NoClassDefFoundError: org.apache.http.entity.mime.content.StringBody

1.出错代码：StringBody strbType = new StringBody("123" , Charset.forName("UTF-8"));

2.问题描述：编译期间没问题，运行后报异常“NoClassDefFoundError: org.apache.http.entity.mime.content.StringBody”

3.问题原因1：如下图，libs1中的包编译时都OK，但该Android项目生成apk时，都没有被编进.dex，所以运行时缺失（原因后面说）。



解决方法A：全部放进libs中后，问题解决；

解决方法B：右键上述3.中libs1目录，点击build path--> use as source folder 即可；

解决方法C：点击面板“Order and Export”，勾选要导出的“entries”，选中下图红框中的jar包即可（所以，生成apk时丢掉的原因是这里要选中最后导出的"entry"）；



4.问题原因2：没有正确引用外部android工程。



解决方法：引用的外部工程应从上图的" Required projects "改为下图的" Library project "方式；



补充说明：至于Library project的概念，提供以下引文供参考

the components, code and resources of the <span style="color:#ff0000;">library project </span>are compiled and packaged into the .apk file of the compiled application.

An Android<span style="color:#ff0000;"> library project </span>can contain Java classes, Android components and resources. Only assets are not supported.

The<span style="color:#ff0000;"> library project </span>must declare all its components, e.g., activities, service, etc. via the AndroidManifest.xml file. The application which uses the library must also declare all the used components via the AndroidManifest.xml file.