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/**
* @Title:
* @Package
* @Description: 动态修改实体类注释中的值(不提倡经常使用)
* @author TangCai
* @date 2016年11月16日 下午3:08:56
* @version V1.0
*/
public class ClassPoolUtils {
/**
* 运行时动态ORM表映射
* @param entityClass 实体类
* @param annotation 注释类
* @param atMethodName 注释类方法
* @param atMethodVal 注释类方法的更新值
* @return 修改注释值后实体类
*/
@SuppressWarnings("unchecked")
public static Class<?> setPool(Class<?> entityClass, Class<?> annotation,
String atMethodName, Object atMethodVal){
Class<?> c = null;
try {
ClassPool classPool = ();
CtClass clazz = (());
ClassFile classFile = ();
//();//冻结
ConstPool constPool = ();
Class<> cl = (Class<>)annotation;
Annotation newAnnotation = createJavassistAnnotation(constPool,(cl),atMethodName,atMethodVal);
AnnotationsAttribute attribute = (AnnotationsAttribute)();
(newAnnotation);
(attribute);
ClassLoader parent = ();
EntityClassLoader loader = new ClassPoolUtils().new EntityClassLoader(parent);
//();//同一个ClassLoader不能多次加载同一个类
c = (loader , null);//替换Class的时候, 加载该Class的ClassLoader也必须用新的
//();//解除冻结
(); //注销class
} catch (Exception e) {
();
}
return c;
}
public static Annotation createJavassistAnnotation(ConstPool constpool,
annotation,String atMethodName, Object atMethodVal) throws Exception {
Annotation annotationCopy = new Annotation(().getName(), constpool);
String typeName = null;
MemberValue mv = null;
for (Method m : ().getDeclaredMethods()) {
Object value = (annotation);
typeName = ().getSimpleName();
if((())) value = atMethodVal;
if(("int"))
mv = new IntegerMemberValue(constpool,(Integer)value);
else if(("String[]")){
String[] stres = (String[])value;
StringMemberValue[] elements = new StringMemberValue[];
for(int i=0;i<;i++)
elements[i] = new StringMemberValue(stres[i],constpool);
ArrayMemberValue amv = new ArrayMemberValue(constpool);
(elements);
mv = amv;
}
else if(("boolean"))
mv = new BooleanMemberValue((Boolean)value,constpool);
else mv = new StringMemberValue((),constpool);
((),mv);
}
return annotationCopy;
}
/**
* @Title:
* @Package
* @Description: 实体类加载器
* 该加载器主要用于运行时动态修改实体后,重新装载实体
* @author TangCai
* @date 2016年11月16日 下午3:18:55
* @version V1.0
*/
public class EntityClassLoader extends ClassLoader {
private ClassLoader parent;
public EntityClassLoader(ClassLoader parent){
= parent;
}
@Override
public Class<?> loadClass(String name) throws ClassNotFoundException {
return (name, false);
}
@Override
protected synchronized Class<?> loadClass(String name, boolean resolve)
throws ClassNotFoundException {
Class<?> clazz = (name);
if(null != parent)
clazz = (name);
if(null == clazz)
(name);
if(null == clazz)
throw new ClassNotFoundException();
if(null != clazz && resolve)
(clazz);
return clazz;
}
}
}