Spring Data Jpa整合PostgreSQL（二）

旧城等待， 2022-05-27 02:50 405阅读 0赞

直接看三吧，这个也没写好

PostgreSQL的话主要还是整理一下使用方法吧，毕竟我现在也只会使用。

PostgreSQL的使用方法与MySQL类似， 但更全面，实现了[SQL-2/SQL-92 和 SQL-3/SQL-99][SQL-2_SQL-92 _ SQL-3_SQL-99]标准。优点缺点就不提了，直接说说怎么用吧。

咱使用pg当然不会只把他当做MySQL来用，而我用它的目的就是jsonb。

0. 导入有用的包

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-data-jpa</artifactId>

<groupId>org.apache.logging.log4j</groupId>

</exclusion>

</exclusions>

</dependency>

<groupId>org.postgresql</groupId>

<artifactId>postgresql</artifactId>

</dependency>

# #

1.基本配置

spring:

datasource:

url: jdbc:postgresql://118.89.146:5432/postgres

username: postgres

password: 123456

driverClassName: org.postgresql.Driver

type: com.alibaba.druid.pool.DruidDataSource

initialization-mode: always

jpa:

show-sql: **true**

database-platform: cn...ledger.dialect.JsonbPostgresDialect

hibernate:

ddl-auto: update

properties:

hibernate:

temp:

use\_jdbc\_metadata\_defaults: **false**

ps： use\_jdbc\_metadata\_defaults这个配置很重要，可以解决SpringBoot2.0版本的一个错误，具体机理我还没有研究，只是参考了一个博客做出的修改。

# #

2. 配置方言

以上的配置与MySQL没什么差别，需要注意是方言的指定，我写的这个需要自己配置方言类：

import org.hibernate.dialect.PostgreSQL94Dialect;

import org.hibernate.dialect.PostgreSQL95Dialect;

import org.hibernate.type.StringType;

import java.sql.Types;

/\*\*

\* @Author ZhenYang

\* @Date Created in 2018/3/14 13:45

\* @Description

\*/

public class JsonbPostgresDialect extends PostgreSQL95Dialect \{

public JsonbPostgresDialect() \{

super();

registerColumnType(Types.JAVA\_OBJECT, "jsonb");

registerHibernateType( Types.ARRAY, StringType.class.getName());

这里我指定了jsonb的类型，下面那个HibernateType是当时测试玩的。

# #

3.配置jsonb类型

import com.alibaba.fastjson.JSON;

import com.fasterxml.jackson.databind.ObjectMapper;

import org.hibernate.HibernateException;

import org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl;

import org.hibernate.boot.registry.classloading.spi.ClassLoaderService;

import org.hibernate.engine.spi.SharedSessionContractImplementor;

import org.hibernate.type.SerializationException;

import org.hibernate.usertype.ParameterizedType;

import org.hibernate.usertype.UserType;

import org.postgresql.util.PGobject;

import org.springframework.util.ObjectUtils;

import java.io.IOException;

import java.io.Serializable;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.Types;

import java.util.Map;

import java.util.Properties;

/\*\*

\* @Author ZhenYang

\* @Date Created in 2018/3/14 13:46

\* @Description

\*/

public class JsonbType implements UserType, ParameterizedType \{

private final ObjectMapper mapper = new ObjectMapper();

;

private static final ClassLoaderService classLoaderService = new ClassLoaderServiceImpl();

public static final String CLASS = "CLASS";

private Class<?> jsonClassType;

@Override

public Object nullSafeGet(ResultSet resultSet, String\[\] strings, SharedSessionContractImplementor sharedSessionContractImplementor, Object o) throws HibernateException, SQLException \{

PGobject oo = (PGobject) resultSet.getObject(strings\[0\]);

if (oo.getValue() != null) \{

System.out.println(jsonClassType.getClass());

return JSON.parseObject(oo.getValue(), jsonClassType);

return null;

@Override

public void nullSafeSet(PreparedStatement preparedStatement, Object o, int i, SharedSessionContractImplementor sharedSessionContractImplementor) throws HibernateException, SQLException \{

if (o == null) \{

preparedStatement.setNull(i, Types.OTHER);

\} else \{

try \{

preparedStatement.setObject(i, mapper.writeValueAsString(o), Types.OTHER);

\} catch (IOException e) \{

e.printStackTrace();

// @Override

// public void nullSafeSet(PreparedStatement st, Object value, int index, SessionImplementor session)

// throws HibernateException, SQLException \{

// if (value == null) \{

// st.setNull(index, Types.OTHER);

// \} else \{

// try \{

// st.setObject(index, mapper.writeValueAsString(value), Types.OTHER);

// \} catch (IOException e) \{

// e.printStackTrace();

// \}

// /\*\*

// \* 重写自定义类型，Jsonb

// \* @param rs

// \* @param names

// \* @param session

// \* @param owner

// \* @return

// \* @throws HibernateException

// \* @throws SQLException

// \*/

// @Override

// public Object nullSafeGet(ResultSet rs, String\[\] names, SessionImplementor session, Object owner)

// throws HibernateException, SQLException \{

// PGobject o = (PGobject) rs.getObject(names\[0\]);

// if (o.getValue() != null) \{

// System.out.println(jsonClassType.getClass());

// return JSON.parseObject(o.getValue(),jsonClassType);

// \}

// return null;

// \}

@Override

public Object deepCopy(Object originalValue) throws HibernateException \{

if (originalValue != null) \{

try \{

System.out.println(mapper.readValue(mapper.writeValueAsString(originalValue), returnedClass()));

return mapper.readValue(mapper.writeValueAsString(originalValue), returnedClass());

\} catch (IOException e) \{

throw new HibernateException("Failed to deep copy object", e);

return null;

@Override

public Serializable disassemble(Object value) throws HibernateException \{

Object copy = deepCopy(value);

if (copy instanceof Serializable) \{

return (Serializable) copy;

throw new SerializationException(

String.format("Cannot serialize '%s', %s is not Serializable.", value, value.getClass()), null);

@Override

public Object assemble(Serializable cached, Object owner) throws HibernateException \{

return deepCopy(cached);

@Override

public Object replace(Object original, Object target, Object owner) throws HibernateException \{

return deepCopy(original);

@Override

public boolean isMutable() \{

return true;

@Override

public int hashCode(Object x) throws HibernateException \{

if (x == null) \{

return 0;

return x.hashCode();

@Override

public boolean equals(Object x, Object y) throws HibernateException \{

return ObjectUtils.nullSafeEquals(x, y);

@Override

public Class<?> returnedClass() \{

return Map.class;

@Override

public int\[\] sqlTypes() \{

return new int\[\]\{ Types.JAVA\_OBJECT\};

@Override

public void setParameterValues(Properties parameters) \{

final String clazz = (String) parameters.get(CLASS);

jsonClassType = classLoaderService.classForName(clazz);

这一段是为了自定义了JsonB的处理类，基本的逻辑就是将从数据库中返回的Json串转化为对象。注释部分是因为SpringBoot1.X和2.X不兼容，导致部分函数需要修改。

# #

4.配置list类型

import com.fasterxml.jackson.core.JsonParseException;

import com.fasterxml.jackson.core.JsonProcessingException;

import com.fasterxml.jackson.databind.JsonMappingException;

import com.fasterxml.jackson.databind.ObjectMapper;

import javax.persistence.AttributeConverter;

import javax.persistence.Converter;

import java.io.IOException;

import java.util.List;

/\*\*

\* @Author : ZhenYang

\* @Despriction :

\* @Date: Created in 2018/6/30 13:47

\* @Modify By:

\*/

@Converter

public class ListString2JsonConverter implements AttributeConverter<List<String>, String> \{

@Override

public String convertToDatabaseColumn(List<String> attribute) \{

if(attribute == null || attribute.size() == 0) return "\[\]";

ObjectMapper mapper = new ObjectMapper();

String json = null;

try \{

json = mapper.writeValueAsString(attribute);

\} catch (JsonProcessingException e) \{

e.printStackTrace();

return json;

@SuppressWarnings("unchecked")

@Override

public List<String> convertToEntityAttribute(String dbData) \{

ObjectMapper mapper = new ObjectMapper();

List<String> list = null;

try \{

list = (List<String>) mapper.readValue(dbData, List.class);

\} catch (JsonParseException e) \{

e.printStackTrace();

\} catch (JsonMappingException e) \{

e.printStackTrace();

\} catch (IOException e) \{

e.printStackTrace();

return list;

这个类自定义了list类型。

# #

5.jsonb在实体类中的应用

import cn.videon.diconde.common.constant.GeneralConstants;

import cn.videon.diconde.ledger.dialect.JsonbType;

import lombok.AllArgsConstructor;

import lombok.Data;

import lombok.EqualsAndHashCode;

import lombok.NoArgsConstructor;

import org.hibernate.annotations.Type;

import org.hibernate.annotations.TypeDef;

import org.hibernate.annotations.TypeDefs;

import javax.persistence.\*;

/\*\*

\* @Author : ZhenYang

\* @Despriction : 元件

\* @Date: Created in 2018/6/25 13:48

\* @Modify By:

\*/

@Entity

@Data

@EqualsAndHashCode(callSuper=false)

@AllArgsConstructor

@NoArgsConstructor

@Table(name = "component", schema = GeneralConstants.ledgerSchema)

@TypeDefs(\{

@TypeDef(name = "JsonbTypeGeometry", typeClass = JsonbType.class, parameters = \{

@org.hibernate.annotations.Parameter(name = JsonbType.CLASS, value = "cn...ledger.entity.pg.NDEGeometry")\}),

\})

public class Component extends BaseEntity \{

//略

@Column(columnDefinition = "jsonb")

@Type(type = "JsonbTypeGeometry")

private NDEGeometry geometry;

@ManyToOne(targetEntity = NDEMaterial.class,cascade=CascadeType.ALL)

@JoinColumn(name = "material\_id", referencedColumnName = "id")

private NDEMaterial material;

import cn.videon.diconde.common.constant.GeneralConstants;

import lombok.AllArgsConstructor;

import lombok.Data;

import lombok.NoArgsConstructor;

import javax.persistence.Column;

import javax.persistence.Entity;

import javax.persistence.Table;

/\*\*

\* @Author : ZhenYang

\* @Despriction : 几何结构

\* @Date: Created in 2018/6/25 14:05

\* @Modify By:

\*/

//@Entity

//@Table(name = "geometry", schema = GeneralConstants.ledgerSchema)

@Data

@NoArgsConstructor

@AllArgsConstructor

public class NDEGeometry\{

//直径

private Double diameter;

//厚度

private Double thickness;

//曲率类型

// @Column(name = "curvature\_type")

private String curvatureType;

//形状概述

// @Column(name = "shape\_desc")

private String shapeDesc;

我拿出来一个相对典型的实体来看看

1.  使用@TypeDefs声明JsonBType并指定具体的model。
2.  NDEGeometry字段使用@Column和 @Type指定自己的类型。
3.  相关的sql操作就自行搜索吧，具体的操作也有一些坑，要多查查。

# #

6.list在实体类中的应用

@Convert(converter = ListString2JsonConverter.class)

private List<String> cite;

这里使用了@Convert来转化list，配合上面自定义的ListString2JsonConverter，就可以用了，至于为什么，暂时还不知道，网上查的。

# #

7.一些SQL操作

刚才说自行搜索是因为这个项目里没写这些，但想了想还是找一下吧，当做记录了，随便找来一个充个数。

public interface BookRepository extends JpaRepository<BookEntity, UUID> \{

@Query("SELECT DISTINCT b.publisher FROM BookEntity b WHERE UPPER(b.publisher) LIKE UPPER(CONCAT('%', ?1, '%'))")

List<String> findDistinctPublisher(String publisher);

@Query(value = "SELECT \* FROM example\_jsonb.books b WHERE b.author->>'firstName' ILIKE CONCAT('%', ?1, '%')", nativeQuery = true)

List<BookEntity> findByAuthorFirstName(String firstName);

@Query(value = "SELECT \* FROM example\_jsonb.books b WHERE b.author->>'lastName' ILIKE CONCAT('%', ?1, '%')", nativeQuery = true)

List<BookEntity> findByAuthorLastName(String lastName);

@Query(value = "SELECT \* FROM example\_jsonb.books b WHERE b.author->>'firstName' ILIKE CONCAT('%', ?1, '%') AND b.author->>'lastName' ILIKE CONCAT('%', ?2, '%')", nativeQuery = true)

List<BookEntity> findByAuthorFirstNameAndLastName(String firstName,

String lastName);

以上这个是针对jsonb的查询操作，和mysql是很不一样的，所以要使用@Query，也不清楚有没有更方便的方法，至少是能用。

之前也试过查询数据库中定义的枚举，但失败了，一直也没再试试。

[SQL-2_SQL-92 _ SQL-3_SQL-99]: https://baike.baidu.com/item/PostgreSQL/530240?fr=aladdin