/**
* 关于String类的常用方法总结
* @author lsq
*
*/
public class StringAPIDemo {
public static void main(String[] args) {
/*
* public char[] toCharArray()将一个字符串变成字符数组
* public byte[] getBytes()将一个字符串变成字节数组
*/
String str = "Hello";
char[] charArray = str.toCharArray();
byte[] bytes = str.getBytes();
//循环输出字符数组
for (int i = 0; i < charArray.length; i++) {
System.out.print(charArray[i]+",");
}
//循环输出字节数组
for (int i = 0; i < bytes.length; i++) {
System.out.print(bytes[i]+",");
}
System.out.println("");
System.out.println("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~");
/*
* public String(char[] value)将字符数组变成一个字符串
* public String(char[] value, int offset, int count)将制定范围内的字符变为字符串，offset是起始点，count是长度
* public String(byte[] bytes)将全部的字节数组变成字符串
* public String(byte[] bytes, int offset, int length)将制定范围内的字节数组变成字符串，offset是起始点，count是长度
*/
char charArray2[] = {'H','E','L','L','O',' ','J','A','V','A'};
byte bytes2[] = {'1','2','3','4'};
String char2str1 = new String(charArray2);
String char2str2 = new String(charArray2, 3, 2);
String byte2str1 = new String(bytes2);
String byte2str2 = new String(bytes2, 1, 2);
System.out.println("char2str1的值是："+char2str1);
System.out.println("char2str2的值是："+char2str2);
System.out.println("byte2str1的值是："+byte2str1);
System.out.println("byte2str2的值是："+byte2str2);
System.out.println("");
System.out.println("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~");
/*
* public char charAt(int index)从一个字符串中取出指定位置的字符
*/
String charAtTest = "charAtTest";
char c = charAtTest.charAt(4);
System.out.println("charAtTest位置为4的字符是："+c);
System.out.println("");
System.out.println("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~");
/*
* public int length()获取字符串的长度
*/
String strLength = "strLength";
int length = strLength.length();
System.out.println(length);
System.out.println("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~");
/*
* 查找指定的字符串是否存在：
* public int indexOf(String str)从头开始查找字符串是否存在，返回int类型，若查找不到，返回-1
* public int indexOf(String str, int fromIndex)从指定位置开始查找指定的字符串是否存在，返回int类型，找不到返回-1
*/
String strindexOf = "abcdefgcdhi";
System.out.println(strindexOf.indexOf("cd"));
System.out.println(strindexOf.indexOf("c",3));
System.out.println(strindexOf.indexOf("j"));
System.out.println("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~");
/*
* public String trim()去掉字符串中左右的空格，但中间的空格不会去掉
*/
String strTrim = " Hello java ";
System.out.println(strTrim.trim());
System.out.println("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~");
/*
* 字符串截取：从一个字符串中取出部分内容
* substring(int beginIndex)从指定位置开始截取至字符串结尾、
* subString(int beginIndex, int endIndex)截取指定范围的字符串，不包括结束位置的字符（☆）
*/
String strsubString = "i love java!";
System.out.println(strsubString.substring(2));
System.out.println(strsubString.substring(2,8));
System.out.println("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~");
/*
* public String[] split(String regex)拆分字符串，以某一个字符串作为拆分点
*/
String strsplit = "Hello World! How are you?";
String[] splits = strsplit.split(" ");
for (int i = 0; i < splits.length; i++) {
System.out.println(splits[i]);
}
System.out.println("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~");
/*
* public String toLowerCase():将字符串字符都变为小写
* public String toUpperCase():将字符串字符都变为大写
*/
String strToCase = "Hello java!";
System.out.println(strToCase.toLowerCase());
System.out.println(strToCase.toUpperCase());
System.out.println("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~");
/*
* 判断是否以指定的字符串开头或者结尾
* public boolean startsWith(String prefix):判断是否以指定的字符串开头
* public boolean endsWith(String suffix):判断是否以指定的字符串结尾
*/
String strWith = "Hello World!";
boolean s = strWith.startsWith("Hel");
System.out.println(s);
boolean e = strWith.endsWith("d!");
System.out.println(e);
System.out.println("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~");
/*
* 判断两个字符串是否相等：
* public boolean equals(Object anObject):区分大小写
* public boolean equalsIgnoreCase(String anotherString):不区分大小写
*/
String strEquals1 = "String";
String strEquals2 = "string";
System.out.println(strEquals1.equals(strEquals2));
System.out.println(strEquals1.equalsIgnoreCase(strEquals2));
System.out.println("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~");
/*
* 字符串替换功能
* public String replace(CharSequence target, CharSequence replacement)
* public String replaceAll(String regex, String replacement):将指定的字符regex替换成指定的replacement
*/
String strReplace = "Hello java!";
System.out.println(strReplace.replace('o', 'l'));
System.out.println(strReplace.replaceAll("java", "World"));
System.out.println("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~");
}
}
