詳解IDEA中便捷內(nèi)存數(shù)據(jù)庫H2的最簡使用方式

?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項(xiàng)目起步依賴-->
      groupId>org.springframework.boot/groupId>
      artifactId>spring-boot-starter-web/artifactId>
      version>2.4.2/version>
    /dependency>
    dependency>
      !--SpringBoot的jpa數(shù)據(jù)訪問組件起步依賴-->
      groupId>org.springframework.boot/groupId>
      artifactId>spring-boot-starter-data-jpa/artifactId>
      version>2.3.1.RELEASE/version>
    /dependency>
    dependency>
      !--自動(dòng)構(gòu)建H2嵌入式或內(nèi)存數(shù)據(jù)庫的依賴-->
      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 JpaRepositoryUser, 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;
  }
}