CentOS JSP如何优化内存使用

在 CentOS 系统上优化 JSP 应用程序的内存使用，可以从以下几个方面进行：

1. 调整 Java 虚拟机（JVM）参数：

   • 为 JVM 分配合适的内存大小。可以通过设置 -Xms 和 -Xmx 参数来调整初始堆内存和最大堆内存。例如，将初始堆内存设置为 256MB，最大堆内存设置为 1024MB：

     -Xms256m -Xmx1024m
     

   • 调整永久代（PermGen）或元空间（Metaspace）的大小。对于 Java 7 及更早版本，请设置 -XX:PermSize 和 -XX:MaxPermSize 参数。对于 Java 8 及更高版本，请设置 -XX:MetaspaceSize 和 -XX:MaxMetaspaceSize 参数。例如：

     -XX:MetaspaceSize=128m -XX:MaxMetaspaceSize=512m
     

   • 启用垃圾回收日志，以便分析垃圾回收行为。可以添加以下参数：

     -XX:+PrintGCDetails -XX:+PrintGCDateStamps -Xloggc:/path/to/gc.log
     

2. 优化 JSP 编译选项：

   • 减少 JSP 页面的编译频率。可以通过设置 development 和 production 模式来实现。在 development 模式下，JSP 页面会在每次请求时重新编译；而在 production 模式下，JSP 页面只会在第一次请求时编译。可以通过在 web.xml 文件中设置 <jsp-config> 元素的 <jsp-property-group> 子元素来实现：

     <jsp-config>
       <jsp-property-group>
         <url-pattern>*.jsp</url-pattern>
         <el-ignored>true</el-ignored>
         <page-encoding>UTF-8</page-encoding>
         <scripting-invalid>false</scripting-invalid>
         <include-prelude>/WEB-INF/jsp/common/taglib.jspf</include-prelude>
         <include-coda>/WEB-INF/jsp/common/footer.jspf</include-coda>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <page-encoding>UTF-8</page-encoding>
         <scripting-invalid>false</scripting-invalid>
         <el-ignored>true</el-ignored>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>
         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
         <is-xml>false</is-xml>
         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>