{"id":1088,"date":"2021-03-08T22:50:16","date_gmt":"2021-03-08T14:50:16","guid":{"rendered":"https:\/\/www.52dixiaowo.com\/java\/?p=1088"},"modified":"2021-03-18T23:55:28","modified_gmt":"2021-03-18T15:55:28","slug":"jsp%e7%9a%84el%e8%a1%a8%e8%be%be%e5%bc%8f","status":"publish","type":"post","link":"https:\/\/www.52dixiaowo.com\/java\/post-1088.html","title":{"rendered":"jsp\u7684EL\u8868\u8fbe\u5f0f"},"content":{"rendered":"\n<p>EL\u8868\u8fbe\u5f0f\u5168\u79f0\uff1aExpression Language \u8868\u8fbe\u5f0f\uff0c\u4e3b\u8981\u7528\u4e8e\u66ff\u6362\u548c\u7b80\u5316jsp\u9875\u9762\u7684java\u4ee3\u7801\u7f16\u5199\uff0cjsp\u9ed8\u8ba4\u652f\u6301EL\u8868\u8fbe\u5f0f\uff0c\u53ef\u4ee5\u4f7f\u7528\u6307\u4ee4\u5173\u95ed<\/p>\n\n\n\n<h5>1.\u57fa\u672c\u8bed\u6cd5\uff1a<\/h5>\n\n\n\n<ul><li>\u539f\u751f\u8868\u8fbe\u5f0f\u65b9\u6cd5\uff1a&lt;%= \u8868\u8fbe\u5f0f %&gt;<\/li><li>EL\u8868\u8fbe\u5f0f\uff1a${\u8868\u8fbe\u5f0f}<\/li><li>\uff08\u82e5\u83b7\u53d6\u4e3anull\uff0cEL\u4e0d\u663e\u793a\uff0c\u539f\u751f\u8868\u8fbe\u5f0f\u8f93\u51fanull\uff09<\/li><\/ul>\n\n\n\n<h5>2.\u8868\u8fbe\u5f0f\u4e3e\u4f8b\uff1a\uff08\u4f7f\u7528\u57df\u5bf9\u8c61\u65f6\uff0c\u9700\u52a0Scope\uff09<\/h5>\n\n\n\n<figure class=\"wp-block-table aligncenter is-style-regular\"><table><tbody><tr><td>\u539f\u751f\u8868\u8fbe\u5f0f<\/td><td>EL\u8868\u8fbe\u5f0f<\/td><td>\u8bf4\u660e<\/td><\/tr><tr><td>&lt; %=request.getParameter(\u201cusername\u201d)% &gt;<\/td><td>${ param.username }<\/td><td>\u9690\u5f0f\u5bf9\u8c61.\u53c2\u6570<\/td><\/tr><tr><td>&lt;%=user.getAddr( ) %&gt;<\/td><td>${user.addr}<\/td><td>\u7c7b.\u5c5e\u6027<\/td><\/tr><tr><td>&lt;%=request.getAttribute(\u201cuserlist\u201d) %><\/td><td>$ { requestScope.userlist }<\/td><td>\u57df\u5bf9\u8c61.\u53c2\u6570<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h5>3.\u9690\u5f0f\u5bf9\u8c61\u662f\u4ec0\u4e48\uff1f\u4e13\u95e8\u4e3aEL\u8868\u8fbe\u5f0f\u65b9\u4fbf\u8bbf\u95ee\u4f7f\u7528\u7684<\/h5>\n\n\n\n<ul><li>param\uff1a\u76f8\u5f53\u4e8erequest.getParameter<\/li><li>paramValues\uff1a\u76f8\u5f53\u4e8erequest.getParamterValues<\/li><li>header\uff1a\u76f8\u5f53\u4e8e request.getHeader<\/li><li>headerValues\uff1a\u76f8\u5f53\u4e8erequest.getHeaderValues<\/li><li>initParam\uff1a\u76f8\u5f53\u4e8eServletContext.getInitparameter<\/li><li>cookie\uff1a\u76f8\u5f53\u4e8ecookie\u503c<\/li><li>pageContext\uff1a\u76f8\u5f53\u4e8e\u5f53\u524d\u9875\u9762\u7684pageContext<\/li><li>\u5b9e\u9645\u4e0arequest\u7b49\u57df\u5bf9\u8c61\u7684\u9690\u5f0f\u5bf9\u8c61\u5c31\u662f\u540e\u9762\u52a0\u4e2aScope<\/li><\/ul>\n\n\n\n<h5>4.\u57fa\u672c\u7b26\u53f7\u5728EL\u4e2d\u7684\u7528\u6cd5<\/h5>\n\n\n\n<ul><li>EL\u4e2d\u83b7\u53d6\u6570\u636e\u7684\u6709.\u548c[]<\/li><li>\u5176\u4f59\u7684+\uff0c-\uff0c*\uff0c\uff01\uff0c()\u7b49\u7b26\u53f7\u4e5f\u53ef\u4ee5\u6b63\u5e38\u4f7f\u7528<\/li><li>empty\u6d4b\u8bd5\u662f\u5426\u4e3a\u7a7a<\/li><\/ul>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>EL\u8868\u8fbe\u5f0f\u5168\u79f0\uff1aExpression Language \u8868\u8fbe\u5f0f\uff0c\u4e3b\u8981\u7528\u4e8e\u66ff\u6362\u548c\u7b80\u5316jsp\u9875\u9762\u7684java\u4ee3\u7801\u7f16\u5199&hellip; <a href=\"https:\/\/www.52dixiaowo.com\/java\/post-1088.html\" class=\"more-link\">\u7ee7\u7eed\u9605\u8bfb <span class=\"screen-reader-text\">jsp\u7684EL\u8868\u8fbe\u5f0f<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[12],"tags":[],"_links":{"self":[{"href":"https:\/\/www.52dixiaowo.com\/java\/wp-json\/wp\/v2\/posts\/1088"}],"collection":[{"href":"https:\/\/www.52dixiaowo.com\/java\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.52dixiaowo.com\/java\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.52dixiaowo.com\/java\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.52dixiaowo.com\/java\/wp-json\/wp\/v2\/comments?post=1088"}],"version-history":[{"count":1,"href":"https:\/\/www.52dixiaowo.com\/java\/wp-json\/wp\/v2\/posts\/1088\/revisions"}],"predecessor-version":[{"id":1182,"href":"https:\/\/www.52dixiaowo.com\/java\/wp-json\/wp\/v2\/posts\/1088\/revisions\/1182"}],"wp:attachment":[{"href":"https:\/\/www.52dixiaowo.com\/java\/wp-json\/wp\/v2\/media?parent=1088"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.52dixiaowo.com\/java\/wp-json\/wp\/v2\/categories?post=1088"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.52dixiaowo.com\/java\/wp-json\/wp\/v2\/tags?post=1088"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}