1 Spring Boot快速入门

1 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，从而简化代码开发，不需要编写各种配置文件，只需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、SpringBoot内嵌tomcat
  • 不需要配置 JSON 解析，支持 REST 架构
  • 个性化配置非常简单
     

2 如何使用

• 创建 Maven 工程，导入相关依赖

<parent>
    <groupId>org.springframework.bootgroupId>
    <version>2.7.5version>
    <artifactId>spring-boot-starter-parentartifactId>
parent>

<dependencies>
    
    <dependency>
        <groupId>org.springframework.bootgroupId>
        <artifactId>spring-boot-starter-webartifactId>
    dependency>
    <dependency>
        <groupId>org.projectlombokgroupId>
        <artifactId>lombokartifactId>
    dependency>
dependencies>
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• 创建实体类

package com.southwind.entiry;

import lombok.Data;

@Data
public class Student {
    private long id;
    private String name;
    private int age;
}
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• StudentRepository

package com.southwind.repository;

import com.southwind.entiry.Student;

import java.util.Collection;

public interface StudentRepository {
    public Collection<Student> findAll();
    public Student findById(long id);
    public void saveOrUpdate(Student student);
    public void deleteById(long id);
}
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package com.southwind.repository;

import com.southwind.entiry.Student;
import org.springframework.stereotype.Repository;

import java.util.Collection;
import java.util.HashMap;
import java.util.Map;

@Repository
public class StudentRepositoryImpl implements StudentRepository{

    private static Map<Long,Student> studentMap;

    static{
        studentMap = new HashMap<>();
        studentMap.put(1L,new Student(1L,"张三",22));
        studentMap.put(2L,new Student(2L,"李四",23));
    }

    @Override
    public Collection<Student> findAll() {
        return studentMap.values();
    }

    @Override
    public Student findById(long id) {
        return studentMap.get(id);
    }

    @Override
    public void saveOrUpdate(Student student) {
        studentMap.put(student.getId(),student);
    }

    @Override
    public void deleteById(long id) {
        studentMap.remove(id);
    }
}
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• StudentHandler

package com.southwind.controller;

import com.southwind.entiry.Student;
import com.southwind.repository.StudentRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.Collection;

@RestController // 返数据
@RequestMapping("/student")
public class StudentHandler {

    @Autowired
    private StudentRepository studentRepository;

    @GetMapping("/findAll")
    public Collection<Student> findAll(){
        return studentRepository.findAll();
    }

    @GetMapping("/findById/{id}")
    public Student findById(@PathVariable("id") Long id){
        return studentRepository.findById(id);
    }

    @PostMapping("/save")   // 因为前端会以JSON数据返回，所以要用 @RequestBody
    public void save(@RequestBody Student student){
        studentRepository.saveOrUpdate(student);
    }

    @PutMapping("/update")
    public void update(@RequestBody Student student){
        studentRepository.saveOrUpdate(student);
    }

    @DeleteMapping("/deleteById/{id}")
    public void deleteById(@PathVariable("id") Long id){
        studentRepository.deleteById(id);
    }
}
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• application.yml

进行端口号的修改：

server:
  port: 9090
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• 启动类

package com.southwind;

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

@SpringBootApplication
public class Application {
    public static void main(String[] args) {
    	// run(类名.class,arg)
        SpringApplication.run(Application.class,args);
    }
}
// 名字不固定，可以自取
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@SpringBootApplication 
表示当前类是 Spring Boot 的入口，Application 类的存放位置必须是其他相关业务类的存放位置的父级。
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其他注解可参考：https://blog.csdn.net/qq_52077925/article/details/126732070
https://blog.csdn.net/qq_52077925/article/details/126775590

• 运行