SpringBoot入门之CRUD

作者: call云飞 | 来源:发表于2017-10-27 09:26 被阅读0次

前言：

在大SpringMVC体系中虽然简化了配置，以及类的数量，一个控制器中多个方法可以分别对应不同的业务。但是从根本上来说，需要的配置还是太多，搭建工程重复性的动作还是太多，开发速度还是不够快。还应当，或者说还可以进一步简化，这时SpringBoot横空出世。

简介：

SpringBoot 开启了各种自动装配，就是为了简化开发，不需要写各种配置文件，只需要引入相关的依赖就能迅速搭建起一个web工程。

不需要任何的web.xml配置。
不需要任何的spring mvc的配置。
不需要配置tomcat ，springboot内嵌tomcat.
不需要配置jackson，良好的restful风格支持，自动通过jackson返回json数据
个性化配置时，最少一个配置文件可以配置所有的个性化信息

需求简介

实现关于Student的增删该查
编码采用restful风格
数据库使用Map结构代替
开发工具使用IntelliJ IDEA

构建工程

1. 工具准备

JDK1.8+
Maven 3.0+
IDEA 2016+

2. 创建过程

create.gif

3. 引入依赖

importDependency.gif

4. pom.xml完整内容

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.springframework</groupId>
    <artifactId>gs-spring-boot</artifactId>
    <version>0.1.0</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.8.RELEASE</version>
    </parent>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    </dependencies>

    <properties>
        <java.version>1.8</java.version>
    </properties>


    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

5. 工程目录结构

-src
  -main
    -java
      -cn
        -itcast
          -springboot
            -dao
            -service
            -entity
            -controller
            -Main.java
    -resouces
           
  -test
- pom

6. 实体Bean，Student.java编写

package cn.itcast.springboot.entity;

import java.io.Serializable;
import java.util.Date;

public class Student implements Serializable{
    private Long id;
    private String name;
    private int age;
    private Date birth;

    public Student() {
    }

    public Student(Long id, String name, int age, Date birth) {
        this.id = id;
        this.name = name;
        this.age = age;
        this.birth = birth;
    }

    public Long getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

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

    public int getAge() {
        return age;
    }

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

    public Date getBirth() {
        return birth;
    }

    public void setBirth(Date birth) {
        this.birth = birth;
    }

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

7. StudentDAO.java接口编写

package cn.itcast.springboot.dao;

import cn.itcast.springboot.entity.Student;

import java.util.Collection;

public interface StudentDAO {

    //获取所有的student
    Collection<Student> getAllStudents();

    /**
     * @param id
     * 根据id获取学生
     *
     * @return Student
     * 返回对应的学生对象
     **/
    Student getStudentById(Long id);


    /**
     * @param student
     * 传入新的student数据
     *
     * @return Collection<Student>
     * 修改成功后返回所有的student
     * */
    Collection<Student> updateStudentById(Student student);


    /**
     * @param student
     * 传入新的student数据
     *
     * @return Collection<Student>
     * 新增成功后返回所有的student
     * */
    Collection<Student> addStudentById(Student student);


    /**
     * @param id
     * 传入要删除的student的id
     *
     * @return Collection<Student>
     * 删除成功后返回所有的student
     * */
    Collection<Student> deleteStudentById(Long id);
}

8. StudentDAOImpl.java 实现类编写

package cn.itcast.springboot.dao;

import cn.itcast.springboot.entity.Student;
import org.springframework.stereotype.Repository;

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

@Repository("fakeDAO")
public class StudentDAOImpl implements StudentDAO {

    Map<Long,Student> studentMap = new HashMap<Long,Student>(){{
        put(10086L,new Student(10086L,"刘德华",50,new Date()));
        put(10087L,new Student(10087L,"张学友",51,new Date()));
        put(10088L,new Student(10088L,"霍建华",52,new Date()));
        put(10089L,new Student(10089L,"郭富城",53,new Date()));
        put(10090L,new Student(10090L,"陈冠希",54,new Date()));
    }};

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

    @Override
    public Student getStudentById(Long id) {
        return studentMap.get(id);
    }

    @Override
    public Collection<Student> updateStudentById(Student student) {
        studentMap.put(student.getId(),student);
        return studentMap.values();
    }

    @Override
    public Collection<Student> addStudentById(Student student) {
        studentMap.put(student.getId(),student);
        return studentMap.values();
    }

    @Override
    public Collection<Student> deleteStudentById(Long id) {
        studentMap.remove(id);
        return studentMap.values();
    }
}

9. StudentService.java 接口编写

package cn.itcast.springboot.service;

import cn.itcast.springboot.entity.Student;

import java.util.Collection;

public interface StudentService {

    //获取所有的student
    Collection<Student> getAllStudents();

    /**
     * @param id
     * 根据id获取学生
     *
     * @return Student
     * 返回对应的学生对象
     **/
    Student getStudentById(Long id);


    /**
     * @param student
     * 传入新的student数据
     *
     * @return Collection<Student>
     * 修改成功后返回所有的student
     * */
    Collection<Student> updateStudentById(Student student);


    /**
     * @param student
     * 传入新的student数据
     *
     * @return Collection<Student>
     * 新增成功后返回所有的student
     * */
    Collection<Student> addStudentById(Student student);


    /**
     * @param id
     * 传入要删除的student的id
     *
     * @return Collection<Student>
     * 删除成功后返回所有的student
     * */
    Collection<Student> deleteStudentById(Long id);
}

10. StudentServiceImpl.java 实现类编写

package cn.itcast.springboot.service;

import cn.itcast.springboot.dao.StudentDAO;
import cn.itcast.springboot.entity.Student;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.Collection;

@Service
public class StudentServiceImpl implements StudentService {

    @Autowired
    private StudentDAO studentDAO;

    @Override
    public Collection<Student> getAllStudents() {
        return studentDAO.getAllStudents();
    }

    @Override
    public Student getStudentById(Long id) {
        return studentDAO.getStudentById(id);
    }

    @Override
    public Collection<Student> updateStudentById(Student student) {
        return studentDAO.updateStudentById(student);
    }

    @Override
    public Collection<Student> addStudentById(Student student) {
        return studentDAO.addStudentById(student);
    }

    @Override
    public Collection<Student> deleteStudentById(Long id) {
        return studentDAO.deleteStudentById(id);
    }
}

11. StudentController.java 控制器编写

package cn.itcast.springboot.controller;

import cn.itcast.springboot.entity.Student;
import cn.itcast.springboot.service.StudentService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.Collection;

@RestController
@RequestMapping("students")
public class StudentController {
   @Autowired
   private StudentService studentService;

   @GetMapping
   public Collection<Student> getAllStudents(){
       return studentService.getAllStudents();
   }
}

12. Main.java 主文件编写

package cn.itcast.springboot;

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

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

13. 文件目录

tree.png

14. 测试运行

show.gif

15. StudentController.java 细节描述

@RequestMapping("students") //配置全局的访问方式
@GetMapping //在全局的访问基础上扩充访问，后面不加参数，表示用来匹配全局访问 http://localhost:8080/students,访问方式为GET

16. 重点知识介绍之@RequestMapping

RequestMapping的原生用法之常见属性
name：指定请求映射的名称，一般省略
value：指定请求映射的路径
method：指定请求的method类型，如，GET、POST、PUT、DELETE等；
consumes：指定处理请求的提交内容类型（Content-Type），例如application/json, text/html;
produces：指定返回的内容类型，仅当request请求头中的(Accept)类型中包含该指定类型才返回；

17. 衍生映射：GetMapping,PostMapping,PutMapping,DeleteMapping

这一系列mapping与RequestMapping相类似,可以看作简化版描述
简单比较如：

RequestMapping(method = RequestMethod.GET),含义与GetMapping相同
PostMapping(method = RequestMethod.POST),含义与PostMapping相同
PutMapping与DeleteMapping同上

18.各种Mapping应用场景综述

修改数据，PutMapping
删除数据，DeleteMapping
查询数据，GetMapping
新增数据，PostMapping
总结：通过请求方式来区分业务类别，使得URI变得更简单

19. 各种Mapping的用法简介

Mapping类型	URL	解释
GET	www.itcast.cn/students	获取所有的学生信息
GET	www.itcast.cn/students/10086	获取id为10086的学生信息
POST	www.itcast.cn/students	添加学生信息
PUT	www.itcast.cn/students/10086/10086	修改id为10086的学生信息
DELETE	www.itcast.cn/students/10086	删除id为10086的学生信息

20. 实际Controller,StudentController.java设计

package cn.itcast.controller;

import cn.itcast.entity.Student;
import cn.itcast.service.StudentService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.*;

import java.util.Collection;


@RestController
@RequestMapping(name = "name", value = "/students",method = RequestMethod.GET)
public class StudentController {
    @Autowired
    private StudentService studentService;

    @GetMapping
    public Collection<Student> getAllStudents() {

        return studentService.getAllStudents();

    }

    @GetMapping(value = "/{id}")
    public Student getStudentById(@PathVariable("id") Long id) {
        return studentService.getStudentById(id);
    }


    @DeleteMapping(value = "/{id}")
    public Collection<Student> deleteStudentById(@PathVariable("id") Long id) {
        return studentService.deleteStudentById(id);
    }

    @PutMapping(consumes = MediaType.APPLICATION_JSON_VALUE)
    public Collection<Student> updateStudentById(@RequestBody Student student) {
        return studentService.updateStudentById(student);
    }

    @PostMapping(consumes = MediaType.APPLICATION_JSON_VALUE)
    public Collection<Student> addStudent(@RequestBody Student student) {
        return studentService.addStudent(student);
    }
}

21. 细节描述

参数占位声明，{paramNam}：
@GetMapping(value = "/{id}")
应用声明参数，@PathVariable("ParamName")
public Student getStudentById(@PathVariable("id") Long id)
完整示例

@GetMapping(value = "/{id}")
    public Student getStudentById(@PathVariable("id") Long id) {
        return studentService.getStudentById(id);
    }

请求参数类型JSON化处理

@PutMapping(consumes = MediaType.APPLICATION_JSON_VALUE)
    public Collection<Student> updateStudentById(@RequestBody Student student) {
        return studentService.updateStudentById(student);
    }

4.1. 通过consumes属性指定请求参数的提交类型为JSON

@PutMapping(consumes = MediaType.APPLICATION_JSON_VALUE)

4.2. 通过@RequestBody 把请求提交的JSON数据转换为对应的JavaBean

public Collection<Student> updateStudentById(@RequestBody Student student)

22. 新增学生演示

addStudent.gif

23. 修改学生演示

updateStudent.gif

24. 删除学生演示

deleteStudent.gif

25. 根据id查询学生演示

queryById.gif

26. 关于日期类型配置

用户输入日期值存储到数据库Map中不需要任何配置
从Map中取出数据时，由于通过jackson封装，所以如果不做特殊配置，会把日期转成从1970-01-01 00:00:00开始到当前时间的毫秒数。
配置日期的显示格式
3.1 在resources目录中创建application.properties文件
3.2 在文件中加入内容
spring.jackson.date-format=yyyy-MM-dd HH:mm:ss
spring.jackson.time-zone=GMT+8
3.3 总览

overview.png

3.4 查询测试

config.gif