今天跟項目組做集成的時候發(fā)現(xiàn)一個很奇怪的亂碼問題，web.xml的filter、jsp頁面均進(jìn)行了編碼設(shè)置， 反復(fù)調(diào)試發(fā)現(xiàn)引起bug的原因是web.xml的下面幾行：
    <filter-mapping>
        <filter-name>SecurityFilter</filter-name>
        <url-pattern>*.do</url-pattern>
    </filter-mapping>

    <filter-mapping>
        <filter-name>CharacterEncoding</filter-name>
        <url-pattern>*.do</url-pattern>
    </filter-mapping>

    <filter-mapping>
        <filter-name>CharacterEncoding</filter-name>
        <url-pattern>*.jsp</url-pattern>
    </filter-mapping>

根 據(jù)servlet2.3規(guī)范filter執(zhí)行是按照web.xml配置的filter-mapping先后順序進(jìn)行執(zhí)行，所以上面的配置會導(dǎo)致遇見 *.do的url請求，先進(jìn)行SecurityFilter的過濾器處理，這時候沒有做編碼處理，已經(jīng)是亂碼，到下面的filter處理時已經(jīng)時亂碼，再 做編碼處理已經(jīng)沒有用處。

修正方式，調(diào)整filter-mapping順序，如下：

    <filter-mapping>
        <filter-name>CharacterEncoding</filter-name>
        <url-pattern>*.do</url-pattern>
    </filter-mapping>

    <filter-mapping>
        <filter-name>CharacterEncoding</filter-name>
        <url-pattern>*.jsp</url-pattern>
    </filter-mapping>

    <filter-mapping>
        <filter-name>SecurityFilter</filter-name>
        <url-pattern>*.do</url-pattern>
    </filter-mapping>