一段拼装sql的小代码

/**
     * 单表查询
     *
     * className：实体类的名字
     * vals：查询的属性
     * pNames：条件的名字
     * pVals：条件的值
     */
    @Override
    public List<Object> get(String className,String[] vals,Object[] pNames,Object[] pVals){
        if(StringUtils.isEmpty(className)) {
            throw new NullParameterException("实体类的名字没有写");
        }

        StringBuffer hql = new StringBuffer();
        if(vals.length != ) {
            hql.append("SELECT ");

            for(int i=; i<vals.length;i++) {
                hql.append("p.");
                hql.append(vals[i]);
                if(i != vals.length-) {
                    hql.append(", ");
                }
            }
        }
        hql.append(" FROM ");
        hql.append(className);
        hql.append(" p");
        if(pNames.length> && pVals.length> && pNames.length==pVals.length) {
            hql.append(" WHERE ");
            for(int i=;i<pNames.length;i++) {
                hql.append(" p.");
                hql.append(pNames[i]);
                hql.append("=");
                hql.append(pVals[i]);
                if(i<pNames.length-) {
                    hql.append(" AND ");
                }
            }
        }
        System.out.println(hql.toString());
        return null;
    }

1. userDao.get("VerificationCode", new String[] {"val1","val2"}, new Object[]{"p1","p2","p3"}, new Object[] {"pv1","pv2","pv3"});
输出：SELECT p.val1, p.val2 FROM VerificationCode p WHERE  p.p1=pv1 AND  p.p2=pv2 AND  p.p3=pv3

　2. userDao.get("VerificationCode", new String[] {}, new Object[]{"p1","p2","p3"}, new Object[] {"pv1","pv2","pv3"});

输出： FROM VerificationCode p WHERE  p.p1=pv1 AND  p.p2=pv2 AND  p.p3=pv3

3. userDao.get("VerificationCode", new String[] {}, new Object[]{}, new Object[] {});

输出：FROM VerificationCode p

　

　4.userDao.get("VerificationCode", new String[] {"p1"}, new Object[]{}, new Object[] {});

　输出：SELECT p.p1 FROM VerificationCode p

/**
* 单表更新操作
*
* className:实体类的名字
* uNames：需要更新的字段
* uVals：更新的值
* wNames：条件字段
* wVals：条件值
* */

public int update(String className,Object[] uNames,Object[] uVals,Object[] wNames,Object[] wVals) {
        if(StringUtils.isEmpty(className)) {
            throw new NullParameterException("实体类的名字没写");
        }
        StringBuffer hql = new StringBuffer("UPDATE ");
        hql.append(className);
        hql.append(" p SET ");
        if(uNames.length==uVals.length && uNames.length> && uVals.length>) {
            for(int i=;i<uNames.length;i++) {
                hql.append("p.");
                hql.append(uNames[i]);
                hql.append("=");
                hql.append("'");
                hql.append(uVals[i]);
                hql.append("'");
                if(i<uNames.length-) {
                    hql.append(",");
                }
            }
        }

        if(wNames.length==wVals.length && wNames.length> && wVals.length>) {
            hql.append(" WHERE ");
            for(int i=;i<wNames.length;i++) {
                hql.append("p.");
                hql.append(wNames[i]);
                hql.append("=");
                hql.append("'");
                hql.append(wVals[i]);
                hql.append("'");
                if(i<wNames.length-) {
                    hql.append(" AND ");
                }
            }
        }
    //    System.out.println(hql.toString());
        return sessionFactory.getCurrentSession().createQuery(hql.toString()).executeUpdate();
    }