注意，实现方式一 与 实现方式二 会存在冲突，所以需要选择一种实现方式，推荐使用实现方式一。
@Getter
@Setter
@Entity
@Table(name = "t_project")
@EntityListeners(value = AuditingEntityListener.class)
public class Project implements PersistentAttributeInterceptable {
@Id
private String id = String.valueOf(System.currentTimeMillis());
/**
* 名称
*/
@Column(nullable = false, length = 100)
private String name;
/**
* json 字符串存储字段
*/
@Lob
// @Lazy
@Basic(fetch = FetchType.LAZY) // FetchType.LAZY 似乎未生效
@Column(name = "config_json")
private JSONObject configJson; // jpa默认生成字段类型为错误的oid，正确应是text
/**
* 文本 or json字符串存储字段
*/
@Lob
@Basic(fetch = FetchType.LAZY)
@Column(name = "config_text")
private String configText; // jpa默认生成正确的字段类型为text
/**
* 创建时间
*/
@Column(name = "create_time", nullable = false)
@CreatedDate
private LocalDateTime createTime;
/**
* 最后一次修改时间
*/
@Column(name = "last_modified_date")
@LastModifiedDate
private LocalDateTime lastModifiedDate;
// 以下是实现懒加载
@Transient
private PersistentAttributeInterceptor interceptor;
@Override
public PersistentAttributeInterceptor $$_hibernate_getInterceptor() {
return interceptor;
}
@Override
public void $$_hibernate_setInterceptor(PersistentAttributeInterceptor interceptor) {
this.interceptor = interceptor;
}
// 需手动添加懒加载字段的 getXXX()方法
public Object getConfigJson() {
if (this.configJson != null) {
return this.configJson;
}
return interceptor.readObject(this, "configJson", this.configJson);
}
public Object getConfigText() {
// 避免二次读取数据库
if (this.configText != null) {
return this.configText;
}
return interceptor.readObject(this, "configText", this.configText);
}
public void setConfigJson(JSONObject configJson) {
if (configJson != null) {
interceptor.writeObject(this, "configJson", this.configJson, configJson);
}
this.configJson = configJson;
}
public void setConfigText(String configText) {
if (configText != null) {
interceptor.writeObject(this, "configText", this.configText, configText);
}
this.configText = configText;
}
}测试
@Transactional
public Project queryById() {
String id = "1719883977407";
Optional<Project> optional = repo.findById(id);
Project entity = optional.get();
System.out.println(entity.getName());
//懒加载字段
System.out.println(entity.getConfigJson());
System.out.println(entity.getConfigText());
return entity;
}可能需要频繁编译maven项目，才会用生效
pom.xml文件
<build>
<plugins>
<plugin>
<groupId>org.hibernate.orm.tooling</groupId>
<artifactId>hibernate-enhance-maven-plugin</artifactId>
<version>${hibernate.version}</version>
<executions>
<execution>
<configuration>
<!--启用简单字段的延迟加载-->
<enableLazyInitialization>true</enableLazyInitialization>
</configuration>
<goals>
<goal>enhance</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>配置文件（可选地，有些版本不需要配置）：
spring:
jpa:
properties:
hibernate:
enable_lazy_load_no_trans: true # 可选地
# open-in-view: true # 默认false，可选地，若出现懒加载异常可打开实体字段：
@Getter
@Setter
@Entity
@Table(name = "t_project")
@EntityListeners(value = AuditingEntityListener.class)
public class Project {
@Id
private String id = String.valueOf(System.currentTimeMillis());
/**
* 名称
*/
@Column(nullable = false, length = 100)
private String name;
/**
* json 字符串存储字段
*/
@Lob
// @Lazy // 未生效
@Basic(fetch = FetchType.LAZY)
@Column(name = "config_json")
private JSONObject configJson; // jpa默认生成字段类型为错误的oid，正确应是text
/**
* 文本 or json字符串存储字段
*/
@Lob
@Basic(fetch = FetchType.LAZY)
@Column(name = "config_text")
private String configText; // jpa默认生成正确的字段类型为text
/**
* 创建时间
*/
@Column(name = "create_time", nullable = false)
@CreatedDate
private LocalDateTime createTime;
}测试
@Test
public void findAllPage_test() {
int page = 0;
int size = 2;
Sort sort = Sort.by(Sort.Direction.DESC, "createTime");
// 查询条件
Project request = new Project();
request.setName("名称-1");
Specification<Project> spec = buildQuery(request);
Page<Project> pageEntity = repo.findAll(spec, PageRequest.of(page, size, sort)); // 支持懒加载
List<Project> projectList = pageEntity.getContent();
projectList.forEach(project -> {
System.out.println(project.getId());
System.out.println(project.getName());
System.out.println(project.getCreateTime());
System.out.println(project.getLastModifiedDate());
System.out.println("-------------特殊字段-------------");
System.out.println(project.getConfigJson());
System.out.println(project.getConfigText());
System.out.println("--------------------------");
});
}
private Specification<Project> buildQuery(Project request) {
// 构建查询条件
return (root, query, cb) -> {
List<Predicate> predicates = new ArrayList<>();
// 关键词
if (!StringUtils.isEmpty(request.getName())) {
predicates.add(cb.like(root.get("name"), request.getName() + "%"));
}
// 将条件连接在一起
return query.where(predicates.toArray(new Predicate[0])).getRestriction();
};
}测试结果：
Hibernate: select project0_.id as id1_0_, project0_.create_time as create_t4_0_, project0_.cycle as cycle5_0_, project0_.internal as internal6_0_, project0_.last_modified_date as last_mod7_0_, project0_.name as name8_0_, project0_.remarks as remarks9_0_, project0_.sort as sort10_0_, project0_.state as state11_0_ from t_project project0_ where project0_.name like ? order by project0_.create_time desc limit ?
1719883977407
名称-1
2024-07-02T09:32:57.781
2024-07-02T09:32:57.781
-------------特殊字段-------------
Hibernate: select project_.config_json as config_j2_0_, project_.config_text as config_t3_0_ from t_project project_ where project_.id=?
{"key":"value"}
大文本字段
--------------------------
会再次查询懒加载字段。
测试：
System.out.println("-------------特殊字段-------------");
// System.out.println(project.getConfigJson());
// System.out.println(project.getConfigText());
System.out.println("--------------------------");
测试结果：
Hibernate: select project0_.id as id1_0_, project0_.create_time as create_t4_0_, project0_.cycle as cycle5_0_, project0_.internal as internal6_0_, project0_.last_modified_date as last_mod7_0_, project0_.name as name8_0_, project0_.remarks as remarks9_0_, project0_.sort as sort10_0_, project0_.state as state11_0_ from t_project project0_ where project0_.name like ? order by project0_.create_time desc limit ?
1719883977407
名称-1
2024-07-02T09:32:57.781
2024-07-02T09:32:57.781
-------------特殊字段-------------
--------------------------