详解IDEA中便捷内存数据库H2的最简使用方式

<?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.example</groupid>

   <artifactid>microservice-simple-provider- user </artifactid>

   <version>1.0-snapshot</version>

   <packaging>jar</packaging>

   <parent>

     <artifactid>spring-boot-starter-parent</artifactid>

     <groupid>org.springframework.boot</groupid>

     <version>2.4.2</version>

   </parent>

   <properties>

     <project.build.sourceencoding>utf-8</project.build.sourceencoding>

     <java.version>1.8</java.version>

   </properties>

   <dependencies>

     <dependency>

       <! --springboot的web项目起步依赖-->

       <groupid>org.springframework.boot</groupid>

       <artifactid>spring-boot-starter-web</artifactid>

       <version>2.4.2</version>

     </dependency>

     <dependency>

       <! --springboot的jpa数据访问组件起步依赖-->

       <groupid>org.springframework.boot</groupid>

       <artifactid>spring-boot-starter-data-jpa</artifactid>

       <version>2.3.1.release</version>

     </dependency>

     <dependency>

       <! --自动构建h2嵌入式或内存数据库的依赖-->

       <groupid>com.h2database</groupid>

       <artifactid>h2</artifactid>

       <version>1.4.200</version>

     </dependency>

   </dependencies>

   <build>

     <plugins>

       <plugin>

         <groupid>org.springframework.boot</groupid>

         <artifactid>spring-boot-maven-plugin</artifactid>

         <version>2.4.2</version>

       </plugin>

     </plugins>

   </build>

</project>

package com.example.models;

import com.fasterxml.jackson.annotation.jsonignoreproperties;

import javax.persistence.*;

import java.math.bigdecimal;

@jsonignoreproperties(value = { "hibernatelazyinitializer" })

@entity

public class user {

   @id

   @generatedvalue(strategy = generationtype.auto)

   private long id;

   @ column

   private string username;

   @ column

   private string name ;

   @ column

   private integer age;

   @ column

   private bigdecimal balance;

   public long getid() {

     return id;

   }

   public void setid(long id) {

     this.id = id;

   }

   public string getusername() {

     return username;

   }

   public void setusername(string username) {

     this.username = username;

   }

   public string getname() {

     return name ;

   }

   public void setname(string name ) {

     this. name = name ;

   }

   public integer getage() {

     return age;

   }

   public void setage( integer age) {

     this.age = age;

   }

   public bigdecimal getbalance() {

     return balance;

   }

   public void setbalance(bigdecimal balance) {

     this.balance = balance;

   }

}

package com.example.dao;

import com.example.models. user ;

import org.springframework.data.jpa.repository.jparepository;

import org.springframework.stereotype.repository;

@repository

public interface userrepository extends jparepository< user , long> {

}

package com.example.controller;

import com.example.dao.userrepository;

import com.example.models. user ;

import org.springframework.beans.factory.annotation.autowired;

import org.springframework.web.bind.annotation.getmapping;

import org.springframework.web.bind.annotation.pathvariable;

import org.springframework.web.bind.annotation.restcontroller;

@restcontroller

public class usercontroller {

   @autowired

   private userrepository userrepository;

   @getmapping( "/{id}" )

   public user findbyid(@pathvariable long id) {

     user oneuser = this.userrepository.getone(id);

     return oneuser;

   }

}