一、前言中國(guó)省市區(qū)還是不少的 ， 省有34個(gè) ， 市有391個(gè) ， 區(qū)有1101個(gè) ， 這是以小編的庫(kù)里的 ， 可能不是最新的 ， 但是個(gè)數(shù)也差不了多少 。
當(dāng)一次返回所有的數(shù)據(jù) ， 并且還要組裝成一個(gè)三級(jí)樹(shù) ， 一般的for ， 會(huì)循環(huán)34*391*1101次 。這樣就是千萬(wàn)級(jí)的 ， 加上與數(shù)據(jù)庫(kù)交互 ， 你跑半天也跑不完 。
最后的處理是組長(zhǎng)提供的思路 ， 果然很快 。
二、思路首先：小編的省市區(qū)是三張表
第一：我們通過(guò)三次IO從數(shù)據(jù)庫(kù)中查詢(xún)出所有省市區(qū)的數(shù)據(jù) ， 下面在進(jìn)行for循環(huán)組裝樹(shù)形效率就很快了！
第二：為了減少I(mǎi)O交互 ， 我們把剛剛?cè)〕鰜?lái)的市和區(qū)構(gòu)建為map<provinceCode,List<City>> ， map<districtCode,List<District>> ， 這樣效率就上來(lái)了！
三、數(shù)據(jù)庫(kù)表設(shè)計(jì)1. 省CREATE TABLE `address_province`(`id` int(11) NOT NULL AUTO_INCREMENT COMMENT 'ID',`code` char(6) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,`name` varchar(16) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,`short_name` varchar(16) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,`new_code` char(6) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,`is_latest` tinyint(3) NULL DEFAULT 1 COMMENT '是否是最新地址 ， 0否1是',`remarks` varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,`created_at` datetime(0) NULL DEFAULT NULL COMMENT '創(chuàng)建時(shí)間',`created_by` varchar(16) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,`updated_at` datetime(0) NULL DEFAULT NULL COMMENT '更新時(shí)間',`updated_by` varchar(16) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,`is_deleted` tinyint(3) UNSIGNED NOT NULL DEFAULT 0 COMMENT '刪除標(biāo)記 ， 0：正常；1：刪除',PRIMARY KEY (`id`) USING BTREE,UNIQUE INDEX `uk_code`(`code`) USING BTREE,INDEX `idx_address_province_name`(`name`) USING BTREE,INDEX `idx_address_province_short_name`(`short_name`) USING BTREE) ENGINE = InnoDB AUTO_INCREMENT = 35 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci COMMENT = '地址省' ROW_FORMAT = Dynamic;2. 市：CREATE TABLE `address_city`(`id` int(11) UNSIGNED NOT NULL AUTO_INCREMENT COMMENT 'ID',`code` char(6) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,`name` varchar(16) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,`new_code` char(6) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,`province_code` char(6) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,`is_latest` tinyint(3) NULL DEFAULT 1 COMMENT '是否是最新地址 ， 0否1是',`remarks` varchar(100) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,`created_at` datetime(0) NULL DEFAULT NULL COMMENT '創(chuàng)建時(shí)間',`created_by` varchar(16) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,`updated_at` datetime(0) NULL DEFAULT NULL COMMENT '更新時(shí)間',`updated_by` varchar(16) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,`is_deleted` tinyint(3) NULL DEFAULT 0 COMMENT '刪除標(biāo)記 ， 0正常1刪除',PRIMARY KEY (`id`) USING BTREE,UNIQUE INDEX `uk_code`(`code`) USING BTREE,INDEX `idx_address_city_name`(`name`) USING BTREE) ENGINE = InnoDB AUTO_INCREMENT = 392 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci COMMENT = '地址市' ROW_FORMAT = Dynamic;3. 區(qū)CREATE TABLE `address_district`(`id` int(11) NOT NULL AUTO_INCREMENT,`code` char(6) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,`name` varchar(16) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,`new_code` char(6) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,`city_code` char(6) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,`province_code` char(6) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,`is_latest` tinyint(3) NULL DEFAULT 1 COMMENT '是否是最新地址 ， 0否1是',`remarks` varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,`created_at` datetime(0) NULL DEFAULT NULL COMMENT '創(chuàng)建時(shí)間',`created_by` varchar(16) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,`updated_at` datetime(0) NULL DEFAULT NULL COMMENT '更新時(shí)間',`updated_by` varchar(16) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,`is_deleted` tinyint(3) NULL DEFAULT 0 COMMENT '刪除標(biāo)記 ， 0正常1刪除',PRIMARY KEY (`id`) USING BTREE,UNIQUE INDEX `uk_code`(`code`) USING BTREE,INDEX `idx_address_district_name`(`name`) USING BTREE) ENGINE = InnoDB AUTO_INCREMENT = 3110 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci COMMENT = '地址縣/區(qū)' ROW_FORMAT = Dynamic;