???Java?????? ??????????
???????????? ???????[ 2017/1/3 10:47:56 ] ??????????????????? Java
????????????????????????????????????????????????????????д?????????????????
????1 ==???????
???????????α????????????
????<code class=" hljs cs">Integer a = 1000??b=1000;
????Integer c = 100??d=100;
????public void mRun(final String name){
????new Runnable() {
????public void run() {
????System.out.println(name);
????}
????};
????}
????System.out.println(a==b);
????System.out.println(c==d); </code>
????????????????ó??????????????????е?????????????????????????????? ?? true ??true????????????????????
????????????′??? ???д?????????? false true?????????==?????????????????????????abcd??????????????????????????????false???????????????????????????????????????????????????????????????????????????????????Integer.java???????????
????<code class=" hljs java">public static Integer valueOf(int i) {
????return i >= 128 || i < -128 ? new Integer(i) : SMALL_VALUES[i + 128];
????}
????/**
????* A cache of instances used by {@link Integer#valueOf(int)} and auto-boxing
????*/
????private static final Integer[] SMALL_VALUES = new Integer[256];
????static {
????for (int i = -128; i < 128; i++) {
????SMALL_VALUES[i + 128] = new Integer(i);
????}
????} </code>
?????????????????Integer c = 100;???????????????????????????????????????????????????Integer???????????Integer????????????valueOf???????????????Integer?а?-128-127 ?????????????????????С????????????????????????????????????????????????????????????????????????false??ture???????????Integer????????-128-127??????????????????????????????true??
????2 String
????<code class=" hljs vhdl">String s1 = "abc";
????String s2 = "abc";
????String s3 = new String("abc");
????System.out.println(s1 == s2);
????System.out.println(s1 == s3); </code>
?????????????????????????????
????????==?????????? ????s1??s2??s3????????????????????????????????false?????????????н????true??false??????????false???????????????true???????????????????Щ?????????????????????????????????????????з????????????????new ?????????????顣????????????????????????????????????????String s1 = “abc”; ????????????????????????洢????????С??????????String s1 = “abc”??????????????”abc”?洢?????????????????????????У??????????????String s2 = “abc” ?????Java????????????????в?????????”abc”?????????????s2????????????????′???????????????????????????????С????????????true ??false?????
????3 final?????
????<code class=" hljs cs">public void mRun(final String name){
????new Runnable() {
????public void run() {
????try {
????Thread.sleep(1000);
????} catch (InterruptedException e) {
????// TODO Auto-generated catch block
????e.printStackTrace();
????}
????System.out.println(name);
????}
????}.start();
????} </code>
?????????????????д????????????????????????????????????????final???η??????????????????????????????????????????????????????????final???η???????????С??鶼?????????????????????????????????????????????????е???????????????????????????????????????????????????????
????????????????????£???????final???????????????????????????????????????????????????????????????????????????????????????mRun??????У?new ????????У??????????????????????????У?mRun???????name?????????????????1?????Syetem.out.printh(name)??С???????name????????????????????????Java??????????????????????????з?λ????????????????final????????Ρ??????????final??????????????????б????????????????????????????????????????????????????????????????????????????????????????Java?????????????????????????????????????ж???С???????????????????????????
????4 Integer??int??Щ??
????<code class=" hljs vhdl">Integer a = new Integer(1000);
????int b = 1000;
????Integer c = new Integer(10);
????Integer d = new Integer(10);
????System.out.println(a == b);
????System.out.println(c == d); </code>
???????????????????????????????????????ó?????????????==?????????????????????
??????????? true ??false
????????????????С??????????????μ????????????????Integer?????-128-127?????????????????????true????????????????????Integer?????????new??????????????????棬????????false?? ???????????????????true????? ???????????1000????????????????Integer??????й??????????????й????a????new???????????????????????false???????????b??????int???????int??Integer????==???????Java???Integer???????????????Integer???int???????????????б?????int?????????????????true??
??????
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