Question

我获得了一个带有gradle作为构建工具的spring项目。由于我熟悉maven，我试图将项目构建工具更改为maven。我在pom.xml中定义了依赖项，就像在build.gradle中使用相同的组ID，工件ID和版本一样。然而，对于项目的maven版本，存在一个依赖项的错误，比较我发现类文件不同的两个依赖项，我搜索并发现没有任何接近我的问题。

在build.gradle中

compile 'org.springframework.data:spring-data-jpa:1.10.4.RELEASE'

在pom.xml中

<!-- https://mvnrepository.com/artifact/org.springframework.data/spring-data-jpa -->
<dependency>
    <groupId>org.springframework.data</groupId>
    <artifactId>spring-data-jpa</artifactId>
    <version>1.10.4.RELEASE</version>
</dependency>

代码的差异可在CrudRepository.class

中找到

在使用pom.xml的项目中，这是类

/*
 * Copyright 2008-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.springframework.data.repository;

import java.util.Optional;

/**
 * Interface for generic CRUD operations on a repository for a specific type.
 * 
 * @author Oliver Gierke
 * @author Eberhard Wolff
 */
@NoRepositoryBean
public interface CrudRepository<T, ID> extends Repository<T, ID> {

/**
 * Saves a given entity. Use the returned instance for further operations as the save operation might have changed the
 * entity instance completely.
 * 
 * @param entity must not be {@literal null}.
 * @return the saved entity will never be {@literal null}.
 */
<S extends T> S save(S entity);

/**
 * Saves all given entities.
 * 
 * @param entities must not be {@literal null}.
 * @return the saved entities will never be {@literal null}.
 * @throws IllegalArgumentException in case the given entity is {@literal null}.
 */
<S extends T> Iterable<S> saveAll(Iterable<S> entities);

/**
 * Retrieves an entity by its id.
 * 
 * @param id must not be {@literal null}.
 * @return the entity with the given id or {@literal Optional#empty()} if none found
 * @throws IllegalArgumentException if {@code id} is {@literal null}.
 */
Optional<T> findById(ID id);

/**
 * Returns whether an entity with the given id exists.
 * 
 * @param id must not be {@literal null}.
 * @return {@literal true} if an entity with the given id exists, {@literal false} otherwise.
 * @throws IllegalArgumentException if {@code id} is {@literal null}.
 */
boolean existsById(ID id);

/**
 * Returns all instances of the type.
 * 
 * @return all entities
 */
Iterable<T> findAll();

/**
 * Returns all instances of the type with the given IDs.
 * 
 * @param ids
 * @return
 */
Iterable<T> findAllById(Iterable<ID> ids);

/**
 * Returns the number of entities available.
 * 
 * @return the number of entities
 */
long count();

/**
 * Deletes the entity with the given id.
 * 
 * @param id must not be {@literal null}.
 * @throws IllegalArgumentException in case the given {@code id} is {@literal null}
 */
void deleteById(ID id);

/**
 * Deletes a given entity.
 * 
 * @param entity
 * @throws IllegalArgumentException in case the given entity is {@literal null}.
 */
void delete(T entity);

/**
 * Deletes the given entities.
 * 
 * @param entities
 * @throws IllegalArgumentException in case the given {@link Iterable} is {@literal null}.
 */
void deleteAll(Iterable<? extends T> entities);

/**
 * Deletes all entities managed by the repository.
 */
void deleteAll();
}

在使用build.gradle的项目中，这是类

/*
 * Copyright 2008-2011 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.springframework.data.repository;

import java.io.Serializable;

/**
 * Interface for generic CRUD operations on a repository for a specific type.
 * 
 * @author Oliver Gierke
 * @author Eberhard Wolff
 */
@NoRepositoryBean
public interface CrudRepository<T, ID extends Serializable> extends Repository<T, ID> {

    /**
     * Saves a given entity. Use the returned instance for further operations as the save operation might have changed the
     * entity instance completely.
     * 
     * @param entity
     * @return the saved entity
     */
    <S extends T> S save(S entity);

    /**
     * Saves all given entities.
     * 
     * @param entities
     * @return the saved entities
     * @throws IllegalArgumentException in case the given entity is {@literal null}.
     */
    <S extends T> Iterable<S> save(Iterable<S> entities);

    /**
     * Retrieves an entity by its id.
     * 
     * @param id must not be {@literal null}.
     * @return the entity with the given id or {@literal null} if none found
     * @throws IllegalArgumentException if {@code id} is {@literal null}
     */
    T findOne(ID id);

    /**
     * Returns whether an entity with the given id exists.
     * 
     * @param id must not be {@literal null}.
     * @return true if an entity with the given id exists, {@literal false} otherwise
     * @throws IllegalArgumentException if {@code id} is {@literal null}
     */
    boolean exists(ID id);

    /**
     * Returns all instances of the type.
     * 
     * @return all entities
     */
    Iterable<T> findAll();

    /**
     * Returns all instances of the type with the given IDs.
     * 
     * @param ids
     * @return
     */
    Iterable<T> findAll(Iterable<ID> ids);

    /**
     * Returns the number of entities available.
     * 
     * @return the number of entities
     */
    long count();

    /**
     * Deletes the entity with the given id.
     * 
     * @param id must not be {@literal null}.
     * @throws IllegalArgumentException in case the given {@code id} is {@literal null}
     */
    void delete(ID id);

    /**
     * Deletes a given entity.
     * 
     * @param entity
     * @throws IllegalArgumentException in case the given entity is {@literal null}.
     */
    void delete(T entity);

    /**
     * Deletes the given entities.
     * 
     * @param entities
     * @throws IllegalArgumentException in case the given {@link Iterable} is {@literal null}.
     */
    void delete(Iterable<? extends T> entities);

    /**
     * Deletes all entities managed by the repository.
     */
    void deleteAll();
}`

它们的导入方式不同，项目中有一个方法findOne(Id id)，带有gradle，但在项目中缺少maven。我无法理解我做错了什么。

Answer 1

Gradle和maven在依赖关系图中有多个工件版本时有不同的冲突解决策略

Maven有一个＆＃34;最近的定义胜出＆＃34;策略，其中版本在传递pom中定义，即最近的＆＃34;你的项目获胜。在我看来，这是一个愚蠢的策略。您可以通过在项目的pom.xml中明确声明所需的版本来强制版本，因为它是＆＃34;最近的＆＃34;
默认情况下，Gradle将选择最高版本号。解决方案策略可在Gradle中完全配置（例如，您可以强制使用特定版本）

对于maven，输入

mvn dependency:tree

对于gradle类型

gradle dependencies

如果您比较结果，您应该看到差异

在不同项目中使用时，相同依赖项的不同类文件

1 个答案: