springboot-jpa的實(shí)現(xiàn)操作
JPA全稱為Java Persistence API(Java持久層API),它是Sun公司在JavaEE 5中提出的Java持久化規(guī)范。
它為Java開(kāi)發(fā)人員提供了一種對(duì)象/關(guān)聯(lián)映射工具,來(lái)管理Java應(yīng)用中的關(guān)系數(shù)據(jù),JPA吸取了目前Java持久化技術(shù)的優(yōu)點(diǎn),旨在規(guī)范、簡(jiǎn)化Java對(duì)象的持久化工作。
JPA對(duì)于單表的或者簡(jiǎn)單的SQL查詢非常友好,甚至可以說(shuō)非常智能。他為你準(zhǔn)備好了大量的拿來(lái)即用的持久層操作方法。甚至只要寫(xiě)findByName這樣一個(gè)接口方法,他就能智能的幫你執(zhí)行根據(jù)名稱查找實(shí)體類(lèi)對(duì)應(yīng)的表數(shù)據(jù),完全不用寫(xiě)SQL。
它相對(duì)于mybatis來(lái)說(shuō)不用寫(xiě)xml等配置,簡(jiǎn)直方便的不行,對(duì)于我們開(kāi)發(fā)者來(lái)說(shuō),誰(shuí)更簡(jiǎn)單,開(kāi)發(fā)效率更高,我們就喜歡誰(shuí)(不喜歡不行,看看產(chǎn)品經(jīng)理手里的菜刀)?。?!
這時(shí)候mybatis就不服了,我確實(shí)需要寫(xiě)一大堆亂七八糟的xml,但是也可以用注解啊。
還不是要寫(xiě)sql,總是一寫(xiě)增刪改查sql,有沒(méi)有把這些常見(jiàn)的增刪改查全部封裝起來(lái),我們直接調(diào)用api,sql讓它們自動(dòng)組裝就好了,說(shuō)實(shí)話我自己封裝了一個(gè)基于mybatis的組件,常見(jiàn)的增刪改查,自己組裝成sql去查詢,后來(lái)由于沒(méi)有oracle,sqlserver的數(shù)據(jù)庫(kù)環(huán)境,對(duì)這些數(shù)據(jù)庫(kù)的時(shí)間等等函數(shù)支持不好,又有jpa和mybatisplus這些現(xiàn)有的,我也就偷懶了
好了我們之前有實(shí)現(xiàn)過(guò)springboot-mybatis
springboot-mybatisplus的整合,現(xiàn)在就來(lái)實(shí)現(xiàn)一下jpa的,你們看看哪個(gè)比較方便好用,可以自己用用看
這是我實(shí)現(xiàn)的demo預(yù)覽
由于我想看到效果,又不想裝postman來(lái)測(cè)試,我就集成了swagger
最終效果如上圖
好了,我直接放代碼了
<?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>com.zkb</groupId> <artifactId>spring-data-jpa</artifactId> <version>1.0-SNAPSHOT</version> <build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId> <configuration> <source>8</source> <target>8</target> </configuration> </plugin> </plugins> </build> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> <version>2.1.1.RELEASE</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-jpa</artifactId> <version>2.1.1.RELEASE</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>8.0.18</version> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <version>1.18.12</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-devtools</artifactId> <version>2.0.4.RELEASE</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <version>2.1.2.RELEASE</version> <scope>test</scope> </dependency> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid</artifactId> <version>1.0.31</version> </dependency> <dependency> <groupId>org.junit.jupiter</groupId> <artifactId>junit-jupiter</artifactId> <version>RELEASE</version> <scope>compile</scope> </dependency> <dependency> <groupId>org.junit.jupiter</groupId> <artifactId>junit-jupiter</artifactId> <version>RELEASE</version> <scope>compile</scope> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-api</artifactId> <version>1.7.25</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-test</artifactId> <version>2.2.2.RELEASE</version> <scope>compile</scope> </dependency> <dependency> <groupId>io.springfox</groupId> <artifactId>springfox-swagger2</artifactId> <version>2.9.2</version> <exclusions> <exclusion> <groupId>io.swagger</groupId> <artifactId>swagger-annotations</artifactId> </exclusion> <exclusion> <groupId>io.swagger</groupId> <artifactId>swagger-models</artifactId> </exclusion> </exclusions> </dependency> <dependency> <groupId>io.swagger</groupId> <artifactId>swagger-annotations</artifactId> <version>1.5.22</version> </dependency> <dependency> <groupId>io.swagger</groupId> <artifactId>swagger-models</artifactId> <version>1.5.22</version> </dependency> <!-- swagger-ui --> <dependency> <groupId>io.springfox</groupId> <artifactId>springfox-swagger-ui</artifactId> <version>2.9.2</version> </dependency> <dependency> <groupId>com.github.xiaoymin</groupId> <artifactId>swagger-bootstrap-ui</artifactId> <version>1.9.1</version> </dependency> </dependencies> </project>
server: port: 5001 spring: datasource: type: com.alibaba.druid.pool.DruidDataSource #Druid 是阿里巴巴開(kāi)源平臺(tái)上一個(gè)數(shù)據(jù)庫(kù)連接池實(shí)現(xiàn),結(jié)合了 C3P0、DBCP、PROXOOL 等 DB 池的優(yōu)點(diǎn),同時(shí)加入了日志監(jiān)控 driver-class-name: com.mysql.cj.jdbc.Driver url: jdbc:mysql://localhost:3306/test-demo?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=UTC&autoReconnect=true&failOverReadOnly=false&zeroDateTimeBehavior=convertToNull username: root password: root dbcp2: min-idle: 5 initial-size: 5 max-total: 5 max-wait-millis: 200 jpa: database: mysql database-platform: org.hibernate.dialect.MySQL5InnoDBDialect show-sql: true hibernate: ddl-auto: update
package com.zkb.entity; import com.fasterxml.jackson.databind.annotation.JsonSerialize; import com.fasterxml.jackson.databind.ser.std.ToStringSerializer; import io.swagger.annotations.ApiModel; import io.swagger.annotations.ApiModelProperty; import lombok.Data; import javax.persistence.*; /** * 實(shí)體類(lèi) */ @Entity @Table(name = "t_user") @Data @ApiModel(value = "用戶信息", description = "用戶信息") public class User { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @ApiModelProperty(value = "主鍵") @JsonSerialize(using = ToStringSerializer.class) private Long id; @Column(name = "username") @ApiModelProperty(value = "用戶名") private String username; @Column(name = "password") @ApiModelProperty(value = "密碼") private String password; }
package com.zkb.dao; import com.zkb.entity.User; import org.springframework.data.jpa.repository.JpaRepository; public interface UserRepository extends JpaRepository<User,Long> { }
package com.zkb.service; import com.zkb.entity.User; import java.util.List; public interface UserService { public void deleteUser(Long id); List<User> getList(); }
package com.zkb.service.impl; import com.zkb.dao.UserRepository; import com.zkb.entity.User; import com.zkb.service.UserService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import java.util.List; @Service public class UserServiceImpl implements UserService { @Autowired private UserRepository userRepository; @Override public void deleteUser(Long id) { System.out.println(userRepository); userRepository.deleteById(id); } @Override public List<User> getList() { return userRepository.findAll(); } }
package com.zkb.controller; import com.zkb.entity.User; import com.zkb.service.UserService; import io.swagger.annotations.Api; import io.swagger.annotations.ApiOperation; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.PostMapping; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestParam; import org.springframework.web.bind.annotation.RestController; import java.util.List; @RestController @RequestMapping("/user") @Api(value = "user",tags = "user") public class UserController { @Autowired private UserService userService; @PostMapping("/del") @ApiOperation(value="刪除",notes = "刪除") public String delete(@RequestParam("id") Long id){ userService.deleteUser(id); return "true"; } @PostMapping("/getList") @ApiOperation(value="查詢所有",notes = "查詢所有") public List<User> getList(){ return userService.getList(); } }
package com.zkb.conf; import io.swagger.annotations.ApiOperation; import io.swagger.models.auth.In; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import springfox.documentation.builders.ApiInfoBuilder; import springfox.documentation.builders.PathSelectors; import springfox.documentation.builders.RequestHandlerSelectors; import springfox.documentation.service.ApiInfo; import springfox.documentation.service.ApiKey; import springfox.documentation.service.Contact; import springfox.documentation.spi.DocumentationType; import springfox.documentation.spring.web.plugins.Docket; import springfox.documentation.swagger2.annotations.EnableSwagger2; import java.util.Arrays; import java.util.List; @Configuration @EnableSwagger2 public class SwaggerApp { @Bean public Docket createRestApi1() { return new Docket(DocumentationType.SWAGGER_2).enable(true).apiInfo(apiInfo()).select() .apis(RequestHandlerSelectors.withMethodAnnotation(ApiOperation.class)) .apis(RequestHandlerSelectors.basePackage("com.zkb.controller")) .paths(PathSelectors.any()).build().securitySchemes(apiKeyList()).groupName("接口中心"); } private ApiInfo apiInfo() { return new ApiInfoBuilder() .title("API") .contact(new Contact("XXXXX", "http://XXXXXX.XXXX/", "")) .version("1.0") .description("API 描述") .build(); } private List<ApiKey> apiKeyList() { return Arrays.asList(new ApiKey("登錄token", "token", In.HEADER.name()), new ApiKey("設(shè)備類(lèi)型(android,ios,pc)---必填", "deviceType", In.HEADER.name())); } }
package com.zkb; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import springfox.documentation.swagger2.annotations.EnableSwagger2; @SpringBootApplication @EnableSwagger2 public class App { public static void main(String[] args) { SpringApplication.run(App.class,args); } }
CREATE TABLE `t_user` ( `id` bigint NOT NULL AUTO_INCREMENT, `username` varchar(50) COLLATE utf8mb4_general_ci DEFAULT NULL, `password` varchar(50) COLLATE utf8mb4_general_ci DEFAULT NULL, PRIMARY KEY (`id`) USING BTREE ) ENGINE=InnoDB AUTO_INCREMENT=1214893367637352451 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci;
非常簡(jiǎn)單的一張表,注意數(shù)據(jù)庫(kù)名稱
到這里就已經(jīng)實(shí)現(xiàn)了一個(gè)非常簡(jiǎn)單的jpa demo了
當(dāng)然我這里只是指路,讓知怎么用
補(bǔ)充:SpringBoot使用JPA實(shí)現(xiàn)增刪查改
一、運(yùn)行環(huán)境
SpringBoot2.3.0
JDK1.8
IDEA2020.1.2
MySQL5.7
二、依賴及應(yīng)用程序配置
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-jpa</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-thymeleaf</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-validation</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.projectlombok</groupId> <artifactId>lombok</artifactId> <optional>true</optional> </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>
1、升級(jí)到SpringBoot2.2,spring-boot-starter-test默認(rèn)使用JUnit 5作為單元測(cè)試框架 ,寫(xiě)單元測(cè)試時(shí)注解@RunWith(Spring.class)升級(jí)為@ExtendWith(SpringExtension.class)
2、升級(jí)到SpringBoot2.3,hibernate-validator從spring-boot-starter-web移除,需要單獨(dú)引入
3、升級(jí)到SpringBoot2.3,MySQL驅(qū)動(dòng)由com.mysql.jdbc.Driver變更為com.mysql.cj.jdbc.Driver;同時(shí),數(shù)據(jù)源url需要添加serverTimezone=UTC&useSSL=false參數(shù)
3、升級(jí)到SpringBoot2.x,默認(rèn)不自動(dòng)注入HiddenHttpMethodFilter,需要設(shè)置spring.mvc.hiddenmethod.filter.enabled=true開(kāi)啟PUT、DELETE方法支持
應(yīng)用程序配置如下:
spring.application.name=springbootjpa management.endpoints.jmx.exposure.include=* management.endpoints.web.exposure.include=* management.endpoint.health.show-details=always # 應(yīng)用服務(wù) WEB 訪問(wèn)端口 server.port=8080 # Actuator Web 訪問(wèn)端口 management.server.port=8081 # mysql setting spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver spring.datasource.url=jdbc:mysql://localhost:3306/springbootjpa?serverTimezone=UTC&useSSL=false spring.datasource.username=username spring.datasource.password=password # JPA setting spring.jpa.properties.hibernate.hbm2ddl.auto=update spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect spring.jpa.show-sql=true # thymeleaf setting spring.thymeleaf.cache=false # delete、put方法支持 spring.mvc.hiddenmethod.filter.enabled=true
三、定義實(shí)體
使用@Entity標(biāo)記實(shí)體類(lèi)
import lombok.Data; import javax.persistence.*; import javax.validation.constraints.NotEmpty; import java.io.Serializable; @Entity @Data public class Article extends BaseEntity implements Serializable { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Long id; @Column(nullable = false, unique = true) @NotEmpty(message = "標(biāo)題不能為空") private String title; @Column(nullable = false) private String body; }
為了自動(dòng)添加創(chuàng)建日期、修改日期、創(chuàng)建人及修改人,我們把創(chuàng)建、修改信息放到父類(lèi)中由實(shí)體類(lèi)繼承,并開(kāi)啟SpringBoot的自動(dòng)審計(jì)功能,將創(chuàng)建/修改信息自動(dòng)注入
1、定義實(shí)體類(lèi)的父類(lèi),@CreatedDate、@LastModifiedDate、@CreatedBy、@LastModifiedBy標(biāo)注相應(yīng)字段
import org.hibernate.annotations.Columns; import org.springframework.data.annotation.CreatedBy; import org.springframework.data.annotation.CreatedDate; import org.springframework.data.annotation.LastModifiedBy; import org.springframework.data.annotation.LastModifiedDate; import org.springframework.data.jpa.domain.support.AuditingEntityListener; import javax.persistence.Column; import javax.persistence.EntityListeners; import javax.persistence.MappedSuperclass; @MappedSuperclass @EntityListeners(AuditingEntityListener.class) public class BaseEntity { @CreatedDate private Long createTime; @LastModifiedDate private Long updateTime; @Column(name = "create_by") @CreatedBy private String createBy; @Column(name = "lastmodified_by") @LastModifiedBy private String lastmodifiedBy; public Long getCreateTime() { return createTime; } public void setCreateTime(Long createTime) { this.createTime = createTime; } public Long getUpdateTime() { return updateTime; } public void setUpdateTime(Long updateTime) { this.updateTime = updateTime; } public String getCreateBy() { return createBy; } public void setCreateBy(String createBy) { this.createBy = createBy; } public String getLastmodifiedBy() { return lastmodifiedBy; } public void setLastmodifiedBy(String lastmodifiedBy) { this.lastmodifiedBy = lastmodifiedBy; } }
@MappedSuperclass注解:
作用于實(shí)體類(lèi)的父類(lèi)上,父類(lèi)不生成對(duì)應(yīng)的數(shù)據(jù)庫(kù)表
標(biāo)注@MappedSuperclass的類(lèi)不能再標(biāo)注@Entity或@Table注解,也無(wú)需實(shí)現(xiàn)序列化接口
每個(gè)子類(lèi)(實(shí)體類(lèi))對(duì)應(yīng)一張數(shù)據(jù)庫(kù)表,數(shù)據(jù)庫(kù)表包含子類(lèi)屬性和父類(lèi)屬性
標(biāo)注@MappedSuperclass的類(lèi)可以直接標(biāo)注@EntityListeners實(shí)體監(jiān)聽(tīng)器
@EntityListeners(AuditingEntityListener.class)注解:
作用范圍僅在標(biāo)注@MappedSuperclass類(lèi)的所有繼承類(lèi)中,并且實(shí)體監(jiān)聽(tīng)器可以被其子類(lèi)繼承或重載
開(kāi)啟JPA的審計(jì)功能,需要在SpringBoot的入口類(lèi)標(biāo)注@EnableJpaAuditing
創(chuàng)建日期、修改日期有默認(rèn)方法注入值,但創(chuàng)建人和修改人注入則需要手動(dòng)實(shí)現(xiàn)AuditorAware接口:
@Configuration public class BaseEntityAuditor implements AuditorAware<String> { @Override public Optional<String> getCurrentAuditor() { return ""; } }
四、DAO層實(shí)現(xiàn)
JPA支持通過(guò)約定方法名進(jìn)行數(shù)據(jù)庫(kù)查詢、修改:
import org.springframework.data.jpa.repository.JpaRepository; import springbootjpa.entity.Article; public interface ArticleRepository extends JpaRepository<Article, Long> { Article findById(long id); }
通過(guò)約定方法名查詢,只需實(shí)現(xiàn)JpaRepository接口聲明查詢方法而不需要具體實(shí)現(xiàn)
此外,可以在方法上標(biāo)注@Query實(shí)現(xiàn)JPQL或原生SQL查詢
JpaRepository<T, ID>,T表示要操作的實(shí)體對(duì)象,ID表示主鍵。該接口繼承了分頁(yè)排序接口PadingAndSortRepository,通過(guò)構(gòu)建Pageable實(shí)現(xiàn)分頁(yè)查詢:
@Autowired private ArticleRepository articleRepository; @RequestMapping("") public ModelAndView articlelist(@RequestParam(value = "start", defaultValue = "0") Integer start, @RequestParam(value = "limit", defaultValue = "5") Integer limit) { start = start < 0 ? 0 : start; Sort sort = Sort.by(Sort.Direction.DESC, "id"); Pageable pageable = PageRequest.of(start, limit, sort); Page<Article> page = articleRepository.findAll(pageable); ModelAndView modelAndView = new ModelAndView("article/list"); modelAndView.addObject("page", page); return modelAndView; }
如果根據(jù)某一字段排序,可以用Sort.by方法構(gòu)建Sort對(duì)象;如果根據(jù)多個(gè)字段排序,首先構(gòu)建Sort.Order數(shù)組List<Sort.Order>,然后再傳入Sort.by方法構(gòu)建Sort對(duì)象。
PageRequest.of方法生成Pageable對(duì)象
五、Contrller 控制器
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.data.domain.Sort; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.*; import org.springframework.web.servlet.ModelAndView; import springbootjpa.entity.Article; import springbootjpa.repository.ArticleRepository; @Controller @RequestMapping("/article") public class ArticleController { @Autowired private ArticleRepository articleRepository; @RequestMapping("") public ModelAndView articlelist(@RequestParam(value = "start", defaultValue = "0") Integer start, @RequestParam(value = "limit", defaultValue = "5") Integer limit) { start = start < 0 ? 0 : start; Sort sort = Sort.by(Sort.Direction.DESC, "id"); Pageable pageable = PageRequest.of(start, limit, sort); Page<Article> page = articleRepository.findAll(pageable); ModelAndView modelAndView = new ModelAndView("article/list"); modelAndView.addObject("page", page); return modelAndView; } @RequestMapping("/add") public String addArticle() { return "article/add"; } @PostMapping("") public String saveArticle(Article article) { articleRepository.save(article); return "redirect:/article"; } @GetMapping("/{id}") public ModelAndView getArticle(@PathVariable("id") Integer id) { Article article = articleRepository.findById(id); ModelAndView modelAndView = new ModelAndView("article/show"); modelAndView.addObject("article", article); return modelAndView; } @DeleteMapping("/{id}") public String deleteArticle(@PathVariable("id") long id) { System.out.println("put 方法"); articleRepository.deleteById(id); return "redirect:/article"; } @GetMapping("edit/{id}") public ModelAndView editArticle(@PathVariable("id") Integer id) { Article article = articleRepository.findById(id); ModelAndView modelAndView = new ModelAndView("article/edit"); modelAndView.addObject("article", article); return modelAndView; } @PutMapping("/{id}") public String editArticleSave(Article article, long id) { System.out.println("put 方法"); article.setId(id); articleRepository.save(article); return "redirect:/article"; } }
因?yàn)?lt;form>表單只能發(fā)送GET或POST請(qǐng)求,spring3引入一個(gè)監(jiān)聽(tīng)器HiddenHttpMethodFilter來(lái)將POST請(qǐng)求轉(zhuǎn)換為PUT或POST請(qǐng)求。
SpringBoot2.x開(kāi)始默認(rèn)不自動(dòng)注入HiddenHttpMethodFilter,需要設(shè)置spring.mvc.hiddenmethod.filter.enabled=true開(kāi)啟PUT、DELETE方法支持
配置完后,前端頁(yè)面需要在表單中加入隱藏域,表明實(shí)際請(qǐng)求方法:
<!-- DELETE 請(qǐng)求 --> <form id="deletePost" method="POST" action=""> <input type="hidden" name="_method" value="delete"> </form> <!-- PUT 請(qǐng)求 --> <form id="putPost" method="POST" action=""> <input type="hidden" name="_method" value="put"> </form>
六、其他
th:value和th:field區(qū)別:
th:value解析成html,表現(xiàn)為:value="${th:value}"
th:field解析成html,表現(xiàn)為:name="${th:name}" value="${th:value}"
以上為個(gè)人經(jīng)驗(yàn),希望能給大家一個(gè)參考,也希望大家多多支持腳本之家。如有錯(cuò)誤或未考慮完全的地方,望不吝賜教。
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