2025/05/12

Spring Boot 3 Data 2

Spring Data JPA

JPA: Java Persistence API，提供 POJO 物件持久化的標準規格，可把 Java 物件直接映射到資料庫中

JPA 是規格，Hibermate, TopLink, OpenJPA 都是 JPA 的實作。目前以 Hibernate 為 Java 最流行的 JPA framework。

Spring Data JPA 底層也是使用 Hibernate，最後透過 JDBC 連接資料庫。

spring-boot-starter-data-jpa 自動設定了 JPA，自動設定類別是

  • JpaRepositoriesAutoConfiguration

  • HibernateJpaAutoConfiguration

pom.xml

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

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>com.mysql</groupId>
            <artifactId>mysql-connector-j</artifactId>
        </dependency>

        <dependency>
            <groupId>org.hibernate.orm</groupId>
            <artifactId>hibernate-community-dialects</artifactId>
        </dependency>

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

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

application.yml

spring:
  application:
    name: data2

  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost/testweb
    username: root
    password: password

  jpa:
    hibernate:
      ddl-auto: update
    show-sql: true
    properties:
      hibernate:
        # dialect: org.hibernate.dialect.MySQLDialect
        dialect: org.hibernate.community.dialect.MySQLLegacyDialect

傳統的 JPA 必需要設定 persistence.xml，但在 spring boot 不需要。

Entity class 只需要有 @Entity，@SpringBootApplication 或是 @EnableAutoConfiguration 就會自動掃描所有 @Entity

Data2Application 直接啟動即可

@SpringBootApplication
public class Data2Application {

    public static void main(String[] args) {
        SpringApplication.run(Data2Application.class, args);
    }

}

UserController.java

package com.test.data2.controller;

import com.test.data2.entity.UserDO;
import com.test.data2.repo.UserRepository;
import lombok.RequiredArgsConstructor;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

@RequiredArgsConstructor
@RestController
public class UserController {

    private final UserRepository userRepository;

    @GetMapping("/user/info/{id}")
    public UserDO getUserInfo(@PathVariable("id") long id){
        UserDO userDO = userRepository.findById(id).orElseGet(null);
        return userDO;
    }

}

UserRepository.java

package com.test.data2.repo;

import com.test.data2.entity.UserDO;
import org.springframework.data.repository.CrudRepository;

public interface UserRepository extends CrudRepository<UserDO, Long> {

}

UserDO.java

package com.test.data2.entity;

import jakarta.persistence.*;
import lombok.Data;

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

@Data
@Entity(name = "user")
public class UserDO implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(nullable = false, unique = true)
    private String username;

    @Column(nullable = false)
    private String phone;

    @Column(name = "create_time", nullable = false)
    private Date createTime;

    @Column(nullable = false)
    private Integer status;

}

啟動後，可從網址 http://localhost:8080/user/info/2 取得 userid = 2 的資料

console 會出現 sql

Hibernate: select ud1_0.id,ud1_0.create_time,ud1_0.phone,ud1_0.status,ud1_0.username from user ud1_0 where ud1_0.id=?

note:

如果掃描不到，可加上 @EntityScan 指定 package/class

Spring data JPA 的 db operation 稱為 repository

  • org.springframework.data.repository.CrudRepository

  • org.springframework.data.repository.ListCrudRepository

  • org.springframework.data.repository.ListPagingRepository

  • org.springframework.data.repository.PagingAndSortingRepository

  • org.springframework.data.repository.kotlin.*

  • org.springframework.data.repository.reactive.*

UserRepository interface 會被自動掃描到，在 controller 能自動注入使用

MyBatis

MyBatis是一個Java持久化框架，它通過 XML 或 annotation 把物件與儲存程序或SQL語句關聯起來，對映成資料庫內對應的 record。

MyBatis-Plus 是 MyBatis 的封裝。

Redis

REmote DIctionary Server: Redis，是一種 key-value 的 NoSQL memory database。通常用在 cache 資料。

spring-boot-starter-data-redis

org.springframework.boot.autoconfigure.AutoConfiguration.imports 有註冊幾個自動設定類別

  • RedisAutoConfiguration

  • RedisReactiveAutoConfiguration

  • RedisRepositoriesAutoConfiguration

RedisAutoConfiguration 對應的參數綁定類別是 RedisProperties

在 application.yml 設定即可使用

spring:
  application:
    name: data3
  data:
    redis:
      host: localhost
      port: 6379
      database: 0
      password: password
#      client-type: jedis

RedisTemplate

有兩個預設的模板可直接使用

  • RedisTemplate

    可處理 <Object, Object>

  • StringRedisTemplate

    只能處理 <String, String> 的資料，預設使用 JDK 的 serializer

因為 StringRedisTemplate 繼承自 RedisTemplate，必須設定兩個 RedisTemplate，所以要搭配 @ConditionalOnSingleCandidate 注入

RedisTemplate 提供的 interface:

interface desc
GeoOperations 地理空間
HashOperations Hash data
HyperLogLogOperations HyperLogLog
ListOperations List
SetOperations Set
ValueOperations String
ZSetOperations Ordered Set

設定 pom.xml，要加上 spring-boot-starter-integration, spring-integration-redis

    <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-redis</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-integration</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.integration</groupId>
            <artifactId>spring-integration-redis</artifactId>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
        </dependency>

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

要新增一個連線，注入 StringRedisTemplate 使用

package com.test.data3;

import lombok.RequiredArgsConstructor;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ValueOperations;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

@RequiredArgsConstructor
@RestController
public class RedisController2 {

    private final StringRedisTemplate stringRedisTemplate;

    @RequestMapping("/redis2/set")
    public String set(@RequestParam("name") String name, @RequestParam("value") String value) {
        ValueOperations<String, String> valueOperations = stringRedisTemplate.opsForValue();
        valueOperations.set(name, value);
        return valueOperations.get(name);
    }

}

呼叫網址 http://localhost:8080/redis2/set?name=test&value=12345 ，就會設定一個 redis key，可使用 redis-cli 檢查

> redis-cli -a password
127.0.0.1:6379> keys *
1) "test"
127.0.0.1:6379> get test
"12345"

也可以直接注入對應的 RedisTemplate 使用 valueOperations

@RequiredArgsConstructor
@RestController
public class RedisController3 {

//    private final StringRedisTemplate stringRedisTemplate;

    @Resource(name = "stringRedisTemplate")
    private ValueOperations<String, String> valueOperations;

    @RequestMapping("/redis3/set")
    public String set(@RequestParam("name") String name, @RequestParam("value") String value) {
        valueOperations.set(name, value);
        return valueOperations.get(name);
    }

}

自訂 RedisTemplate

@Configuration
public class RedisConfig {

    @Bean
    public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory factory) {
        RedisTemplate<String, Object> template = new RedisTemplate<>();
        template.setConnectionFactory(factory);

        StringRedisSerializer stringSerializer = new StringRedisSerializer();
        RedisSerializer jacksonSerializer = getJacksonSerializer();

        template.setKeySerializer(stringSerializer);
        template.setValueSerializer(jacksonSerializer);
        template.setHashKeySerializer(stringSerializer);
        template.setHashValueSerializer(jacksonSerializer);
        template.setEnableTransactionSupport(true);
        template.afterPropertiesSet();

        return template;
    }

    private RedisSerializer getJacksonSerializer() {
        ObjectMapper om = new ObjectMapper();
        om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
        om.activateDefaultTyping(LaissezFaireSubTypeValidator.instance,
                ObjectMapper.DefaultTyping.NON_FINAL);
        return new GenericJackson2JsonRedisSerializer(om);
    }
}

這裡 key 使用了 StringRedisSerializer, value 使用了 GenericJackson2JsonRedisSerializer

以下是幾個常用的 serializer

serializer desc
StringRedisSerializer String/byte[] 轉換器
JdkSerializationRedisSerializer JDK serializer
OxmSerializer XML serializer
Jackson2JsonRedisSerializer JSON serializer, 需要定義 JavaType
GenericJackson2JsonRedisSerializer JSON serializer, 不需要定義 JavaType

MongoDB

springboot 提供兩種 starter

  • spring-boot-starter-data-mongodb

  • spring-boot-starter-data-mongodb-reactive

首先修改 pom.xml

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

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-mongodb</artifactId>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
        </dependency>

在 org.springframework.boot.autoconfigure.AutoConfiguration.imports 註冊了幾個自動設定類別

  • MongoDataAutoConfiguration

  • MongoReactiveDataAutoConfiguration

  • MongoRepositoriesAutoConfiguration

  • MongoAutoConfiguration

  • MongoReactiveAutoConfiguration

設定 application.yml

spring:
  data:
    mongodb:
      uri: mongodb://localhost:27017/test

使用 mongoTemplate

@RequiredArgsConstructor
@RestController
public class MongoController {

    public static final String COLLECTION_NAME = "test";
    private final MongoTemplate mongoTemplate;

    @RequestMapping("/mongo/insert")
    public User insert(@RequestParam("name") String name, @RequestParam("sex") int sex) {
        // add
        User user = new User(RandomUtils.nextInt(), name, sex);
        mongoTemplate.insert(user, COLLECTION_NAME);

        // query
        Query query = new Query(Criteria.where("name").is(name));
        return mongoTemplate.findOne(query, User.class, COLLECTION_NAME);
    }
}

新增 User.java

package com.test.data4;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.springframework.data.mongodb.core.mapping.Document;

@NoArgsConstructor
@AllArgsConstructor
@Data
@Document(collection = "test")
public class User {
    private long id;
    private String name;
    private int sex;

}

發送網址 http://localhost:8080/mongo/insert?name=test&sex=1

就會 insert 一筆資料到 mongodb collection: test

/* 1 */
{
    "_id" : NumberLong(708252679),
    "name" : "test",
    "sex" : 1,
    "_class" : "com.test.data4.User"
}

MongoRepository

新增 UserRepository

package com.test.data4;

import org.springframework.data.mongodb.repository.MongoRepository;

import java.util.List;

public interface UserRepository extends MongoRepository<User, Long> {

    List<User> findByName(String name);

}

修改 MongoController.java

    private final UserRepository userRepository;

    @RequestMapping("/mongo/insert2")
    public User repoInsert(@RequestParam("name") String name, @RequestParam("sex") int sex) {
        // add
        User user = new User(RandomUtils.nextInt(), name, sex);
        userRepository.save(user);

        // query
        return userRepository.findByName(name).get(0);
    }

發送網址 http://localhost:8080/mongo/insert2?name=test2&sex=1

就會新增 test2

Elasticsearch

springboot 支援3種客戶端

  • Elasticsearch 官方 REST 客戶端

  • Elasticsearch 官方 Java API Client

  • spring data elasticsearch 提供的 ReactiveElasticsearchClient

pom.xml

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-elasticsearch</artifactId>
        </dependency>

在 org.spingframework.boot.autoconfigure.AutoConfiguration.imports 註冊了

  • ElasticsearchDataAutoConfiguration

  • ElasticsearchRepositoriesAutoConfiguration

  • ReactiveElasticsearchRepositoriesAutoConfiguration

  • ElasticsearchClientAutoConfiguration

  • ElasticsearchRestClientAutoConfiguration

  • ReactiveElasticsearchClientAutoConfiguration

參數綁定 ElasticsearchProperties

參數 spring.elasticsearch.*

application.yml

spring:
  elasticsearch:
    uris: http://localhost:9200
    connection-timeout: 5s
    socket-timeout: 10s
    username: elastic
    password: password

這邊是用關閉 xpack，使用 http 的方式連線

改用 https 可參考

ref: spring-boot-starter-data-elasticsearch es带x-pack后台配置 - 微信公众号-醉鱼Java - 博客园

使用 ElasticsearchTemplate

EsController.java

import lombok.RequiredArgsConstructor;
import org.apache.commons.lang3.RandomUtils;
import org.springframework.data.elasticsearch.client.elc.ElasticsearchTemplate;
import org.springframework.data.elasticsearch.core.mapping.IndexCoordinates;
import org.springframework.data.elasticsearch.core.query.Criteria;
import org.springframework.data.elasticsearch.core.query.CriteriaQuery;
import org.springframework.data.elasticsearch.core.query.Query;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

@RequiredArgsConstructor
@RestController
public class EsController {

    public static final String INDEX_JAVA = "java";
    private final ElasticsearchTemplate elasticsearchTemplate;

    @RequestMapping("/es/insert")
    public User insert(@RequestParam("name") String name, @RequestParam("sex") int sex) throws InterruptedException {
        // add
        User user = new User(RandomUtils.nextInt(), name, sex);
        IndexCoordinates indexCoordinates =  IndexCoordinates.of(INDEX_JAVA);
        User save = elasticsearchTemplate.save(user, indexCoordinates);

        // delay and query
        Thread.sleep(1000l);
        Query query = new CriteriaQuery(Criteria.where("name").is(name));
        return elasticsearchTemplate.searchOne(query, User.class, indexCoordinates).getContent();
    }
}

User.java

@NoArgsConstructor
@AllArgsConstructor
@Data
@Document(indexName = "java")
public class User {
    private long id;
    private String name;
    private int sex;

}

使用 UserRepository

修改 EsController.java

    private final UserRepository userRepository;
    @RequestMapping("/es/repo/insert")
    public User repoInsert(@RequestParam("name") String name, @RequestParam("sex") int sex) {
        // add
        User user = new User(RandomUtils.nextInt(), name, sex);
        userRepository.save(user);

        // query
        return userRepository.findByName(name).get(0);
    }

UserRepository.java

import org.springframework.data.elasticsearch.repository.ElasticsearchRepository;

import java.util.List;

public interface UserRepository extends ElasticsearchRepository<User, Long> {

    List<User> findByName(String name);

}

程式跟 MongoDB 類似

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