一、項目功能概述

電商秒殺需要完成的3個功能：

1.展示一個商品列表頁面，我們可以從中看到可秒殺的商品列表

2.點擊進入商品詳情頁，獲取該商品的詳細信息

3.秒殺時間開始后，點擊進入下單確認頁面，并支付成功

二、基于SpringBoot進行項目環(huán)境搭建

步驟1：創(chuàng)建一個maven工程，使用quickStart骨架。

步驟2：在pom.xml導(dǎo)入SpringBoot相關(guān)依賴。

<?xml version='1.0' encoding='UTF-8'?> <project xmlns='http://maven.apache.org/POM/4.0.0' xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' xsi:schemaLocation='http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd'> <modelVersion>4.0.0</modelVersion> <groupId>org.example</groupId> <artifactId>Spike</artifactId> <version>1.0-SNAPSHOT</version> <name>Spike</name> <!-- FIXME change it to the project’s website --> <url>http://www.example.com</url> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.0.5.RELEASE</version> </parent> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <maven.compiler.source>1.8</maven.compiler.source> <maven.compiler.target>1.8</maven.compiler.target> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.11</version> <scope>test</scope> </dependency> </dependencies> <build> <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) --> <plugins> <!-- clean lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#clean_Lifecycle --> <plugin> <artifactId>maven-clean-plugin</artifactId> <version>3.1.0</version> </plugin> <!-- default lifecycle, jar packaging: see https://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging --> <plugin> <artifactId>maven-resources-plugin</artifactId> <version>3.0.2</version> </plugin> <plugin> <artifactId>maven-compiler-plugin</artifactId> <version>3.8.0</version> </plugin> <plugin> <artifactId>maven-surefire-plugin</artifactId> <version>2.22.1</version> </plugin> <plugin> <artifactId>maven-jar-plugin</artifactId> <version>3.0.2</version> </plugin> <plugin> <artifactId>maven-install-plugin</artifactId> <version>2.5.2</version> </plugin> <plugin> <artifactId>maven-deploy-plugin</artifactId> <version>2.8.2</version> </plugin> <!-- site lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#site_Lifecycle --> <plugin> <artifactId>maven-site-plugin</artifactId> <version>3.7.1</version> </plugin> <plugin> <artifactId>maven-project-info-reports-plugin</artifactId> <version>3.0.0</version> </plugin> </plugins> </pluginManagement> </build> </project>

步驟3：在main/java/app中，我們對SpringBoot和SpringMVC進行簡單的配置工作。掌握這幾個注解的作用。

package org.example;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.EnableAutoConfiguration;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RestController;//SpringBoot會幫我們啟動tomcat，并加載默認配置@EnableAutoConfiguration//SpringMVC相關(guān)配置@RestControllerpublic class App { @RequestMapping('/') public String home(){ //網(wǎng)頁中輸出 return 'Hello World!'; } public static void main( String[] args ){ //控制臺輸出 System.out.println( 'Hello World!' ); SpringApplication.run(App.class,args); }}

運行結(jié)果：

用瀏覽器打開http://localhost:8080/，我們可以看到頁面上輸出：Hello World！

同時，控制臺也輸出了Hello World！，以及一些Spring相關(guān)的信息。

SpringBoot小技巧：可以在resource目錄下創(chuàng)建一個application.propeties配置文件，在其中寫：server.port = 端口號來設(shè)置端口號。

步驟4：接入mybatis，首先在pom.xml添加需要的依賴（mysql，druid連接池，mybatis）

寫一個plugin標簽，引入對應(yīng)的mybatis自動生成文件的插件 {

添加對應(yīng)的依賴：mybatis generator的core（第一次使用要單獨在前面導(dǎo)入依賴，不可直接放在plugin中），mysql數(shù)據(jù)庫的解析

寫一個excution標簽：設(shè)置允許移動生成的文件，允許自動覆蓋文件（實際工作中不可以）

寫一個configuration標簽：指定mybatis generator 配置文件的路徑 }

1 <?xml version='1.0' encoding='UTF-8'?> 2 3 <project xmlns='http://maven.apache.org/POM/4.0.0' xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' 4 xsi:schemaLocation='http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd'> 5 <modelVersion>4.0.0</modelVersion> 6 7 <groupId>org.example</groupId> 8 <artifactId>Spike</artifactId> 9 <version>1.0-SNAPSHOT</version> 10 11 <name>Spike</name> 12 <!-- FIXME change it to the project’s website --> 13 <url>http://www.example.com</url> 14 15 <parent> 16 <groupId>org.springframework.boot</groupId> 17 <artifactId>spring-boot-starter-parent</artifactId> 18 <version>2.0.5.RELEASE</version> 19 </parent> 20 21 <properties> 22 <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> 23 <maven.compiler.source>1.8</maven.compiler.source> 24 <maven.compiler.target>1.8</maven.compiler.target> 25 </properties> 26 27 <dependencies> 28 <dependency> 29 <groupId>org.springframework.boot</groupId> 30 <artifactId>spring-boot-starter-web</artifactId> 31 </dependency> 32 <dependency> 33 <groupId>mysql</groupId> 34 <artifactId>mysql-connector-java</artifactId> 35 <version>5.1.6</version> 36 </dependency> 37 <dependency> 38 <groupId>com.alibaba</groupId> 39 <artifactId>druid</artifactId> 40 <version>1.1.3</version> 41 </dependency> 42 <dependency> 43 <groupId>org.mybatis.spring.boot</groupId> 44 <artifactId>mybatis-spring-boot-starter</artifactId> 45 <version>1.3.1</version> 46 </dependency> 47 <dependency> 48 <groupId>junit</groupId> 49 <artifactId>junit</artifactId> 50 <version>4.11</version> 51 <scope>test</scope> 52 </dependency> 53 <dependency> 54 <groupId>org.mybatis.generator</groupId> 55 <artifactId>mybatis-generator-core</artifactId> 56 <version>1.3.5</version> 57 </dependency> 58 </dependencies> 59 60 <build> 61 <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) --> 62 <plugins> 63 <!-- clean lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#clean_Lifecycle --> 64 <plugin> 65 <artifactId>maven-clean-plugin</artifactId> 66 <version>3.1.0</version> 67 </plugin> 68 <!-- default lifecycle, jar packaging: see https://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging --> 69 <plugin> 70 <artifactId>maven-resources-plugin</artifactId> 71 <version>3.0.2</version> 72 </plugin> 73 <plugin> 74 <artifactId>maven-compiler-plugin</artifactId> 75 <version>3.8.0</version> 76 </plugin> 77 <plugin> 78 <artifactId>maven-surefire-plugin</artifactId> 79 <version>2.22.1</version> 80 </plugin> 81 <plugin> 82 <artifactId>maven-jar-plugin</artifactId> 83 <version>3.0.2</version> 84 </plugin> 85 <plugin> 86 <artifactId>maven-install-plugin</artifactId> 87 <version>2.5.2</version> 88 </plugin> 89 <plugin> 90 <artifactId>maven-deploy-plugin</artifactId> 91 <version>2.8.2</version> 92 </plugin> 93 94 <!-- site lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#site_Lifecycle --> 95 <plugin> 96 <artifactId>maven-site-plugin</artifactId> 97 <version>3.7.1</version> 98 </plugin> 99 <plugin>100 <artifactId>maven-project-info-reports-plugin</artifactId>101 <version>3.0.0</version>102 </plugin>103 104 <plugin>105 <groupId>org.mybatis.generator</groupId>106 <artifactId>mybatis-generator-maven-plugin</artifactId>107 <version>1.3.5</version>108 <dependencies>109 <dependency>110<groupId>org.mybatis.generator</groupId>111<artifactId>mybatis-generator-core</artifactId>112<version>1.3.5</version>113 </dependency>114 <dependency>115<groupId>mysql</groupId>116<artifactId>mysql-connector-java</artifactId>117<version>5.1.6</version>118 </dependency>119 </dependencies>120 <executions>121 <execution>122<id>mybatis generator</id>123<phase>package</phase>124<goals>125 <goal>generate</goal>126</goals>127 </execution>128 </executions>129 <configuration>130 <!--允許移動生成的文件-->131 <verbose>true</verbose>132 <!--允許自動覆蓋文件-->133 <overwrite>true</overwrite>134 <!--mybatis generator 配置文件的路徑-->135 <configurationFile>136src/main/resource/mybatis-generator.xml137 </configurationFile>138 </configuration>139 </plugin>140 141 </plugins>142 </pluginManagement>143 </build>144 </project>

步驟5：創(chuàng)建mysql底層的數(shù)據(jù)庫與相關(guān)表格

1.創(chuàng)建數(shù)據(jù)庫spike

2.創(chuàng)建一個user_info表格

3.創(chuàng)建一個user_password表格，并設(shè)置user_id為外鍵關(guān)聯(lián)user_info的id

步驟6：在步驟4中，我們最后指定了mybatis generator 配置文件的路徑，于是我們在指定路徑（resource目錄下）創(chuàng)建一個mybatis generator.xml，并進行如下配置：

<?xml version='1.0' encoding='UTF-8'?><!DOCTYPE generatorConfiguration PUBLIC '-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN' 'http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd'><generatorConfiguration> <context targetRuntime='MyBatis3' > <!--數(shù)據(jù)庫連接地址賬號密碼--> <jdbcConnection driverClass='com.mysql.jdbc.Driver' connectionURL='jdbc:mysql://127.0.0.1:3306/spike' userId='root' password='0322'> </jdbcConnection> <!--生成Data Object類存放位置--> <javaModelGenerator targetPackage='org.example.dataobject' targetProject='src/main/java'> <property name='enableSubPackages' value='true'/> <property name='trimStrings' value='true'/> </javaModelGenerator> <!--生成映射文件存放位置--> <sqlMapGenerator targetPackage='mapping' targetProject='src/main/resources'> <property name='enableSubPackages' value='true'/> </sqlMapGenerator> <!--生成dao類存放位置--> <javaClientGenerator targetPackage='org.example.dao' type='XMLMAPPER' targetProject='src/main/java'> <property name='enableSubPackages' value='true'/> </javaClientGenerator> <!--生成對應(yīng)表及類名--> <table tableName='user_info' domainObjectName='UserDo' enableCountByExample='false'enableUpdateByExample='false' enableDeleteByExample='false'enableSelectByExample='false' selectByExampleQueryId='false' ></table> <table tableName='user_password' domainObjectName='UserPasswordDO' enableCountByExample='false'enableUpdateByExample='false' enableDeleteByExample='false'enableSelectByExample='false' selectByExampleQueryId='false' ></table> </context></generatorConfiguration>

步驟7：根據(jù)步驟6中指定的位置，我們在org.example目錄下新建一個dataobject的包，一個dao包。并測試是否能夠成功生成相應(yīng)的文件：

run——edit configurations——+maven——command line:mybatis-generator:generate——apply

然后我們運行這個新建的命令，可以看到resources/mapping下多了兩個文件：

dataobject包與dao包下生成了如下文件：

手動刪除兩個Example文件。

步驟8：為了接入mybatis對應(yīng)mysql的數(shù)據(jù)源，我們繼續(xù)編寫application.properties文件

server.port = 8090 mybatis.mapperLocations = classpath:mapping/*.xml spring.datasource.name = Spike spring.datasource.url = jdbc:mysql://127.0.0.1:3306/Spike spring.datasource.username = root spring.datasource.password = 0322 #使用druid數(shù)據(jù)源 spring.datasource.type = com.alibaba.druid.pool.DruidDataSource spring.datasource.driverClassName = com.mysql.jdbc.Driver

步驟9：回到app.java

將@EnableAutoConfiguration注解改為@SpringBootApplication(scanBasePackages = 'org.example')，作用是將app交給spring托管，并且指定為主啟動類。

添加注解@MapperScan('org.example.dao')，把dao存放的地方設(shè)置在對應(yīng)注解下面。

最后，寫一個方法來測試我們的搭建工作是否完成，（事先在表格中添加一條數(shù)據(jù)）

package org.example; import org.example.dao.UserDoMapper; import org.example.dataobject.UserDo; import org.mybatis.spring.annotation.MapperScan; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; //SpringBoot會幫我們啟動tomcat，并加載默認配置 @SpringBootApplication(scanBasePackages = {'org.example'}) //SpringMVC相關(guān)配置 @RestController @MapperScan('org.example.dao') public class App { @Autowired private UserDoMapper userDoMapper; @RequestMapping('/') public String home(){ UserDo userDo = userDoMapper.selectByPrimaryKey(1); if(userDo == null){ return '用戶對象不存在'; }else{ return userDo.getName(); } } public static void main( String[] args ){ //控制臺輸出 System.out.println( 'Hello World!' ); SpringApplication.run(App.class,args); } }app.java

打開http://localhost:8090/，我們可以看到頁面上顯示了我們添加的數(shù)據(jù)中name字段的內(nèi)容。

三、用戶模塊開發(fā)

1.使用SpingMVC模式開發(fā)用戶信息

步驟1：補全框架結(jié)構(gòu)：

步驟2：service層的編寫：

UserService接口：

package org.example.service;import org.example.service.model.UserModel;public interface UserService { UserModel getUserById(Integer id);}

UserService實現(xiàn)類：

@Servicepublic class UserServiceImpl implements UserService { @Autowired private UserDoMapper userDoMapper; @Autowired private UserPasswordDOMapper userPasswordDOMapper; @Override public UserModel getUserById(Integer id) { UserDo userDo = userDoMapper.selectByPrimaryKey(id); if(userDo == null){ return null; } //通過用戶id獲取對應(yīng)的用戶加密密碼信息 UserPasswordDO userPasswordDO = userPasswordDOMapper.selectByUserId(userDo.getId()); return convertFromDataObject(userDo,userPasswordDO); } public UserModel convertFromDataObject(UserDo userDo, UserPasswordDO userPasswordDO) { if(userDo == null){ return null; } UserModel userModel = new UserModel(); BeanUtils.copyProperties(userDo,userModel); if(userPasswordDO != null){ userModel.setEncriptPassword(userPasswordDO.getEncriptPassword()); } return userModel; }}

UserModel類：存放數(shù)據(jù)庫的所有對應(yīng)字段與getters&setters，用于service層與數(shù)據(jù)庫數(shù)據(jù)的解耦，使service層無法直接接觸數(shù)據(jù)庫

1 package org.example.service.model; 2 3 public class UserModel { 4 private Integer id; 5 private String name; 6 private Byte gender; 7 private Integer age; 8 private String telephone; 9 private String registerMode;10 private String thirdPartyId;11 private String encriptPassword;12 13 public Integer getId() {14 return id;15 }16 17 public void setId(Integer id) {18 this.id = id;19 }20 21 public String getName() {22 return name;23 }24 25 public void setName(String name) {26 this.name = name;27 }28 29 public Byte getGender() {30 return gender;31 }32 33 public void setGender(Byte gender) {34 this.gender = gender;35 }36 37 public Integer getAge() {38 return age;39 }40 41 public void setAge(Integer age) {42 this.age = age;43 }44 45 public String getTelephone() {46 return telephone;47 }48 49 public void setTelephone(String telephone) {50 this.telephone = telephone;51 }52 53 public String getRegisterMode() {54 return registerMode;55 }56 57 public void setRegisterMode(String registerMode) {58 this.registerMode = registerMode;59 }60 61 public String getThirdPartyId() {62 return thirdPartyId;63 }64 65 public void setThirdPartyId(String thirdPartyId) {66 this.thirdPartyId = thirdPartyId;67 }68 69 public String getEncriptPassword() {70 return encriptPassword;71 }72 73 public void setEncriptPassword(String encriptPassword) {74 this.encriptPassword = encriptPassword;75 }76 }

步驟3：修改UserPasswordDOMapper.xml，添加一個selectByUserId操作的配置

<select parameterType='java.lang.Integer' resultMap='BaseResultMap'> select <include refid='Base_Column_List' /> from user_password where user_id = #{userId,jdbcType=INTEGER} </select>

同步修改UserPasswordDOMapper.java，添加一行代碼：

UserPasswordDO selectByUserId(Integer userId);

步驟4：編寫Controller包中的UserController.java

@Controller('user')@RequestMapping('/user')public class UserController { @Autowired private UserService userService; @RequestMapping('/get') @ResponseBody public UserModel getUser(@RequestParam(name='id') Integer id) { //調(diào)用service服務(wù)獲取對應(yīng)id的用戶對象并返回給前端 UserModel userModel = userService.getUserById(id); return userModel; }}

運行后，訪問http://localhost:8090/user/get?id=1（需要事先添加好一條完整的數(shù)據(jù)），可以看到頁面上輸出了這條數(shù)據(jù)的完整信息。

步驟5：發(fā)現(xiàn)問題：在UserController中，我們把userModel模型直接返回給前端，導(dǎo)致密碼直接輸出在頁面中，這是非常不專業(yè)的。

因此，我們在controller層（包）中需要新建一個模型對象。在controller層中新建一個viewobject包，并在其中寫一個viewobject類，里面只寫需要展示在前端的字段與getters&setters。

1 package org.example.controller.viewobject; 2 3 public class UserVO { 4 //只寫前端用戶所需要的信息 5 private Integer id; 6 private String name; 7 private Byte gender; 8 private Integer age; 9 private String telephone;10 11 public Integer getId() {12 return id;13 }14 15 public void setId(Integer id) {16 this.id = id;17 }18 19 public String getName() {20 return name;21 }22 23 public void setName(String name) {24 this.name = name;25 }26 27 public Byte getGender() {28 return gender;29 }30 31 public void setGender(Byte gender) {32 this.gender = gender;33 }34 35 public Integer getAge() {36 return age;37 }38 39 public void setAge(Integer age) {40 this.age = age;41 }42 43 public String getTelephone() {44 return telephone;45 }46 47 public void setTelephone(String telephone) {48 this.telephone = telephone;49 }50 }

同時，我們修改UserController類，將UserModel轉(zhuǎn)化為viewobject后，再返回給前端。

@Controller('user')@RequestMapping('/user')public class UserController { @Autowired private UserService userService; @RequestMapping('/get') @ResponseBody public UserVO getUser(@RequestParam(name='id') Integer id) { //調(diào)用service服務(wù)獲取對應(yīng)id的用戶對象并返回給前端 UserModel userModel = userService.getUserById(id); //將核心領(lǐng)域模型對象轉(zhuǎn)化為可供UI使用的viewobject return convertFromModel(userModel); } private UserVO convertFromModel(UserModel userModel){ if(userModel == null){ return null; } UserVO userVO = new UserVO(); BeanUtils.copyProperties(userModel,userVO); return userVO; }}

這一步中，我們做了一個完整的從數(shù)據(jù)庫中讀取數(shù)據(jù)，展示在前端頁面上的操作。

controller層——>service層——>dao層

dataobject層負責(zé)數(shù)據(jù)存儲到service的傳輸，并且在用戶的service的服務(wù)中組裝了對應(yīng)的核心領(lǐng)域模型。

controller層做了到用戶viewobject之間的傳遞，保證密碼等信息不會輸出到前端。

2.定義通用的返回對象

步驟1：自主管理前端頁面的返回——返回正確信息

org.example包下創(chuàng)建一個response包，在其中創(chuàng)建一個CommonReturnType.java文件。

在該文件中，設(shè)置兩個屬性：status，data，并生成對應(yīng)的getters&setters。然后寫兩個構(gòu)造方法，包含了兩個屬性的設(shè)置。

package org.example.response; public class CommonReturnType { //表名對應(yīng)請求的返回處理結(jié)果，success/fail private String status; //若status返回success，則data內(nèi)返回前端需要的json數(shù)據(jù) //若status返回success，則data內(nèi)使用通用的錯誤碼格式 private Object data; //定義一個通用的創(chuàng)建方法 public static CommonReturnType create(Object result){ return CommonReturnType.create(result,'success'); } public static CommonReturnType create(Object result,String status){ CommonReturnType type = new CommonReturnType(); type.setStatus(status); type.setData(result); return type; } public String getStatus() { return status; } public void setStatus(String status) { this.status = status; } public Object getData() { return data; } public void setData(Object data) { this.data = data; } }

修改我們的UserController.java，將返回值改為CommonReturnType，由CommonReturnType調(diào)用create方法來引用UserVO中的信息。以下代碼為需要修改的部分：

public CommonReturnType getUser(@RequestParam(name='id') Integer id) { //調(diào)用service服務(wù)獲取對應(yīng)id的用戶對象并返回給前端 UserModel userModel = userService.getUserById(id); //將核心領(lǐng)域模型對象轉(zhuǎn)化為可供UI使用的viewobject UserVO userVO = convertFromModel(userModel); //返回通用對象 return CommonReturnType.create(userVO); }

運行后，我們?nèi)匀辉L問http://localhost:8090/user/get?id=1，可以看到頁面上輸出了：

步驟2：自主管理前端頁面的返回——返回錯誤信息

org.example包下創(chuàng)建一個error包，在其中創(chuàng)建一個CommonError接口，寫3個方法：獲取錯誤碼，獲取錯誤信息，設(shè)置錯誤信息

public interface CommonError { public int getErrCode(); public String getErrMsg(); public CommonError setErrMsg(String errMsg); }

error包下寫一個枚舉類型的EmBusinessError，實現(xiàn)CommonError接口。

package org.example.error;public enum EmBusinessError implements CommonError{ //通用錯誤類型10001 PARAMETER_VALIDATION_ERROR(10001,'參數(shù)不合法'), //未知錯誤10002 UNKNOWN_ERROR(10002,'未知錯誤'), //20000開頭相關(guān)為用戶信息相關(guān)錯誤定義 USER_NOT_EXIST(20001,'用戶不存在'), ; private EmBusinessError(int errCode,String errMsg){ this.errCode = errCode; this.errMsg = errMsg; } private int errCode; private String errMsg; @Override public int getErrCode() { return this.errCode; } @Override public String getErrMsg() { return this.errMsg; } @Override public CommonError setErrMsg(String errMsg) { this.errMsg = errMsg; return this; }}

error包下寫一個BusinessException，實現(xiàn)CommonError接口，并繼承Exception類。

public class BusinessException extends Exception implements CommonError{ private CommonError commonError; //直接接收EmBusinessError的傳參用于構(gòu)造業(yè)務(wù)異常 public BusinessException(CommonError commonError) { super(); this.commonError = commonError; } public BusinessException(CommonError commonError,String errMsg) { super(); this.commonError = commonError; this.commonError.setErrMsg(errMsg); } @Override public int getErrCode() { return this.commonError.getErrCode(); } @Override public String getErrMsg() { return this.commonError.getErrMsg(); } @Override public CommonError setErrMsg(String errMsg) { this.commonError.setErrMsg(errMsg); return this; }}

UserController中添加如下代碼：

//若獲取的對應(yīng)用戶信息不存在 if(userModel==null){ throw new BusinessException(EmBusinessError.USER_NOT_EXIST); }

步驟3：異常處理

在controller目錄下單獨寫一個BaseController類，定義exceptionhandler解決未被controller層吸收的exception。

import java.util.Map;public class BaseController { //定義exceptionhandler解決未被controller層吸收的exception @ExceptionHandler(Exception.class) @ResponseStatus(HttpStatus.OK) @ResponseBody public Object handlerException(HttpServletRequest request, Exception ex){ Map<String,Object> responseData = new HashMap<>(); if(ex instanceof BusinessException){ BusinessException businessException = (BusinessException)ex; responseData.put('errCode',businessException.getErrCode()); responseData.put('errMsg',businessException.getErrMsg()); }else{ responseData.put('errCode', EmBusinessError.UNKNOWN_ERROR.getErrCode()); responseData.put('errMsg',EmBusinessError.UNKNOWN_ERROR.getErrMsg()); } return CommonReturnType.create(responseData,'fail'); }}

然后，UserController類需要繼承BaseController類。

運行后，我們訪問http://localhost:8090/user/get?id=2，（id=2的數(shù)據(jù)是不存在的），可以看到頁面為：

為了程序的健壯性，我們在BaseController中添加了一個unknown error。我們可以手動地來測試一下這段代碼是否起了作用：

修改UserController部分代碼如下：

if(userModel==null){ userModel.setEncriptPassword('123'); //throw new BusinessException(EmBusinessError.USER_NOT_EXIST); }

運行后，我們再次訪問http://localhost:8090/user/get?id=2，可以看到頁面為：

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