springboot 整合 springdata
阿新 • • 發佈：2018-12-03
用膩了ssm，尤其是mybatis，每次使用者需求變動要求改表的時候都要刪掉各種實體類和mapper.xml然後再重新生成，所以最近小研究了一下springdata，demo框架：springboot + springdata
首先是maven的pom.xml：
<?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.example</groupId> <artifactId>demo</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>demo</name> <description>Demo project for Spring Boot</description> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.0.4.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>1.8</java.version> </properties> <dependencies> <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> <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-devtools --> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-devtools</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> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
springboot配置檔案：application.properties
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/hrms?useUnicode=true&characterEncoding=utf8&useSSL=true spring.datasource.username=root spring.datasource.password=123456 spring.datasource.driver-class-name=com.mysql.jdbc.Driver spring.jpa.database=mysql #自動建表 spring.jpa.hibernate.ddl-auto=update #設定資料庫方言 spring.jpa.database-platform=org.hibernate.dialect.MySQL5InnoDBDialect #列印sql spring.jpa.show-sql=true
spring.jpa.hibernate.ddl-auto配置自動建表，有四個屬性
create：每次啟動時刪除表，再根據實體類建表
create-drop：每次啟動時根據實體類建表，退出時刪表
update：每次啟動時根據實體類更新表結構（表資料不變）
validate：每次啟動時根據實體類校驗表結構
spring.jpa.database-platform配置資料庫方言
如果你的實體類中有外來鍵，請配置此項，否則啟動報錯Specified key was too long; max key length is 1000 bytes，因為springdata預設的資料庫方言是org.hibernate.dialect.MySQL5Dialect，資料庫引擎是MyISAM，它既不支援高階事務也不支援外來鍵。
以簡單的系統管理為例，構建三個實體類UserEntity.java、RoleEntity.java、PermissionEntity.java：
UserEntity：
package com.example.demo.entity;
import javax.persistence.*;
import java.util.Objects;
import java.util.Set;
/**
* @ClassName UserEntity
* @Description TODO
* @Author Rock-PC5
* @Date 2018/9/19 13:45
* @Version 1.0
**/
@Entity
@Table(name = "user", schema = "hrms", catalog = "")
public class UserEntity {
@Id
@Column(name = "id")
private String id;
@Column(name = "username")
private String username;
@Column(name = "password")
private String password;
@ManyToMany
@JoinTable(name = "user_role", joinColumns = {@JoinColumn(name = "user_id", referencedColumnName = "id")}, inverseJoinColumns = {@JoinColumn(name = "role_id", referencedColumnName = "id")})
private Set<RoleEntity> roleEntitySet;
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public Set<RoleEntity> getRoleEntitySet() {
return roleEntitySet;
}
public void setRoleEntitySet(Set<RoleEntity> roleEntitySet) {
this.roleEntitySet = roleEntitySet;
}
}
RoleEntity：
package com.example.demo.entity;
import javax.persistence.*;
import java.util.Set;
/**
* @ClassName RoleEntity
* @Description TODO
* @Author Rock-PC5
* @Date 2018/9/19 13:45
* @Version 1.0
**/
@Entity
@Table(name = "role", schema = "hrms", catalog = "")
public class RoleEntity {
@Id
@Column(name = "id")
private String id;
@Column(name = "name")
private String name;
@Column(name = "description")
private String description;
@ManyToMany(mappedBy = "roleEntitySet")
private Set<UserEntity> userEntitySet;
@ManyToMany
@JoinTable(name = "role_permission", joinColumns = {@JoinColumn(name = "role_id", referencedColumnName = "id")}, inverseJoinColumns = {@JoinColumn(name = "permission_id", referencedColumnName = "id")})
private Set<PermissionEntity> permissionEntitySet;
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
public Set<UserEntity> getUserEntitySet() {
return userEntitySet;
}
public void setUserEntitySet(Set<UserEntity> userEntitySet) {
this.userEntitySet = userEntitySet;
}
public Set<PermissionEntity> getPermissionEntitySet() {
return permissionEntitySet;
}
public void setPermissionEntitySet(Set<PermissionEntity> permissionEntitySet) {
this.permissionEntitySet = permissionEntitySet;
}
}
PermissionEntity：
package com.example.demo.entity;
import javax.persistence.*;
import java.util.Objects;
import java.util.Set;
/**
* @ClassName PermissionEntity
* @Description TODO
* @Author Rock-PC5
* @Date 2018/9/19 13:45
* @Version 1.0
**/
@Entity
@Table(name = "permission", schema = "hrms", catalog = "")
public class PermissionEntity {
@Id
@Column(name = "id")
private String id;
@Column(name = "name")
private String name;
@Column(name = "description")
private String description;
@ManyToMany(mappedBy = "permissionEntitySet")
private Set<RoleEntity> roleEntitySet;
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
public Set<RoleEntity> getRoleEntitySet() {
return roleEntitySet;
}
public void setRoleEntitySet(Set<RoleEntity> roleEntitySet) {
this.roleEntitySet = roleEntitySet;
}
}
簡單介紹一下其中的註解：
@Entity：指明該類是一個實體類
@Table：指明該類與表的對映關係
name指明該類所對映的表名，如果不寫預設為類名
schema指明該類所對映到的資料庫，如果不寫預設為連線到的資料庫名
catelog的作用與schema一致
@Id：指明該屬性為主鍵
@Column：name指定該屬性所對應的欄位名
@ManyToMany：指明表間的多對多關係，mappedBy的作用是把維護表的任務交給與其關聯的實體類，值為與其關聯的實體類的對應外來鍵的引數名。除此之外還有@ManyToOne，@OneToMany，@OneToOne等。
@JoinTable：新建第三張關聯表來維護兩實體類的關聯關係
name：新建表的表名
joinColumns：該實體類對應表外來鍵的欄位名集合
inverseJoinColumns：與其關聯的實體類對應表外來鍵的欄位名集合
@JoinColumn：新建表中新建的欄位
name：新建的欄位名
referencedColumnName：該欄位在主表中欄位名
然後啟動專案就可以了，生成的表如圖所示：
在初體驗springdata的時候，最直觀的感受就是專案目錄的簡潔，完全不需要那些dao、service以及然人看了想吐的mapper.xml，僅僅需要一個jpa即可操作一個實體類：
那jpa的程式碼如下：
UserJpa：
package com.example.demo.jpa;
import com.example.demo.entity.UserEntity;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
import java.io.Serializable;
/**
* @ClassName UserJpa
* @Description TODO
* @Author Rock-PC5
* @Date 2018/9/18 16:12
* @Version 1.0
**/
public interface UserJpa extends JpaRepository<UserEntity, String>, JpaSpecificationExecutor<UserEntity>, Serializable {
}
RoleJpa：
package com.example.demo.jpa;
import com.example.demo.entity.RoleEntity;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
import java.io.Serializable;
/**
* @ClassName RoleJpa
* @Description TODO
* @Author Rock-PC5
* @Date 2018/9/19 13:16
* @Version 1.0
**/
public interface RoleJpa extends JpaRepository<RoleEntity, String>, JpaSpecificationExecutor<RoleEntity>, Serializable {
}
PermissionJpa：
package com.example.demo.jpa;
import com.example.demo.entity.PermissionEntity;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
import java.io.Serializable;
/**
*@author FastKing
*@Description
*@Date 15:03 2018/9/19
*@Param
*@return
**/
public interface PermissionJpa extends JpaRepository<PermissionEntity, String>, JpaSpecificationExecutor<PermissionEntity>, Serializable {
}
你只需要繼承JpaRepository和JpaSpecificationExecutor，前者的第一個引數寫對應實體類，第二個引數寫對應實體類主鍵型別，後者的引數就是對應實體類
jpa的使用方法就和ssm中的service一樣，這裡給一個示例的Controller：
package com.example.demo.controller;
import com.example.demo.entity.UserEntity;
import com.example.demo.jpa.UserJpa;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Example;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;
/**
* @ClassName HelloController
* @Description TODO
* @Author FastKing
* @Date 2018/9/13 9:02
* @Version 1.0
**/
@RestController
public class HelloController {
@Autowired
private UserJpa userJpa;
@RequestMapping(value = "/login/{username}/{password}", method = RequestMethod.GET)
public Object login(@PathVariable String username, @PathVariable String password) {
UserEntity userEntity = new UserEntity();
userEntity.setUsername(username);
userEntity.setPassword(password);
Example<UserEntity> userEntityExample = Example.of(userEntity);
List<UserEntity> userList = userJpa.findAll(userEntityExample);
return userList.size();
}
@RequestMapping(value = "/list")
public Object list() {
return userJpa.findAll();
}
}
Example的用法可以類比Mybatis的xxxExample
更新一下三個實體類，
以UserEntity為例：
package com.example.demo.entity;
import javax.persistence.*;
import java.util.Set;
/**
* @ClassName UserEntity
* @Description TODO
* @Author FastKing
* @Date 2018/9/19 13:45
* @Version 1.0
**/
@Entity
@Table(name = "user", schema = "hrms", catalog = "")
public class UserEntity {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "id" ,columnDefinition = ("int COMMENT 'id'"))
private Integer id;
@Column(name = "username" ,columnDefinition = ("varchar(255) COMMENT '使用者名稱'"))
private String username;
@Column(name = "password" ,columnDefinition = ("varchar(255) COMMENT '密碼'"))
private String password;
@Column(name = "salt",columnDefinition = ("varchar(255) COMMENT '鹽值'"))
private String salt;
@Column(name = "isLocked",columnDefinition = ("tinyint COMMENT '是否鎖定（0否1是）'"))
private Byte isLocked;
@Column(name = "isForbidden",columnDefinition = ("tinyint COMMENT '是否禁用（0否1是）'"))
private Byte isForbidden;
@ManyToMany
@JoinTable(name = "user_role", joinColumns = {@JoinColumn(name = "user_id", referencedColumnName = "id",columnDefinition = ("int COMMENT '使用者id'"))}, inverseJoinColumns = {@JoinColumn(name = "role_id", referencedColumnName = "id",columnDefinition = ("int COMMENT '角色id'"))})
private Set<RoleEntity> roleEntitySet;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public Set<RoleEntity> getRoleEntitySet() {
return roleEntitySet;
}
public void setRoleEntitySet(Set<RoleEntity> roleEntitySet) {
this.roleEntitySet = roleEntitySet;
}
public String getSalt() {
return salt;
}
public void setSalt(String salt) {
this.salt = salt;
}
public Byte getIsLocked() {
return isLocked;
}
public void setIsLocked(Byte isLocked) {
this.isLocked = isLocked;
}
public Byte getIsForbidden() {
return isForbidden;
}
public void setIsForbidden(Byte isForbidden) {
this.isForbidden = isForbidden;
}
}
@Column中的columnDefinition用來定義對應資料庫中的欄位型別和註釋，如果你要設定欄位型別為varchar必須指定長度，否則報sql語法錯誤
@GeteratedValue如果設定為auto，mysql會自動選擇squence自增策略，生成一個hibernate_squence表，用來記錄其他表的主鍵。由於mysql不支援這種自增策略，改為identity即可