社群网站建设,赣州网上房地产,怎么提高网站速度,为企业建网站过时了1 需求
1.1 Field Summary 1.2 Constructor Summary
public String() : 空构造public String(byte[] bytes) : 把字节数组转成字符串public String(byte[] bytes,int index, int length) : 把字节数组的一部分转成字符串public String(char[] value) : 把字符数组转成字符串p…1 需求
1.1 Field Summary 1.2 Constructor Summary
public String() : 空构造public String(byte[] bytes) : 把字节数组转成字符串public String(byte[] bytes,int index, int length) : 把字节数组的一部分转成字符串public String(char[] value) : 把字符数组转成字符串public String(char[] value,int index, int count) : 把字符数组的一部分转成字符串 1.3 Method Summary
判断字符串是否为空 public boolean isEmpty()获取字符串的长度 public int length()判断字符串是否相等 public boolean equals(Object anObject)public boolean contentEquals(StringBuffer sb)public boolean contentEquals(CharSequence cs)public boolean equalsIgnoreCase(String anotherString)判断是否包含子字符串 public boolean contains(CharSequence s)public boolean matches(String regex)…… public boolean startsWith(String prefix, int toffset)public boolean startsWith(String prefix)…… public boolean endsWith(String suffix) 分割字符串 public String[] split(String regex)public String[] split(String regex, int limit)…… public int indexOf(int ch)public int indexOf(int ch, int fromIndex)public int indexOf(String str)public int indexOf(String str, int fromIndex)判断某个字符最后出现的位置 public int lastIndexOf(int ch)public int lastIndexOf(int ch, int fromIndex)public int lastIndexOf(String str)public int lastIndexOf(String str, int fromIndex)字符串替换 public String replace(char oldChar, char newChar)public String replace(CharSequence target, CharSequence replacement)public String replaceFirst(String regex, String replacement)public String replaceAll(String regex, String replacement)字符串查找 public String substring(int beginIndex)public String substring(int beginIndex, int endIndex)public CharSequence subSequence(int beginIndex, int endIndex) 2 接口 3.X 示例字符串定义两种方式
public class Test {public static void main(String[] args) {String s1 hello;String s2 new String(hello);System.out.println(s1 s2);}
} 参考资料
JAVA字符串的两种定义方式的区别_java中字符串的定义方式及区别-CSDN博客 3.X 示例未初始化报错
public class Test {public static void main(String[] args) {String s1;System.out.println(s1);}
} 3.X 示例空字符串
public class Test {public static void main(String[] args) {String s1 ;System.out.println(s1.isEmpty());System.out.println(s1.length());}
} 3.X 示例null字符串
public class Test {public static void main(String[] args) {String s1 null;System.out.println(s1.isEmpty());}
} public class Test {public static void main(String[] args) {String s1 null;System.out.println(s1.length());}
} 4 参考资料
java基础-String_public string{byte[] bytes,-CSDN博客
