String

Posted 2021-02-19

鏍囩锛?a href='http://www.mamicode.com/so/1/%e5%ad%90%e4%b8%b2' title='瀛愪覆'>瀛愪覆   format   涓枃   tps   builder   eal   reg   ==   

hashCode

 public int hashCode() {
        int h = hash;
        if (h == 0 && value.length > 0) {   //hash 榛樿鍊间负0(姝ゆ椂杩樻病鏈夎绠梙ash) && String涓殑瀛楄妭鏁扮粍鏈夊€?浣跨敤 String str="avc"; hash鍒濆鍊间负0锛屼娇鐢╪ew String("avc"),鏋勯€犳椂璁＄畻)
            char val[] = value;

            for (int i = 0; i < value.length; i++) {
                h = 31 * h + val[i];        //涓轰粈涔堜娇鐢?1锛?https://www.cnblogs.com/nullllun/p/8350178.html
            }
            hash = h;
        }
        return h;
    }

toCharArray

   
   public char[] toCharArray() {
        // Cannot use Arrays.copyOf because of class initialization order issues
        char result[] = new char[value.length];
        System.arraycopy(value, 0, result, 0, value.length);
        return result;
    }


銆€銆€System涓殑鏂规硶
      src         鍘熸暟缁?      srcPos      浠庡厓鏁版嵁鐨勮捣濮嬩綅缃紑濮?      dest        鐩爣鏁扮粍
      destPos     鐩爣鏁扮粍鐨勫紑濮嬭捣濮嬩綅缃?      length      瑕乧opy鐨勬暟缁勭殑闀垮害
    public static native void arraycopy(Object src,  int  srcPos,
                                        Object dest, int destPos,
                                        int length);

getChars

    public void getChars(int srcBegin, int srcEnd, char dst[], int dstBegin) {
        if (srcBegin < 0) {
            throw new StringIndexOutOfBoundsException(srcBegin);
        }
        if (srcEnd > value.length) {
            throw new StringIndexOutOfBoundsException(srcEnd);
        }
        if (srcBegin > srcEnd) {
            throw new StringIndexOutOfBoundsException(srcEnd - srcBegin);
        }
        System.arraycopy(value, srcBegin, dst, dstBegin, srcEnd - srcBegin);
    }

toCharArray 涓?getChars 閮芥槸璋冪敤浜?System.arraycopy

equals

銆€銆€閲嶅啓浜嗘柟娉曪紝鍏堝垽鏂?=锛屽啀鍒ゆ柇鏄惁涓篠tring绫诲瀷锛屽啀鍒ゆ柇闀垮害鐩哥瓑锛屽啀鍒ゆ柇姣忎竴涓厓绱?/pre>

    public boolean equals(Object anObject) {
        if (this == anObject) {
            return true;
        }
        if (anObject instanceof String) {
            String anotherString = (String) anObject;
            int n = value.length;
            if (n == anotherString.value.length) {
                char v1[] = value;
                char v2[] = anotherString.value;
                int i = 0;
                while (n-- != 0) {
                    if (v1[i] != v2[i])
                        return false;
                    i++;
                }
                return true;
            }
        }
        return false;
    }



    2.3 length
            瀛楄妭鏁扮粍鐨勫ぇ灏?
    2.4 isEmpty
    2.5 charAt
    2.6 codePointAt
            瀵瑰簲绱㈠紩浣嶇疆鐨?ascII鐮佽〃(涓枃)鎴朥nicode浠ｇ爜鐐?鑻辨枃)

    2.7 equals
            閲嶅啓浜嗘柟娉曪紝鎯冲垽鏂?/span>==锛屽啀鍒ゆ柇鏄惁涓篠tring绫诲瀷锛屽啀鍒ゆ柇闀垮害鐩哥瓑锛屽啀鍒ゆ柇姣忎竴涓厓绱?
    2.8 contentEquals
            鍙傛暟浼? StringBuffer 鍜?StringBuilder 锛屽绾跨▼涓嶅畨鍏ㄧ殑鍔犻攣锛屾墍浠ヤ笉濂界敤

    2.9  equalsIgnoreCase
    2.10 compareTo
            鐢ㄥ瓧绗︿覆1璺熷瓧绗︿覆2浣滄瘮杈冿紝濡傛灉瀛楃涓?鐨勫瓧鍏搁『搴忓湪瀛楃涓?鍓嶉潰锛屽垯杩斿洖涓€涓礋鏁般€傝嫢鍦ㄥ悗闈紝鍒欒繑鍥炰竴涓鏁般€傝嫢涓や釜瀛楃涓茬殑瀛楀吀椤哄簭鐩稿悓锛屽垯杩斿洖0銆?            鎺掑簭鐨勬椂鍊欎娇鐢?    2.11 compareToIgnoreCase
    2.12 regionMatches
            浠庡綋鍓嶅瓧绗︿覆鐨刦irstStart浣嶇疆寮€濮嬶紝鍙栦竴涓暱搴︿负len鐨勫瓙涓诧紱鐒跺悗浠庡彟涓€涓瓧绗︿覆other鐨刼therStart浣嶇疆寮€濮嬩篃鍙栦竴涓暱搴︿负len鐨勫瓙涓诧紝鐒跺悗姣旇緝杩欎袱涓瓙涓叉槸鍚︾浉鍚岋紝濡傛灉杩欎袱涓瓙涓茬浉鍚屽垯杩斿洖true锛屽惁鍒欒繑鍥瀎alse
    2.13 startsWith(String prefix, int toffset)
            娴嬭瘯婧愬瓧绗︿覆鏄惁浠庣储寮晅offset澶勫紑濮嬩互瀛楃涓瞤refix寮€濮?    2.14 indexOf
    2.15 lastIndexOf
    2.16 substring
    2.17 concat
    2.18 replace
    2.19 matches
            璇ユ柟娉曠敤鏉ュ垽鏂繖涓瓧绗︿覆鏄惁鍖归厤缁欏畾鐨勬鍒欒〃杈惧紡
    2.20 replaceFirst

    2.21 replaceAll
    2.22 split
    2.23 join
    2.24 toLowerCase
    2.25 toUpperCase
    2.26 trim
    2.27 toString
    2.28 valueOf
    2.29 format
            瀛楃涓叉牸寮忓寲  https://segmentfault.com/a/1190000019350486

 





以上是关于String的主要内容，如果未能解决你的问题，请参考以下文章
 
 如何理解这段代码片段中的两对括号？
 Failed to convert property value of type ‘java.lang.String‘ to required type ‘int‘ for property(代码片段
 面试常用的代码片段
 21个常用代码片段
 js常用代码片段
 java.lang.NullPointerException: Attempt to invoke virtual method ‘int android.database.sqlite异常(代码片段