Spring Data JPA事务支持

一 点睛

Spring Data JPA对所有默认方法都开启了事务支持，且查询类事务默认启用readOnly=true属性。

二 SimpleJpaRepository缩减版源码

@Repository
@Transactional(readOnly = true)
public class SimpleJpaRepository<T, ID extends Serializable> implements JpaRepository<T, ID>,
        JpaSpecificationExecutor<T> {
    ......
    @Transactional
    public void delete(ID id) {
    ......
    }
 
    @Transactional
    public void delete(T entity) {
    ......
    }
 
 
    @Transactional
    public void delete(Iterable<? extends T> entities) {
    ......
    }
 
 
    @Transactional
    public void deleteInBatch(Iterable<T> entities) {
    ......
    }
 
 
    @Transactional
    public void deleteAll() {
    ......
    }
 
 
    @Transactional
    public void deleteAllInBatch() {
    ......
    }
 
 
    public T findOne(ID id) {
    ......
    }
 
 
    protected Map<String, Object> getQueryHints() {
    ......
    }
 
    private JpaEntityGraph getEntityGraph() {
    ......
    }
 
 
    @Override
    public T getOne(ID id) {
    ......
    }
 
 
    public boolean exists(ID id) {
    ......
    }
 
 
    public List<T> findAll() {
    ......
    }
 
 
    public List<T> findAll(Iterable<ID> ids) {
    ......
    }
 
 
    public List<T> findAll(Sort sort) {
    ......
    }
 
 
    public Page<T> findAll(Pageable pageable) {
    ......
    }
 
 
    public T findOne(Specification<T> spec) {
    ......
    }
 
 
    public List<T> findAll(Specification<T> spec) {
    ......
    }
 
 
    public Page<T> findAll(Specification<T> spec, Pageable pageable) {
    ......
    }
 
 
    public List<T> findAll(Specification<T> spec, Sort sort) {
    ......
    }
 
 
    public long count() {
    ......
    }
 
 
    public long count(Specification<T> spec) {
 
    ......
    }
 
 
    @Transactional
    public <S extends T> S save(S entity) {
    ......
    }
 
 
    @Transactional
    public <S extends T> S saveAndFlush(S entity) {
    ......
    }
 
    @Transactional
    public <S extends T> List<S> save(Iterable<S> entities) {
    ......
    }
 
    ......
}

三 源码分析

从源码分析可以看出，SimpleJpaRepository在类级别定义了@Transactional(readOnly = true)，而在和save、delete相关的操作重写了@Transactional属性，此时readOnly属性是false，其余查询操作readOnly仍然为true。