Spring Data JPA

時間 2019-11-11

標籤 spring data jpa 欄目 Spring 简体版

原文原文鏈接

配置相關bean

數據源

<context:property-placeholder ignore-resource-not-found="true" location="classpath:jdbc-${spring.profiles.active}.properties"/>

<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource" init-method="init" destroy-method="close">

    

    <property name="url" value="${ds.url}"/>

    <property name="username" value="${ds.username}"/>

    <property name="password" value="${ds.password}"/>

    

    <property name="initialSize" value="5"/>

    <property name="minIdle" value="5"/>

    <property name="maxActive" value="50"/>

    

    <property name="maxWait" value="60000"/>

    

    <property name="timeBetweenEvictionRunsMillis" value="60000"/>

    

    <property name="minEvictableIdleTimeMillis" value="300000"/>

    <property name="validationQuery" value="SELECT 'x'"/>

    <property name="testWhileIdle" value="true"/>

    <property name="testOnBorrow" value="false"/>

    <property name="testOnReturn" value="false"/>

    

    <property name="removeAbandoned" value="true"/>

    <property name="removeAbandonedTimeout" value="1800"/>

   <property name = "logAbandoned" value = "true"/>

   

    <property name="poolPreparedStatements" value="false"/>

    

    <property name="filters" value="stat"/>

    

    <property name="connectionProperties" value="druid.stat.slowSqlMillis=200;druid.stat.logSlowSql=true"/>
</bean>
實體掃描並生成Repository

<bean id="hibernateJpaVendorAdapter" class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">

    <property name="databasePlatform" value="org.hibernate.dialect.MySQL5Dialect"/>
</bean>

<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">

    <property name="dataSource" ref="dataSource"/>

    <property name="jpaVendorAdapter" ref="hibernateJpaVendorAdapter"/>

    <property name="packagesToScan" value="com.qingbo.sapling"/>

    <property name="jpaProperties">

        <props>

            

            <prop key="hibernate.ejb.naming_strategy">org.hibernate.cfg.ImprovedNamingStrategy</prop>

            <prop key="hibernate.hbm2ddl.auto">update</prop>

            <prop key="hibernate.show_sql">true</prop>

            <prop key="hibernate.format_sql">true</prop>

        </props>

    </property>
</bean>


<jpa:repositories base-package="com.qingbo.sapling" />
事務，校驗，測試時須要加事務註解@Transactional，網站運行須要配置OpenEntityManagerInViewFilter

<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">

    <property name="entityManagerFactory" ref="entityManagerFactory"/>
</bean>

<tx:annotation-driven  proxy-target-class="true"/>


<bean id="validator" class="org.springframework.validation.beanvalidation.LocalValidatorFactoryBean"/>
maven插件任務配置pom.xml，（這個是可選的，會自動生成不少類，可用於支持 QueryDslPredicateExecutor 查詢接口）



<plugin>

    <groupId>com.mysema.maven</groupId>

    <artifactId>apt-maven-plugin</artifactId>

    <version>1.1.0</version>

    <configuration>

        <processor>com.mysema.query.apt.jpa.JPAAnnotationProcessor</processor>

    </configuration>

    <dependencies>

        <dependency>

            <groupId>com.mysema.querydsl</groupId>

            <artifactId>querydsl-apt</artifactId>

            <version>3.3.1</version>

        </dependency>

    </dependencies>

    <executions>

        <execution>

            <phase>generate-sources</phase>

            <goals>

                <goal>process</goal>

            </goals>

            <configuration>

                <outputDirectory>target/generated-sources/annotations</outputDirectory>

            </configuration>

        </execution>

    </executions>
</plugin>
網站配置web.xml

<filter>

      <filter-name>sessionFilter</filter-name>

      <filter-class>org.springframework.orm.jpa.support.OpenEntityManagerInViewFilter</filter-class>

      <init-param>

          <param-name>singleSession</param-name>

          <param-value>false</param-value>

      </init-param>

</filter>

<filter-mapping>

      <filter-name>sessionFilter</filter-name>

      <url-pattern>*.html</url-pattern>
</filter-mapping>

dao持久層接口Repository，數據庫表實體類也在這一層

核心查詢接口：能夠實現如下接口，也能夠註解@RepositoryDefinition編寫本身的接口
CrudRepository，提供基於鍵值ID和實體Entity的增Create刪Delete改Update查Retrieve，T findOne(ID id);
PagingAndSortingRepository，提供分頁和排序功能，Page<T> findAll(Pageable pageable)
JpaRepository，增長批量操做和刷新輸出功能，void flush();
JpaSpecificationExecutor，複雜查詢接口（持久層查詢分頁），Page<T> findAll(Specification<T> spec, Pageable pageable);
QueryDslPredicateExecutor ，querydsl查詢接口支持，
使用樣例：
interface UserRepository extends PagingAndSortingRepository<User, Long> //普通分頁排序，能夠添加本身的findBy命名查詢接口
, JpaSpecificationExecutor<User> //支持Criteria複查查詢
, QueryDslPredicateExecutor<User> //支持querydsl方式查詢
簡單查詢方法命名規範，如下方法只需定義接口無需本身寫實現代碼，
支持方法前綴：findBy+find+readBy+read+getBy+get，
支持屬性名及And和Or拼接，
支持屬性操做Between+LessThan+GreaterThan+IsNull+[Is]NotNull+Like+NotLike+OrderBy+Desc+Not+In+NotIn（支持集合數組或可變參數），
支持屬性嵌套findByAddressZipCode(ZipCode)可查詢address.zipCode（支持findByAddress_ZipCode以避免歧義addressCode.zip），

其餘判斷詞還有：findByStartDateAfter，findByEndDateBefore，findByNameStartingWith，findByAgeOrderByName，findByActiveTrue，
支持排序和分頁：Page<User> findByName(String name, Pageable pageable);//也支持Sort sort參數
List<User> findByName(String, Sort sort);//支持返回List結果，避免構建Page而進行其餘查詢（count計算總數等），同時須要再定義count接口
支持擴展自定義接口：extends MyInterfaceCustom, Repository，而後實現類MyInterfaceCustomImpl，注入@PersistenceContext EntityManager em; 自定義接口方法查庫
支持自定義全局接口：MyRepository extends JpaRepository，MyRepositoryImpl extends SimpleJpaRepository implements MyRepository，而後定義MyRepositoryFactoryBean extends JpaRepositoryFactoryBean提供MyRepositoryFactory extends JpaRepositoryFactory，在getTargetRepository方法裏返回new MyRepositoryImpl，最後在repositories配置factory-class便可
命名查詢，這些最好少用，代碼裏面最好不要有sql類語句

配置文件META-INF/orm.xml

<named-query name="User.findByLastname">

<query>select u from User u where u.lastname = ?1</query>
</named-query>
註解實體類查詢

@Entity @ NamedQuery(name = "User.findByEmailAddress", query = "select u from User u where u.emailAddress = ?1")

public class User {
}

public interface UserRepository extends JpaRepository<User, Long> {

    List<User> findByLastname(String lastname); //spring會優先查找NamedQuery，其次分析方法名
}
註解接口方法，支持簡單統計sql查詢語句（複雜條件統計還得研究JPA查詢條件）

public interface UserRepository extends JpaRepository<User, Long> {

    @Query("select u from User u where u.emailAddress = ?1")

    User findByEmailAddress(String emailAddress);

  @Query(value="select count(ts_user_id) from ts_user group by register_type limit ?1, ?2", nativeQuery=true)
    List registerPage(int offset, int length);

}
使用命名參數

public interface UserRepository extends JpaRepository<User, Long> {

    @Query("select u from User u where u.firstname = :firstname or u.lastname = :lastname")

    User findByLastnameOrFirstname(@Param("lastname") String lastname, @Param ( "firstname" ) String firstname);
}
定義更新方法，注意這裏參數序號也許比上面命名參數更方便

public class Snippet {

    @Modifying @Transactional @Query ( "update User u set u.firstname = ?1 where u.lastname = ?2" )

    int setFixedFirstnameFor(String firstname, String lastname);
}

複雜查詢條件
Specification，複雜查詢條件封裝，Predicate toPredicate(Root<T> root, CriteriaQuery<?> query, CriteriaBuilder cb);
Predicate，條件組合
Root，查詢根能夠有多個
CriteriaQuery，提供獲得查詢根的方法
CriteriaBuilder，構件查詢對象，CriteriaQuery<Object> createQuery();
簡單查詢代碼，直接使用Root+CriteriaQuery+CriteriaBuilder

Specification<TsUser> spec = new Specification<TsUser>() {

    @Override

    public Predicate toPredicate(Root<TsUser> root, CriteriaQuery<?> query, CriteriaBuilder cb) {

        List<Predicate> predicates = new ArrayList<Predicate>();

        if(StringUtils.isNotBlank(userSearch.getUserName())) predicates.add(cb.like(root.<String>get("userName"), "%"+userSearch.getUserName()+"%"));

   query.where(predicates.toArray( new Predicate[0]));

        return null;

    }
};
封裝查詢代碼，使用Criteria封裝多個條件並返回Predicate判斷

Specification<TsUser> spec = new Specification<TsUser>() {

    @Override

    public Predicate toPredicate(Root<TsUser> root, CriteriaQuery<?> query, CriteriaBuilder cb) {

        Criteria<TsUser> c = new Criteria<TsUser>();

        c.add(Restrictions.like("userName", userSearch.getUserName())); // UserSearch是前端封裝的查詢表單對象

c.add(Restrictions.between("createdAt", DateUtil.parse(costSearch.getDateFrom()), DateUtil.parse(costSearch.getDateTo()))); //區間查詢

        c.add(Restrictions.like("tsUserreg.userAlias", userSearch.getUserAlias())); //查詢其餘相關表字段

   c.add(Restrictions. eq ( "status" , userSearch.getStatus())); // 精確查詢

        return c.toPredicate(root, query, cb);

    }
};
//再次簡化，原來Criteria封裝並無使用Root+CriteriaQuery+CriteriaBuilder，因此添加spec()函數生成Specification查詢條件

Criteria<TsUser> c = new Criteria<>();

c.add(Restrictions.like("userName", userSearch.getUserName()));

c.add(Restrictions. like ( "tsAccount.paymentAccountId" , userSearch.getPaymentAccountId()));

c.add(Restrictions.eq("tsUserreg.roleIds", userSearch.getRole()));//實際上應該封裝find_in_set函數，暫時僅支持單一角色

Pageable pageable = new PageRequest(pager.getCurrentPage()-1, pager.getPageSize(), Direction. DESC , "id" );

Page<User> users = userService.userPage(c.spec(), pageable);
Restrictions.java片斷

public static SimpleExpression eq(String fieldName, Object value) {

    if(StringUtils.isEmpty(value))return null;

    return new SimpleExpression (fieldName, value, Operator.EQ);
}

public static BetweenExpression between(String fieldName, Object value, Object value2) {

    if(StringUtils.isEmpty(value) && StringUtils.isEmpty(value2)) return null;

    return new BetweenExpression(fieldName, value, value2);
}
AbstractExpression，計算查詢路徑（支持屬性嵌套，例如address.zipCode）

public abstract class AbstractExpression implements Criterion {

Path getExpression(Root<?> root, String fieldName) {

        Path expression = null;

        if(fieldName.contains(".")){

            String[] names = StringUtils.split(fieldName, ".");

            expression = root.get(names[0]);

            for (int i = 1; i < names.length; i++) {

                expression = expression.get(names[i]);

            }

        }else{ expression = root.get(fieldName); }

        return expression;

    }
}
SimpleExpression，支持Equal、Like、LessThan等條件

public Predicate toPredicate(Root<?> root, CriteriaQuery<?> query, CriteriaBuilder builder) {

   Path expression = getExpression(root, fieldName );

   switch ( operator ) {

    case EQ:

        return builder.equal(expression, value);

   case LIKE :

        return builder.like((Expression<String>) expression, "%" + value + "%");

    }
}

BetweenExpression，支持區間查詢

public Predicate toPredicate(Root<?> root, CriteriaQuery<?> query, CriteriaBuilder builder) {

    Path expression = getExpression(root, fieldName);

    if(StringUtils.isEmpty(value)) {

        return builder.greaterThanOrEqualTo(expression, (Comparable)value);

    }else if(StringUtils.isEmpty(value2)) {

        return builder.lessThanOrEqualTo(expression, (Comparable)value2);

    }else {

        return builder.between(expression, (Comparable)value, (Comparable)value2);

    }
}
Criteria，

public class Criteria<T> implements Specification<T>{

    private List<Criterion> criterions = new ArrayList<Criterion>();

    public Predicate toPredicate(Root<T> root, CriteriaQuery<?> query, CriteriaBuilder builder) {

        if (!criterions.isEmpty()) {

            List<Predicate> predicates = new ArrayList<Predicate>();

            for(Criterion c : criterions){

                predicates.add(c.toPredicate(root, query,builder));

            }

            // 將全部條件用 and 聯合起來

            if (predicates.size() > 0) {

                return builder.and(predicates.toArray(new Predicate[predicates.size()]));

            }

        }

        return builder.conjunction(); // 沒有條件時至關於true

    }

    public void add(Criterion criterion){

        if(criterion!=null){

            criterions.add(criterion);

        }

    }

  public Specification<T> spec() {

        return new Specification<T>() {

            public Predicate toPredicate(Root<T> root, CriteriaQuery<?> query, CriteriaBuilder cb) {

                return Criteria.this.toPredicate(root, query, cb);

            }

        };
    }

}
querydsl查詢接口支持，查詢根、字段都對象化了（querydsl maven-plugin任務生成的類），不像Criteria封裝有實體類屬性名稱硬編碼

QTask $ = QTask.task;

BooleanExpression titleStartWith = $.title.startsWith("Study");

BooleanExpression descEndWith = $.description.endsWith("org/");

Iterable<Task> result = taskDao.findAll(titleStartWith.and(descEndWith));

domain領域層，領域對象是業務核心層，與持久層鬆散耦合（須要領域對象與表實體類之間轉換）；

查詢分頁，domain領域層接口只是銜接service業務層和dao持久層，將數據庫表對象TsUser轉換爲領域對象User

public Page<User> userPage(Specification<TsUser> spec, Pageable pageable) {

    Page<TsUser> page = userRepository.findAll(spec, pageable);

    List<User> content = new ArrayList<User>();

    Iterator<TsUser> iterator = page.iterator();

    while(iterator.hasNext()) {

        content.add(User.formUser(iterator.next()));

    }

    return new PageImpl<User>(content, pageable, page.getTotalElements());
}
Audit審計，記錄實體建立和修改的管理帳戶，

domain領域對象需實現接口Auditable<U, ID>（U是審計類型，一般是用戶名或用戶實體類），void setCreatedBy(final U createdBy);
orm.xml註冊監聽器

<persistence-unit-metadata>

    <persistence-unit-defaults>

        <entity-listeners>

             <entity-listener class = "org.springframework.data.jpa.domain.support.AuditingEntityListener" />

        </entity-listeners>

    </persistence-unit-defaults>
</persistence-unit-metadata>
激活AuditorAware的自定義實現，其方法T getCurrentAuditor();返回的就是審計的用戶（能夠是String用戶名或User用戶對象，是setCreatedBy(U)的參數）
<jpa:auditing auditor-aware-ref="yourAuditorAwareBean" />

service業務層，面向前端頁面封裝表單對象，定義接口並調用domain層來實現（須要表單對象與領域對象之間轉換），建議每一個web項目都有各自的service層（如front-service，admin-service等）

查詢分頁，須要構建Specification查詢條件，將領域對象User轉換爲頁面表單對象UserItem

Specification<TsUser> spec = new Specification<TsUser>() {

    @Override

    public Predicate toPredicate(Root<TsUser> root, CriteriaQuery<?> query, CriteriaBuilder cb) {

        Criteria<TsUser> c = new Criteria<TsUser>();

        c.add(Restrictions.like("userName", userSearch.getUserName()));

   c.add(Restrictions. eq ( "tsUserreg.status" , userSearch.getStatus()));

        return c.toPredicate(root, query, cb);

    }
};
Page<User> users = userService.userPage(spec, pageable);

List<UserItem> userItems = new ArrayList<UserItem>();

for (User user : users.getContent()) {

    UserItem userItem = UserItem.formUserItem(user);

   userItems.add(userItem);
}

web控制層（按項目劃分如front-web，admin-web等）

前端開發人員負責內容
頁面：jsp或vm
控制：Controller
業務接口及頁面對象：front-service，UserItem等，自定義接口並提供假數據展現到頁面
後臺開發人員負責內容
負責domain和dao層設計開發（若是前端開發人員面向domain層開發，則造成緊耦合，會影響項目進度）
負責實現front-service等服務項目的接口實現，提供數據庫數據

數據校驗和異常處理

web層數據校驗：spring會自動校驗@Valid參數並將結果存入BindingResult對象，UserItem等對象須要使用@NotNull等校驗註解
UserController.userUpdate(@Valid UserItem, BindingResult bindingResult, Model model){ if(bindingResult.hasErrors()) return NOT_VALID_PAGE; }
service+domain數據校驗
建議用AOP實現，全局拋校驗異常，而後轉異常處理邏輯
異常處理，

@Service("excetionResolver")

public class ExceptionResolver extends DefaultHandlerExceptionResolver {

    @Override

    protected ModelAndView doResolveException(HttpServletRequest request,

            HttpServletResponse response, Object handler, Exception ex) {

        if(ex instanceof AuthorizationException) {//未受權或過時則拒絕訪問，校驗失敗異常可相似處理

            if(request.getRequestURI().contains("admin/home.html")) {

                return new ModelAndView("redirect:login.html");

            }

            return new ModelAndView("admin/denied");

        } else if (ex instanceof AuthenticationException) {//錯誤密碼超過5次等，認證錯誤

            return new ModelAndView("redirect:login.html");
        }
// return new ModelAndView( "admin/error" );//其餘業務異常，顯示錯誤頁面
    return null;//不認識的異常直接拋出，保證service底層異常的事務能夠回滾

    }

}