Springboot链接数据库并curd

谁践踏了优雅 2022-06-03 04:47 200阅读 0赞

本人创建的maven项目

**首先我们要添加数据库的starter  和mysql数据库依赖:**

<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>cn.et</groupId>
      <artifactId>SbLesson</artifactId>
      <version>0.0.1-SNAPSHOT</version>
      <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.9.RELEASE</version>
    </parent>
    <dependencies>
    
    	
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
       <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
    </dependency>
    
    </dependencies>
    </project>

**添加数据库的四大要素:**

spring.datasource.url=jdbc:mysql://localhost/myfood
    spring.datasource.username=root
    spring.datasource.password=123456
    spring.datasource.driver-class-name=com.mysql.jdbc.Driver

**最主要的类:**

package cn.et.dao;
    
    
    import org.springframework.data.repository.CrudRepository;
    
    
    import cn.et.Food;
    
    
    public interface FoodRepository extends CrudRepository<Food, Integer> {
    
    
    }

**然后需要创建数据库的实体类:**

package cn.et;
    
    import javax.persistence.Column;
    import javax.persistence.Entity;
    import javax.persistence.GeneratedValue;
    import javax.persistence.GenerationType;
    import javax.persistence.Id;
    
    @Entity
    public class Food {
    	@Id
    	@GeneratedValue(strategy=GenerationType.AUTO)
    	private int foodid;
    	@Column
    	private String foodname;
    	@Column
    	private int price;
    	@Column
    	private String imgpath;
    	public int getFoodid() {
    		return foodid;
    	}
    	public void setFoodid(int foodid) {
    		this.foodid = foodid;
    	}
    	public String getFoodname() {
    		return foodname;
    	}
    	public void setFoodname(String foodname) {
    		this.foodname = foodname;
    	}
    	public int getPrice() {
    		return price;
    	}
    	public void setPrice(int price) {
    		this.price = price;
    	}
    	public String getImgpath() {
    		return imgpath;
    	}
    	public void setImgpath(String imgpath) {
    		this.imgpath = imgpath;
    	}
    	
    }

**最后就是创建项目的Controller层:**

package cn.et;
    import java.util.HashMap;
    import java.util.List;
    import java.util.Map;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.jdbc.core.JdbcTemplate;
    import org.springframework.web.bind.annotation.PathVariable;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    import cn.et.dao.FoodRepository;
    @RestController
    @SpringBootApplication
    public class SbController {
    	 
    	@Autowired
    	JdbcTemplate jdbc;
    	@Autowired
    	FoodRepository er;
    	
    	@RequestMapping("/hello")
    	public Map hello(){
    		Map map = new HashMap();
    		map.put("id", 1);
    		map.put("name", "zs");
    		
    		return map;
    	}
    	
    @RequestMapping("/food/{foodid}")
    	public Map getFood(@PathVariable String foodid){
    		List<Map<String, Object>> queryForList = jdbc.queryForList("select * from food where foodid="+foodid);
    		return queryForList.get(0);
    	}
    //添加
    @RequestMapping("/saveFood")
    public String saveFood(){
    	Food food = new Food();
    	food.setFoodname("sss");
    	food.setImgpath("45454");
    	food.setPrice(15);
    	er.save(food);
    	return "1";
    }
    
    //查询
    @RequestMapping("/queryFood")
    public Food queryFood(){
    	Food food = er.findOne(39);
    	return food;
    }
    	
    
    	public static void main(String[] args) {
    		 SpringApplication.run(SbController.class, args);
    	}
    	
    }

**最后访问 通过访问 (http://localhost:8080/savefood)进行添加数据库的数据 如果返回值为 "1" 则添加成功  否则失败**