我们在使用hibernate的时候,查询的时候都会和实体中的一些字段相结合去查询,当然字段少了,还算是比较简单,当字段多了,就不那么容易了,所以就自己写了个方法,根据实体中的字段信息去查询,废话不多说上代码:
/** * 根据实体查询,将所有的参数封装到实体中查询即可,不可查询为null的信息 * @param t * @return * @throws SecurityException * @throws NoSuchMethodException * @throws IllegalArgumentException * @throws IllegalAccessException * @throws InvocationTargetException */ public List<T> queryAll(T t) throws SecurityException, NoSuchMethodException, IllegalArgumentException, IllegalAccessException, InvocationTargetException{ //存放参数 List<Object> paraList = new ArrayList<Object>(); List<T> list = new ArrayList<T>(); StringBuffer sb = new StringBuffer("from "); sb.append(entityClass.getSimpleName()).append(" where 1=1 "); if( t == null){ list = find(sb.toString()); return list; } //拼接hql语句 //获取类中所有的属性 Field[] fields = t.getClass().getDeclaredFields(); for(Field field : fields){ //字段名称 String fieldName = field.getName(); //方法名称 String methodName = getMethodName(fieldName, "get"); //方法 Method method = UserInfo.class.getDeclaredMethod(methodName); //方法的返回值类型 String methodReturnType = method.getReturnType().getSimpleName(); Object obj = null; obj = method.invoke(t); //返回值为空则跳过 if( obj == null ){ continue; } if ("String".equals(methodReturnType)) { String str = String.valueOf(obj.toString()); sb.append(" and ").append(fieldName).append("= ? "); paraList.add(str); } else if ("Date".equals(methodReturnType)) { Date date = (Date)obj; sb.append(" and ").append(fieldName).append("= ? "); paraList.add(date); } else if ("Integer".equals(methodReturnType) || "int".equals(methodReturnType)) { Integer i = Integer.valueOf(obj.toString()); sb.append(" and ").append(fieldName).append("= ? "); paraList.add(i); } else if ("Long".equalsIgnoreCase(methodReturnType)) { Long L = Long.valueOf(obj.toString()); sb.append(" and ").append(fieldName).append("= ? "); paraList.add(L); } else if ("Double".equalsIgnoreCase(methodReturnType)) { Double d = Double.valueOf(obj.toString()); sb.append(" and ").append(fieldName).append("= ? "); paraList.add(d); } else if ("Boolean".equalsIgnoreCase(methodReturnType)) { Boolean b = Boolean.valueOf(obj.toString()); sb.append(" and ").append(fieldName).append("= ? "); paraList.add(b); } } Query query = createQuery(sb.toString(), paraList.toArray()); list = query.list(); return list; } /** * 或实体中属性的get或set方法 * @param methodName 字段名 * @param methodType 方法类型:get或set * @return */ private String getMethodName(String methodName, String methodType){ if( methodName == null || "".equals(methodName.trim()) ){ return null; } StringBuffer sb = new StringBuffer(); sb.append(methodType); sb.append(methodName.substring(0, 1).toUpperCase()); sb.append(methodName.substring(1)); return sb.toString(); }
本人反射学得比较浅显,希望高手能够多多指点。