\u4ece\u8be5\u89d2\u5ea6\u770b\u7684\u8bddJava\u5185\u5b58\u7ed3\u6784\u5305\u542b\u4ee5\u4e0b\u90e8\u5206\uff1a<\/p>
1\u3001\u6808\u533a\uff1a\u7531\u7f16\u8bd1\u5668\u81ea\u52a8\u5206\u914d\u91ca\u653e\uff0c\u5177\u4f53\u65b9\u6cd5\u6267\u884c\u7ed3\u675f\u540e\uff0c\u7cfb\u7edf\u81ea\u52a8\u91ca\u653eJVM\u5185\u5b58\u8d44\u6e90\u3002<\/p>
\u5176\u4f5c\u7528\u6709\u4fdd\u5b58\u5c40\u90e8\u53d8\u91cf\u7684\u503c\uff0c\u5305\u62ec\uff1a1.\u7528\u6765\u4fdd\u5b58\u57fa\u672c\u6570\u636e\u7c7b\u578b\u7684\u503c\uff1b2.\u4fdd\u5b58\u7c7b\u7684\u5b9e\u4f8b\uff0c\u5373\u5806\u533a\u5bf9\u8c61\u7684\u5f15\u7528\u3002\u4e5f\u53ef\u4ee5\u7528\u6765\u4fdd\u5b58\u52a0\u8f7d\u65b9\u6cd5\u65f6\u7684\u5e27\u3002<\/p>
2\u3001\u5806\u533a\uff1a\u4e00\u822c\u7531\u7a0b\u5e8f\u5458\u5206\u914d\u91ca\u653e\uff0cJVM\u4e0d\u5b9a\u65f6\u67e5\u770b\u8fd9\u4e2a\u5bf9\u8c61\uff0c\u5982\u679c\u6ca1\u6709\u5f15\u7528\u6307\u5411\u8fd9\u4e2a\u5bf9\u8c61\u5c31\u56de\u6536\u3002<\/p>
\u5176\u4f5c\u7528\u4e3a\u7528\u6765\u5b58\u653e\u52a8\u6001\u4ea7\u751f\u7684\u6570\u636e\uff0c\u5305\u62ecnew\u51fa\u6765\u7684\u5b9e\u4f8b\uff0c\u5b57\u7b26\u6570\u7ec4\u7b49\u3002\u6ce8\u610f\u521b\u5efa\u51fa\u6765\u7684\u5bf9\u8c61\u53ea\u5305\u542b\u5c5e\u4e8e\u5404\u81ea\u7684\u6210\u5458\u53d8\u91cf\uff0c\u5e76\u4e0d\u5305\u62ec\u6210\u5458\u65b9\u6cd5\u3002<\/p>
\u56e0\u4e3a\u540c\u4e00\u4e2a\u7c7b\u7684\u5bf9\u8c61\u62e5\u6709\u5404\u81ea\u7684\u6210\u5458\u53d8\u91cf\uff0c\u5b58\u50a8\u5728\u5404\u81ea\u7684\u5806\u4e2d\uff0c\u4f46\u662f\u4ed6\u4eec\u5171\u4eab\u8be5\u7c7b\u7684\u65b9\u6cd5\uff0c\u5e76\u4e0d\u662f\u6bcf\u521b\u5efa\u4e00\u4e2a\u5bf9\u8c61\u5c31\u628a\u6210\u5458\u65b9\u6cd5\u590d\u5236\u4e00\u6b21\u3002<\/p>
3\u3001\u4ee3\u7801\u533a\uff1a\u5b58\u653e\u7a0b\u5e8f\u4e2d\u65b9\u6cd5\u7684\u4e8c\u8fdb\u5236\u4ee3\u7801\uff0c\u800c\u4e14\u662f\u591a\u4e2a\u5bf9\u8c61\u5171\u4eab\u4e00\u4e2a\u4ee3\u7801\u7a7a\u95f4\u533a\u57df\u3002<\/p>
4\u3001\u6570\u636e\u533a\uff1a\u7528\u6765\u5b58\u653estatic\u5b9a\u4e49\u7684\u9759\u6001\u6210\u5458\u3002<\/p>
5\u3001\u5e38\u91cf\u6c60\uff1aJVM\u4e3a\u6bcf\u4e2a\u5df2\u52a0\u8f7d\u7684\u7c7b\u578b\u7ef4\u62a4\u4e00\u4e2a\u5e38\u91cf\u6c60\uff0c\u5e38\u91cf\u6c60\u5c31\u662f\u8fd9\u4e2a\u7c7b\u578b\u7528\u5230\u7684\u5e38\u91cf\u7684\u4e00\u4e2a\u6709\u5e8f\u96c6\u5408\u3002\u5305\u62ec\u76f4\u63a5\u5e38\u91cf(\u57fa\u672c\u7c7b\u578b\uff0cString)\u548c\u5bf9\u5176\u4ed6\u7c7b\u578b\u3001\u65b9\u6cd5\u3001\u5b57\u6bb5\u7684\u7b26\u53f7\u5f15\u7528\u3002\u6c60\u4e2d\u7684\u6570\u636e\u548c\u6570\u7ec4\u4e00\u6837\u901a\u8fc7\u7d22\u5f15\u8bbf\u95ee\u3002\u7531\u4e8e\u5e38\u91cf\u6c60\u5305\u542b\u4e86\u4e00\u4e2a\u7c7b\u578b\u6240\u6709\u7684\u5bf9\u5176\u4ed6\u7c7b\u578b\u3001\u65b9\u6cd5\u3001\u5b57\u6bb5\u7684\u7b26\u53f7\u5f15\u7528\uff0c\u6240\u4ee5\u5e38\u91cf\u6c60\u5728Java\u7684\u52a8\u6001\u94fe\u63a5\u4e2d\u8d77\u4e86\u6838\u5fc3\u4f5c\u7528\u3002\u5e38\u91cf\u6c60\u5b58\u5728\u4e8e\u5806\u4e2d\u3002<\/p>
\u4e0b\u56fe\u5927\u81f4\u63cf\u8ff0\u4e86JAVA\u7684\u5185\u5b58\u5206\u914d<\/p>
![\"\"](\"..\/..\/upload\/2017_05\/170521204923951.png\")
<\/p>
\u4e8c\u3001\u4ece\u64cd\u4f5c\u7cfb\u7edf\u4e0a\u7684\u8fdb\u7a0b\u7684\u89d2\u5ea6\u3002<\/p>
\u8fd9\u91cc\u5207\u8bb0\u4e00\u70b9\uff1aJVM\u89c4\u8303\u6240\u63cf\u8ff0\u7684\u62bd\u8c61JVM\u6982\u5ff5\u4e0e\u5b9e\u9645\u5b9e\u73b0\u5e76\u4e0d\u603b\u4e00\u4e00\u5bf9\u5e94\u3002<\/p>
\u63a5\u6765\u4e0b\u6211\u4eec\u6765\u770b\u4e00\u6bb5\u4ee3\u7801\u5b9e\u4f8b\u4e0e\u6ce8\u91ca\uff1a<\/p>
public class TestStringConstant {
public static void main(String args[]) {
\/\/ \u5b57\u7b26\u4e32\u5e38\u91cf\uff0c\u5206\u914d\u5728\u5e38\u91cf\u6c60\u4e2d\uff0c\u7f16\u8bd1\u5668\u4f1a\u5bf9\u5176\u8fdb\u884c\u4f18\u5316\uff0c Interned table
\/\/ \u5373\u5f53\u4e00\u4e2a\u5b57\u7b26\u4e32\u5df2\u7ecf\u5b58\u5728\u65f6\uff0c\u4e0d\u518d\u91cd\u590d\u521b\u5efa\u4e00\u4e2a\u76f8\u540c\u7684\u5bf9\u8c61\uff0c\u800c\u662f\u76f4\u63a5\u5c06s2\u4e5f\u6307\u5411"hello".
String s1 = "hello";
String s2 = "hello";
\/\/ new\u51fa\u6765\u7684\u5bf9\u8c61\uff0c\u5206\u914d\u5728heap\u4e2d.s3\u4e0es4\u867d\u7136\u5b83\u4eec\u6307\u5411\u7684\u5b57\u7b26\u4e32\u5185\u5bb9\u662f\u76f8\u540c\u7684\uff0c\u4f46\u662f\u662f\u4e24\u4e2a\u4e0d\u540c\u7684\u5bf9\u8c61.
\/\/ \u56e0\u6b64==\u8fdb\u884c\u6bd4\u8f83\u65f6\uff0c\u5176\u6240\u5b58\u7684\u5f15\u7528\u662f\u4e0d\u540c\u7684\uff0c\u6545\u4e0d\u4f1a\u76f8\u7b49
String s3 = new String("world");
String s4 = new String("world");
System.out.println(s1 == s2); \/\/ true
System.out.println(s3 == s4); \/\/ false
System.out.println(s3.equals(s4)); \/\/ true
\/\/ String\u4e2dequals\u65b9\u6cd5\u5df2\u7ecf\u88ab\u91cd\u5199\u8fc7\uff0c\u6bd4\u8f83\u7684\u662f\u5185\u5bb9\u662f\u5426\u76f8\u7b49.
}
}<\/p>
\u90a3\u4e48\u5bf9\u4e8e\u4e0a\u4f8b\u4ee3\u7801\u4e2d\u63d0\u5230\u7684\u7f16\u8bd1\u5668\u7684\u4f18\u5316\uff0c\u4e0b\u9762\u5c06\u8fdb\u884c\u66f4\u8fdb\u4e00\u6b65\u7684\u8be6\u7ec6\u4ecb\u7ecd\u3002\u8bf7\u770b\u4e0b\u4f8b\u4ee3\u7801\uff1a<\/p>
class A {
private String a = "aa";
public boolean methodB() {
String b = "bb";
final String c = "cc";
return false;
}
}<\/p>
\u3000\u3000"aa"\u3001"bb"\u7684String\u5bf9\u8c61\u6309JVM\u89c4\u8303\u5728Java heap\u4e0a\uff0c\u5728JDK8\u4e4b\u524d\u7684HotSpot VM\u5b9e\u73b0\u91cc\u5728PermGen\uff0c\u5728JDK7\u5f00\u59cb\u7684HotSpot VM\u91cc\u5728\u666e\u901aJava heap\u91cc\uff08\u800c\u4e0d\u5728PermGen\u91cc\uff09\uff1b"cc"\u5982\u679c\u5b58\u5728\u7684\u8bdd\u4e5f\u4e00\u6837\uff0c\u4f46\u662f\u53ef\u80fd\u4f1a\u4e0d\u5b58\u5728\u3002<\/p>
\u8fd9\u4e9bString\u5bf9\u8c61\u5c5e\u4e8e\u201cinterned String\u201d\u3002String\u662fJava\u5bf9\u8c61\uff0c\u6839\u636eJVM\u89c4\u8303\u7684\u5b9a\u4e49\u5b83\u5fc5\u987b\u5b58\u5728\u4e8eJava heap\u4e2d\uff0cinterned String\u4e5f\u4e0d\u4f8b\u5916\u3002Interned String\u7279\u522b\u7684\u5730\u65b9\u5728\u4e8eJVM\u4f1a\u6709\u4e2aStringTable\u5b58\u7740interned String\u7684\u5f15\u7528\uff0c\u4fdd\u8bc1\u5185\u5bb9\u76f8\u540c\u7684String\u5bf9\u8c61\u4e0d\u88ab\u91cd\u590dintern\u3002\uff08\u8fd9\u91cc\u4fbf\u662f\u7f16\u8bd1\u5668\u7684\u4f18\u5316\uff09<\/p>
\u8fd9\u4e2aStringTable\u600e\u6837\u5b9e\u73b0JVM\u89c4\u8303\u91cc\u5e76\u6ca1\u6709\u89c4\u5b9a\uff0c\u4e0d\u8fc7\u901a\u5e38\u5b83\u5e76\u4e0d\u4fdd\u5b58String\u5bf9\u8c61\u7684\u5185\u5bb9\uff0c\u800c\u53ea\u662f\u4fdd\u5b58String\u5bf9\u8c61\u7684\u5f15\u7528\u800c\u5df2\u3002<\/p>
a\u53d8\u91cf\u4f5c\u4e3aA\u7c7b\u7684\u5bf9\u8c61\u5b9e\u4f8b\u5b57\u6bb5\uff0c\u4f1a\u8ddf\u968fA\u7684\u5b9e\u4f8b\u5728Java heap\u4e0a\u3002<\/p>
b\u53d8\u91cf\u4f5c\u4e3a\u5c40\u90e8\u53d8\u91cf\u4f1a\u5728Java\u7ebf\u7a0b\u6808\u4e0a\u3002<\/p>
c\u53d8\u91cf\u867d\u7136\u4e5f\u662f\u5c40\u90e8\u53d8\u91cf\uff0c\u4f46\u56e0\u4e3a\u6709final\u4fee\u9970\u5e76\u4e14\u6709\u521d\u59cb\u5316\u4e3a\u4e00\u4e2a\u5e38\u91cf\u503c\uff0c\u6240\u4ee5c\u662f\u4e00\u4e2a\u5e38\u91cf\u3002\u5b83\u53ef\u80fd\u4f1a\u88ab\u4f18\u5316\u6389\uff08\u5c31\u6ca1\u6709c\u8fd9\u4e2a\u53d8\u91cf\u4e86\uff09\uff0c\u4e5f\u53ef\u80fd\u8ddfb\u4e00\u6837\u4f5c\u4e3a\u5c40\u90e8\u53d8\u91cf\u5728Java\u7ebf\u7a0b\u6808\u4e0a\u3002<\/p>
\u5f53methodB()\u88ab\u89e3\u91ca\u6267\u884c\u65f6\uff0c\u8f93\u5165\u7684\u5b57\u8282\u7801\u662f\u600e\u6837\u7684\u5c31\u4f1a\u600e\u6837\u6267\u884c\uff0c\u800c\u7531\u4e8ejava<\/a>c\u7684\u5b9e\u73b0\u4e0d\u4f1a\u4f18\u5316\u6389\u53d8\u91cfb\uff0c\u6240\u4ee5\u8c03\u7528methodB()\u65f6\u5b83\u4e00\u5b9a\u4f1a\u5728Java\u7ebf\u7a0b\u6808\u4e0a\u7684\u5c40\u90e8\u53d8\u91cf\u533a\u91cc\uff1b\u5f53\u5b57\u8282\u7801\u91cc\u53d8\u91cfc\u5b58\u5728\u65f6\uff0c\u5b83\u4e5f\u8ddfb\u4e00\u6837\u5728Java\u7ebf\u7a0b\u6808\u7684\u5c40\u90e8\u53d8\u91cf\u533a\u3002<\/p> \u5f53methodB()\u88abJIT\u7f16\u8bd1\u6267\u884c\u65f6\uff0c\u7531\u4e8e\u5c40\u90e8\u53d8\u91cfb\u3001c\u90fd\u6ca1\u6709\u88ab\u4f7f\u7528\uff0c\u6240\u4ee5\u5b83\u4eec\u7ecf\u8fc7JIT\u7f16\u8bd1\u540e\u5c31\u6d88\u5931\u4e86\uff0c\u8c03\u7528methodB()\u4e0d\u4f1a\u5728\u6808\u4e0a\u7ed9b\u6216c\u53d8\u91cf\u5206\u914d\u4efb\u4f55\u7a7a\u95f4\u3002<\/p> \u901a\u8fc7\u4ee5\u4e0a\u76f8\u4fe1\u5927\u5bb6\u5bf9\u4e8e\u5b57\u7b26\u4e32\u5e38\u91cf\u7684\u5206\u914d\u533a\u57df\u4ee5\u53cajava<\/a>\u7684\u5185\u5b58\u5206\u914d\u6709\u4e86\u4e00\u4e2a\u8f83\u4e3a\u5f62\u8c61\u7684\u4e86\u89e3\u3002<\/p> \u4e0b\u9762\u662f\u4e00\u4e9b\u76f8\u5173\u77e5\u8bc6\u70b9\u7684\u8865\u5145\u4e0e\u6ce8\u610f\u4e8b\u9879\uff1a<\/p> 1.\u5206\u6e05\u4ec0\u4e48\u662f\u5b9e\u4f8b\u4ec0\u4e48\u662f\u5bf9\u8c61\u3002Class a= new Class();\u6b64\u65f6a\u53eb\u5b9e\u4f8b\uff0c\u800c\u4e0d\u80fd\u8bf4a\u662f\u5bf9\u8c61\u3002\u5b9e\u4f8b\u5728\u6808\u4e2d\uff0c\u5bf9\u8c61\u5728\u5806\u4e2d\uff0c\u64cd\u4f5c\u5b9e\u4f8b\u5b9e\u9645\u4e0a\u662f\u901a\u8fc7\u5b9e\u4f8b\u7684\u6307\u9488\u95f4\u63a5\u64cd\u4f5c\u5bf9\u8c61\u3002\u591a\u4e2a\u5b9e\u4f8b\u53ef\u4ee5\u6307\u5411\u540c\u4e00\u4e2a\u5bf9\u8c61\u3002<\/p> 2.\u6808\u4e2d\u7684\u6570\u636e\u548c\u5806\u4e2d\u7684\u6570\u636e\u9500\u6bc1\u5e76\u4e0d\u662f\u540c\u6b65\u7684\u3002\u65b9\u6cd5\u4e00\u65e6\u7ed3\u675f\uff0c\u6808\u4e2d\u7684\u5c40\u90e8\u53d8\u91cf\u7acb\u5373\u9500\u6bc1\uff0c\u4f46\u662f\u5806\u4e2d\u5bf9\u8c61\u4e0d\u4e00\u5b9a\u9500\u6bc1\u3002\u56e0\u4e3a\u53ef\u80fd\u6709\u5176\u4ed6\u53d8\u91cf\u4e5f\u6307\u5411\u4e86\u8fd9\u4e2a\u5bf9\u8c61\uff0c\u76f4\u5230\u6808\u4e2d\u6ca1\u6709\u53d8\u91cf\u6307\u5411\u5806\u4e2d\u7684\u5bf9\u8c61\u65f6\uff0c\u5b83\u624d\u9500\u6bc1\uff0c\u800c\u4e14\u8fd8\u4e0d\u662f\u9a6c\u4e0a\u9500\u6bc1\uff0c\u8981\u7b49\u5783\u573e\u56de\u6536\u626b\u63cf\u65f6\u624d\u53ef\u4ee5\u88ab\u9500\u6bc1\u3002<\/p> 3.\u4ee5\u4e0a\u7684\u6808\u3001\u5806\u3001\u4ee3\u7801\u6bb5\u3001\u6570\u636e\u6bb5\u7b49\u7b49\u90fd\u662f\u76f8\u5bf9\u4e8e\u5e94\u7528\u7a0b\u5e8f\u800c\u8a00\u7684\u3002\u6bcf\u4e00\u4e2a\u5e94\u7528\u7a0b\u5e8f\u90fd\u5bf9\u5e94\u552f\u4e00\u7684\u4e00\u4e2aJVM\u5b9e\u4f8b\uff0c\u6bcf\u4e00\u4e2aJVM\u5b9e\u4f8b","orderid":"0","title":"\u6d45\u8c08Java\u4e2d\u5b57\u7b26\u4e32\u5e38\u91cf\u7684\u50a8\u5b58\u4f4d\u7f6e(\u4e00)","smalltitle":"","mid":"0","fname":"linux\u7f16\u7a0b\u57fa\u7840","special_id":"0","bak_id":"0","info":"0","hits":"448","pages":"2","comments":"0","posttime":"2017-05-27 17:36:33","list":"1495877793","username":"admin","author":"","copyfrom":"","copyfromurl":"","titlecolor":"","fonttype":"0","titleicon":"0","picurl":"https:\/\/www.cppentry.com\/upload_files\/","ispic":"0","yz":"1","yzer":"","yztime":"0","levels":"0","levelstime":"0","keywords":"\u6d45\u8c08<\/A> Java<\/A> \u5b57\u7b26\u4e32<\/A> \u5e38\u91cf<\/A> \u50a8\u5b58<\/A> \u4f4d\u7f6e<\/A>","jumpurl":"","iframeurl":"","style":"","template":"a:3:{s:4:\"head\";s:0:\"\";s:4:\"foot\";s:0:\"\";s:8:\"bencandy\";s:0:\"\";}","target":"0","ip":"218.17.197.194","lastfid":"0","money":"0","buyuser":"","passwd":"","allowdown":"","allowview":"","editer":"","edittime":"0","begintime":"0","endtime":"0","description":"\u6d45\u8c08Java\u4e2d\u5b57\u7b26\u4e32\u5e38\u91cf\u7684\u50a8\u5b58\u4f4d\u7f6e","lastview":"1713928388","digg_num":"7062","digg_time":"0","forbidcomment":"0","ifvote":"0","heart":"","htmlname":"","city_id":"0"},"page":"1"}