mysql - Spring : (MVC) java heap space -> lazy loading not working

Question

(首先..对不起我的英语..)

所以我一直在致力于一个spring roo项目..我正在从一个大约有 30 个表的 mysql 数据库进行逆向工程。问题是它向我抛出“java.lang.OutOfMemoryError:Java堆空间”错误因为延迟加载不起作用，正如我在调试日志记录中看到的那样

表中的行数并不多。我的意思是我的表中没有一个表的行数超过 15 行。

我已经尝试添加

@OneToMany(mappedBy = "unidadId", fetch = FetchType.LAZY)
private Set<Area> areas;
@Fetch(FetchMode.SELECT)

public Set<com.springroo.gqr.dominio.Area> getAreas() {
    return areas;
}

@ManyToOne (fetch = FetchType.LAZY) //which does exactly the oposite: EAGER :S and it makes it even slooooooower..
@JoinColumn(name = "unidad_id", referencedColumnName = "id", nullable = false)
private Unidad unidadId;

所以我把它改为

@ManyToOne (optional=false)
@JoinColumn(name = "unidad_id", referencedColumnName = "id", nullable = false)
private Unidad unidadId;

我也尝试过

@LazyCollection(LazyCollectionOption.EXTRA)

还有

@LazyCollection(LazyCollectionOption.TRUE)

我尝试通过将默认惰性设置为 true 来更改我的持久性文件 - ..但是..什么也没有:(

看起来无论我做什么， hibernate 都不会更改为延迟加载所以我想知道我必须在哪里设置延迟加载，或者我错过了什么..

谁能帮我..？

这是我的 ROO 脚本

project --topLevelPackage com.springroo.GQR
jpa setup --provider HIBERNATE --database MYSQL --databaseName bd_gqr --userName root --password ******
database reverse engineer --schema bd_gqr --package ~.dominio
web mvc setup
web flow 
web mvc all --package ~.web
web mvc language --code es
security setup
perform tests
perform eclipse

这些是我的类(class):公开课区{

@ManyToOne(optional = false)
@JoinColumn(name = "unidad_id", referencedColumnName = "id", nullable = false)
private Unidad unidadId;

@OneToMany(mappedBy = "areaId", fetch = FetchType.LAZY)
@Fetch(FetchMode.SELECT)
private Set<Empleado> empleadoes;

@OneToMany(mappedBy = "areaId", fetch = FetchType.LAZY)
@Fetch(FetchMode.SELECT)
private Set<Queja> quejas;


@Column(name = "nombre", length = 45, unique = true)
@NotNull
private String nombre;

public String getNombre() {
    return nombre;
}

public void setNombre(String nombre) {
    this.nombre = nombre;
}
public Unidad AgetUnidadId() {
    return unidadId;
}

public void setUnidadId(Unidad unidadId) {
    this.unidadId = unidadId;
}

public Set<com.springroo.gqr.dominio.Empleado> getEmpleadoes() {
    return empleadoes;
}

public void setEmpleadoes(Set<com.springroo.gqr.dominio.Empleado> empleadoes) {
    this.empleadoes = empleadoes;
}

public Set<com.springroo.gqr.dominio.Queja> getQuejas() {
    return quejas;
}

public void setQuejas(Set<com.springroo.gqr.dominio.Queja> quejas) {
    this.quejas = quejas;
}

}

public class Unidad {

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "id")
private Integer id;

public Integer getId() {
    return this.id;
}

public void setId(Integer id) {
    this.id = id;
}

@OneToMany(mappedBy = "unidadId", fetch = FetchType.LAZY)
private Set<Area> areas;

@Fetch(FetchMode.SELECT)
public Set<com.springroo.gqr.dominio.Area> getAreas() {
    return areas;
}

public void setAreas(Set<com.springroo.gqr.dominio.Area> areas) {
    this.areas = areas;
}
}

这些是我的表定义:

 <table name="area">
    <column name="id" primaryKey="true" required="true" scale="0" size="10" type="4,INT"/>
    <column name="unidad_id" primaryKey="false" required="true" scale="0" size="10" type="4,INT"/>
    <column name="nombre" primaryKey="false" required="true" scale="0" size="45" type="12,VARCHAR"/>
    <foreign-key foreignTable="unidad" name="fk_area_unidad1" onDelete="cascade" onUpdate="cascade">
        <option key="exported" value="false"/>
        <reference foreign="id" local="unidad_id"/>
    </foreign-key>
    <foreign-key foreignTable="empleado" name="fk_empleado_area1" onDelete="cascade" onUpdate="cascade">
        <option key="exported" value="true"/>
        <reference foreign="area_id" local="id"/>
    </foreign-key>
    <foreign-key foreignTable="queja" name="fk_quejas_areas1" onDelete="cascade" onUpdate="cascade">
        <option key="exported" value="true"/>
        <reference foreign="area_id" local="id"/>
    </foreign-key>
    <unique name="PRIMARY">
        <unique-column name="id"/>
    </unique>
    <unique name="nombre_UNIQUE">
        <unique-column name="nombre"/>
    </unique>
    <index name="fk_area_unidad1">
        <index-column name="unidad_id"/>
    </index>
</table>


    <table name="unidad">
    <column name="id" primaryKey="true" required="true" scale="0" size="10" type="4,INT"/>
    <column name="clues" primaryKey="false" required="true" scale="0" size="25" type="12,VARCHAR"/>
    <column name="nombre" primaryKey="false" required="true" scale="0" size="100" type="12,VARCHAR"/>
    <foreign-key foreignTable="area" name="fk_area_unidad1" onDelete="cascade" onUpdate="cascade">
        <option key="exported" value="true"/>
        <reference foreign="unidad_id" local="id"/>
    </foreign-key>
    <unique name="PRIMARY">
        <unique-column name="id"/>
    </unique>
    <unique name="nombre_UNIQUE">
        <unique-column name="nombre"/>
    </unique>
    <unique name="clues_UNIQUE">
        <unique-column name="clues"/>
    </unique>
</table>

部分调试日志记录:

Hibernate: select quejas0_.area_id as area3_4_2_, quejas0_.id as id2_, quejas0_.id as id18_1_, quejas0_.area_id as area3_18_1_, quejas0_.folio as folio18_1_, quejas0_.medio_id as medio4_18_1_, quejas0_.tramite_id as tramite5_18_1_, medioqueja1_.id as id13_0_, medioqueja1_.medio as medio13_0_ from queja quejas0_ inner join medio_queja medioqueja1_ on quejas0_.medio_id=medioqueja1_.id where quejas0_.area_id=?

所以问题是..在哪里以及如何告诉 roo/hibernate 不要加载不必要的表

Answer 1

我也有问题。我有 1 个表仅使用 MySQL。数据包含 500k 行。

使用 Spring Roo，按照教程运行所有脚本来设置逆向工程和所有内容。当服务器运行时。转到localhost:8080，它运行正常。但是点击List All，java堆空间!