idea 将代码块抽取为方法快捷键-白红宇

idea 将代码块抽取为方法快捷键

阅读量：3707 次

发布时间：2019-05-21

本文共 8746 字，大约阅读时间需要 29 分钟。

前言

遇到业务逻辑很复杂的模块，有时候一个方法一写就好几百行。这个时候很多代码可以抽成一个方法，从而使业务逻辑很复杂的方法变得易读。当然，你必须要在关键的地方写上注释，方便后面的人维护。

Idea提供了一个抽取功能，可以将变量、代码块等抽取出来，减少重复代码，提高代码可读性。

用来重构代码，非常方便快捷。开发效率也会提高！！

具体操作

抽取方法的快捷键是 Ctrl + Alt + M，其中 M 代表 Method，即方法。

以下代码分别演示了抽取前，抽取后的变化，可以看出抽取后的代码结构更清晰简单，阅读性更好。

提取前：

// 大转盘 设置某用户下次必中某商品public void updateTurntableNextAward(Integer userId, Integer awardId, HttpServletRequest request) {
        //验证奖品    BsTurntableAward award = turntableAwardMapper.selectByPrimaryKey(awardId);    if (award == null) {
            throw new BusiException(E.INVALID_PARAMETER, "奖品不存在");    }    if (award.getState() != 1) {
            throw new BusiException(E.INVALID_PARAMETER, "奖品已停售");    }    Jedis jedis = RedisPool.getJedis();    SysUser sysUser = (SysUser) request.getSession().getAttribute(R.LOGIN_USER);    try {
            if (jedis.hexists(Rkey.USER_INFO, userId.toString())) {
                String hget = jedis.hget(Rkey.TURNTALE_NEXT_AWARD, userId.toString());            if (StringUtils.isEmpty(hget)) {
                    //第一次设置                BsTurntableNextAward record = new BsTurntableNextAward();                record.setAwardId(awardId);                record.setState(0);                record.setUserId(userId);                record.setSysUser(sysUser.getUserName());                turntableNextAwardMapper.insert(record);                //修改必中商品的已抽取库存总量：extractAmount + 1                turntableAwardMapper.updateExtractAmountAddOneByAwardId(awardId);                //新增操作，redis 对应商品总投放量加一                jedis.hincrBy(Rkey.BRANCH_AWARD_ACTIVE_STOCK, awardId.toString(), 1);                //操作数据库 商品对应投放库存加一                 //下面这部分可以抽取为1个方法，选中这部分，按下快捷键 Ctrl + Alt + M，填写方法名称即可抽取                Date now = new Date();                String formatDate = DateUtil.formatDate(now, "yyyy-MM-dd HH:mm");                BsTurntableActivity nowPeriodActivity = turntableActivityMapper.queryNowPeriodActivity(formatDate);                String curActivityId = nowPeriodActivity.getId().toString();                BsTurntableActivity turntableActivity = new BsTurntableActivity();                turntableActivity.setId(curActivityId;                if (nowPeriodActivity.getAwardId1().equals(awardId)) {
                        turntableActivity.setAmount1(nowPeriodActivity.getAmount1() + 1);                } else if (nowPeriodActivity.getAwardId2().equals(awardId)) {
                        turntableActivity.setAmount2(nowPeriodActivity.getAmount2() + 1);                } else if (nowPeriodActivity.getAwardId3().equals(awardId)) {
                        turntableActivity.setAmount3(nowPeriodActivity.getAmount3() + 1);                } else if (nowPeriodActivity.getAwardId4().equals(awardId)) {
                        turntableActivity.setAmount4(nowPeriodActivity.getAmount4() + 1);                } else if (nowPeriodActivity.getAwardId5().equals(awardId)) {
                        turntableActivity.setAmount5(nowPeriodActivity.getAmount5() + 1);                } else if (nowPeriodActivity.getAwardId6().equals(awardId)) {
                        turntableActivity.setAmount6(nowPeriodActivity.getAmount6() + 1);                }            } else {
                    //替换操作                Integer oldAwardId = Integer.valueOf(hget);                // 查询用户是否有 没有抽取的必中记录                BsTurntableNextAward record = turntableNextAwardMapper.queryDataByUserAndState(userId, 0);                if (record != null) {
                        record.setAwardId(awardId);                    record.setSysUser(sysUser.getUserName());                    turntableNextAwardMapper.updateByPrimaryKeySelective(record);                    //修改之前设置的必中商品已抽取库存总量：extractAmount - 1                    turntableAwardMapper.updateExtractAmountReduceOneByAwardId(oldAwardId);                    //修改必中商品的已抽取库存总量：extractAmount + 1                    turntableAwardMapper.updateExtractAmountAddOneByAwardId(awardId);                }                //更新替换操作，原有商品总投放量减一                jedis.hincrBy(Rkey.BRANCH_AWARD_ACTIVE_STOCK, oldAwardId.toString(), -1);                //更新替换操作，替换商品总投放量加一                jedis.hincrBy(Rkey.BRANCH_AWARD_ACTIVE_STOCK, awardId.toString(), 1);            }            jedis.hset(Rkey.TURNTALE_NEXT_AWARD, userId.toString(), awardId.toString());            //数据库        } else {
                throw new BusiException(E.CUSTOM_ERROR_MSG, "用户不存在");        }    } finally {
            RedisPool.returnJedis(jedis);    }}

抽取之后，代码如下：

public void updateTurntableNextAward(Integer userId, Integer awardId, HttpServletRequest request) {
        //验证奖品    BsTurntableAward award = turntableAwardMapper.selectByPrimaryKey(awardId);    if (award == null) {
            throw new BusiException(E.INVALID_PARAMETER, "奖品不存在");    }    if (award.getState() != 1) {
            throw new BusiException(E.INVALID_PARAMETER, "奖品已停售");    }    Jedis jedis = RedisPool.getJedis();    SysUser sysUser = (SysUser) request.getSession().getAttribute(R.LOGIN_USER);    try {
            if (jedis.hexists(Rkey.USER_INFO, userId.toString())) {
                String hget = jedis.hget(Rkey.TURNTALE_NEXT_AWARD, userId.toString());            if (StringUtils.isEmpty(hget)) {
                    //第一次设置                BsTurntableNextAward record = new BsTurntableNextAward();                record.setAwardId(awardId);                record.setState(0);                record.setUserId(userId);                record.setSysUser(sysUser.getUserName());                turntableNextAwardMapper.insert(record);                //修改必中商品的已抽取库存总量：extractAmount + 1                turntableAwardMapper.updateExtractAmountAddOneByAwardId(awardId);                //新增操作，redis 对应商品总投放量加一                jedis.hincrBy(Rkey.BRANCH_AWARD_ACTIVE_STOCK, awardId.toString(), 1);                //操作数据库 商品对应投放库存加一                //下面这部分可以抽取为1个方法，选中这部分，按下快捷键 Ctrl + Alt + M，填写方法名称即可抽取                updateAmountAddOneWhenSettingBizhong(awardId);            } else {
                    //替换操作                Integer oldAwardId = Integer.valueOf(hget);                // 查询用户是否有 没有抽取的必中记录                BsTurntableNextAward record = turntableNextAwardMapper.queryDataByUserAndState(userId, 0);                if (record != null) {
                        record.setAwardId(awardId);                    record.setSysUser(sysUser.getUserName());                    turntableNextAwardMapper.updateByPrimaryKeySelective(record);                    //修改之前设置的必中商品已抽取库存总量：extractAmount - 1                    turntableAwardMapper.updateExtractAmountReduceOneByAwardId(oldAwardId);                    //修改必中商品的已抽取库存总量：extractAmount + 1                    turntableAwardMapper.updateExtractAmountAddOneByAwardId(awardId);                }                //更新替换操作，原有商品总投放量减一                jedis.hincrBy(Rkey.BRANCH_AWARD_ACTIVE_STOCK, oldAwardId.toString(), -1);                //更新替换操作，替换商品总投放量加一                jedis.hincrBy(Rkey.BRANCH_AWARD_ACTIVE_STOCK, awardId.toString(), 1);            }            jedis.hset(Rkey.TURNTALE_NEXT_AWARD, userId.toString(), awardId.toString());            //数据库        } else {
                throw new BusiException(E.CUSTOM_ERROR_MSG, "用户不存在");        }    } finally {
            RedisPool.returnJedis(jedis);    }}// 操作数据库 设置必中 对应商品库存加一private void updateAmountAddOneWhenSettingBizhong(Integer awardId) {
        Date now = new Date();    String formatDate = DateUtil.formatDate(now, "yyyy-MM-dd HH:mm");    BsTurntableActivity nowPeriodActivity = turntableActivityMapper.queryNowPeriodActivity(formatDate);    String curActivityId = nowPeriodActivity.getId().toString();    BsTurntableActivity turntableActivity = new BsTurntableActivity();    turntableActivity.setId(curActivityId);    if (nowPeriodActivity.getAwardId1().equals(awardId)) {
            turntableActivity.setAmount1(nowPeriodActivity.getAmount1() + 1);    } else if (nowPeriodActivity.getAwardId2().equals(awardId)) {
            turntableActivity.setAmount2(nowPeriodActivity.getAmount2() + 1);    } else if (nowPeriodActivity.getAwardId3().equals(awardId)) {
            turntableActivity.setAmount3(nowPeriodActivity.getAmount3() + 1);    } else if (nowPeriodActivity.getAwardId4().equals(awardId)) {
            turntableActivity.setAmount4(nowPeriodActivity.getAmount4() + 1);    } else if (nowPeriodActivity.getAwardId5().equals(awardId)) {
            turntableActivity.setAmount5(nowPeriodActivity.getAmount5() + 1);    } else if (nowPeriodActivity.getAwardId6().equals(awardId)) {
            turntableActivity.setAmount6(nowPeriodActivity.getAmount6() + 1);    }    turntableActivityMapper.updateByPrimaryKeySelective(turntableActivity);}

ps:

1.选中要提取的部分，按下快捷键 Ctrl + Alt + M，填写方法名称即可抽取

2.有可能提取的时候，提取的参数不够(不满足我们的期望)，可以等提取结束后手动修改，加入需要的参数。

转载地址：http://lczjn.baihongyu.com/

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