为什么/ classes 中的reverse()方法使用按位运算符？StringBufferStringBuilder
我想知道它的优点.
public AbstractStringBuilder reverse() {
boolean hasSurrogate = false;
int n = count - 1;
for (int j = (n-1) >> 1; j >= 0; --j) {
char temp = value[j];
char temp2 = value[n - j];
if (!hasSurrogate) {
hasSurrogate = (temp >= Character.MIN_SURROGATE && temp <= Character.MAX_SURROGATE)
|| (temp2 >= Character.MIN_SURROGATE && temp2 <= Character.MAX_SURROGATE);
}
value[j] = temp2;
value[n - j] = temp;
}
if (hasSurrogate) {
// Reverse back …我创建了一个运行良好的 Web Spring 应用程序。但是，当我重新启动应用程序时，出现以下错误（但应用程序仍然工作正常）：
SEVERE: Exception sending context initialized event to listener instance of class org.springframework.web.context.ContextLoaderListener
java.lang.NoClassDefFoundError: org/springframework/core/OrderComparator$OrderSourceProvider
at org.springframework.context.support.AbstractRefreshableApplicationContext.createBeanFactory(AbstractRefreshableApplicationContext.java:200)
at org.springframework.context.support.AbstractRefreshableApplicationContext.refreshBeanFactory(AbstractRefreshableApplicationContext.java:126)
at org.springframework.context.support.AbstractApplicationContext.obtainFreshBeanFactory(AbstractApplicationContext.java:540)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:454)
at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:403)
at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:306)
at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:106)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4812)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5255)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1408)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1398)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.ClassNotFoundException: org.springframework.core.OrderComparator$OrderSourceProvider
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1308)
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1142)
... 16 more
Apr 08, 2016 3:16:02 PM org.apache.catalina.core.StandardContext startInternal
SEVERE: One or more listeners failed to start. Full details will be …