初始化好工程之后

入门

新建一个HelloController.java

package com.example.girl1;import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;@RestController
public class HelloController {@RequestMapping(value = "/girl",method = RequestMethod.GET)public String say(){return "1111111";}
}复制代码

在浏览器中输入localhost:8080/girl 内容就是1111111

启动方式

1. idea直接启动

2. mvn

• mvn spring-boot:run

3. 打包成jar包启动

• mvn install
• cd target
• java -jar jar包名

项目属性配置

resource 目录下 将application.xxx修改成application.yml

server:port: 8080servlet:context-path: /first
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之后访问就得 ：http://localhost:8080/first/girl

配置文件属性的使用

server:port: 8080
cupSize: A复制代码

HelloController.java中

@RestController
public class HelloController {// 通过注解把配置文件中的cupSize注入到变量中@Value("${cupSize}")private String cupSize;@RequestMapping(value = "/girl",method = RequestMethod.GET)public String say(){return cupSize;}
}
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打开浏览器就能看到cupSize了

属性多的时候就加个前缀来区分

新建一个类 GirlProperties.java

package com.example.girl1;import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;// 获取前缀是girl的配置
@Component
@ConfigurationProperties(prefix = "girl")
public class GirlProperties {private  String cupSize;private  Integer age;public Integer getAge() {return age;}public void setAge(Integer age) {this.age = age;}public String getCupSize() {return cupSize;}public void setCupSize(String cupSize) {this.cupSize = cupSize;}
}复制代码

配置文件

server:port: 8080
girl:cupSize: Aage: 18
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HelloController

@RestController
public class HelloController {@Autowiredprivate GirlProperties girlProperties;@RequestMapping(value = "/girl",method = RequestMethod.GET)public Integer say(){return girlProperties.getAge();}
}
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这样就能做到用前缀来区分，自己打开浏览器看看就明白了

配置的开发环境和生产环境

• application.yml

// application.ymlspring:profiles:active: dev
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• application-dev.yml

server:port: 8080
girl:cupSize: Bage: 18复制代码

• application-prod.yml

server:port: 8081
girl:cupSize: Aage: 20复制代码

• 可以在idea中启动开发环境，
• 在mvn install 后生成的jar包启动开发环境

java -jar jar包名 --spring.profiles.active=prod
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Controller的使用

• @Controller 处理http请求
• @RestController Spring4之后新加的注解，原来返回json需要@RequestBody配合@Controller(RestController相当于这两个的组合RequestBody和Controller)
• @RequestMapping 配置url映射

@RequestMapping

// 如果想访问两个
@RequestMapping(value = {"/girl","/hello"},method = RequestMethod.GET)
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// 可以给类加，访问就得 ：localhost:8080/hello/girl了
@RestController
@RequestMapping("/hello")
public class HelloController {@Autowiredprivate GirlProperties girlProperties;@RequestMapping(value = {"/girl"},method = RequestMethod.GET)public Integer say(){return girlProperties.getAge();}
}
// RequestMethod方式有很多
可以使用postman来测试api
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处理url里面的参数

• @PathVariable 获取url里面的数据
• @RequestParam 获取请求参数的值
• @GetMapping 组合注解

@PathVariable

@RestController
public class HelloController {@Autowiredprivate GirlProperties girlProperties;@RequestMapping(value = {"/girl/{id}"},method = RequestMethod.GET)public Integer say(@PathVariable("id") Integer myId){return myId;}
}
// localhost:8080/girl/100
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@RequestParam

//localhost:8080/girl?id=100
@RestController
public class HelloController {@Autowiredprivate GirlProperties girlProperties;@RequestMapping(value = {"/girl"},method = RequestMethod.GET)public Integer say(@RequestParam("id") Integer myId){return myId;}
}
// 另一种写法
@RestController
public class HelloController {@Autowiredprivate GirlProperties girlProperties;@RequestMapping(value = {"/girl"},method = RequestMethod.GET)// 默认值和是否必须传入public Integer say(@RequestParam(value = "id",required = false,defaultValue = "10") Integer myId){return myId;}
}
// RequestMapping 可以写成GetMapping
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数据库操作

在pom.xml导入包

// jpa和mysql的<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-jpa</artifactId></dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId></dependency>
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结束后导入一下包

配置文件的配置

// 运行前先新建一个dbgirl的数据库，utf8mb4
// application.yml
spring:profiles:active: devdatasource:driver-class-name: com.mysql.jdbc.Driverurl: jdbc:mysql://127.0.0.1:3306/dbgirlusername: rootpassword: 123456jpa:hibernate:ddl-auto: update // create会把之前的表删掉在新建一个show-sql: true
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新建一个Girl类

package com.example.girl1;import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
// 这个注解表示这个类就是对应数据库中的表
@Entity
public class Girl {@Id@GeneratedValueprivate Integer id;private String cupSize;private Integer age;public Girl() {}public Integer getAge() {return age;}public void setAge(Integer age) {this.age = age;}public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}public String getCupSize() {return cupSize;}public void setCupSize(String cupSize) {this.cupSize = cupSize;}
}
// 之后表中的那些字段就是girl类中对应过去的
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接口编写

get    /girls    获取女生列表post    /girls    创建一个女生get    /girls/id   通过id查询一个女生put    /girls/id    通过id更新一个女生delete    /girls/id    通过id删除一个女生
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获取女生列表

新建一个GirlRepository.java的接口

package com.example.girl1;import org.springframework.data.jpa.repository.JpaRepository;// Girl类名，Integer是id的类型
public interface GirlRepository extends JpaRepository<Girl,Integer> {}复制代码

新建GirlController.java

package com.example.girl1;import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;import java.util.List;
@RestController
public class GirlController {@Autowiredprivate GirlRepository girlRepository;/** 查询女生列表* */@GetMapping(value = "/girls")public List<Girl> girlList(){return girlRepository.findAll();}
}
// 使用postman测试
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创建一个女生

 /** 新增一个女生* */@PostMapping(value = "/girls")public Girl girlAdd(@RequestParam("cupSize") String cupSize,@RequestParam("age") Integer age){Girl girl = new Girl();girl.setCupSize(cupSize);girl.setAge(age);return  girlRepository.save(girl);}
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通过id查询一个女生

 // 查询一个女生@GetMapping(value = "/girls/{id}")public Girl girlFindOne(@PathVariable("id") Integer id){return  girlRepository.findById(id).orElse(null);}
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通过id更新一个女生

  // 更新@PutMapping(value = "/girls/{id}")public Girl  girlUpdate(@PathVariable("id") Integer id,@RequestParam("cupSize") String cupSize,@RequestParam("age") Integer age){Girl girl = new Girl();girl.setId(id);girl.setCupSize(cupSize);girl.setAge(age);return girlRepository.save(girl);}
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通过id删除一个女生

 // 删除@DeleteMapping(value = "/girls/{id}")public  void  girlDelete(@PathVariable("id") Integer id){girlRepository.deleteById(id);}
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通过年龄查询女生列表

 // 通过年龄查询女生列表@GetMapping(value = "/girls/age/{age}")public List<Girl> girlListByAge(@PathVariable("age") Integer age){return  girlRepository.findByAge(age);}
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GirlRepository.java中

package com.first.first;import org.springframework.data.jpa.repository.JpaRepository;import java.util.List;public interface GirlRepository extends JpaRepository<Girl,Integer> {// 通过年龄查询public List<Girl> findByAge(Integer age);
}复制代码

事务管理

需求是如果我有两条数据，一条插入失败的话另一条就不能插入，这时候需要加一个事务

GirlService.java

package com.example.girl1;import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;@Service
public class GirlService {@Autowiredprivate GirlRepository girlRepository;@Transactionalpublic void insertTwo(){Girl girlA= new Girl();girlA.setAge(10);girlA.setCupSize("B");girlRepository.save(girlA);Girl girlB= new Girl();girlA.setAge(11);girlA.setCupSize("F");girlRepository.save(girlB);}
}// 在Girlcontroller里新增@Autowiredprivate GirlService girlService;@PostMapping(value = "/girls/two")public void girlTwo(){girlService.insertTwo();}复制代码