spring boot（一）

特点：
不要web.xml（但是有@requestMapping类似里面的url-pattern）
不要springmvc.xml
不要tomcat，内嵌有tomcat
不需要配置Json解析，支持Rest

里面的repository包里类似以前的dao
里面的handler类似以前的servlet
handler里的注解类似以前的web.xml里的配置

创建一个普通maven工程 结构如下

pom.xml里添加依赖

<!--继承父包-->
<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.0.6.RELEASE</version>
</parent>
<dependencies>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <version>1.18.6</version>
    </dependency>
// web启动jar包
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
        <version>2.0.1.RELEASE</version>
    </dependency>
</dependencies>

创建一个pojo类 Student

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

repository包里一个接口，一个repository实现类

public interface StudentRepository {
    public Collection<Student> findAll();
    public Student findById(long id);
    public void save(Student student);
    public void deleteById(long id);
}

/*进行自动注入的注解*/
@Repository
public class repositoryImpl implements StudentRepository {
    private  static Map<Long,Student> studentMap ;
    static {
        studentMap = new HashMap<>();
        studentMap.put(1l,new Student(0l,"g",33));
        studentMap.put(2l,new Student(3l,"gd",43));
        studentMap.put(3l,new Student(5l,"fg",23));
    }
    @Override
    public Collection<Student> findAll() {
        return studentMap.values();
    }
    @Override
    public Student findById(long id) {
        return studentMap.get(id);
    }
    @Override
    public void save(Student student) {
        studentMap.put(student.getId(),student);
    }
    @Override
    public void deleteById(long id) {
        studentMap.remove(id);
    }
}

handler

@RestController
@RequestMapping("/student")
public class HelloHandler {
    @Autowired
    private repositoryImpl  repo;
    @GetMapping("/findByAll")
    public Collection<Student> findAll(){
        return repo.findAll();
    }
    @GetMapping("/findById/{id}")
    public Student findById(@PathVariable("id") long id){
        return repo.findById(id);
    }
    @PostMapping("/save")
    public void save(@RequestBody Student student){
        repo.save(student);
    }
    @DeleteMapping("/dele")
    public void delete(@PathVariable("id") long id){
        repo.deleteById(id);
    }
}

入口启动类 Application

@SpringBootApplication
public class Aplication {
    public static void main(String[] args) {
        SpringApplication.run(Aplication.class,args);
    }
}

注意Application类的位置，否则会404报错