生成动态hql查询

Question

动态生成hibernate查询的方法

public static String generateConditionQury(Class aClass,
            String returnProperty, String[] propertyName,
            Object[] propertyValue, String orderProperty, boolean isDescending) {

    if (propertyName != null && propertyValue != null) {
        if (propertyName.length != propertyValue.length)
            throw new RuntimeException(
                    "Null or Un-mached property name-value pair");
    }

    StringBuffer sb = new StringBuffer();
    try {
        if (CommonUtils.isEmpty(returnProperty)) {
            sb.append("select al from ");
        } else {
            if (aClass.newInstance() instanceof CampusAbstractModel) {
                sb.append("select al.").append(returnProperty).append(
                        ",al.modifiedGroup ");
                sb.append(" from ");
            } else {
                sb.append("select al.").append(returnProperty).append(
                        " from ");
            }
        }
        sb.append(aClass.getName()).append(" as").append(" al");
        if (propertyName != null && propertyValue != null) {
            for (int i = 0; i < propertyValue.length; i++) {
                if (i == 0) {
                    sb.append(" where ");
                } else {
                    sb.append(" and ");
                }
                sb.append(" al.").append(propertyName[i]);
                if (propertyValue[i] == null) {
                    sb.append(" is null ");
                } else {
                    sb.append(" = ? ");
                }
            }
        }
        sb.append(" order by");
        if (orderProperty != null) {
            sb.append(" al.").append(orderProperty);
            if (isDescending) {
                sb.append(" desc");
            }
        } else {
            sb.append(" al.id");
        }
    } catch (InstantiationException e) {
        e.printStackTrace();
    } catch (IllegalAccessException e) {
        e.printStackTrace();
    }
    return sb.toString();
}

Answer 1

**Optimized way to generate hql query dynamically**


public static String generateQueryUtilQuery(Class aClass,
            String[] returnProperty, String[] propertyNames,
            Object[] propertyValues, String orderProperty,
            boolean isDescending, boolean isLike, boolean isDistinct) {

        if (propertyNames != null && propertyValues != null) {
            if (propertyNames.length != propertyValues.length)
                throw new RuntimeException(
                        "Null or Un-mached property name-value pair");
        }
        StringBuffer sb = null;
        if (isDistinct) {
            sb = new StringBuffer("select distinct ");
        } else {
            sb = new StringBuffer("select ");
        }
        try {
            for (int i = 0; i < returnProperty.length; i++) {
                if (i != 0) {
                    sb.append(",");
                }
                sb.append("al.").append(returnProperty[i]);
            }
            if (aClass.newInstance() instanceof CampusAbstractModel) {
                sb.append(", al.modifiedGroup ");
            }
            sb.append(" from ");
            sb.append(aClass.getName()).append(" as al ");
            if (propertyNames != null) {
                for (int i = 0; i < propertyNames.length; i++) {
                    if (i == 0) {
                        sb.append(" where ");
                    } else {
                        sb.append(" and ");
                    }
                    if (isLike && propertyValues != null
                            && propertyValues[i] instanceof String) {
                        sb.append(" upper(").append(" al.");
                        sb.append(propertyNames[i]).append(")");
                        sb.append(" like ? ");
                    } else if (isLike
                            && (propertyValues == null || propertyValues[i] == null)) {
                        sb.append(" al.").append(propertyNames[i]);
                        sb.append(" like '%'");
                    } else {
                        sb.append(" al.").append(propertyNames[i]);
                        if (propertyValues == null || propertyValues[i] == null) {
                            sb.append(" is null ");
                        } else {
                            sb.append(" = ? ");
                        }
                    }
                }
            }
            if (!CommonUtils.isEmpty(orderProperty)) {
                sb.append(" order by ");
                sb.append("al.").append(orderProperty);
                if (isDescending) {
                    sb.append(" desc ");
                }
            } else if (!isDistinct) {
                sb.append(" order by ");
                sb.append(" al.id ");
                if (isDescending) {
                    sb.append(" desc ");
                }
            }
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        }
        return sb.toString();
    }