利用IDEA构建springboot应用--controller例子

深藏阁楼爱情的钟 2024-04-17 05:53 30阅读 0赞

微服务是一个新兴的软件架构，就是把一个大型的单个应用程序和服务拆分为数十个的支持微服务。一个微服务的策略可以让工作变得更为简便，它可扩展单个组件而不是整个的应用程序堆栈，从而满足服务等级协议。

# 第一个SpringBoot程序 #

这里使用的开发软件是`IntelliJ Idea`，和`Eclipse`差不太多，界面更炫酷，功能更强大；`Android Studio`就是基于`IntelliJ` 开发的，我之前使用过`Android Studio`，它俩界面几乎一样。

## maven配置的中央仓库阿里云镜像 ##

setting.xml

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

<mirrors>
 <mirror>
 <id>alimaven</id>
 <name>aliyun maven</name>
 <url>http://maven.aliyun.com/nexus/content/groups/public/</url>
 <mirrorOf>central</mirrorOf> 
 </mirror>
 </mirrors>

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

## 使用`IDEA`创建SpringBoot项目 ##

![format_png][]

![format_png 1][]

![format_png 2][]

![format_png 3][]

![format_png 4][]删除三个不必要的文件

项目结构为：

![format_png 5][]

项目默认的 maven `pom.xml`文件

pom.xml

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

<?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>com.newer</groupId>
 <artifactId>springboot</artifactId>
 <version>0.0.1-SNAPSHOT</version>
 <packaging>jar</packaging>
 
 <name>springboot</name>
 <description>Demo project for Spring Boot</description>
 
 <parent>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-parent</artifactId>
 <version>2.0.6.RELEASE</version>
 <relativePath/> 
 </parent>
 
 <properties>
 <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
 <java.version>1.8</java.version>
 </properties>
 
 <dependencies>
 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-web</artifactId>
 </dependency>
 
 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-test</artifactId>
 <scope>test</scope>
 </dependency>
 </dependencies>
 
 <build>
 <plugins>
 <plugin>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-maven-plugin</artifactId>
 </plugin>
 </plugins>
 </build>
 
 
 </project>

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

运行`SpirngbootdemoApplication`的main方法，就能开始运行

控制台输出：

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

"C:\Program Files\Java\jdk1.8.0_91\bin\java" ....
    
      .   ____          _            __ _ _
     /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
    ( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
     \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
      '  |____| .__|_| |_|_| |_\__, | / / / /
     =========|_|==============|___/=/_/_/_/
     :: Spring Boot ::        (v1.4.2.RELEASE)
     2016-12-16 14:56:52.083  INFO 15872 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
    2016-12-16 14:56:52.215  INFO 15872 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
    2016-12-16 14:56:52.255  INFO 15872 --- [           main] com.jxust.SpirngbootdemoApplication      : Started SpirngbootdemoApplication in 7.795 seconds (JVM running for 9.177)

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

创建一个`HelloController`，位于`controller`包下

![format_png 6][]

HelloController.java

<table> 
 <tbody> 
 <tr> 
 <td> 1 2 3 4 5 6 7 8 </td> 
 <td> <code>@RestController</code> <code>public</code>&nbsp;<code>class</code>&nbsp;<code>HelloController { </code> &nbsp; <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>@RequestMapping</code><code>(</code><code>"/hello"</code><code>)</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>public</code>&nbsp;<code>String say(){ </code> <code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>return</code>&nbsp;<code>"Hello SpringBoot!"</code><code>;</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>}</code> <code>}</code> </td> 
 </tr> 
 </tbody> 
</table>

<table> 
 <tbody> 
 <tr> 
 <td> 1 </td> 
 <td> <code>@RestController</code>&nbsp;<code>Spring4 之后新加的注解,原来返回json需要</code><code>@ResponseBody</code><code>配合</code><code>@Controller</code><code>,现在一个顶俩</code> </td> 
 </tr> 
 </tbody> 
</table>

在浏览器中输入`http://localhost:8080/hello`就能输出`Hello SpringBoot!`这句话。

![format_png 7][]

## 自定义属性配置 ##

用到的是`application.properties`这个文件

![format_png 8][]

### 配置端口号和访问前缀 ###

`application.properties`

<table> 
 <tbody> 
 <tr> 
 <td> 1 2 </td> 
 <td> <code>server.port=</code><code>8086</code> <code>server.servlet.context-path=/springboot</code> </td> 
 </tr> 
 </tbody> 
</table>

![format_png 9][]

除了使用`.properties`格式的文件，还可以使用`.yml`格式的配置文件(推荐)，更加简便   
`application.yml`

![format_png 10][]

把原来的`application.properties`文件删除   
注意格式，空格不能少

### 获取配置文件中的属性值 ###

我们也可以在配置文件中，配置数据，在 Controller 中获取,比如：   
`application.yml`

![format_png 11][]

> HelloController 获取配置文件中的值

`HelloController.java`

<table> 
 <tbody> 
 <tr> 
 <td> 1 2 3 4 5 6 7 8 9 10 11 </td> 
 <td> <code>@RestController</code> <code>public</code>&nbsp;<code>class</code>&nbsp;<code>HelloController { </code> &nbsp; <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>@Value</code><code>(</code><code>"${name}"</code><code>)</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>private</code>&nbsp;<code>String name;</code> &nbsp; <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>@RequestMapping</code><code>(value =&nbsp;</code><code>"/hello"</code>&nbsp;<code>,method = RequestMethod.GET)</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>public</code>&nbsp;<code>String getName(){ </code> <code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>return</code>&nbsp;<code>name;</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>}</code> <code>}</code> </td> 
 </tr> 
 </tbody> 
</table>

返回的为name的值

![format_png 12][]

配置文件中值配置方式的多样化  
配置文件的值可以是多个，也可以是组合，如：

application.yml

或者

application.yml

<table> 
 <tbody> 
 <tr> 
 <td> 1 2 3 </td> 
 <td> <code>name: 小胖</code> <code>age:&nbsp;</code><code>22</code> <code>content:&nbsp;</code><code>"name: ${name},age: ${age}"</code> </td> 
 </tr> 
 </tbody> 
</table>

或者

application.yml

<table> 
 <tbody> 
 <tr> 
 <td> 1 2 3 4 5 6 </td> 
 <td> <code>server:</code> <code>&nbsp;&nbsp;</code><code>port:&nbsp;</code><code>8081</code> <code>&nbsp;&nbsp;</code><code>context-path: /springboot</code> <code>person:</code> <code>&nbsp;&nbsp;</code><code>name: 小胖</code> <code>&nbsp;&nbsp;</code><code>age:&nbsp;</code><code>22</code> </td> 
 </tr> 
 </tbody> 
</table>

前两种配置获取值的方式都是一样的,但是对于这种方式，person 有相应的两个属性，需要这样处理

`PersonProperties.java`

package com.newer.springboot.dao;
 
 import org.springframework.boot.context.properties.ConfigurationProperties;
 import org.springframework.stereotype.Component;
 
 /**
 * @author:Mr.Tan
 * @Create:2018-10-26-17-07
 **/
 @Component//（把普通pojo实例化到spring容器中，相当于配置文件中的<bean id="" class=""/>）
 @ConfigurationProperties(prefix="person")
 public class PersonProperties {
 private String name;
 private Integer age;
 
 public String getName() {
 return name;
 }
 
 public void setName(String name) {
 this.name = name;
 }
 
 public Integer getAge() {
 return age;
 }
 
 public void setAge(Integer age) {
 this.age = age;
 }
 }

@Component//（把普通pojo实例化到spring容器中，相当于配置文件中的<bean id="" class=""/>）

> `Alt+insert`快捷键提示生成 `Getter and Setter`

`pom.xml`需要加入下面的依赖,处理警告

<table> 
 <tbody> 
 <tr> 
 <td> 1 2 3 4 5 6 </td> 
 <td> <code>&lt;!--处理警告--&gt;</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>&lt;dependency&gt;</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>&lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>&lt;artifactId&gt;spring-boot-configuration-processor&lt;/artifactId&gt;</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>&lt;optional&gt;</code><code>true</code><code>&lt;/optional&gt;</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>&lt;/dependency&gt;</code> </td> 
 </tr> 
 </tbody> 
</table>

HelloController.java

<table> 
 <tbody> 
 <tr> 
 <td> 1 2 3 4 5 6 7 8 9 10 11 12 13 </td> 
 <td> <code>@RestController</code> <code>public</code>&nbsp;<code>class</code>&nbsp;<code>HelloController { </code> &nbsp; <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>@Autowired</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>private</code>&nbsp;<code>PersonProperties personProperties;</code> &nbsp; &nbsp; <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>@RequestMapping</code><code>(value =&nbsp;</code><code>"/hello"</code><code>,method = RequestMethod.GET)</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>public</code>&nbsp;<code>String say(){ </code> <code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>return</code>&nbsp;<code>personProperties.getName()+personProperties.getAge();</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>}</code> &nbsp; <code>}</code> </td> 
 </tr> 
 </tbody> 
</table>

![format_png 13][]

### 关于配置文件`application.yml`的多套配置 ###

<table> 
 <tbody> 
 <tr> 
 <td> 1 2 </td> 
 <td> <code>类似 il8n 文件国际化的配置方式i18n_en_US.properties和i18n_zh_CN.properties</code> <code>这样能解决，需要频繁修改配置的尴尬</code> </td> 
 </tr> 
 </tbody> 
</table>

![format_png 14][]

由`application.yml`配置文件决定使用那套配置文件。

**`application.yml`**

![format_png 15][]

**application-a.yml**

![format_png 16][]

** application-b.yml**

![format_png 17][]

# SpringBoot增删改查实例 #

## 完整的项目结构 ##

![format_png 18][]

## Controller的使用 ##

<table> 
 <tbody> 
 <tr> 
 <td> 1 2 3 4 5 </td> 
 <td> <code>@Controller</code>&nbsp;<code>处理http请求</code> &nbsp; <code>@RestController</code>&nbsp;<code>Spring4 之后新加的注解，原来返回json需要</code><code>@ResponseBody</code><code>配合</code><code>@Controller</code> &nbsp; <code>@RequestMapping</code>&nbsp;<code>配置url映射</code> </td> 
 </tr> 
 </tbody> 
</table>

对于 REST 风格的请求

![format_png 19][]

对于 Controller 中的方法上的注解

<table> 
 <tbody> 
 <tr> 
 <td> 1 2 3 4 </td> 
 <td> <code>@RequestMapping</code><code>(value =&nbsp;</code><code>"/hello"</code><code>,method = RequestMethod.GET)</code> <code>@RequestMapping</code><code>(value =&nbsp;</code><code>"/hello"</code><code>,method = RequestMethod.POST)</code> <code>@RequestMapping</code><code>(value =&nbsp;</code><code>"/hello"</code><code>,method = RequestMethod.DELETE)</code> <code>@RequestMapping</code><code>(value =&nbsp;</code><code>"/hello"</code><code>,method = RequestMethod.PUT)</code> </td> 
 </tr> 
 </tbody> 
</table>

SpringBoot 对上面的注解进行了简化

<table> 
 <tbody> 
 <tr> 
 <td> 1 2 3 4 </td> 
 <td> <code>@GetMapping</code><code>(value =&nbsp;</code><code>"/girls"</code><code>)</code> <code>@PostMapping</code><code>(value =&nbsp;</code><code>"/girls"</code><code>)</code> <code>@PutMapping</code><code>(value =&nbsp;</code><code>"/girls/{id}"</code><code>)</code> <code>@DeleteMapping</code><code>(value =&nbsp;</code><code>"/girls/{id}"</code><code>)</code> </td> 
 </tr> 
 </tbody> 
</table>

浏览器需要发送不同方式的请求,可以采用postman

## spring-data-jpa ##

`JPA`全称`Java Persistence API.JPA`通过`JDK 5.0`注解或`XML`描述对象－关系表的映射关系，并将运行期的实体对象持久化到数据库中。

## 利用JPA创建MySQL数据库 ##

`pom.xml`加入`JPA`和`MySQL`的依赖

<table> 
 <tbody> 
 <tr> 
 <td> 1 2 3 4 5 6 7 8 9 </td> 
 <td> <code>&lt;dependency&gt;</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>&lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>&lt;artifactId&gt;spring-boot-starter-data-jpa&lt;/artifactId&gt;</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>&lt;/dependency&gt;</code> &nbsp; <code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>&lt;dependency&gt;</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>&lt;groupId&gt;mysql&lt;/groupId&gt;</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>&lt;artifactId&gt;mysql-connector-java&lt;/artifactId&gt;</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>&lt;/dependency&gt;</code> </td> 
 </tr> 
 </tbody> 
</table>

### 配置`JPA`和数据库 ###

`application.yml`

<table> 
 <tbody> 
 <tr> 
 <td> 1 2 3 4 5 6 7 8 9 10 11 12 13 </td> 
 <td> <code>spring:</code> <code>&nbsp;&nbsp;</code><code>profiles:</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>active: a</code> <code>&nbsp;&nbsp;</code><code>datasource:</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>driver-</code><code>class</code><code>-name: com.mysql.jdbc.Driver</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>url:&nbsp; jdbc:mysql:</code><code>//127.0.0.1:3306/test</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>username:&nbsp; root</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>password:&nbsp; password</code> &nbsp; <code>&nbsp;&nbsp;</code><code>jpa:</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>hibernate:</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>ddl-auto: update</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>show-sql:&nbsp;</code><code>true</code> </td> 
 </tr> 
 </tbody> 
</table>

<table> 
 <tbody> 
 <tr> 
 <td> 1 2 </td> 
 <td> <code>格式很重要</code> <code>需要自己手动去创建 db_person 数据库　　</code> </td> 
 </tr> 
 </tbody> 
</table>

### 创建与数据表对应的实体类Person ###

![format_png 20][]

Person.java

<table> 
 <tbody> 
 <tr> 
 <td> 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 </td> 
 <td> <code>package</code>&nbsp;<code>com.newer.springboot.pojo;</code> &nbsp; <code>import</code>&nbsp;<code>javax.persistence.Entity;</code> <code>import</code>&nbsp;<code>javax.persistence.GeneratedValue;</code> <code>import</code>&nbsp;<code>javax.persistence.Id;</code> &nbsp; <code>/**</code> <code>&nbsp;</code><code>* @author:Mr.Tan</code> <code>&nbsp;</code><code>* @Create:2018-10-27-04-05</code> <code>&nbsp;</code><code>**/</code> &nbsp; <code>@Entity</code> <code>public</code>&nbsp;<code>class</code>&nbsp;<code>Person { </code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>@Id</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>@GeneratedValue</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>private</code>&nbsp;&nbsp;<code>Integer id;</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>private</code>&nbsp;<code>String name;</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>private</code>&nbsp;<code>Integer age;</code> &nbsp; <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>//必须要有构造函数</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>public</code>&nbsp;<code>Person() { </code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>}</code> &nbsp; <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>public</code>&nbsp;<code>Integer getId() { </code> <code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>return</code>&nbsp;<code>id;</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>}</code> &nbsp; <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>public</code>&nbsp;<code>void</code>&nbsp;<code>setId(Integer id) { </code> <code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>this</code><code>.id = id;</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>}</code> &nbsp; <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>public</code>&nbsp;<code>String getName() { </code> <code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>return</code>&nbsp;<code>name;</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>}</code> &nbsp; <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>public</code>&nbsp;<code>void</code>&nbsp;<code>setName(String name) { </code> <code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>this</code><code>.name = name;</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>}</code> &nbsp; <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>public</code>&nbsp;<code>Integer getAge() { </code> <code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>return</code>&nbsp;<code>age;</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>}</code> &nbsp; <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>public</code>&nbsp;<code>void</code>&nbsp;<code>setAge(Integer age) { </code> <code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>this</code><code>.age = age;</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>}</code> <code>}</code> </td> 
 </tr> 
 </tbody> 
</table>

运行项目后，查看数据库，会自动创建表 person

![format_png 21][]

接下来就可以进行person表的增删改查了

### 创建控制器`PersonController.java` ###

![format_png 22][]

首先创建一个接口`PersonRepository`，位于`dao`包下,`PersonController`调用该接口继承自`JpaRepository`的方法，来实现和数据库交互

<table> 
 <tbody> 
 <tr> 
 <td> 1 </td> 
 <td> <code>这个PersonRepository接口的功能，与SSM框架中 dao 层接口功能有异曲同工之妙；在SSM框架中，Service层通过该接口，间接执行Mybatis数据库映射文件(.xml)里的相应sql语句，执行数据库增删改查的操作。(Mapper自动实现DAO接口)</code> </td> 
 </tr> 
 </tbody> 
</table>

PersonRepository.java

<table> 
 <tbody> 
 <tr> 
 <td> 1 2 3 4 5 6 7 8 9 10 11 </td> 
 <td> <code>import</code>&nbsp;<code>com.newer.springboot.pojo.Person;</code> <code>import</code>&nbsp;<code>org.springframework.data.jpa.repository.JpaRepository;</code> &nbsp; &nbsp; <code>/**</code> <code>&nbsp;</code><code>* @author:Mr.Tan</code> <code>&nbsp;</code><code>* @Create:2018-10-26-17-07</code> <code>&nbsp;</code><code>**/</code> <code>public</code>&nbsp;<code>interface</code>&nbsp;<code>PersonProperties&nbsp;</code><code>extends</code>&nbsp;<code>JpaRepository&lt;Person, Integer&gt; { </code> &nbsp; <code>}</code> </td> 
 </tr> 
 </tbody> 
</table>

PersonController.java

在数据库中添加两条数据

![format_png 23][]

启动项目执行请求`http://localhost:8086/springboot/person`

### 其他增删改查的方法 ###

`PersonController.java`

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

package com.newer.springboot.Controller;
 
 import com.newer.springboot.dao.PersonProperties;
 import com.newer.springboot.pojo.Person;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.web.bind.annotation.*;
 
 import java.util.List;
 
 /**
 * @author:Mr.Tan
 * @Create:2018-10-27-04-09
 **/
 @RestController
 public class PersonController {
 
 @Autowired
 private PersonProperties personProperties;
 
 @GetMapping("/person")
 private List<Person> personList(){
 return personProperties.findAll();
 }
 
 /* 
 新增一个人员*/
 
 @PostMapping(value = "/personadd")
 private Person add(@RequestParam ("name")String name,@RequestParam("age")Integer age){
 Person person =new Person();
 person.setName(name);
 person.setAge(age);
 return personProperties.save(person);
 }
 
 /**
 * 根据id查找一个人员
 */
 
 @GetMapping(value = "/person/{id}")
 public Person personFindOne(@PathVariable("id") Integer id) {
 return personProperties.findById(id).get();
 }
 
 /**
 * 删除一个员工
 */
 @DeleteMapping(value = "/person/{id}")
 public void deletep(@PathVariable("id") Integer id){
 personProperties.deleteById(id);
 }
 
 /**
 * 更新一个员工
 */
 @PutMapping(value = "/per/{id}")
 public Person put(@PathVariable("id") Integer id,
 @RequestParam ("name") String name,
 @RequestParam ("age") Integer age){
 Person person=new Person();
 person.setName(name);
 person.setAge(age);
 return personProperties.save(person);
 }
 }

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

获取所有人员

![format_png 24][]

增加一个人员

![format_png 25][]

根据id查找一个员工

![format_png 26][]

删除一个员工

![format_png 27][]

更新一个员工

![format_png 28][]

### 根据年龄查询 ###

在`Personpository`增加一个方法`findByAge(Integer age)`

<table> 
 <tbody> 
 <tr> 
 <td> 1 2 3 4 </td> 
 <td> <code>public</code>&nbsp;<code>interface</code>&nbsp;<code>PersonProperties&nbsp;</code><code>extends</code>&nbsp;<code>JpaRepository&lt;Person, Integer&gt; { </code> <code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code><code>//通过年龄来查询</code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>public</code>&nbsp;<code>List&lt;Person&gt;&nbsp; findbyage( Integer age);</code> <code>}</code> </td> 
 </tr> 
 </tbody> 
</table>

在`PersonController`中加入相应的查询方法

<table> 
 <tbody> 
 <tr> 
 <td> 1 2 3 4 5 6 7 8 9 </td> 
 <td> <code>/**</code> <code>&nbsp;&nbsp;</code><code>* 根据年龄来查找</code> <code>&nbsp;&nbsp;&nbsp;</code><code>* @param age</code> <code>&nbsp;&nbsp;</code><code>* @return</code> <code>&nbsp;&nbsp;</code><code>*/</code> <code>&nbsp;</code><code>@GetMapping</code><code>(value =&nbsp;</code><code>"/person/age/{age}"</code><code>)</code> <code>&nbsp;</code><code>public</code>&nbsp;<code>List&lt;Person&gt;&nbsp; personListByAge(</code><code>@PathVariable</code><code>(</code><code>"age"</code><code>) Integer age){ </code> <code>&nbsp;&nbsp;&nbsp;&nbsp;</code><code>return</code>&nbsp;<code>personProperties.findByage(age);</code> <code>&nbsp;</code><code>}</code> </td> 
 </tr> 
 </tbody> 
</table>

![format_png 29][]

## 事务管理 ##

两条 sql 语句同时在一个方法中执行，为了防止一个 sql 语句执行成功而另一个 sql 语句执行失败，引入了事务管理，需要在方法上加 `@Transactional`事务注解

![format_png 30][]

PersonService.java

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

package com.newer.springboot.service;
    
    import com.newer.springboot.dao.PersonProperties;
    import com.newer.springboot.pojo.Person;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    
    import javax.transaction.Transactional;
    
    /**
     * @author:Mr.Tan
     * @Create:2018-10-27-23-04
     **/
    @Service
    public class PersonService {
        @Autowired
        private PersonProperties personProperties;
    
        /**
         * 事务管理测试
         * 两条数据同时成功，或者同时不成功
         * 保证数据库数据的完整性和一致性
         */
        @Transactional
        public void insertTwo(){
            Person personA = new Person();
            personA.setName("秋雅");
            personA.setAge(19);
            personProperties.save(personA);
    
            System.out.print(1/0);
    
            Person personB = new Person();
            personB.setName("梦特娇");
            personB.setAge(25);
            personProperties.save(personB);
    
        }
    }

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

在`PersonController`中测试

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

...
        @Autowired
        private PersonService personService;
        ...
         /**
         * 事务测试
         */
        @PostMapping("/person/two")
        public void personTwo(){
            personService.insertTwo();
        }

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

重新运行项目，执行请求 post方式`http://localhost:8081/springboot/person/two`   
数据库并没有添加第一条数据，说明存在事务管理

![format_png 31][]

转载：[https://www.cnblogs.com/tanlei-sxs/p/9855071.html][https_www.cnblogs.com_tanlei-sxs_p_9855071.html]

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[https_www.cnblogs.com_tanlei-sxs_p_9855071.html]: https://www.cnblogs.com/tanlei-sxs/p/9855071.html