（转载）SpringBoot学习笔记

这次的学习以一个简单的Student Demo为示例。

1、代码：

主程序类DemoApplication.java。

 1 package com.julion.demo; 2  3 import org.springframework.boot.SpringApplication; 4 import org.springframework.boot.autoconfigure.SpringBootApplication; 5  6 @SpringBootApplication 7 public class DemoApplication { 8  9     public static void main(String[] args) {10 11         SpringApplication.run(DemoApplication.class, args);12 13     }14 }

 

实体类Student.java。

 1 package com.julion.demo.domain; 2  3 import javax.persistence.Entity; 4 import javax.persistence.GeneratedValue; 5 import javax.persistence.Id; 6 import javax.validation.constraints.Min; 7  8 @Entity 9 public class Student {10 11     @Id12     @GeneratedValue13     private int id;14 15     @Min(value = 10, message = "未满10岁不来塞")16     private int age;17 18     private String name;19 20     public Student(){21 22     }23 24     public int getId() {25         return id;26     }27 28     public void setId(int id) {29         this.id = id;30     }31 32     public int getAge() {33         return age;34     }35 36     public void setAge(int age) {37         this.age = age;38     }39 40     public String getName() {41         return name;42     }43 44     public void setName(String name) {45         this.name = name;46     }47 }

 

结果类Result.java。

 1 package com.julion.demo.domain; 2  3 public class Result<T> { 4  5     private int code; 6  7     private String message; 8  9     private T data;10 11     public int getCode() {12         return code;13     }14 15     public void setCode(int code) {16         this.code = code;17     }18 19     public String getMessage() {20         return message;21     }22 23     public void setMessage(String message) {24         this.message = message;25     }26 27     public T getData() {28         return data;29     }30 31     public void setData(T data) {32         this.data = data;33     }34 }

 

数据相关类StudentRepository.java。

 1 package com.julion.demo.repository; 2  3 import com.julion.demo.domain.Student; 4 import org.springframework.data.jpa.repository.JpaRepository; 5  6 import java.util.List; 7  8 public interface StudentRepository extends JpaRepository<Student, Integer> { 9 10     public List<Student> findByAge(int age);11 12 }

 

控制类StudentController.java。

 1 package com.julion.demo.controller; 2  3 import com.julion.demo.domain.Result; 4 import com.julion.demo.domain.Student; 5 import com.julion.demo.repository.StudentRepository; 6 import com.julion.demo.util.ResultUtil; 7 import org.springframework.beans.factory.annotation.Autowired; 8 import org.springframework.validation.BindingResult; 9 import org.springframework.web.bind.annotation.*;10 11 import javax.validation.Valid;12 import java.util.List;13 14 @RestController15 public class StudentController {16 17     @Autowired18     private StudentRepository studentRepository;19 20     @GetMapping(value = "/student")21     public List<Student> getList(){22         return studentRepository.findAll();23     }24 25     @PostMapping(value = "/student")26     public Result<Student> insert(@Valid Student student, BindingResult bindingResult){27         if (bindingResult.hasErrors()){28             return ResultUtil.error(1, bindingResult.getFieldError().getDefaultMessage());29         }30 31         return ResultUtil.success(studentRepository.save(student));32     }33 34     @GetMapping(value = "/student/{id}")35     public Student getOne(@PathVariable("id") int id){36         return studentRepository.findOne(id);37     }38 39     @PutMapping(value = "/student/{id}")40     public Student updateOne(@PathVariable("id") int id,41                              @RequestParam("age") int age,42                              @RequestParam("name") String name){43         Student student = new Student();44         student.setName(name);45         student.setId(id);46         student.setAge(age);47 48         return studentRepository.save(student);49     }50 51     @DeleteMapping(value = "/student/{id}")52     public void deleteOne(@PathVariable("id") int id){53         studentRepository.delete(id);54     }55 56     @GetMapping(value = "student/age/{age}")57     public List<Student> getOneByAge(@PathVariable("age") int age){58         return studentRepository.findByAge(age);59     }60 61 }

 

AOP相关类HttpAspect.java。

 1 package com.julion.demo.aspect; 2  3  4 import com.julion.demo.domain.Student; 5 import org.aspectj.lang.JoinPoint; 6 import org.aspectj.lang.annotation.*; 7 import org.slf4j.Logger; 8 import org.slf4j.LoggerFactory; 9 import org.springframework.stereotype.Component;10 import org.springframework.web.context.request.RequestContextHolder;11 import org.springframework.web.context.request.ServletRequestAttributes;12 13 import javax.servlet.http.HttpServletRequest;14 15 @Aspect16 @Component17 public class HttpAspect {18 19     private static final Logger logger = LoggerFactory.getLogger(HttpAspect.class);20 21     @Pointcut("execution(public * com.julion.demo.controller.StudentController.*(..))")22     public void log(){23     }24 25     @Before("log()")26     public void doBefore(JoinPoint joinPoint){27         logger.info("i am before");28         ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();29         HttpServletRequest request = attributes.getRequest();30 31         //url32         logger.info("url={}", request.getRequestURL());33 34         //method35         logger.info("method={}", request.getMethod());36 37         //ip38         logger.info("ip={}",request.getRemoteAddr());39 40         //类方法41         logger.info("class_method={}", joinPoint.getSignature().getDeclaringTypeName() + "." + joinPoint.getSignature().getName());42 43         //参数44         logger.info("args={}", joinPoint.getArgs());45     }46 47     @After("log()")48     public void doAfter(){49         logger.info("i am after");50     }51 52     @AfterReturning(returning = "object", pointcut = "log()")53     public void doAfterReturning(Object object){54         logger.info("response={}", object.toString());55     }56 57 }

 

结果工具类ResultUtil.java。

 1 package com.julion.demo.util; 2  3 import com.julion.demo.domain.Result; 4  5 public class ResultUtil { 6  7     public static Result success(Object object){ 8         Result result = new Result(); 9         result.setCode(0);10         result.setMessage("成功");11         result.setData(object);12         return result;13     }14 15     public static Result success(){16         return success(null);17     }18 19     public static Result error(int code, String message){20         Result result = new Result();21         result.setCode(code);22         result.setMessage(message);23         result.setData(null);24         return result;25     }26 27 }

 

配置文件application.properties。

server.port=8081server.context-path=/demospring.datasource.driver-class-name=com.mysql.jdbc.Driverspring.datasource.url=jdbc:mysql://127.0.0.1:3306/dbdemospring.datasource.username=rootspring.datasource.password=rootspring.jpa.hibernate.ddl-auto=updatespring.jpa.show-sql=true

 

2、关于注解：

1) @Entity：注明是实体类。

2) @Aspect：注明是切面。

    @PointCut：标注controller的切点。

    @Before：在controller切点前进行。

    @After：在controller切点后进行。

    @AfterReturning：在controller返回后进行。

3) @RestController：注明是controller。与@Controller和@ResponseBody同时注解的功能相当。

    @Autowired：注入。

    @GetMapping：注明是Get方法。用以查询。

    @PostMapping：注明是Post方法。用以增加。

    @PutMapping：注明是Put方法。用以更新。

    @DeleteMapping：注明是Delete方法。用以删除。

    @RequestMapping：注明是请求。

    @PathVairable：用以获取形如/xxx/value格式中的value。

    @RequestParam：用以获取形如?key=value中的value。

4) @Service：注明是Service。

    @Component：注明是Component。