利用spring的parent属性+javaassist+annotation 根据interface定义生成对应的实现类
定义一个FactoryBean实现类APIFactoryBean用于父类：
<bean id="apiFactoryBean" abstract="true" class="com.common.bean.APIFactoryBean" />
主要成员变量及方法如下:
public class APIFactoryBean implements FactoryBean, InitializingBean, ApplicationContextAware {
private ApplicationContext springContext;
@Resource(name = "baseDao")
private BaseDao baseDao;
private Class<?> target; // interface class
@Override
public Object getObject() throws Exception {
try {
Class<?> clazz = JavassistIbatisHelper.generate(this.target, this.springContext);
Constructor<?>[] constructors = clazz.getConstructors();
Constructor<?> constructor = null;
for (int i = 0; i < constructors.length; i++) {
if (constructors[i].getParameterTypes().length == 2) {
constructor = constructors[i];
return constructor.newInstance(this.baseDao, this.springContext);
}
}
throw new JavassitBuildBeanException(Errors.UNKOWN.getCode(), target.getCanonicalName()
+ "APIFactoryBean Exception ");
} catch (Throwable e) {
logger.error(e.getMessage(), e);
throw new JavassitBuildBeanException(Errors.UNKOWN.getCode(), target.getCanonicalName()
+ " APIFactoryBean Throwable ", e);
}
}
...
}
其中：JavassistIbatisHelper的generate方法利用 javaassist根据传入的类名（即target参数）及一些其他的参数(通过annotation定义)动态的生成需要构造的类。
定义一个需要实现JavassitTest1API接口的类：
<bean id="javassitTest1API" parent="apiFactoryBean">
<property name="target" value="com.api.JavassitTest1API"/>
</bean>
JavassitTest1API接口定义如下：
public interface JavassitTest1API {
@Sql(value = "sample.loadTest1")
public ResultGeneralModel<Test1> loadTest1ById(@SqlParam(name = "id") String id）;
}
类似的可以通过继承APIFactoryBean实现构造多个类：
如：
<bean id="javassitTest2API" parent="apiFactoryBean">
<property name="target" value="com.api.JavassitTest2API"/>
</bean>
JavassitTest2API接口定义如下：
public interface JavassitTest2API {
@Sql(value = "sample.loadTest2")
public ResultGeneralModel<Test2> loadTest2ById(@SqlParam(name = "id") String id）;
}