Question

我是Hibernate的新手。我需要将文件存储在postgres中，列的数据类型为bytea。我在互联网上四处寻找这个案例的工作演示，但我无法找到任何。

Hibernate映射：



<property name="fileData" type="binary">
   <column name="fileData" not-null="true" />
</property>

POJO：

org.hibernate.tool.schema.spi.SchemaManagementException: Schema-validation: wrong column type encountered in column [fileData] in table [nmondata]; found [bytea (Types#BINARY)], but expecting [binary(255) (Types#VARBINARY)]
    at org.hibernate.tool.schema.internal.SchemaValidatorImpl.validateColumnType(SchemaValidatorImpl.java:105)
    at org.hibernate.tool.schema.internal.SchemaValidatorImpl.validateTable(SchemaValidatorImpl.java:92)
    at org.hibernate.tool.schema.internal.SchemaValidatorImpl.doValidation(SchemaValidatorImpl.java:50)
    at org.hibernate.tool.hbm2ddl.SchemaValidator.validate(SchemaValidator.java:91)
    at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:473)
    at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:444)
    at com.psl.perf.hibernate.util.HibernateUtil.<clinit>(HibernateUtil.java:34)
    at com.psl.perf.DAO.NmonReportFileDaoImpl.save(NmonReportFileDaoImpl.java:15)
    at com.psl.perf.service.DataService.saveNmonCSV(DataService.java:249)
    at com.psl.perf.main.Main2.main(Main2.java:8)
Jan 22, 2016 12:26:18 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl stop
INFO: HHH10001008: Cleaning up connection pool [jdbc:postgresql://x.x.x.x:5432/perf]
Exception in thread "main" java.lang.NullPointerException
    at com.psl.perf.DAO.NmonReportFileDaoImpl.save(NmonReportFileDaoImpl.java:17)
    at com.psl.perf.service.DataService.saveNmonCSV(DataService.java:249)
    at com.psl.perf.main.Main2.main(Main2.java:8)

表：



    private byte[] fileData;
        public byte[] getFileData() {
            return fileData;
        }
        public void setFileData(byte[] fileData) {
            this.fileData = fileData;
        }

错误：


    create table nmonData(id int, buildNumber int, path text, fileName text, fileData bytea);

有人可以共享工作演示或链接吗？

这对我有用 评论<property name="hbm2ddl.auto">validate</property> hibernate配置文件为我做了伎俩，但我现在很困惑关于什么应该是列和成员变量的数据类型用于存储文件的java。

Answer 1

我假设您需要将文件内容存储到PG bytea列中。

PostgreSQL DDL

CREATE TABLE data_object
(
  obj_id bigserial NOT NULL,
  obj_name character(30),
  obj_file bytea,
  CONSTRAINT data_object_pkey PRIMARY KEY (obj_id)
)

Java对象

@Entity
@Table (name = "data_object")
public class DataObject {

    @Id
    @GeneratedValue (strategy = GenerationType.IDENTITY)
    @Column(name = "obj_id")
    private Long id;

    @Column(name = "obj_name")
    private String name;

    @Column(name = "obj_file")
    private byte[] file;

    // getters, setters, hasCode, equals, toString

驱动程序代码

byte[] data = new byte[FILE_SIZE];
// read file contents into data
DataObject obj = new DataObject();
obj.setFile(data);
// save obj using your hibernate session

我使用的是Hibernate 4.3.7和PG 9.4.1

如何使用hibernate在postgres数据库中存储文件？

1 个答案: