CentOS JSP如何優化內存使用

在 CentOS 系統上優化 JSP 應用程序的內存使用，可以從以下幾個方面進行：

1. 調整 Java 虛擬機（JVM）參數：

   • 為 JVM 分配合適的內存大小?？梢酝ㄟ^設置 -Xms 和 -Xmx 參數來調整初始堆內存和最大堆內存。例如，將初始堆內存設置為 256MB，最大堆內存設置為 1024MB：

     -Xms256m -Xmx1024m
     

   • 調整永久代（PermGen）或元空間（Metaspace）的大小。對于 Java 7 及更早版本，請設置 -XX:PermSize 和 -XX:MaxPermSize 參數。對于 Java 8 及更高版本，請設置 -XX:MetaspaceSize 和 -XX:MaxMetaspaceSize 參數。例如：

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

   • 啟用垃圾回收日志，以便分析垃圾回收行為?？梢蕴砑右韵聟担?pre class="hljs">-XX:+PrintGCDetails -XX:+PrintGCDateStamps -Xloggc:/path/to/gc.log

2. 優化 JSP 編譯選項：

   • 減少 JSP 頁面的編譯頻率?？梢酝ㄟ^設置 development 和 production 模式來實現。在 development 模式下，JSP 頁面會在每次請求時重新編譯；而在 production 模式下，JSP 頁面只會在第一次請求時編譯?？梢酝ㄟ^在 web.xml 文件中設置 <jsp-config> 元素的 <jsp-property-group> 子元素來實現：

     <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>
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         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
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         <default-content-type>text/html</default-content-type>
         <buffer>8kb</buffer>
         <auto-flush>true</auto-flush>
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         <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>
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         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
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         <default-content-type>text/html</default-content-type>
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         <default-content-type>text/html</default-content-type>
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         <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>
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         <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>
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         <deferred-syntax-allowed-as-literal>true</deferred-syntax-allowed-as-literal>
         <trim-directive-whitespaces>true</trim-directive-whitespaces>