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小程序类加载器在小程序的jar中找不到类

classloader applet java

A. Levy · 技术社区 · 16 年前

Exception in thread "thread applet-com.company.program.cm.hmi.MediatorApplet-1" java.lang.NoClassDefFoundError: com/company/program/cm/cs/JDataStore
    at com.company.program.cm.hmi.MediatorApplet.getMediator(MediatorApplet.java:63)
    at com.company.program.cm.hmi.MediatorApplet.init(MediatorApplet.java:49)
    at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.ClassNotFoundException: com.company.program.cm.cs.JDataStore
    at sun.plugin2.applet.Applet2ClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClassInternal(Unknown Source)
    ... 4 more
Caused by: java.io.IOException: open HTTP connection failed:http://localhost:8080/TransportHMI/pages/com/company/program/cm/cs/JDataStore.class
    at sun.plugin2.applet.Applet2ClassLoader.getBytes(Unknown Source)
    at sun.plugin2.applet.Applet2ClassLoader.access$000(Unknown Source)
    at sun.plugin2.applet.Applet2ClassLoader$1.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    ... 8 more

JDataStore jar tvf CM_Library.jar

<applet id="mediator-applet"
        width="0"
        height="0"
        codebase="./"
        archive="CM_Library.jar"
        code="com.company.program.cm.hmi.MediatorApplet">
</applet>

1 回复 | 直到 16 年前

Community CDub 8 年前

a suggestion related question 埃迪的回答并没有解决那个特定的问题,但它确实为我提供了解决方案。

从我的问题中不太明显的是,JDataStore类继承了另一个包含在不同jar中的类。几个月来,我不必处理JDataStore的实现细节,所以我完全忘记了它的父类org.json.simple。JSONObject不在CM_Library.jar中,但在json_simple-1.0.2.jar中。修复相当简单,只需将缺少的jar复制到代码库目录中,并将缺少的jar添加到applet标签中逗号分隔的存档列表中即可 archive

<applet id="mediator-applet"
        width="0"
        height="0"
        codebase="./"
        archive="CM_Library.jar, json_simple-1.0.2.jar"
        code="com.company.program.cm.hmi.MediatorApplet">
</applet>