前置知识： maven, idea

最简易的项目及启动

1.idea快速新建项目

2.application.properties配置（非必需）

3.启动方式

1.idea新建项目

2.maven spring-boot:run

进入项目目录， 执行maven spring-boot:run

3.maven编译后执行

maven install

cd target

java -jar ***.jar

配置文件的方式

不用properties的方式， 用yml的形式

yml取值方式

单个值

server:
  port: 8081
  context-path: /demo

age: 10
name: mark

java代码

/**
 * @author mengqa
 **/
@RestController
public class DemoController {

    @Value("${age}")
    private Integer age;

    @RequestMapping(method = RequestMethod.GET, value="hello")
    public Integer hello() {
        return age;
    }

}

配置里再使用配置变量

server:
  port: 8081
  context-path: /demo

age: 10
name: mark
student: "age:${age}, name:${mark}"

java代码

@Value("${studentStr}")
private String studentStr;

@RequestMapping(method = RequestMethod.GET, value="hello")
public String hello() {
    return studentStr;
}

对象

server:
  port: 8081
  context-path: /demo

student:
    age: 10
    name: mark

java代码

/**
 参数Bean
 * @author mengqa
 **/
@Component
@ConfigurationProperties(prefix = "student")
public class StudentProperties {

    private Integer age;

    private String name;

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public String toString() {
        return "StudentProperties{" +
                "age=" + age +
                ", name='" + name + '\'' +
                '}';
    }
}

// ------------------------------------------
// Controller代码：
    @Autowired
    private StudentProperties studentProperties;

    @RequestMapping(method = RequestMethod.GET, value="hello")
    public String hello() {
        return studentProperties.toString();
    }

浏览器输出：StudentProperties{age=20, name='mark'}

生产环境和开发环境

分别定义生产和开发环境配置文件

application-prod.yml

server:
  port: 8082
  context-path: /demo

application-dev.yml

server:
  port: 8081
  context-path: /demo

配置主文件appliaction.yml 写上spring.profiles.active

spring:
  profiles:
    active: prod

代表读取生产配置文件

maven编译后执行也行：

java -jar ***.jar --spring.profiles.active=prod

Controller相关

@RequestMapping

多url映射

@RequestMapping(value={"/hello", "/test"}, method = RequestMethod.GET)

组合注解

@GetMapping
@PostMapping
@DeleteMapping...

@PathVariable

获取Url中的参数
http://localhost:8082/demo/show/213

@RequestMapping(method = RequestMethod.GET, value="show/{id}")
public String show(@PathVariable String id) {
    return id;
}

@RequestParam

http://localhost:8082/demo/show?id=213

@RequestMapping(method = RequestMethod.GET, value="show/{id}")
public String show(@PathVariable String id) {
    return id;
}

// 设默认值
@RequestMapping(method = RequestMethod.GET, value="show")
public String show(@RequestParam(value = "id", required = false, defaultValue = "000") String reId) {
    return reId;
}

boot数据库操作

pom依赖

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
</dependency>

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>

配置中加入数据库配置

spring:
  profiles:
    active: prod
  datasource:
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://127.0.0.1:3306/sc?useUnicode=true&characterEncoding=UTF-8
    username: root
    password: mqa
  jpa:
    hibernate:
      ddl-auto: update  
    show-sql: true

# ddl-auto: update  表示自动建表（已经存在的表不会删除）

java准备

1. 实体类

package com.example.demo.domain;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Transient;
import java.util.List;

/**
 * @author mengqa
 **/
@Entity
public class Student {

    private String name;

    private Integer age;

    @Id
    @GeneratedValue
    private Integer id;

    @Transient
    private List<Score> scores;

    public Student() {
    }

    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;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public List<Score> getScores() {
        return scores;
    }

    public void setScores(List<Score> scores) {
        this.scores = scores;
    }

    @Override
    public String toString() {
        return "Student{" +
                "name='" + name + '\'' +
                ", age=" + age +
                ", id=" + id +
                ", scores=" + scores +
                '}';
    }
}

1. 数据层继承JPA接口

public interface IStudentDao extends JpaRepository<Student, Integer> {

}

1. Service暂时省略, 写Controller Api接口, 增删改查

/**
 * @author mengqa
 **/
@RestController
@RequestMapping("/student")
public class StudentController {

    @Autowired
    private IStudentDao studentDao;


    @GetMapping("/list")
    public List<Student> list() {
        return studentDao.findAll();
    }

    @PostMapping("/save")
    public Student save(@RequestBody Student student) {
        return studentDao.save(student);
    }

    @GetMapping("/show/{id}")
    public Student show(@PathVariable Integer id) {
        return studentDao.findOne(id);
    }

    @PutMapping("/update")
    public Student update(@RequestBody Student student) {
        return studentDao.save(student);
    }

    @DeleteMapping("/del/{id}")
    public void delete(@PathVariable Integer id) {
        studentDao.delete(id);
    }

}

1. jpa扩展查询

public interface IStudentDao extends JpaRepository<Student, Integer> {
    List<Student> findByNameAndAge(String name, Integer age);
}

1. 事务控制通过 @Transactional-事务注解实现