Java字符串处理：高效移除末尾逗号及空白字符的教程

public class StringCleaner {
    public static void main(String[] args) {
        String str1 = "kushalhs, mayurvm, narendrabz, ";
        String str2 = "itemA, itemB, itemC,";
        String str3 = "singleItem ";
        String str4 = "noTrailingComma";
        String str5 = ""; // 空字符串

        // 移除末尾的 ", "
        String cleanedStr1 = str1.replaceAll(", $", "");
        System.out.println("原始字符串1: "" + str1 + """);
        System.out.println("清理后字符串1: "" + cleanedStr1 + """); // 输出: "kushalhs, mayurvm, narendrabz"

        // 移除末尾的 "," (注意这里正则表达式需要调整)
        String cleanedStr2 = str2.replaceAll(",$", "");
        System.out.println("原始字符串2: "" + str2 + """);
        System.out.println("清理后字符串2: "" + cleanedStr2 + """); // 输出: "itemA, itemB, itemC"

        // 如果没有匹配项，字符串保持不变
        String cleanedStr3 = str3.replaceAll(", $", "");
        System.out.println("原始字符串3: "" + str3 + """);
        System.out.println("清理后字符串3: "" + cleanedStr3 + """); // 输出: "singleItem "

        String cleanedStr4 = str4.replaceAll(", $", "");
        System.out.println("原始字符串4: "" + str4 + """);
        System.out.println("清理后字符串4: "" + cleanedStr4 + """); // 输出: "noTrailingComma"

        // 对空字符串的处理是健壮的
        String cleanedStr5 = str5.replaceAll(", $", "");
        System.out.println("原始字符串5: "" + str5 + """);
        System.out.println("清理后字符串5: "" + cleanedStr5 + """); // 输出: ""
    }
}

import org.openqa.selenium.By;
import org.openqa.selenium.WebElement;
import java.util.ArrayList;
import java.util.List;

public class DropdownTextProcessor {

    // 假设 getDropDownOptions(By locator) 方法已存在，用于获取WebElement列表
    // private static List<WebElement> getDropDownOptions(By locator) { /* ... */ }

    public static ArrayList<String> getDropDownTextList(By locator) {
        List<WebElement> countryList = new ArrayList<>(); // 模拟获取到的WebElement列表
        // 模拟添加一些带有末尾逗号的文本
        countryList.add(new MockWebElement("Option A, "));
        countryList.add(new MockWebElement("Option B,"));
        countryList.add(new MockWebElement("Option C"));
        countryList.add(new MockWebElement("Option D , "));
        countryList.add(new MockWebElement("")); // 空文本

        ArrayList<String> countryTextList = new ArrayList<>();

        for (WebElement e : countryList) {
            String text = e.getText();
            // 应用正则表达式移除末尾逗号及零个或多个空白字符
            text = text.replaceAll(",\s*$", "");

            if (!text.isEmpty()) { // 检查是否为空字符串
                countryTextList.add(text);
            }
        }
        return countryTextList;
    }

    public static void main(String[] args) {
        ArrayList<String> cleanedList = getDropDownTextList(By.id("someDropdown"));
        System.out.println("清理后的下拉列表文本:");
        for (String item : cleanedList) {
            System.out.println(""" + item + """);
        }
        // 输出:
        // 清理后的下拉列表文本:
        // "Option A"
        // "Option B"
        // "Option C"
        // "Option D"
    }

    // 模拟 WebElement 类
    static class MockWebElement implements WebElement {
        private String text;
        public MockWebElement(String text) { this.text = text; }
        @Override public String getText() { return text; }
        // 其他 WebElement 方法省略
        @Override public void click() {} @Override public void submit() {} @Override public void sendKeys(CharSequence... keysToSend) {} @Override public void clear() {} @Override public String getTagName() { return null; } @Override public String getAttribute(String name) { return null; } @Override public boolean isSelected() { return false; } @Override public boolean isEnabled() { return false; } @Override public List<WebElement> findElements(By by) { return null; } @Override public WebElement findElement(By by) { return null; } @Override public boolean isDisplayed() { return false; } @Override public org.openqa.selenium.Point getLocation() { return null; } @Override public org.openqa.selenium.Dimension getSize() { return null; } @Override public org.openqa.selenium.Rectangle getRect() { return null; } @Override public String getCssValue(String propertyName) { return null; } @Override public <X> X getScreenshotAs(org.openqa.selenium.OutputType<X> target) throws org.openqa.selenium.WebDriverException { return null; }
    }
}

import java.util.ArrayList;
import java.util.StringJoiner;

public class ListJoiner {
    public static void main(String[] args) {
        ArrayList<String> items = new ArrayList<>();
        items.add("Apple");
        items.add("Banana");
        items.add("Orange");

        // 使用 StringJoiner 拼接，通常 StringJoiner 会自动处理末尾分隔符
        // 但如果使用其他方式（如循环手动拼接），可能会出现末尾分隔符
        StringJoiner sj = new StringJoiner(", ");
        for (String item : items) {
            sj.add(item);
        }
        String finalString = sj.toString();
        System.out.println("StringJoiner 拼接结果 (通常是干净的): "" + finalString + """);

        // 模拟一个手动拼接导致末尾有 ", " 的情况
        StringBuilder sb = new StringBuilder();
        for (String item : items) {
            sb.append(item).append(", ");
        }
        String manualJoinedString = sb.toString();
        System.out.println("手动拼接结果 (可能包含末尾分隔符): "" + manualJoinedString + """);

        // 移除手动拼接结果末尾的 ", "
        String cleanedManualJoinedString = manualJoinedString.replaceAll(",\s*$", "");
        System.out.println("清理后的手动拼接结果: "" + cleanedManualJoinedString + """);
    }
}