鍏跺疄閮借繕鐩哥埍錛屼絾蹇呴』闈㈠鐜板疄錛屼笉鍐嶄細琚蹇嗗拰紱誨紑鏃朵駭鐢熺殑鐥涜嫤钂欒斀鑷繁鐨勫弻鐪箋?br />
鐢ㄦ硶錛歫avac <閫夐」> <婧愭枃浠?gt;
鍏朵腑錛屽彲鑳界殑閫夐」鍖呮嫭錛?br />
-g 鐢熸垚鎵鏈夎皟璇曚俊鎭?br />
-g:none 涓嶇敓鎴愪換浣曡皟璇曚俊鎭?br />
-g:{lines,vars,source} 鍙敓鎴愭煇浜涜皟璇曚俊鎭?br />
-nowarn 涓嶇敓鎴愪換浣曡鍛?br />
-verbose 杈撳嚭鏈夊叧緙栬瘧鍣ㄦ鍦ㄦ墽琛岀殑鎿嶄綔鐨勬秷鎭?br />
-deprecation 杈撳嚭浣跨敤宸茶繃鏃剁殑 API 鐨勬簮浣嶇疆
-classpath <璺緞> 鎸囧畾鏌ユ壘鐢ㄦ埛綾繪枃浠剁殑浣嶇疆
-cp <璺緞> 鎸囧畾鏌ユ壘鐢ㄦ埛綾繪枃浠剁殑浣嶇疆
-sourcepath <璺緞> 鎸囧畾鏌ユ壘杈撳叆婧愭枃浠剁殑浣嶇疆
-bootclasspath <璺緞> 瑕嗙洊寮曞綾繪枃浠剁殑浣嶇疆
-extdirs <鐩綍> 瑕嗙洊瀹夎鐨勬墿灞曠洰褰曠殑浣嶇疆
-endorseddirs <鐩綍> 瑕嗙洊絳懼悕鐨勬爣鍑嗚礬寰勭殑浣嶇疆
-d <鐩綍> 鎸囧畾瀛樻斁鐢熸垚鐨勭被鏂囦歡鐨勪綅緗?br />
-encoding <緙栫爜> 鎸囧畾婧愭枃浠朵嬌鐢ㄧ殑瀛楃緙栫爜
-source <鐗堟湰> 鎻愪緵涓庢寚瀹氱増鏈殑婧愬吋瀹規?br />
-target <鐗堟湰> 鐢熸垚鐗瑰畾 VM 鐗堟湰鐨勭被鏂囦歡
-version 鐗堟湰淇℃伅
-help 杈撳嚭鏍囧噯閫夐」鐨勬彁瑕?br />
-X 杈撳嚭闈炴爣鍑嗛夐」鐨勬彁瑕?br />
-J<鏍囧織> 鐩存帴灝?<鏍囧織> 浼犻掔粰榪愯鏃剁郴緇?br />
jar
鐢ㄦ硶錛歫ar {ctxu}[vfm0Mi] [jar-鏂囦歡] [manifest-鏂囦歡] [-C 鐩綍] 鏂囦歡鍚?...
閫夐」錛?br />
-c 鍒涘緩鏂扮殑瀛樻。
-t 鍒楀嚭瀛樻。鍐呭鐨勫垪琛?br />
-x 灞曞紑瀛樻。涓殑鍛藉悕鐨勶紙鎴栨墍鏈夌殑銆曟枃浠?br />
-u 鏇存柊宸插瓨鍦ㄧ殑瀛樻。
-v 鐢熸垚璇︾粏杈撳嚭鍒版爣鍑嗚緭鍑轟笂
-f 鎸囧畾瀛樻。鏂囦歡鍚?br />
-m 鍖呭惈鏉ヨ嚜鏍囨槑鏂囦歡鐨勬爣鏄庝俊鎭?br />
-0 鍙瓨鍌ㄦ柟寮忥紱鏈敤ZIP鍘嬬緝鏍煎紡
-M 涓嶄駭鐢熸墍鏈夐」鐨勬竻鍗曪紙manifest銆曟枃浠?br />
-i 涓烘寚瀹氱殑jar鏂囦歡浜х敓绱㈠紩淇℃伅
-C 鏀瑰彉鍒版寚瀹氱殑鐩綍錛屽茍涓斿寘鍚笅鍒楁枃浠訛細
濡傛灉涓涓枃浠跺悕鏄竴涓洰褰曪紝瀹冨皢琚掑綊澶勭悊銆?br />
娓呭崟錛坢anifest銆曟枃浠跺悕鍜屽瓨妗ｆ枃浠跺悕閮介渶瑕佽鎸囧畾錛屾寜'm' 鍜?'f'鏍囧織鎸囧畾鐨勭浉鍚岄『搴忋?br />
紺轟緥1錛氬皢涓や釜class鏂囦歡瀛樻。鍒頒竴涓悕涓?'classes.jar' 鐨勫瓨妗ｆ枃浠朵腑錛?br />
jar cvf classes.jar Foo.class Bar.class
紺轟緥2錛氱敤涓涓瓨鍦ㄧ殑娓呭崟錛坢anifest錛夋枃浠?'mymanifest' 灝?foo/ 鐩綍涓嬬殑鎵鏈?br />
鏂囦歡瀛樻。鍒頒竴涓悕涓?'classes.jar' 鐨勫瓨妗ｆ枃浠朵腑錛?br />
jar cvfm classes.jar mymanifest -C foo/ .
java
鐢ㄦ硶: java [-閫夐」] 綾?[鍙傛暟...]
(鎵ц涓涓被)
鎴栬?java [-閫夐」] -jar jar鏂囦歡 [鍙傛暟...]
(鎵ц涓涓猨ar鏂囦歡)
鍏朵腑錛屽彲鑳界殑閫夐」鍖呮嫭錛?br />
-client 閫夋嫨 "client" VM(ginger547:搴旇鏄寚Virtual Machine)
-server 閫夋嫨 "server" VM
-hotspot 涓?"client" VM鍚屼箟 [涓嶈禐鎴怾
榛樿鎯呭喌鐨刅M鏄痗lient.
-cp <涓涓枃浠跺す鍜寊ip/jar鏂囦歡緇勬垚鐨勭被鎼滅儲璺緞>
-classpath <涓涓枃浠跺す鍜寊ip/jar鏂囦歡緇勬垚鐨勭被鎼滅儲璺緞>
涓涓敱鏂囦歡澶癸紝JAR鍘嬬緝鏂囦歡錛屾垨鑰匷IP鍘嬬緝鏂囦歡緇勬垚鐨勭敤鏉ユ悳绱㈢被鐨勫垪琛?br />
-D<鍚嶅瓧>=<鍊?gt;
璁劇疆涓涓郴緇熷睘鎬?br />
-verbose[:class|gc|jni]
浣胯緇嗚緭鍑哄彉鐨勫彲鐢?br />
-version 鎵撳嵃浜у搧鐗堟湰鐒跺悗閫鍑?br />
-version:<鍊?gt;
鍙繍琛屾寚瀹氱増鏈?br />
-showversion 鎵撳嵃浜у搧鐗堟湰鍚庣戶緇?br />
-jre-restrict-search | -jre-no-restrict-search
鍦ㄧ増鏈悳绱㈢殑鏃跺欙紝鍖呭惈/鎺掗櫎鐢ㄦ埛縐佷漢鐨凧RE
-? -help 鎵撳嵃甯姪淇℃伅
-X 鎵撳嵃闈炴爣鍑嗛夐」甯姪
-ea[:<鍖呭悕>...|:<綾誨悕>]
-enableassertions[:<鍖呭悕>...|:<綾誨悕>]
浣挎柇璦鍙敤
-da[:<鍖呭悕>...|:<綾誨悕>]
-disableassertions[:<鍖呭悕>...|:<綾誨悕>]
鏄柇璦涓嶅彲鐢?br />
-esa | -enablesystemassertions
浣跨郴緇熺駭鏂█鍙敤
-dsa | -disablesystemassertions
浣跨郴緇熺駭鏂█涓嶅彲鐢?br />
-agentlib:<搴撳悕>[=<閫夐」>]
鍔犺澆鏈湴浠ｇ悊搴?lt;搴撳悕>,渚嬪. -agentlib:hprof
鍚屾椂鍙煡鐪? -agentlib:jdwp=help鍜?-agentlib:hprof=help
-agentpath:<璺緞鍚?gt;[=<閫夐」>]
閫氳繃鍏ㄨ礬寰勫悕鏉ュ姞杞芥湰鍦頒唬鐞嗗簱
-javaagent:<jar璺緞>[=<閫夐」>]
鍔犺澆Java緙栫▼璇█浠ｇ悊錛屽彲鏌ョ湅 java.lang.instrument
鏌ヨ閲嶅鏁版嵁 閮藉垪鍑烘潵
select id,nickname from t_player group by nickname having count(*) > 1;
鏌ヨ鎵鏈夐噸鍚嶇殑鏁版嵁 鍙垪鍑轟笉鍚岀殑銆?br />
濡傛灉鎯沖垹闄ょ浉鍏蟲暟鎹紝閭ｆ牱闈炲緱瑕佺敤in浜嗐傛渶濂藉啓紼嬪簭錛岀敤prepareStatement鍘繪洿鏂幫紝in鏄笉鑳界敤绱㈠紩鐨勶紝鎵浠ヨ秴綰ф參錛屾墍浠ョ▼搴忎紭鍖栫浉鍏蟲暟鎹簱鐨勬搷浣滄槸寰堟湁蹇呰鐨勩?
public class RandomSelection<T> {
private java.util.Random random = new Random(); private ArrayList<T> list;
public RandomSelection() {
list = new ArrayList<T>();
} public void add(T element) { list.add(element); } public T getRandomElement() { int index = random.nextInt(list.size()); return list.get(index); }
}
鐩存帴鏉ヤ嬌鐢ㄣ傚綋鎴戜滑new RandomSelection<String>() new RandomSelection<Integer>() 鐨勬椂鍊欙紝閲岄潰鐨勬柟娉曠殑綾誨瀷錛屼篃灝辯‘瀹氫簡銆?br />
public interface ISomeReason<X extends Enum<X>> { public X getImplClassType();}瀹炵幇涓涓瓙綾匯傝繖閲岀湅鍒扮戶鎵挎槸浼犲叆浜嗘帴鍙ｆ硾鍨嬩腑鐨刋鍙傛暟錛屽弬鏁板氨鏄疄鐜扮被鑷繁鐨勭被鍨嬨?br />
public enum ATypeReason implements ISomeReason<ATypeReason> { ABC(1), DEF(2), ; int index; private ATypeReason(int param) { this.index = param; } public int getIndex() { return this.index; } @Override public ATypeReason getImplClassType() { return this }}浣犱篃鍙互鐩存帴瀹炵幇錛屼笉浼犲叆X錛岄偅涔堝湪浣跨敤榪欎釜綾誨瀷鐨勫疄渚嬪幓浼犲叆鏌愪竴涓寚瀹氱被鍨嬬殑鏂規硶鍙傛暟鏃訛紝浼氭彁紺洪敊璇紝涓嶅埄浜庝唬鐮佸仴澹с?br />
public class MainTest { public static void useATypeReason(ISomeReason<ATypeReason> reason){ sysout(reason.getImplClassType().getIndex());} //ATypeReason鐨勭被鍨嬫病鏈夋寚瀹氭硾鍨嬪弬鏁伴傜敤浜庢帀榪欎釜鎺ュ彛 public static void dontCareParamType(ISomeReason<?> reason) { sysout(reason.getImplClassType()); //涓嶈兘璋冪敤 sysout(reason.getImplClassType().getIndex()); }}浣犲彲浠ユ妸ISomeReason鎺ュ彛瀹氫箟濡備笅錛屾洿涓ユ牸銆?br />
public interface ISomeReason<E extends Enum<E> & ISomeReason<E>> { public E type();}