本文整理了Java中java.lang.String.isEmpty()方法的一些代码示例，展示了String.isEmpty()的具体用法。这些代码示例主要来源于Github/Stackoverflow/Maven等平台，是从一些精选项目中提取出来的代码，具有较强的参考意义，能在一定程度帮忙到你。String.isEmpty()方法的具体详情如下：
包路径：java.lang.String
类名称：String
方法名：isEmpty

String.isEmpty介绍

[英]Returns true if, and only if, #length() is 0.
[中]当且仅当#length（）为0时返回true。

代码示例

代码示例来源：origin: spring-projects/spring-framework

public PatternVirtualFileVisitor(String rootPath, String subPattern, PathMatcher pathMatcher) {
  this.subPattern = subPattern;
  this.pathMatcher = pathMatcher;
  this.rootPath = (rootPath.isEmpty() || rootPath.endsWith("/") ? rootPath : rootPath + "/");
}

代码示例来源：origin: stackoverflow.com

public static boolean empty( final String s ) {
 // Null-safe, short-circuit evaluation.
 return s == null || s.trim().isEmpty();
}

代码示例来源：origin: spring-projects/spring-framework

/**
 * Check that the given {@code String} is neither {@code null} nor of length 0.
 * <p>Note: this method returns {@code true} for a {@code String} that
 * purely consists of whitespace.
 * @param str the {@code String} to check (may be {@code null})
 * @return {@code true} if the {@code String} is not {@code null} and has length
 * @see #hasLength(CharSequence)
 * @see #hasText(String)
 */
public static boolean hasLength(@Nullable String str) {
  return (str != null && !str.isEmpty());
}

代码示例来源：origin: stackoverflow.com

List<String> list = new ArrayList<>();

// This is a clever way to create the iterator and call iterator.hasNext() like
// you would do in a while-loop. It would be the same as doing:
//     Iterator<String> iterator = list.iterator();
//     while (iterator.hasNext()) {
for (Iterator<String> iterator = list.iterator(); iterator.hasNext();) {
  String string = iterator.next();
  if (string.isEmpty()) {
    // Remove the current element from the iterator and the list.
    iterator.remove();
  }
}

代码示例来源：origin: spring-projects/spring-framework

@Override
  public T convert(String source) {
    if (source.isEmpty()) {
      // It's an empty enum identifier: reset the enum value to null.
      return null;
    }
    return (T) Enum.valueOf(this.enumType, source.trim());
  }
}

代码示例来源：origin: spring-projects/spring-framework

protected boolean isNamespaceDeclaration(QName qName) {
  String prefix = qName.getPrefix();
  String localPart = qName.getLocalPart();
  return (XMLConstants.XMLNS_ATTRIBUTE.equals(localPart) && prefix.isEmpty()) ||
      (XMLConstants.XMLNS_ATTRIBUTE.equals(prefix) && !localPart.isEmpty());
}

代码示例来源：origin: spring-projects/spring-framework

@Override
public Character convert(String source) {
  if (source.isEmpty()) {
    return null;
  }
  if (source.length() > 1) {
    throw new IllegalArgumentException(
        "Can only convert a [String] with length of 1 to a [Character]; string value '" + source + "'  has length of " + source.length());
  }
  return source.charAt(0);
}

代码示例来源：origin: square/okhttp

static void checkName(String name) {
 if (name == null) throw new NullPointerException("name == null");
 if (name.isEmpty()) throw new IllegalArgumentException("name is empty");
 for (int i = 0, length = name.length(); i < length; i++) {
  char c = name.charAt(i);
  if (c <= '\u0020' || c >= '\u007f') {
   throw new IllegalArgumentException(Util.format(
     "Unexpected char %#04x at %d in header name: %s", (int) c, i, name));
  }
 }
}

代码示例来源：origin: google/guava

@Override
 public void parse(CacheBuilderSpec spec, String key, String value) {
  checkArgument(value != null && !value.isEmpty(), "value of key %s omitted", key);
  try {
   parseInteger(spec, Integer.parseInt(value));
  } catch (NumberFormatException e) {
   throw new IllegalArgumentException(
     format("key %s value set to %s, must be integer", key, value), e);
  }
 }
}

代码示例来源：origin: google/guava

@Override
 protected String computeNext() {
  if (lines.hasNext()) {
   String next = lines.next();
   // skip last line if it's empty
   if (lines.hasNext() || !next.isEmpty()) {
    return next;
   }
  }
  return endOfData();
 }
};

代码示例来源：origin: google/guava

@Override
 public void parse(CacheBuilderSpec spec, String key, String value) {
  checkArgument(value != null && !value.isEmpty(), "value of key %s omitted", key);
  try {
   parseLong(spec, Long.parseLong(value));
  } catch (NumberFormatException e) {
   throw new IllegalArgumentException(
     format("key %s value set to %s, must be integer", key, value), e);
  }
 }
}

代码示例来源：origin: spring-projects/spring-framework

private String resolveExpression(A annotation) {
  for (String attributeName : EXPRESSION_ATTRIBUTES) {
    Object val = AnnotationUtils.getValue(annotation, attributeName);
    if (val instanceof String) {
      String str = (String) val;
      if (!str.isEmpty()) {
        return str;
      }
    }
  }
  throw new IllegalStateException("Failed to resolve expression: " + annotation);
}

代码示例来源：origin: spring-projects/spring-framework

@Override
  public T convert(String source) {
    if (source.isEmpty()) {
      return null;
    }
    return NumberUtils.parseNumber(source, this.targetType);
  }
}

代码示例来源：origin: spring-projects/spring-framework

/**
 * Base64-decode the given byte array from an UTF-8 String.
 * @param src the encoded UTF-8 String
 * @return the original byte array
 */
public static byte[] decodeFromString(String src) {
  if (src.isEmpty()) {
    return new byte[0];
  }
  return decode(src.getBytes(DEFAULT_CHARSET));
}

代码示例来源：origin: square/okhttp

static int readInt(BufferedSource source) throws IOException {
 try {
  long result = source.readDecimalLong();
  String line = source.readUtf8LineStrict();
  if (result < 0 || result > Integer.MAX_VALUE || !line.isEmpty()) {
   throw new IOException("expected an int but was \"" + result + line + "\"");
  }
  return (int) result;
 } catch (NumberFormatException e) {
  throw new IOException(e.getMessage());
 }
}

代码示例来源：origin: google/guava

private static String firstCharOnlyToUpper(String word) {
  return word.isEmpty()
    ? word
    : Ascii.toUpperCase(word.charAt(0)) + Ascii.toLowerCase(word.substring(1));
 }
}

代码示例来源：origin: square/okhttp

/**
 * Sets this request's {@code Cache-Control} header, replacing any cache control headers already
 * present. If {@code cacheControl} doesn't define any directives, this clears this request's
 * cache-control headers.
 */
public Builder cacheControl(CacheControl cacheControl) {
 String value = cacheControl.toString();
 if (value.isEmpty()) return removeHeader("Cache-Control");
 return header("Cache-Control", value);
}

代码示例来源：origin: spring-projects/spring-framework

private String getPartName(MethodParameter methodParam, @Nullable RequestPart requestPart) {
  String partName = (requestPart != null ? requestPart.name() : "");
  if (partName.isEmpty()) {
    partName = methodParam.getParameterName();
    if (partName == null) {
      throw new IllegalArgumentException("Request part name for argument type [" +
          methodParam.getNestedParameterType().getName() +
          "] not specified, and parameter name information not found in class file either.");
    }
  }
  return partName;
}

代码示例来源：origin: spring-projects/spring-framework

private String getPartName(MethodParameter methodParam, @Nullable RequestPart requestPart) {
  String partName = (requestPart != null ? requestPart.name() : "");
  if (partName.isEmpty()) {
    partName = methodParam.getParameterName();
    if (partName == null) {
      throw new IllegalArgumentException("Request part name for argument type [" +
          methodParam.getNestedParameterType().getName() +
          "] not specified, and parameter name information not found in class file either.");
    }
  }
  return partName;
}

代码示例来源：origin: spring-projects/spring-framework

private Expression parseTemplate(String expressionString, ParserContext context) throws ParseException {
  if (expressionString.isEmpty()) {
    return new LiteralExpression("");
  }
  Expression[] expressions = parseExpressions(expressionString, context);
  if (expressions.length == 1) {
    return expressions[0];
  }
  else {
    return new CompositeStringExpression(expressionString, expressions);
  }
}