@[toc]
\u5c0f\u4f19\u4f34\u4eec\u77e5\u9053\uff0c\u677e\u54e5\u6700\u8fd1\u5728\u5f55 TienChin \u9879\u76ee\uff0c\u7528\u7684 RuoYi-Vue \u811a\u624b\u67b6\uff0c\u524d\u7aef\u5173\u4e8e\u7f51\u7edc\u8bf7\u6c42\u7684\u5730\u65b9\uff0c\u5f88\u591a\u90fd\u6d89\u53ca\u5230\u4e86 Promise\uff0c\u4e3a\u4e86\u8ba9\u5c0f\u4f19\u4f34\u4eec\u80fd\u66f4\u597d\u7684\u7406\u89e3\u524d\u7aef\u4ee3\u7801\uff0c\u54b1\u4eec\u62bd\u7a7a\u6574\u4e00\u7bc7\u6587\u7ae0\u548c\u5927\u5bb6\u804a\u804a\u6574\u4e2a Promise\u3002<\/p>\n
\u5047\u8bbe\u6211\u73b0\u5728\u6709\u8fd9\u6837\u4e00\u4e2a\u9700\u6c42\uff0c\u7528\u6237\u5148\u53bb\u767b\u5f55\uff0c\u767b\u5f55\u6210\u529f\u4e4b\u540e\uff0c\u518d\u53bb\u670d\u52a1\u7aef\u83b7\u53d6\u7528\u6237\u4fe1\u606f\uff0c\u83b7\u53d6\u5230\u7528\u6237\u4fe1\u606f\u4e4b\u540e\u518d\u53bb\u670d\u52a1\u7aef\u83b7\u53d6\u524d\u7aef\u7684\u52a8\u6001\u83dc\u5355\u3002\u4e00\u822c\u6211\u4eec\u7684 Ajax \u8bf7\u6c42\u90fd\u662f\u5f02\u6b65\u5f62\u5f0f\uff0c\u4e3a\u4e86\u786e\u4fdd\u4e0a\u4e00\u6b65\u64cd\u4f5c\u6210\u529f\u518d\u6267\u884c\u4e0b\u4e00\u4e2a\u8bf7\u6c42\uff0c\u6240\u4ee5\u6700\u7ec8\u53d1\u51fa\u7684\u8bf7\u6c42\u4f2a\u4ee3\u7801\u7c7b\u4f3c\u4e0b\u9762\u8fd9\u6837\uff1a<\/p>\n
$.ajax({\n url:'\/login',\n data:loginForm,\n success: function (data) {\n \/\/\u767b\u5f55\u6210\u529f\n $.ajax({\n url:'\/getInfo',\n success: function (userInfo) {\n \/\/\u83b7\u53d6\u7528\u6237\u4fe1\u606f\u6210\u529f\n $.ajax({\n url: '\/getMenus',\n success: function (menus) {\n \/\/\u83b7\u53d6\u83dc\u5355\u6210\u529f\n }\n })\n }\n })\n }\n})<\/code><\/pre>\n\u4e3a\u4e86\u786e\u4fdd\u4e00\u4e2a\u5f02\u6b65\u4efb\u52a1\u6267\u884c\u5b8c\u6210\u540e\uff0c\u518d\u6267\u884c\u4e0b\u4e00\u4e2a\u5f02\u6b65\u4efb\u52a1\uff0c\u6211\u4eec\u4e0d\u5f97\u4e0d\u5728\u56de\u8c03\u51fd\u6570\u4e2d\u4e0d\u505c\u7684\u5199\u4e0b\u53bb\uff0c\u4e0a\u9762\u6211\u4e3e\u7684\u4f8b\u5b50\u662f\u4e09\u4e2a\u8bf7\u6c42\u5d4c\u5957\uff0c\u5b9e\u9645\u4e0a\u53ef\u80fd\u4f1a\u66f4\u591a\u3002\u3002\u3002\u8fd9\u5c31\u662f\u524d\u7aef\u6240\u8c13\u7684\u56de\u8c03\u5730\u72f1\u3002\u800c Promise \u5c31\u662f\u6765\u89e3\u51b3\u56de\u8c03\u5730\u72f1\u7684\u3002<\/p>\n
2. Promise<\/h2>\n
Promise \u4ece\u5b57\u9762\u4e0a\u7406\u89e3\uff0c\u5c31\u662f\u627f\u8bfa\uff0c\u627f\u8bfa\u5c06\u6765\u5728\u67d0\u4e00\u4e2a\u65f6\u95f4\u4f1a\u505a\u67d0\u4e00\u4ef6\u4e8b\u3002\u901a\u8fc7 Promise \u6211\u4eec\u53ef\u4ee5\u5c06\u5f02\u6b65\u4efb\u52a1\u6267\u884c\u7684\u4ee3\u7801\u548c\u5904\u7406\u7684\u4ee3\u7801\u5b8c\u5168\u5206\u79bb\u5f00\u3002<\/p>\n
\u8fd8\u662f\u7b2c\u4e00\u5c0f\u8282\u8fd9\u4e2a\u4f8b\u5b50\uff0c\u5982\u679c\u6211\u4eec\u7528 Promise \u5199\uff0c\u90a3\u4e48\u65b9\u5f0f\u5982\u4e0b\uff1a<\/p>\n
function login(resolve, reject) {\n setTimeout(() => {\n let number = Math.random();\n if (number > 0.5) {\n resolve("login success")\n } else {\n reject("login failed")\n }\n }, 2000);\n}\nfunction getInfo(resolve, reject) {\n setTimeout(() => {\n let number = Math.random();\n if (number > 0.5) {\n resolve("getInfo success")\n } else {\n reject("getInfo failed")\n }\n }, 2000);\n}\nfunction getMenus(resolve, reject) {\n setTimeout(() => {\n let number = Math.random();\n if (number > 0.5) {\n resolve("getMenus success")\n } else {\n reject("getMenus failed")\n }\n }, 2000);\n}\nnew Promise(login).then(data => {\n console.log("login:", data);\n return new Promise(getInfo);\n}).then(data => {\n console.log("getInfo:", data);\n return new Promise(getMenus);\n}).then(data => {\n console.log("getMenus", data);\n}).catch(err => {\n console.log("err:", err);\n})<\/code><\/pre>\n\u6211\u4eec\u5728 Promise \u4e2d\u5199\u5f02\u6b65\u4efb\u52a1\u6267\u884c\u7684\u4ee3\u7801\uff0c\u5728\u4e0a\u9762\u7684\u6848\u4f8b\u4e2d\uff0c\u677e\u54e5\u901a\u8fc7 setTImeout \u65b9\u6cd5\u6a21\u62df\u4e86\u4e00\u4e2a\u8017\u65f6\u64cd\u4f5c\uff0c\u5f02\u6b65\u4efb\u52a1\u6267\u884c\u5b8c\u6bd5\u540e\uff0c\u6211\u4eec\u8c03\u7528 resolve \u65b9\u6cd5\u8fd4\u56de\u8c03\u7528\u7684\u7ed3\u679c\uff08\u4f1a\u8fdb\u5165\u5230\u4e0b\u4e00\u6b65\u7684 then \u4e2d\uff09\uff0c\u4e5f\u53ef\u4ee5\u8c03\u7528 reject \u65b9\u6cd5\u8868\u793a\u8c03\u7528\u5931\u8d25\uff08\u4f1a\u8fdb\u5165\u5230 catch \u4e2d\uff09\u3002<\/p>\n
3. then<\/h2>\n
then \u4e2d\u7684\u8fd4\u56de\u503c\u53ef\u4ee5\u5206\u4e3a\u4e09\u79cd\u60c5\u51b5\u3002<\/p>\n
3.1 \u6b63\u5e38 return<\/h3>\n
then \u4e2d\u65b9\u6cd5\u7684\u53c2\u6570\uff0c\u662f\u4e0a\u4e00\u4e2a Promise \u5bf9\u8c61 resolve \u7684\u503c\uff0c\u4e00\u4e2a Promise \u5bf9\u8c61\u53ef\u4ee5\u6709\u591a\u4e2a then\uff0c\u4f8b\u5982\u4e0a\u9762\u6848\u4f8b\u7684\u767b\u5f55\u529f\u80fd\uff0c\u6211\u4eec\u53ef\u4ee5\u4e00\u76f4 then \u4e0b\u53bb\uff1a<\/p>\n
function login(resolve, reject) {\n setTimeout(() => {\n let number = Math.random();\n if (number > 0.5) {\n resolve("login success")\n } else {\n reject("login failed")\n }\n }, 2000);\n}\nnew Promise(login).then(data => {\n console.log("then1:", data);\n return data;\n}).then(data => {\n console.log("then2:", data);\n return data;\n}).then(data => {\n console.log("then3:", data);\n}).catch(err => {\n console.log("err:", err);\n})<\/code><\/pre>\n\u8fd9\u6837\u53ef\u4ee5\u4e00\u76f4\u8fd4\u56de\uff0c\u8fd9\u6709\u70b9\u50cf\u6211\u4eec Java \u4e2d\u7684\u6d41\u5f0f\u7f16\u7a0b\u3002<\/p>\n
3.2 \u629b\u51fa\u5f02\u5e38<\/h3>\n
\u5728 then \u4e2d\uff0c\u6211\u4eec\u53ef\u4ee5\u5bf9\u8fd4\u56de\u7ed3\u679c\u8fdb\u884c\u5224\u65ad\uff0c\u4e0d\u6ee1\u8db3\u6761\u4ef6\u4e5f\u53ef\u4ee5\u76f4\u63a5\u629b\u51fa\u5f02\u5e38\uff0c\u8fd9\u6837\u5c31\u4f1a\u8fdb\u5165\u5230\u6700\u8fd1\u7684 catch \u4ee3\u7801\u5757\u4e2d\u3002\u5982\u4e0b\u6848\u4f8b\uff1a<\/p>\n
function login(resolve, reject) {\n setTimeout(() => {\n let number = Math.random();\n if (number > 0.5) {\n resolve("login success")\n } else {\n reject("login failed")\n }\n }, 2000);\n}\nnew Promise(login).then(data => {\n console.log("then1:", data);\n throw new Error("\u51fa\u9519\u5566");\n}).then(data => {\n console.log("then2:", data);\n return data;\n}).then(data => {\n console.log("then3:", data);\n}).catch(err => {\n console.log("err:", err);\n})<\/code><\/pre>\n\u50cf\u4e0a\u9762\u8fd9\u6bb5\u4ee3\u7801\uff0c\u5982\u679c\u8fdb\u5165\u5230\u7b2c\u4e00\u4e2a then \u4e2d\uff0c\u7b2c\u4e00\u4e2a then \u76f4\u63a5\u629b\u51fa\u5f02\u5e38\uff0c\u8fd9\u6837\u76f4\u63a5\u5c31\u8fdb\u5165\u5230 catch \u4e2d\u4e86\uff0c\u540e\u9762\u7684 then \u5c31\u90fd\u4e0d\u4f1a\u6267\u884c\u4e86\u3002<\/p>\n
3.3 \u8fd4\u56de Promise<\/h3>\n
\u7b2c\u4e09\u79cd\u60c5\u51b5\u5c31\u662f then \u4e2d\u4e5f\u53ef\u4ee5\u8fd4\u56de\u4e00\u4e2a Promise \u5bf9\u8c61\uff0c\u8fd9\u4e2a\u5c31\u5982\u540c\u6211\u4eec\u7b2c\u4e8c\u5c0f\u8282\u7684\u6848\u4f8b\uff0c\u6211\u8fd9\u91cc\u5c31\u4e0d\u518d\u8d58\u8ff0\u4e86\u3002<\/p>\n
\u5c31\u8bf4\u4e00\u53e5\uff0c\u5982\u679c then \u4e2d\u8fd4\u56de\u7684\u662f\u4e00\u4e2a Promise \u5bf9\u8c61\uff0c\u90a3\u4e48\u63a5\u4e0b\u6765\u7684 then \u5176\u5b9e\u662f\u8fd9\u4e2a Promise \u5bf9\u8c61\u7684 then\uff0c\u800c\u4e0d\u662f\u4e00\u5f00\u59cb\u7684 Promise \u7684 then \u4e86\u3002\u4f8b\u5982\u5982\u4e0b\u4f2a\u4ee3\u7801\uff1a<\/p>\n
A.then((data)=>{return B}).then(xxx)<\/code><\/pre>\n\u5047\u8bbe A \u548c B \u90fd\u662f Promise \u5bf9\u8c61\uff0c\u90a3\u4e48\u7b2c\u4e8c\u4e2a then \u65b9\u6cd5\u662f B \u7684 then\u3002<\/p>\n
\u597d\u5566\uff0c\u8fd9\u5c31\u662f then \u4e2d\u7684\u4e09\u79cd\u8fd4\u56de\u503c\u60c5\u51b5\u3002<\/p>\n
4. catch<\/h2>\n
catch \u4e3b\u8981\u662f\u7528\u6765\u5904\u7406\u5f02\u5e38\u7684\u60c5\u51b5\uff0c\u4e24\u79cd\u60c5\u51b5\u4e0b\u4f1a\u8fdb\u5165\u5230 catch \u4e2d\uff1a<\/p>\n
\n- Promise \u6267\u884c\u7684\u65f6\u5019\u901a\u8fc7 reject \u8fd4\u56de\u6570\u636e\u3002<\/li>\n
- then \u4e2d\u629b\u51fa Error<\/li>\n<\/ul>\n
\u51fa\u4e86\u95ee\u9898\uff0c\u5c31\u7531\u6700\u8fd1\u7684<\/strong> catch \u6765\u5904\u7406\u3002<\/p>\n5. finally<\/h2>\n
\u6700\u540e\u8fd8\u6709\u4e00\u4e2a finally \u7528\u6765\u515c\u5e95\uff0c\u8fd9\u4e00\u5957\u4e0b\u6765\u611f\u89c9\u6709\u70b9\u50cf\u6211\u4eec Java \u4e2d\u7684 try-catch-finally\uff0c\u4e5f\u5c31\u662f\u524d\u9762\u65e0\u8bba\u5982\u4f55\uff0c\u6700\u7ec8 finally \u4e2d\u7684\u4ee3\u7801\u90fd\u4f1a\u6267\u884c\u3002\u4e0d\u8fc7\u4e0d\u540c\u4e8e Java \u4e2d\u7684 finally\uff0cPromise \u4e2d\u7684 finally \u5728\u6700\u7ec8\u6267\u884c\u5b8c\u6bd5\u540e\uff0c\u8fd8\u53ef\u4ee5\u7ee7\u7eed then\u3002\u3002\u3002\u524d\u7aef\u7684\u871c\u6c41\u64cd\u4f5c\u3002<\/p>\n
6. \u5176\u4ed6\u65b9\u6cd5<\/h2>\n
\u6700\u540e\uff0c\u6211\u4eec\u518d\u6765\u770b\u770b Promise \u4e2d\u7684\u5176\u4ed6\u9759\u6001\u65b9\u6cd5\u3002<\/p>\n
6.1 Promise.all()<\/h3>\n
Promise.all() \u65b9\u6cd5\u53ef\u4ee5\u63a5\u6536\u591a\u4e2a Promise \u5bf9\u8c61\uff0c\u5e76\u4e14\u53ea\u8fd4\u56de\u4e00\u4e2a Promise \u5b9e\u4f8b\uff0c\u8fd9\u4e2a\u65b9\u6cd5\u4f1a\u7b49\u6240\u6709\u8f93\u5165\u7684 Promise \u5bf9\u8c61\u7684 resolve \u65b9\u6cd5\u90fd\u8fd4\u56de\u7684\u65f6\u5019\uff0c\u6216\u8005\u6240\u6709\u8f93\u5165\u7684 Promise \u5bf9\u8c61\u4e2d\u6709\u4e00\u4e2a reject \u7684\u65f6\u5019\uff0c\u8fd9\u4e2a all \u5c31\u4f1a\u6267\u884c\u7ed3\u675f\uff0c\u6765\u770b\u5982\u4e0b\u4e00\u4e2a\u6848\u4f8b\uff1a<\/p>\n
const promise1 = Promise.resolve(3);\nconst promise2 = 42;\nconst promise3 = new Promise((resolve, reject) => {\n setTimeout(resolve, 3000, 'foo');\n});\nPromise.all([promise1, promise2, promise3]).then((values) => {\n console.log(values);\n}).catch(err=>{\n console.log("err", err);\n})<\/code><\/pre>\n\u5f53 promise1\u3001promise2 \u4ee5\u53ca promise3 \u90fd\u6267\u884c\u4e86 resolve \u7684\u65f6\u5019\uff0c\u5c31\u4f1a\u8fdb\u5165\u5230 then \u4e2d\uff0c\u8fd9\u4e09\u4e2a\u4e2d\u6709\u4efb\u610f\u4e00\u4e2a\u6267\u884c\u4e86 reject \u5c31\u4f1a\u8fdb\u5165\u5230 catch \u4e2d\u3002<\/p>\n
6.2 Promise.race()<\/h3>\n
Promise.race() \u65b9\u6cd5\u53ef\u4ee5\u63a5\u6536\u591a\u4e2a Promise \u5bf9\u8c61\uff0c\u4e00\u65e6\u8fed\u4ee3\u5668\u4e2d\u7684\u67d0\u4e2a Promise resolve \u6216 reject\uff0c\u8fd4\u56de\u7684 Promise \u5c31\u4f1a resolve \u6216 reject\u3002<\/p>\n
\u548c all \u65b9\u6cd5\u7684\u533a\u522b\u5728\u4e8e\uff0crace \u65b9\u6cd5\u662f\u8c01\u6267\u884c\u7684\u5feb\uff0c\u5c31\u7528\u8c01\u7684\u7ed3\u679c\u3002\u6211\u4eec\u6765\u770b\u5982\u4e0b\u4e00\u6bb5\u4ee3\u7801\uff1a<\/p>\n
const promise1 = new Promise((resolve, reject) => {\n setTimeout(resolve, 500, 'one');\n});\nconst promise2 = new Promise((resolve, reject) => {\n setTimeout(reject, 600, 'two');\n});\nPromise.race([promise1, promise2]).then((value) => {\n console.log(value);\n});<\/code><\/pre>\npromise1 \u6267\u884c\u65f6\u95f4\u77ed\uff0cpromise2 \u6267\u884c\u65f6\u95f4\u957f\uff0c\u6240\u4ee5\u6700\u7ec8\u7ed3\u679c\u5c31\u662f promise1 \u7684\u7ed3\u679c\u3002<\/p>\n
6.3 Promise.reject()<\/h3>\n
Promise.reject() \u65b9\u6cd5\u8fd4\u56de\u4e00\u4e2a\u5e26\u6709 reject \u539f\u56e0\u7684 Promise \u5bf9\u8c61\u3002\u6765\u770b\u5982\u4e0b\u4e00\u6bb5\u4ee3\u7801\uff1a<\/p>\n
function resolved(result) {\n console.log('Resolved');\n}\nfunction rejected(result) {\n console.error(result);\n}\nPromise.reject("error").then(resolved).catch(rejected);<\/code><\/pre>\n\u8fd9\u4e2a\u6267\u884c\u7684\u65f6\u5019\u5c31\u4f1a\u8fdb\u5165\u5230 catch \u4e2d\u3002<\/p>\n
6.4 Promise.resolve()<\/h3>\n
Promise.resolve(value) \u65b9\u6cd5\u8fd4\u56de\u4e00\u4e2a\u4ee5\u7ed9\u5b9a\u503c\u89e3\u6790\u540e\u7684 Promise \u5bf9\u8c61\u3002<\/p>\n
const promise1 = Promise.resolve(3);\npromise1.then(data=>{\n console.log("data", data);\n},err=>{\n console.log("err", err);\n})<\/code><\/pre>\n\u8fd9\u4e2a\u7528\u6cd5\u6bd4\u8f83\u7b80\u5355\uff0c\u6ca1\u5565\u597d\u8bf4\u7684\u3002<\/p>\n
\u8fd8\u6709\u4e00\u4e9b\u5176\u4ed6\u65b9\u6cd5\u6211\u5c31\u4e0d\u4e00\u4e00\u5217\u4e3e\u4e86\uff0c\u611f\u5174\u8da3\u7684\u5c0f\u4f19\u4f34\u4eec\u53ef\u4ee5\u770b\u770b MDN \u4e0a\u7684\u76f8\u5173\u8bb2\u89e3\uff1ahttps:\/\/developer.mozilla.org\/zh-CN\/docs\/Web\/JavaScript\/Reference\/Global_Objects\/Promise<\/a>\u3002<\/p>\n\u597d\u5566\uff0c\u8fd9\u4e2a\u4e1c\u897f\u641e\u61c2\u4e86\uff0c\u6211\u4eec\u518d\u53bb\u770b TienChin \u9879\u76ee\u7684\u524d\u7aef\uff0c\u5c31\u4f1a\u975e\u5e38\u5bb9\u6613\u4e86\uff01<\/p>\n