（28）運算符優先級 · Java編程那些事

? ## Java編程那些事兒28—運算符優先級鄭州游戲學院?陳躍峰出自：[http://blog.csdn.net/mailbomb](http://blog.csdn.net/mailbomb) ? **4.7 運算符優先級** 在實際的開發中，可能在一個運算式中出現多個運算符，那么計算時，就按照優先級級別的高低進行計算，級別高的運算符先運算，級別低的運算符后計算，具體運算符的優先級見下表：運算符優先級表 <table style="BORDER-RIGHT: medium none; BORDER-TOP: medium none; MARGIN-LEFT: 69.2pt; BORDER-LEFT: medium none; BORDER-BOTTOM: medium none; BORDER-COLLAPSE: collapse" border="1" cellspacing="0" cellpadding="0"><tbody><tr><td style="padding-bottom: 0cm; padding-left: 5.4pt; width: 42.55pt; padding-right: 5.4pt; padding-top: 0cm; border: black 1pt solid;" width="57" valign="top"><div>優先級</div></td><td style="border-bottom: black 1pt solid; border-left: medium none; padding-bottom: 0cm; padding-left: 5.4pt; width: 169.8pt; padding-right: 5.4pt; border-top: black 1pt solid; border-right: windowtext 1pt solid; padding-top: 0cm;" width="226" valign="top"><div>運算符</div></td><td style="border-bottom: black 1pt solid; border-left: medium none; padding-bottom: 0cm; padding-left: 5.4pt; width: 64.05pt; padding-right: 5.4pt; border-top: black 1pt solid; border-right: black 1pt solid; padding-top: 0cm;" width="85" valign="top"><div>結合性</div></td></tr><tr><td style="border-bottom: black 1pt solid; border-left: black 1pt solid; padding-bottom: 0cm; padding-left: 5.4pt; width: 42.55pt; padding-right: 5.4pt; border-top: medium none; border-right: black 1pt solid; padding-top: 0cm;" width="57" valign="top"><div>1</div></td><td style="border-bottom: black 1pt solid; border-left: medium none; padding-bottom: 0cm; padding-left: 5.4pt; width: 169.8pt; padding-right: 5.4pt; border-top: medium none; border-right: windowtext 1pt solid; padding-top: 0cm;" width="226" valign="top"><div>()?[]?.</div></td><td style="border-bottom: black 1pt solid; border-left: medium none; padding-bottom: 0cm; padding-left: 5.4pt; width: 64.05pt; padding-right: 5.4pt; border-top: medium none; border-right: black 1pt solid; padding-top: 0cm;" width="85" valign="top"><div>從左到右</div></td></tr><tr><td style="border-bottom: black 1pt solid; border-left: black 1pt solid; padding-bottom: 0cm; padding-left: 5.4pt; width: 42.55pt; padding-right: 5.4pt; border-top: medium none; border-right: black 1pt solid; padding-top: 0cm;" width="57" valign="top"><div>2</div></td><td style="border-bottom: black 1pt solid; border-left: medium none; padding-bottom: 0cm; padding-left: 5.4pt; width: 169.8pt; padding-right: 5.4pt; border-top: medium none; border-right: windowtext 1pt solid; padding-top: 0cm;" width="226" valign="top"><div>!?+(正) ?-(負)?~?++?--</div></td><td style="border-bottom: black 1pt solid; border-left: medium none; padding-bottom: 0cm; padding-left: 5.4pt; width: 64.05pt; padding-right: 5.4pt; border-top: medium none; border-right: black 1pt solid; padding-top: 0cm;" width="85" valign="top"><div>從右向左</div></td></tr><tr><td style="border-bottom: black 1pt solid; border-left: black 1pt solid; padding-bottom: 0cm; padding-left: 5.4pt; width: 42.55pt; padding-right: 5.4pt; border-top: medium none; border-right: black 1pt solid; padding-top: 0cm;" width="57" valign="top"><div>3</div></td><td style="border-bottom: black 1pt solid; border-left: medium none; padding-bottom: 0cm; padding-left: 5.4pt; width: 169.8pt; padding-right: 5.4pt; border-top: medium none; border-right: windowtext 1pt solid; padding-top: 0cm;" width="226" valign="top"><div>*?/?%</div></td><td style="border-bottom: black 1pt solid; border-left: medium none; padding-bottom: 0cm; padding-left: 5.4pt; width: 64.05pt; padding-right: 5.4pt; border-top: medium none; border-right: black 1pt solid; padding-top: 0cm;" width="85" valign="top"><div>從左向右</div></td></tr><tr><td style="border-bottom: black 1pt solid; border-left: black 1pt solid; padding-bottom: 0cm; padding-left: 5.4pt; width: 42.55pt; padding-right: 5.4pt; border-top: medium none; border-right: black 1pt solid; padding-top: 0cm;" width="57" valign="top"><div>4</div></td><td style="border-bottom: black 1pt solid; border-left: medium none; padding-bottom: 0cm; padding-left: 5.4pt; width: 169.8pt; padding-right: 5.4pt; border-top: medium none; border-right: windowtext 1pt solid; padding-top: 0cm;" width="226" valign="top"><div>+(加)?-(減)</div></td><td style="border-bottom: black 1pt solid; border-left: medium none; padding-bottom: 0cm; padding-left: 5.4pt; width: 64.05pt; padding-right: 5.4pt; border-top: medium none; border-right: black 1pt solid; padding-top: 0cm;" width="85" valign="top"><div>從左向右</div></td></tr><tr><td style="border-bottom: black 1pt solid; border-left: black 1pt solid; padding-bottom: 0cm; padding-left: 5.4pt; width: 42.55pt; padding-right: 5.4pt; border-top: medium none; border-right: black 1pt solid; padding-top: 0cm;" width="57" valign="top"><div>5</div></td><td style="border-bottom: black 1pt solid; border-left: medium none; padding-bottom: 0cm; padding-left: 5.4pt; width: 169.8pt; padding-right: 5.4pt; border-top: medium none; border-right: windowtext 1pt solid; padding-top: 0cm;" width="226" valign="top"><div><<?>>?>>></div></td><td style="border-bottom: black 1pt solid; border-left: medium none; padding-bottom: 0cm; padding-left: 5.4pt; width: 64.05pt; padding-right: 5.4pt; border-top: medium none; border-right: black 1pt solid; padding-top: 0cm;" width="85" valign="top"><div>從左向右</div></td></tr><tr><td style="border-bottom: black 1pt solid; border-left: black 1pt solid; padding-bottom: 0cm; padding-left: 5.4pt; width: 42.55pt; padding-right: 5.4pt; border-top: medium none; border-right: black 1pt solid; padding-top: 0cm;" width="57" valign="top"><div>6</div></td><td style="border-bottom: black 1pt solid; border-left: medium none; padding-bottom: 0cm; padding-left: 5.4pt; width: 169.8pt; padding-right: 5.4pt; border-top: medium none; border-right: windowtext 1pt solid; padding-top: 0cm;" width="226" valign="top"><div><?<=?>?>=?instanceof</div></td><td style="border-bottom: black 1pt solid; border-left: medium none; padding-bottom: 0cm; padding-left: 5.4pt; width: 64.05pt; padding-right: 5.4pt; border-top: medium none; border-right: black 1pt solid; padding-top: 0cm;" width="85" valign="top"><div>從左向右</div></td></tr><tr><td style="border-bottom: black 1pt solid; border-left: black 1pt solid; padding-bottom: 0cm; padding-left: 5.4pt; width: 42.55pt; padding-right: 5.4pt; border-top: medium none; border-right: black 1pt solid; padding-top: 0cm;" width="57" valign="top"><div>7</div></td><td style="border-bottom: black 1pt solid; border-left: medium none; padding-bottom: 0cm; padding-left: 5.4pt; width: 169.8pt; padding-right: 5.4pt; border-top: medium none; border-right: windowtext 1pt solid; padding-top: 0cm;" width="226" valign="top"><div>==<span>?? !=</span></div></td><td style="border-bottom: black 1pt solid; border-left: medium none; padding-bottom: 0cm; padding-left: 5.4pt; width: 64.05pt; padding-right: 5.4pt; border-top: medium none; border-right: black 1pt solid; padding-top: 0cm;" width="85" valign="top"><div>從左向右</div></td></tr><tr><td style="border-bottom: black 1pt solid; border-left: black 1pt solid; padding-bottom: 0cm; padding-left: 5.4pt; width: 42.55pt; padding-right: 5.4pt; border-top: medium none; border-right: black 1pt solid; padding-top: 0cm;" width="57" valign="top"><div>8</div></td><td style="border-bottom: black 1pt solid; border-left: medium none; padding-bottom: 0cm; padding-left: 5.4pt; width: 169.8pt; padding-right: 5.4pt; border-top: medium none; border-right: windowtext 1pt solid; padding-top: 0cm;" width="226" valign="top"><div>&(按位與)</div></td><td style="border-bottom: black 1pt solid; border-left: medium none; padding-bottom: 0cm; padding-left: 5.4pt; width: 64.05pt; padding-right: 5.4pt; border-top: medium none; border-right: black 1pt solid; padding-top: 0cm;" width="85" valign="top"><div>從左向右</div></td></tr><tr><td style="border-bottom: black 1pt solid; border-left: black 1pt solid; padding-bottom: 0cm; padding-left: 5.4pt; width: 42.55pt; padding-right: 5.4pt; border-top: medium none; border-right: black 1pt solid; padding-top: 0cm;" width="57" valign="top"><div>9</div></td><td style="border-bottom: black 1pt solid; border-left: medium none; padding-bottom: 0cm; padding-left: 5.4pt; width: 169.8pt; padding-right: 5.4pt; border-top: medium none; border-right: windowtext 1pt solid; padding-top: 0cm;" width="226" valign="top"><div>^</div></td><td style="border-bottom: black 1pt solid; border-left: medium none; padding-bottom: 0cm; padding-left: 5.4pt; width: 64.05pt; padding-right: 5.4pt; border-top: medium none; border-right: black 1pt solid; padding-top: 0cm;" width="85" valign="top"><div>從左向右</div></td></tr><tr><td style="border-bottom: black 1pt solid; border-left: black 1pt solid; padding-bottom: 0cm; padding-left: 5.4pt; width: 42.55pt; padding-right: 5.4pt; border-top: medium none; border-right: black 1pt solid; padding-top: 0cm;" width="57" valign="top"><div>10</div></td><td style="border-bottom: black 1pt solid; border-left: medium none; padding-bottom: 0cm; padding-left: 5.4pt; width: 169.8pt; padding-right: 5.4pt; border-top: medium none; border-right: windowtext 1pt solid; padding-top: 0cm;" width="226" valign="top"><div>|</div></td><td style="border-bottom: black 1pt solid; border-left: medium none; padding-bottom: 0cm; padding-left: 5.4pt; width: 64.05pt; padding-right: 5.4pt; border-top: medium none; border-right: black 1pt solid; padding-top: 0cm;" width="85" valign="top"><div>從左向右</div></td></tr><tr><td style="border-bottom: black 1pt solid; border-left: black 1pt solid; padding-bottom: 0cm; padding-left: 5.4pt; width: 42.55pt; padding-right: 5.4pt; border-top: medium none; border-right: black 1pt solid; padding-top: 0cm;" width="57" valign="top"><div>11</div></td><td style="border-bottom: black 1pt solid; border-left: medium none; padding-bottom: 0cm; padding-left: 5.4pt; width: 169.8pt; padding-right: 5.4pt; border-top: medium none; border-right: windowtext 1pt solid; padding-top: 0cm;" width="226" valign="top"><div>&&</div></td><td style="border-bottom: black 1pt solid; border-left: medium none; padding-bottom: 0cm; padding-left: 5.4pt; width: 64.05pt; padding-right: 5.4pt; border-top: medium none; border-right: black 1pt solid; padding-top: 0cm;" width="85" valign="top"><div>從左向右</div></td></tr><tr><td style="border-bottom: black 1pt solid; border-left: black 1pt solid; padding-bottom: 0cm; padding-left: 5.4pt; width: 42.55pt; padding-right: 5.4pt; border-top: medium none; border-right: black 1pt solid; padding-top: 0cm;" width="57" valign="top"><div>12</div></td><td style="border-bottom: black 1pt solid; border-left: medium none; padding-bottom: 0cm; padding-left: 5.4pt; width: 169.8pt; padding-right: 5.4pt; border-top: medium none; border-right: windowtext 1pt solid; padding-top: 0cm;" width="226" valign="top"><div>||</div></td><td style="border-bottom: black 1pt solid; border-left: medium none; padding-bottom: 0cm; padding-left: 5.4pt; width: 64.05pt; padding-right: 5.4pt; border-top: medium none; border-right: black 1pt solid; padding-top: 0cm;" width="85" valign="top"><div>從左向右</div></td></tr><tr><td style="border-bottom: black 1pt solid; border-left: black 1pt solid; padding-bottom: 0cm; padding-left: 5.4pt; width: 42.55pt; padding-right: 5.4pt; border-top: medium none; border-right: black 1pt solid; padding-top: 0cm;" width="57" valign="top"><div>13</div></td><td style="border-bottom: black 1pt solid; border-left: medium none; padding-bottom: 0cm; padding-left: 5.4pt; width: 169.8pt; padding-right: 5.4pt; border-top: medium none; border-right: windowtext 1pt solid; padding-top: 0cm;" width="226" valign="top"><div>?:</div></td><td style="border-bottom: black 1pt solid; border-left: medium none; padding-bottom: 0cm; padding-left: 5.4pt; width: 64.05pt; padding-right: 5.4pt; border-top: medium none; border-right: black 1pt solid; padding-top: 0cm;" width="85" valign="top"><div>從右向左</div></td></tr><tr><td style="border-bottom: black 1pt solid; border-left: black 1pt solid; padding-bottom: 0cm; padding-left: 5.4pt; width: 42.55pt; padding-right: 5.4pt; border-top: medium none; border-right: black 1pt solid; padding-top: 0cm;" width="57" valign="top"><div>14</div></td><td style="border-bottom: black 1pt solid; border-left: medium none; padding-bottom: 0cm; padding-left: 5.4pt; width: 169.8pt; padding-right: 5.4pt; border-top: medium none; border-right: windowtext 1pt solid; padding-top: 0cm;" width="226" valign="top"><div>=?+=?-=?*=?/=?%=?&=?|=?^= ?~= ?<<=?>>=<span>?? >>>=</span></div></td><td style="border-bottom: black 1pt solid; border-left: medium none; padding-bottom: 0cm; padding-left: 5.4pt; width: 64.05pt; padding-right: 5.4pt; border-top: medium none; border-right: black 1pt solid; padding-top: 0cm;" width="85"><div>從右向左</div></td></tr></tbody></table> 說明： 1、?該表中優先級按照從高到低的順序書寫，也就是優先級為1的優先級最高，優先級14的優先級最低。 2、?結合性是指運算符結合的順序，通常都是從左到右。從右向左的運算符最典型的就是負號，例如3+-4，則意義為3加-4，符號首先和運算符右側的內容結合。 3、?instanceof作用是判斷對象是否為某個類或接口類型，后續有詳細介紹。 4、?注意區分正負號和加減號，以及按位與和邏輯與的區別其實在實際的開發中，不需要去記憶運算符的優先級別，也不要刻意的使用運算符的優先級別，對于不清楚優先級的地方使用小括號去進行替代，示例代碼： ~~~ ???????? int m = 12; ???????? int n = m << 1 + 2; ???????? int n = m << (1 + 2);?//這樣更直觀 ~~~ 這樣書寫代碼，更方便編寫代碼，也便于代碼的閱讀和維護。 ?