Android 字符串工具类

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public class StringUtils {// 判断字符串是否为空public static boolean isEmpty(String str) {return str == null || str.trim().isEmpty();}// 判断字符串是否为非空public static boolean isNotEmpty(String str) {return !isEmpty(str);}// 连接字符串数组为一个字符串public static String join(String[] strings, String delimiter) {if (strings == null) return "";return TextUtils.join(delimiter, strings);}// 去除字符串两端的空格public static String trim(String str) {return str.trim();}// 检查字符串是否包含指定子字符串public static boolean contains(String str, String subStr) {return str.contains(subStr);}// 将字符串转换为大写public static String toUpperCase(String str) {return str.toUpperCase();}// 将字符串转换为小写public static String toLowerCase(String str) {return str.toLowerCase();}// 截取子字符串public static String substring(String str, int startIndex, int endIndex) {return str.substring(startIndex, endIndex);}// 判断两个字符串是否相等public static boolean equals(String str1, String str2) {return str1.equals(str2);}// 获取字符串长度public static int length(String str) {return str.length();}
}

使用实例：

public class MainActivity extends AppCompatActivity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);// 示例字符串String testString = "  Hello, World!  ";// 检查字符串是否为空if (StringUtils.isEmpty(testString)) {Log.d("StringUtils", "String is empty");} else {// 去除字符串两端的空格String trimmedString = StringUtils.trim(testString);Log.d("StringUtils", "Trimmed String: " + trimmedString);// 判断字符串是否包含指定子字符串if (StringUtils.contains(trimmedString, "Hello")) {Log.d("StringUtils", "String contains 'Hello'");}// 将字符串转换为大写String upperCaseString = StringUtils.toUpperCase(trimmedString);Log.d("StringUtils", "Uppercase String: " + upperCaseString);// 将字符串转换为小写String lowerCaseString = StringUtils.toLowerCase(trimmedString);Log.d("StringUtils", "Lowercase String: " + lowerCaseString);// 截取子字符串String subString = StringUtils.substring(trimmedString, 2, 7);Log.d("StringUtils", "Substring: " + subString);// 判断两个字符串是否相等if (StringUtils.equals(upperCaseString, lowerCaseString)) {Log.d("StringUtils", "Strings are equal");}// 获取字符串长度int len = StringUtils.length(trimmedString);Log.d("StringUtils", "Length of string: " + len);}}
}