java String類方法

10月8日學習：

public class StringDemoCharArray {
    public static void main(String[] args) {
        //1、new String
        char[] helloArray = {'r', 'u', 'n', 'o', 'o', 'b'};
        String helloString = new String(helloArray);
        System.out.println("helloString:" + helloString);
        //2、size
        int size = helloString.length();
        System.out.println("--------------------------------------------");
        System.out.println("size:" + size);
        //3、concat
        String siteChinaName = "菜鳥驛站";
        String siteEnglishName = "runoob";
        System.out.println("--------------------------------------------");
        System.out.println("concat:" + siteChinaName.concat(siteEnglishName));
        //4、charAt
        char[] c = {'h', 'e', 'l', 'l', 'o'};
        String hello = new String(c);
        char c1 = hello.charAt(0);
        System.out.println("--------------------------------------------");
        System.out.println("charAt:" + c1);
        //5、codePointAt
        String strCodePointAt = "123";
        int intIndex = strCodePointAt.codePointAt(0);
        System.out.println("--------------------------------------------");
        System.out.println("intIndex:" + intIndex);
        //6、codePointBefore
        String strCodePointBefore = "JAVA";
        int intIndexBefore = strCodePointBefore.codePointBefore(3);
        System.out.println("--------------------------------------------");
        System.out.println("intIndexBefore:" + intIndexBefore);
        //7、codePointCount
        String strCodePointCount = "12345";
        int intIndexCount = strCodePointCount.codePointCount(1, 4);
        System.out.println("--------------------------------------------");
        System.out.println("intIndexCount:" + intIndexCount);
        //8、compareTo
        String strCompareTo1 = "helloaa";
        String strCompareTo2 = "helloAa";
        int intCompareTo = strCompareTo1.compareTo(strCompareTo2);
        System.out.println("--------------------------------------------");
        System.out.println("intCompareTo:" + intCompareTo);
        if (intCompareTo > 0) {
            System.out.println("strCompareTo1與strCompareTo2長度比較:" + strCompareTo1.length() + ">" + strCompareTo2.length());
        } else if (intCompareTo == 0) {
            System.out.println("strCompareTo1 == strCompareTo2長度");
        } else {
            System.out.println("strCompareTo1與strCompareTo2長度比較:" + strCompareTo1.length() + "<" + strCompareTo2.length());
        }
        //9、compareToIgnoreCase
        String strCompareToIgnoreCase1="hello";
        String strCompareToIgnoreCase2="HELLO";
        int intCompareToIgnoreCase = strCompareToIgnoreCase1.compareToIgnoreCase(strCompareToIgnoreCase2);
        System.out.println("--------------------------------------------");
        if (intCompareToIgnoreCase > 0) {
            System.out.println("strCompareToIgnoreCase1與strCompareToIgnoreCase2長度比較:" + strCompareToIgnoreCase1.length() + ">" + strCompareToIgnoreCase2.length());
        } else if (intCompareToIgnoreCase == 0) {
            System.out.println("strCompareToIgnoreCase1 == strCompareToIgnoreCase2長度");
        } else {
            System.out.println("strCompareToIgnoreCase1與strCompareToIgnoreCase2長度比較:" + strCompareToIgnoreCase1.length() + "<" + strCompareToIgnoreCase2.length());
        }
        //10、contains
        String strContains1 = "helloworld";
        String strContains2 = "world";
        boolean intContains = strContains1.contains(strContains2);
        System.out.println("--------------------------------------------");
        System.out.println("intContains:"+intContains);
        //11、contentEquals(CharSequence)
        String strContentEquals1 = "hello";
        String strContentEquals2 = "hello";
        CharSequence cs = "123";
        System.out.println("--------------------------------------------");
        System.out.println("strContentEquals1:" + strContentEquals1.contentEquals("hello"));
        System.out.println("strContentEquals2:" + strContentEquals2.contentEquals("a"));
        System.out.println("strContentEquals1:" + strContentEquals1.contentEquals(cs));
        //12、contentEquals(StringBuffer)
        String strBufferContentEquals1 = "hello";
        String strBufferContentEquals2 = "hello";
        StringBuffer stringBuffer =new StringBuffer("strBufferContentEquals2");
        System.out.println("--------------------------------------------");
        System.out.println("strBufferContentEquals2:"+strBufferContentEquals2.contentEquals(stringBuffer));
    }
}

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