amount of request body to swallow.
server.tomcat.max-threads=200 # Maximum amount of worker threads.
server.tomcat.min-spare-threads=10 # Minimum amount of worker threads.
server.tomcat.port-header=X-Forwarded-Port # Name of the HTTP header used to override the original port value.
server.tomcat.protocol-header= # Header that holds the incoming protocol, usually named "X-Forwarded-Proto".
server.tomcat.protocol-header-https-value=https # Value of the protocol header indicating whether the incoming request uses SSL.
server.tomcat.redirect-context-root=true # Whether requests to the context root should be redirected by appending a / to the path.
server.tomcat.remote-ip-header= # Name of the HTTP header from which the remote IP is extracted. For instance, `X-FORWARDED-FOR`.
server.tomcat.resource.allow-caching=true # Whether static resource caching is permitted for this web application.
server.tomcat.resource.cache-ttl= # Time-to-live of the static resource cache.
server.tomcat.uri-encoding=UTF-8 # Character encoding to use to decode the URI.另外还可以通过源码来查看tomcat的相关配置属性，位于org.springframework.boot.autoconfigure包下org.springframework.boot.autoconfigure.web.ServerProperties 中，部分源码如下：
/**
* Tomcat properties.
*/
public static class Tomcat {
/**
* Access log configuration.
*/
private final Accesslog accesslog = new Accesslog();
/**
* Regular expression that matches proxies that are to be trusted.
*/
private String internalProxies = "10\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}|" // 10/8
+ "192\\.168\\.\\d{1,3}\\.\\d{1,3}|" // 192.168/16
+ "169\\.254\\.\\d{1,3}\\.\\d{1,3}|" // 169.254/16
+ "127\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}|" // 127/8
+ "172\\.1[6-9]{1}\\.\\d{1,3}\\.\\d{1,3}|" // 172.16/12
+ "172\\.2[0-9]{1}\\.\\d{1,3}\\.\\d{1,3}|"
+ "172\\.3[0-1]{1}\\.\\d{1,3}\\.\\d{1,3}|" //
+ "0:0:0:0:0:0:0:1|::1";
.......(省略)
/**
* Maximum amount of worker threads.
*/
private int maxThreads = 200;
/**
* Minimum amount of worker threads.
*/
private int minSpareThreads = 10;
.......(省略)
/**
* Maximum number of connections that the server accepts and processes at any
* given time. Once the limit has been reached, the operating system may still
* accept connections based on the "acceptCount" property.
*/
private int maxConnections = 10000;
/**
* Maximum queue length for incoming connection requests when all possible request
* processing threads are in use.
*/
private int acceptCount = 100;
.......(省略)
}
在默认情况下，经常会关注的几个属性值：
-
server.tomcat.max-threads=200：最大工作线程数是200 -
server.tomcat.min-spare-threads=10：最小工作线程数是10 -
server.tomcat.max-connections = 10000：最大连接数为10000
如果需要覆盖默认的配置，可以在application.properties或者application.yml中指定相关属性值
server:
tomcat:
uri-encoding: UTF-8
max-threads: 20
min-spare-threads: 5
max-connections: 10002. jetty容器
有关jetty的默认属性配置如下：
server.jetty.acceptors=-1 # Number of acceptor threads to use. When the value is -1, the default, the number of acceptors is derived from the operating environment.
server.jetty.accesslog.append=false # Append to log.
server.jetty.accesslog.date-format=dd/MMM/yyyy:HH:mm:ss Z # Timestamp format of the request log.
server.jetty.accesslog.enabled=false # Enable access log.
server.jetty.accesslog.extended-format=false # Enable extended NCSA format.
server.jetty.accesslog.file-date-format= # Date format to place in log file name.
server.jetty.accesslog.filename= # Log filename. If not specified, logs redirect to "System.err".
server.jetty.accesslog.locale= # Locale of the request log.
server.jetty.accesslog.log-cookies=false # Enable logging of the request cookies.
server.jetty.accesslog.log-latency=false # Enable logging of request processing time.
server.jetty.accesslog.log-server=false # Enable logging of the request hostname.
server.jetty.accesslog.retention-period=31 # Number of days before rotated log files are deleted.
server.jetty.accesslog.time-zone=GMT # Timezone of the request log.
server.jetty.max-http-post-size=200000B # Maximum size of the HTTP post or put content.
server.jetty.selectors=-1 # Number of selector threads to use. When the value is -1, the default, the number of selectors is derived from the operating environment.默认情况下，spring-boot-starter-web 使用的容器为 tomcat，如果想要替换成jetty，只需要在pom文件中移除tomcat依赖，然后引入jetty依赖即可
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<!-- 移除默认的tomcat -->
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
</exclusion>
</exclusions>
</dependency>
<!-- 添加jetty依赖 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jetty</artifactId>
</dependency>3. undertow容器
有关内嵌的undertow的默认属性配置如下：
server.undertow.accesslog.dir= # Undertow access log directory.
server.undertow.accesslog.enabled=false # Whether to enable the 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 # Whether to enable access log rotation.
server.undertow.accesslog.suffix=log # Log file name suffix.
server.undertow.buffer-size= # Size of each buffer.
server.undertow.direct-buffers= # Whether to allocate buffers outside the Java heap. The default is derived from the maximum amount of memory that is available to the JVM.
server.undertow.eager-filter-init=true # Whether servlet filters should be initialized on startup.
server.undertow.io-threads= # Number of I/O threads to create for the worker. The default is derived from the number of available processors.
server.undertow.max-http-post-size=-1B # Maximum size of the HTTP post content. When the value is -1, the default, the size is unlimited.
server.undertow.worker-threads= # Number of worker threads. The default is 8 times the number of I/O threads.主要关注的两个属性：
-
server.undertow.io-threads：默认情况下IO线程数等于CPU处理器个数 -
server.undertow.worker-threads：默认情况下Worker线程数等于IO线城数的8倍
同上，如果想要使用undertow容器，只需要在pom文件中移除tomcat依赖，然后引入undertow依赖即可
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<!-- 移除默认的tomcat -->
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
</exclusion>
</exclusions>
</dependency>
<!-- 添加undertow依赖 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-undertow</artifactId>
</dependency>参考资料：
