spring boot初體驗

開發工具

下載IDEA
Idea下maven的配置和使用
IntelliJ IDEA: 無法創建Java Class文件

數據庫工具

下載mysql安裝工具,安裝到PC
下載Navicat Premium作爲可視化的數據工具

測試工具

下載postman進行測試

開始

demo的結構如圖:
在這裏插入圖片描述
StudentController.java

package com.example.controller;

import com.example.entity.Student;
import com.example.service.StudentService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.web.bind.annotation.*;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.List;

@RestController  //控制層註解並實現返回格式爲json
@RequestMapping("/s") //配置訪問路徑
public class StudentController {
    @Autowired
    private StudentService studentService;

    @PostMapping("/add")
    public Student save(Student student){
        return studentService.save(student);
    }

    @PostMapping("/update")
    public Student update(Student student){
        Student s = studentService.findStuById(student.getId());
        s.setName(student.getName());
        s.setAge(student.getAge());
        s.setSex(student.getSex());
        return studentService.save(s);
    }

    @GetMapping("/del/{id}")
    public String del(@PathVariable int id){
        studentService.delete(id);
        return "yes";
    }

    @GetMapping("/findByName/{name}")
    public List<Student> findByName(@PathVariable String name){
        return studentService.findStuByName(name);
    }

    @GetMapping("/query")
    public Page<Student> findByPage(Integer page, HttpServletResponse response){
        response.setHeader("Access-Control-Allow-Origin","*");
        if (page == null || page <= 0) {
            page = 0;
        } else {
            page -= 1;
        }

        return studentService.findAll(page,5);
    }
}

StudentDao.java

package com.example.dao;

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.Query;
import org.springframework.data.repository.query.Param;

import com.example.entity.Student;
import java.util.List;

public interface StudentDao extends JpaRepository<Student,Integer> {
    //簡單的增刪改查不需要寫,這個只不過爲了辨別寫了個名,不寫也有底層的findById方法
    Student findStudentById(Integer id);
//稍複雜的SQL語句需要自定義,格式如下
    @Query(name = "findStuByName",nativeQuery = true,value = "select * from student where name=:name")
    List<Student> findStuByName(@Param("name") String name);
}

Student.java

package com.example.entity;
import javax.persistence.*;

@Entity
@Table(name="student")
public class Student {
    @Id //設置主鍵
    @GeneratedValue(strategy = GenerationType.IDENTITY) //自增
    private Integer id;
    private String name;
    private int age;
    private String sex;

    public Student() {
    }

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

    public Integer getId() {
        return id;
    }

    public void setId(Integer 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 String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

}

StudentService.java

package com.example.service;

import org.springframework.data.domain.Page;

import com.example.entity.Student;
import java.util.List;

public interface StudentService {
    Student save(Student student);
    void delete(Integer id);
    Student findStuById(Integer id);
    List<Student> findStuByName(String name);

    Page<Student> findAll(int page, int pageSize);

}

StudentServiceImpl.java

package com.example.service;


import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.stereotype.Service;


import com.example.entity.Student;
import java.util.List;
import com.example.dao.StudentDao;

@Service  //告訴springboot控制層實現類不然找不到注入
public class StudentServiceImpl  implements StudentService{
    @Autowired
    private StudentDao studentDao;
    @Override
    public Student save(Student student) {
        return studentDao.save(student);
    }

    @Override
    public void delete(Integer id) {
        studentDao.deleteById(id);
    }

    @Override
    public Student findStuById(Integer id) {
        return studentDao.findStudentById(id);
    }

    @Override
    public List<Student> findStuByName(String name) {
        return studentDao.findStuByName(name);
    }

    @Override
    public Page<Student> findAll(int page, int pageSize) {
        Pageable pageable= (Pageable) PageRequest.of(page,pageSize);
        return studentDao.findAll(pageable);
    }
}

springBoot學習筆記之application.yml配置文件
在application.properties 文件的同級目錄下新建一個 application.yml 文件,刪除了application.properties
,application.yml 文件的配置:

spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/springboot?useUnicode=true&autoReconnect=true&useSSL=false&zeroDateTimeBehavior=convertToNull&serverTimezone=UTC
    username: root
    password: root
  jpa:
      show-sql: true
      database-platform: org.hibernate.dialect.MySQL5InnoDBDialect
      database: mysql
      hibernate:
        ddl-auto: update

server:
    port: 8088


注意
1. ddl-auto: update一定要配置,要不然不能自動生成表格
2.SpringbootApplication一定和controller文件夾同級,要不然同樣不能自動生成表格

pom.xml

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.5.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>springboot</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>springboot</name>
    <description>Demo project for Spring Boot</description>

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

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

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <!-- druid數據庫連接池-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.10</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/com.github.pagehelper/pagehelper-spring-boot-starter -->
        <!--分頁插件-->
        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper-spring-boot-starter</artifactId>
            <version>1.2.10</version>
        </dependency>

    </dependencies>

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

</project>

如果沒有錯誤的話,就可以運行了,通過postman來測試
application.yml文件裏有port: 8088,說明端口是8080,然後嘗試訪問StudentController裏的add方法

@RestController  //控制層註解並實現返回格式爲json
@RequestMapping("/s") //配置訪問路徑
public class StudentController {
    @Autowired
    private StudentService studentService;

    @PostMapping("/add")
    public Student save(Student student){
        return studentService.save(student);
    }

在這裏插入圖片描述
postman訪問:POST localhost:8088/s/add?name=你好&age=20&sex=男,就可以在數據庫中查看到這幾個字段

在這裏插入圖片描述
在這裏插入圖片描述
其他方法:
GET: localhost:8088/s/query
GET:localhost:8088/s/del/1
GET:localhost:8088/s/update?id=1&name=測試2&age=30&sex=女
findByName方法有個問題,如果按照這樣寫,只能接收非中文的參數,比如
GET:localhost:8088/s/findByName/112
如果要支持中文,需要寫成這樣:

   @GetMapping("/findByName")
    public List<Student> findByName(@RequestParam String name){
        return studentService.findStuByName(name);
    }

GET:localhost:8088/s/findByName?name=測試1
參考資料:
簡單springboot項目實現增刪改查加分頁

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