Android使用KSOAP2调用WebService及正确导入jar包的问题_JAVA_编程开发_程序员俱乐部

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[size=13px;]<span style="font-family: courier new, courier;">[size=16px;]错误信息[/size]<br>[/size]</span>

[size=13px;]<span style="font-family: courier new, courier;">??? 最近在学Android使用KSOAP2调用现有的Webservice的方法，期间在网上找了很多代码，但是每次在Android模拟器中运行的时候程序都会崩溃，搞得自己都快崩溃了。。。。[/size]</span>

[size=13px;]<span style="font-family: courier new, courier;">??? 查看了一下LogCat中的错误报告，发现是因为java.lang.NoClassDefFoundError导致程序崩溃的：[/size]<br></span>

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<ol class="dp-j">
<li class="alt"><span><span>ERROR/AndroidRuntime(</span><span class="number">600</span><span>):?java.lang.NoClassDefFoundError:?org.ksoap2.serialization.SoapObject????</span></span></li>
<li>
<span>????at?webservice.weather.WeatherActivity.getWeather(WeatherActivity.java:</span><span class="number">104</span><span>)????</span>
</li>
<li class="alt">
<span>????at?webservice.weather.WeatherActivity.showWeather(WeatherActivity.java:</span><span class="number">84</span><span>)????</span>
</li>
<li>
<span>????at?webservice.weather.WeatherActivity.access$</span><span class="number">0</span><span>(WeatherActivity.java:</span><span class="number">80</span><span>)????</span>
</li>
<li class="alt">
<span>????at?webservice.weather.WeatherActivity$</span><span class="number">1</span><span>.onClick(WeatherActivity.java:</span><span class="number">75</span><span>)????</span>
</li>
<li>
<span>????at?android.view.View.performClick(View.java:</span><span class="number">2408</span><span>)????</span>
</li>
<li class="alt">
<span>????at?android.view.View$PerformClick.run(View.java:</span><span class="number">8816</span><span>)????</span>
</li>
<li>
<span>????at?android.os.Handler.handleCallback(Handler.java:</span><span class="number">587</span><span>)????</span>
</li>
<li class="alt">
<span>????at?android.os.Handler.dispatchMessage(Handler.java:</span><span class="number">92</span><span>)????</span>
</li>
<li>
<span>????at?android.os.Looper.loop(Looper.java:</span><span class="number">123</span><span>)????</span>
</li>
<li class="alt">
<span>????at?android.app.ActivityThread.main(ActivityThread.java:</span><span class="number">4627</span><span>)????</span>
</li>

<span>????at?java.lang.reflect.Method.invokeNative(Native?Method)????</span>

<li class="alt">
<span>????at?java.lang.reflect.Method.invoke(Method.java:</span><span class="number">521</span><span>)????</span>
</li>
<li>
<span>????at?com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:</span><span class="number">868</span><span>)????</span>
</li>
<li class="alt">
<span>????at?com.android.internal.os.ZygoteInit.main(ZygoteInit.java:</span><span class="number">626</span><span>)????</span>
</li>

<span>????at?dalvik.system.NativeStart.main(Native?Method)??</span>

</ol>

<textarea class="java" style="display: none;" cols="20" rows="2" name="code" readonly>ERROR/AndroidRuntime(600): java.lang.NoClassDefFoundError: org.ksoap2.serialization.SoapObject 
    at webservice.weather.WeatherActivity.getWeather(WeatherActivity.java:104) 
    at webservice.weather.WeatherActivity.showWeather(WeatherActivity.java:84) 
    at webservice.weather.WeatherActivity.access$0(WeatherActivity.java:80) 
    at webservice.weather.WeatherActivity$1.onClick(WeatherActivity.java:75) 
    at android.view.View.performClick(View.java:2408) 
    at android.view.View$PerformClick.run(View.java:8816) 
    at android.os.Handler.handleCallback(Handler.java:587) 
    at android.os.Handler.dispatchMessage(Handler.java:92) 
    at android.os.Looper.loop(Looper.java:123) 
    at android.app.ActivityThread.main(ActivityThread.java:4627) 
    at java.lang.reflect.Method.invokeNative(Native Method) 
    at java.lang.reflect.Method.invoke(Method.java:521) 
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 
    at dalvik.system.NativeStart.main(Native Method)</textarea>

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[size=16px;]解决方法[/size]<br>[size=13px;]</span>

[size=13px;]<span style="font-family: courier new, courier;">找了很多资料，最后才发现是jar包的导入有问题。。。。以前开发java程序时导入jar包都是用一下的方法：[/size][/size]

[size=13px;]<span style="font-family: courier new, courier;">??? 工程点击右键->Build Path->Add Libraries->User Library->选择包含需要的jar包的Library(如果没有的话就点击User Libraries新建一个Library，然后再选中)[/size]</span>

[size=13px;]<span style="font-family: courier new, courier;">但是，在Android中这样导入jar包会导致程序在模拟器中运行时抛出[/size]java.lang.NoClassDefFoundError异常，在Android中导入jar包的步骤如下：</span>

[size=13px;]????? <span style="color: #ff0000;">工程点击右键->[/size]</span>[size=13px;]<span style="font-family: courier new, courier;"><span style="color: #ff0000;">Build Path->Add External Archives->选择要导入的jar包[/size]</span></span>

[size=13px;]<span style="font-family: courier new, courier;"><span style="color: black;"><span style="color: black;">另外还有一个问题就是：Android模拟器访问Tomcat上部署的webservice程序时，不能用localhost或者本机IP，Android默认访问本机地址为10.0.2.2。[/size]</span></span></span>

[size=13px;]<span style="font-family: courier new, courier;"><span style="color: #ff0000;"><span style="color: #000000; font-size: 16px;">原因猜想[/size]</span></span></span>

[size=13px;]<span style="font-family: courier new, courier;"><span style="color: #ff0000;"><span style="color: #000000;">??? 对于产生上述NoClassDefFoundError的原因，查看一下工程中的classpath文件就可以找到。如果是利用第一种方法导入的jar包的话，classpath文件中会生成这样一条语句：<span style="color: #ff0000;"><classpathentry kind="con" path="org.eclipse.jdt.USER_LIBRARY/KSOAP2"/>[/size]，这种导入jar包的方法依赖于开发环境eclipse；而如果用第二种方法导入jar包的话，会在classpath中产生如下的语句：</span></span></span></span>

[size=13px;]<span style="font-family: courier new, courier;"><span style="color: #ff0000;"><span style="color: #000000;"><span style="color: #ff0000;"><classpathentry kind="lib" path="D:/JAVATOOLS/ksoap2-android-assembly-2.5.2-jar-with-dependencies.jar"/>，<span style="color: #000000;">这种导入方式是用的绝对路径，与eclipse开发环境无关，而且以这种方式导入后，jar包的信息会被加到工程class.dex中，进而会被打包到apk中。[/size]</span></span></span></span></span>

[size=13px;]<span style="font-family: courier new, courier;"><span style="color: #ff0000;"><span style="color: #000000;">??? 我猜想，在运行虚拟机的时候，虚拟机是脱离了eclipse开发环境的，所以第一种依赖于eclipse环境的导入方式会出现上述错误；而第二种导入方式由于不依靠eclipse，将jar包的信息放到了class.dex中，所以运行无误！[/size]</span></span></span>