在启动tomct的时候，或者是使用SpringBoot启动应用的时候，会出现internal error: SHA-1 not available.。这个错误：
org.springframework.context.ApplicationContextException: Unable to start embedded container; nested exception is java.lang.InternalError: internal error: SHA-1 not available.
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.onRefresh(EmbeddedWebApplicationContext.java:137) ~[spring-boot-1.5.6.RELEASE.jar!/:1.5.6.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:537) ~[spring-context-4.3.10.RELEASE.jar!/:4.3.10.RELEASE]
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122) ~[spring-boot-1.5.6.RELEASE.jar!/:1.5.6.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:693) ~[spring-boot-1.5.6.RELEASE.jar!/:1.5.6.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:360) ~[spring-boot-1.5.6.RELEASE.jar!/:1.5.6.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:303) ~[spring-boot-1.5.6.RELEASE.jar!/:1.5.6.RELEASE]
at org.poem.Main.main(Main.java:20) [classes!/:1.0-SNAPSHOT]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_144]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_144]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_144]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_144]
at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:48) [spring.war:1.0-SNAPSHOT]
at org.springframework.boot.loader.Launcher.launch(Launcher.java:87) [spring.war:1.0-SNAPSHOT]
at org.springframework.boot.loader.Launcher.launch(Launcher.java:50) [spring.war:1.0-SNAPSHOT]
at org.springframework.boot.loader.WarLauncher.main(WarLauncher.java:59) [spring.war:1.0-SNAPSHOT]
Caused by: java.lang.InternalError: internal error: SHA-1 not available.
at sun.security.provider.SecureRandom.init(SecureRandom.java:108) ~[na:1.8.0_144]
at sun.security.provider.SecureRandom.<init>(SecureRandom.java:79) ~[na:1.8.0_144]
at java.security.SecureRandom.getDefaultPRNG(SecureRandom.java:198) ~[na:1.8.0_144]
at java.security.SecureRandom.<init>(SecureRandom.java:162) ~[na:1.8.0_144]
at java.io.File$TempDirectory.<clinit>(File.java:1901) ~[na:1.8.0_144]
at java.io.File.createTempFile(File.java:2006) ~[na:1.8.0_144]
at java.io.File.createTempFile(File.java:2070) ~[na:1.8.0_144]
at org.springframework.boot.context.embedded.AbstractEmbeddedServletContainerFactory.createTempDir(AbstractEmbeddedServletContainerFactory.java:245) ~[spring-boot-1.5.6.RELEASE.jar!/:1.5.6.RELEASE]
at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory.getEmbeddedServletContainer(TomcatEmbeddedServletContainerFactory.java:167) ~[spring-boot-1.5.6.RELEASE.jar!/:1.5.6.RELEASE]
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.createEmbeddedServletContainer(EmbeddedWebApplicationContext.java:164) ~[spring-boot-1.5.6.RELEASE.jar!/:1.5.6.RELEASE]
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.onRefresh(EmbeddedWebApplicationContext.java:134) ~[spring-boot-1.5.6.RELEASE.jar!/:1.5.6.RELEASE]
... 14 common frames omitted
Caused by: java.security.NoSuchAlgorithmException: SHA MessageDigest not available
at sun.security.jca.GetInstance.getInstance(GetInstance.java:159) ~[na:1.8.0_144]
at java.security.Security.getImpl(Security.java:695) ~[na:1.8.0_144]
at java.security.MessageDigest.getInstance(MessageDigest.java:167) ~[na:1.8.0_144]
at sun.security.provider.SecureRandom.init(SecureRandom.java:106) ~[na:1.8.0_144]
... 24 common frames omitted
这个错误是查询不到SHA算法，这个算法是在jre下面，查询不到就错误了。
我的是在Linux操作系统之下，查询服务，找到你的jdk目录，进入/jre/lib目录，查看是不是有一个jees.jar的jar包，如果没有，恭喜你，报错是正常的，就是这么任性,，因为使用到的SHA算法，就是在这个jar包里面，找不到就会出错咯。
使用 unpack200 jsse.pack jsse.jar 生成这个jar包就可以了，重启启动，完美解决。