java String类方法

10月8日学习：

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 = "菜鸟驿站";        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与strCompareTo2长度比较:" + strCompareTo1.length() + ">" + strCompareTo2.length());        } else if (intCompareTo == 0) {            System.out.println("strCompareTo1 == strCompareTo2长度");        } else {            System.out.println("strCompareTo1与strCompareTo2长度比较:" + 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与strCompareToIgnoreCase2长度比较:" + strCompareToIgnoreCase1.length() + ">" + strCompareToIgnoreCase2.length());        } else if (intCompareToIgnoreCase == 0) {            System.out.println("strCompareToIgnoreCase1 == strCompareToIgnoreCase2长度");        } else {            System.out.println("strCompareToIgnoreCase1与strCompareToIgnoreCase2长度比较:" + 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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