为什么修剪不起作用？ [英] Why trim is not working?

问题描述

我正在尝试修剪字符串中的前导空格，我不知道我的方法有什么问题，任何建议都会受到赞赏吗？

I am trying to trim leading whitespaces from the string and I do not know what is wrong with my approach, any suggestions would be appreciated ?

代码：

this.poNumber = poNumber.equals（）？ poNumber：poNumber.trim（）;

我正在从csv文件中读取poNumber为IG078565和IG083060并且输出也得到相同的值相同的空格，不确定原因？

am reading poNumber from csv file as "     IG078565 and IG083060 " and output also am getting same value with same whitespaces, not sure why ?

更新

添加完整的方法以获得更好的效果上下文：

Adding complete method for better context:

public BillingDTO(String currency, String migrationId, String chargeId, String priceId, String poNumber, String otc,
            String billingClassId, String laborOnly) {
        super();
        this.currency = currency.equals("") ? currency : currency.trim();
        this.migrationId = migrationId.equals("") ? migrationId : migrationId.trim();
        this.chargeId = chargeId.equals("") ? chargeId : chargeId.trim();
        this.priceId = priceId.equals("") ? priceId : priceId.trim();
        this.poNumber = poNumber.equals("") ? poNumber : poNumber.trim();
            //poNumber.trim();
        //System.out.println("poNumber:"+this.poNumber.trim());
        //this.poNumber = poNumber.equals("") ? poNumber : poNumber.trim();
        this.otc = otc.equals("") ? otc : otc.trim();
        this.billingClassId = billingClassId.equals("") ? billingClassId : billingClassId.trim();
        this.laborOnly = laborOnly.equals("") ? "N" : laborOnly;
    }

谢谢。

推荐答案

更新您的空白区域似乎不是空格（ascii = 32）。你的代码是160，这是一个不间断的空间。 trim（）无法处理它。所以你必须这样做：

Update It appears your whitespace is not a whitespace (ascii=32). Yours is with code 160, which is a no-breaking space. trim() does not handle it. So you must do something like this:

this.poNumber = poNumber.replace(String.valueOf((char) 160), " ").trim();

你最好创建一个实用程序 - YourStringUtils.trim（string）并执行两项操作 - .trim（）和替换（..）

You'd better create an utility - YourStringUtils.trim(string) and there perform the two operations - both .trim() and the replace(..)

原始答案：

只需使用 this.poNumber = poNumber.trim（）;

如果有可能 poNumber 要 null ，那么你可以使用null-safe this.poNumber = StringUtils.trim （poNumber）; 来自 commons-lang 。

If there is a possibility for poNumber to be null, then you can use the null-safe this.poNumber = StringUtils.trim(poNumber); from commons-lang.

如果你想要 trimToEmpty（..） > null 要转换为空字符串。

You can also use trimToEmpty(..) from the same class, if you want null to be transformed to an empty string.

如果你不想依赖commons-lang，那么只需添加一个if -clause：

If you don't want to rely on commons-lang, then just add an if-clause:

if (poNumber != null) {
    this.poNumber = poNumber.trim();
}

正如问题评论中所述 - 确保您正在检查权利修剪后变量。您应该检查实例变量。你的参数（或局部变量，我无法分辨）不会改变，因为字符串是不可变的。

As noted in the comments under the question - make sure you are checking the right variable after the trimming. You should check the instance variable. Your parameter (or local variable, I can't tell) does not change, because strings are immutable.

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