Spring Boot学习之初识Spring Boot

Spring Boot

Spring Boot 是一个快速开发框架，可以迅速搭建出一套基于Spring框架体系的应用，是Spring Cloud的基础，Spring Boot开启了各种自动装配，从而简化了代码的开发，不需要编写各种配置文件，只要引入相关依赖就可以迅速搭建一个应用。

• 特点
• 不需要web.xml
• 不需要springmvc.xml
• 不需要tomcat,Spring Boot内嵌了tomcat
• 不需要配置JSON解析，支持REST架构
• 个性化的配置非常简单
• 如何使用
• 创建maven工程，导入相关依赖

    1 <?xml version="1.0" encoding="UTF-8"?>

    2 <project xmlns="http://maven.apache.org/POM/4.0.0"

    3                   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>com.wiggin</groupId>

    8         <artifactId>aispringboot</artifactId>

    9         <version>1.0-SNAPSHOT</version>

   10 

   11         <!-- 继承父包 -->

   12         <parent>

   13                 <groupId>org.springframework.boot</groupId>

   14                 <artifactId>spring-boot-starter-parent</artifactId>

   15                 <version>2.0.7.RELEASE</version>

   16         </parent>

   17         <dependencies>

   18                 <!-- web启动的jar包 -->

   19                 <dependency>

   20                         <groupId>org.springframework.boot</groupId>

   21                         <artifactId>spring-boot-starter-web</artifactId>

   22                         <version>2.3.2.RELEASE</version>

   23                 </dependency>

   24                 <dependency>

   25                         <groupId>org.projectlombok</groupId>

   26                         <artifactId>lombok</artifactId>

   27                         <version>1.18.12</version>

   28                 </dependency>

   29 

   30         </dependencies>

   31 </project>

• 创建Student实体类

    1 package com.wiggin.entity;

    2 

    3 import lombok.AllArgsConstructor;

    4 import lombok.Data;

    5 import lombok.NoArgsConstructor;

    6 

    7 @Data

    8 @AllArgsConstructor

    9 @NoArgsConstructor

   10 public class Student {

   11         private long id;

   12         private String name;

   13         private int age;

   14 }

• 创建StudentRepository功能仓

    1 package com.wiggin.repository;

    2 

    3 import com.wiggin.entity.Student;

    4 

    5 import java.util.Collection;

    6 import java.util.List;

    7 

    8 public interface StudentRepository {

    9         public Collection<Student> findAll();

   10         public Student findById(long id);

   11         public void saveOrUpdate(Student student);

   12         public void deleteById(long id);

   13 }

• 创建StudentRepositoryImpl功能仓实现类实体类

    1 package com.wiggin.repository.impl;

    2 

    3 import com.wiggin.entity.Student;

    4 import com.wiggin.repository.StudentRepository;

    5 import org.springframework.stereotype.Repository;

    6 

    7 import java.util.Collection;

    8 import java.util.HashMap;

    9 import java.util.List;

   10 import java.util.Map;

   11 

   12 @Repository

   13 public class StudentRepositoryImpl implements StudentRepository {

   14         private static Map<Long,Student> studentMap;

   15         static {

   16                 studentMap = new HashMap<>();

   17                 studentMap.put(1L,new Student(1L,"张三",22));

   18                 studentMap.put(2L,new Student(2L,"李四",23));

   19                 studentMap.put(3L,new Student(3L,"王五",24));

   20         }

   21         @Override

   22         public Collection<Student> findAll() {

   23                 return studentMap.values();

   24         }

   25 

   26         @Override

   27         public Student findById(long id) {

   28                 return studentMap.get(id);

   29         }

   30 

   31         @Override

   32         public void saveOrUpdate(Student student) {

   33                 studentMap.put(student.getId(),student);

   34         }

   35 

   36         @Override

   37         public void deleteById(long id) {

   38                 studentMap.remove(id);

   39         }

   40 }

• 创建StudentHandler控制器

    1 package com.wiggin.controller;

    2 

    3 import com.wiggin.entity.Student;

    4 import com.wiggin.repository.StudentRepository;

    5 import org.springframework.beans.factory.annotation.Autowired;

    6 import org.springframework.web.bind.annotation.*;

    7 

    8 import java.util.Collection;

    9 

   10 @RestController

   11 @RequestMapping("/student")

   12 public class StudentHandler {

   13         @Autowired

   14         private StudentRepository studentRepository;

   15 

   16         @GetMapping("/findAll")

   17         public Collection<Student> findAll(){

   18                 return studentRepository.findAll();

   19         }

   20         @GetMapping("/findById/{id}")

   21         public Student findById(@PathVariable long id){

   22                 return studentRepository.findById(id);

   23         }

   24         @PostMapping("/save")

   25         public void save(@RequestBody Student student){

   26             studentRepository.saveOrUpdate(student);

   27         }

   28         @PostMapping("/update")

   29         public void update(@RequestBody Student student){

   30                 studentRepository.saveOrUpdate(student);

   31         }

   32         @DeleteMapping("/delete/{id}")

   33         public void deleteById(@PathVariable long id){

   34                 studentRepository.deleteById(id);

   35         }

   36 }

• 创建Application启动类

    1 package com.wiggin;

    2 

    3 import org.springframework.boot.SpringApplication;

    4 import org.springframework.boot.autoconfigure.SpringBootApplication;

    5 

    6 // Application文件要在所有类的上级

    7 @SpringBootApplication

    8 public class Application {

    9         public static void main(String[] args) {

   10                 SpringApplication.run(Application.class,args);

   11         }

   12 }

注意：启动类一定要放在所有功能类文件的上级，这样才能被扫描。

• 创建application.yml更改接口地址

    1 server:

    2     port: 9090

注意：层与层之间要有缩进的不同，以反映层级关系。