HibernateCRUD基础框架(2)-HQL语句构造器(HqlQueryBuilder,HqlUpdateBuilder)(一)

上篇讲述了最基本的实体类，本篇接着讲述HQL语句构造器，包括查询和更新等。

优点：通过面向对象的方式构造HQL语句，更快捷，不需要手动拼接HQL。

缺点：封装可能降低性能，只能支持常用的和较为简单的HQL构造。

部分功能不完善，待开发。

1.HQL语句构造器

package cn.fansunion.hibernate.sql;

import org.apache.commons.lang.text.StrBuilder;

import cn.fansunion.hibernate.sql.entity.From;
import cn.fansunion.hibernate.sql.entity.GroupBy;
import cn.fansunion.hibernate.sql.entity.OrderGroup;
import cn.fansunion.hibernate.sql.entity.SearchCondition;

/**
 * HQL语句构造器。
 * 

 * 目前只适用于1张表的情况，只有查询条件支持占位符，建议使用完全构造的sql语句（是否会产生sql注入，待研究）。
 *
 * @author LeiWen@FansUnion.cn
 */
public class HqlQueryBuilder extends ConstantBase {

    // 查询条件组合策略
    // -----------------------------------
    // *************From******************
    // -----------------------------------
    private String select;

    private From from;

    // -----------------------------------
    // *************Where******************
    // -----------------------------------
    private SearchCondition searchCondition;

    // -----------------------------------
    // *************Group by**************
    // -----------------------------------

    private GroupBy groupBy;

    // -----------------------------------
    // *************Order by******************
    // -----------------------------------
    private OrderGroup orderGroup;

    // -----------------------------------
    // 通过构造方法，创建查询构造器。各种字段组合形式的构造方法太多，只给出3种比较常见的。
    // 建议使用链式构造或setter方法设置属性。
    // -----------------------------------
    public HqlQueryBuilder() {

    }

    public HqlQueryBuilder(From from) {
        this.from = from;
    }

    public HqlQueryBuilder(From from, SearchCondition searchCondition,
            GroupBy groupBy, OrderGroup orderGroup) {
        this.from = from;

        this.searchCondition = searchCondition;
        this.groupBy = groupBy;
        this.orderGroup = orderGroup;
    }

    public HqlQueryBuilder select(String select) {
        this.select = select;
        return this;
    }

    // -----------------------------------
    // 支持链式用法,暂时不能很好地支持**************
    // -----------------------------------
    public HqlQueryBuilder from(From from) {
        this.from = from;
        return this;
    }

    public HqlQueryBuilder from(String model) {
        doFrom(model, "");
        return this;
    }

    public HqlQueryBuilder from(String model, String alias) {
        doFrom(model, alias);
        return this;
    }

    public HqlQueryBuilder from(Class
   clazz) {
        doFrom(clazz.getSimpleName());
        return this;
    }

    public HqlQueryBuilder from(Class
   clazz, String alias) {
        doFrom(clazz.getSimpleName(), alias);
        return this;
    }

    private void doFrom(String model) {
        doFrom(model, null);
    }

    private void doFrom(String model, String alias) {
        this.from = new From(model, alias);
    }

    public HqlQueryBuilder searchCodition(SearchCondition searchCondition) {
        this.searchCondition = searchCondition;
        return this;
    }

    public HqlQueryBuilder groupBy(GroupBy groupBy) {
        this.groupBy = groupBy;
        return this;
    }

    public HqlQueryBuilder orderBy(OrderGroup orderGroup) {
        this.orderGroup = orderGroup;
        return this;
    }

    /**
     * 转换成HQL语句
     */
    public String toHql() {

        StrBuilder builder = new StrBuilder();
        if (select != null) {
            builder.append(select).append(EMPTY);
        }
        if (from != null) {
            builder.append(from);
        }

        if (searchCondition != null) {
            builder.append(searchCondition);
        }
        if (groupBy != null) {
            builder.append(groupBy);
        }
        if (orderGroup != null) {
            builder.append(orderGroup);
        }

        return bu