JPA自动BigDecimal转换 [英] JPA automatic BigDecimal conversion

问题描述

我们正在使用MyEclipse生成jpa访问层.之后，我们将生成模型和数据层访问服务.对于某些领域，我们在定义精度时遇到了一些问题.

We are generating our jpa access layers with MyEclipse. Afterwards we have the generated models and data layer access services. We ran into some problems for some fields with a defined precision.

实体:

@Entity
public class TestEntity{
   @Column(name="DECTEST", scale = 3, precision = 13)
   BigDecimal decTest;

}

现在，我们创建一个bean并尝试保存它:

Now we create a bean and try to save it:

TestEntity te = new TestEntity();
te.setDecTest(new BigDecimal(1.2));

TestEntityService.save(te);

我们收到以下错误: 引起原因:com.ibm.db2.jcc.c.SqlException:[ibm] [db2] [jcc] [t4] [1037] [11190]在BigDecimal转换期间发生了异常.有关详细信息，请参见随附的Throwable.

We get the following error: Caused by: com.ibm.db2.jcc.c.SqlException: [ibm][db2][jcc][t4][1037][11190] Exception occurred during BigDecimal conversion. See attached Throwable for details.

Caused by: com.ibm.db2.jcc.a.a: [ibm][db2][jcc][converters][608][10994] Overflow occurred during numeric data type conversion of "1.1999999999999999555910790149937383830547332763671875".
at com.ibm.db2.jcc.a.e.a(e.java:61)
at com.ibm.db2.jcc.b.jb.a(jb.java:1772)
... 73 more

问题似乎是我们的BigDecimals比例比数据库中的比例高.

The problem seems to be that our BigDecimals scale is higher then the one from the database.

一种可行的解决方法是:

A working workaround is:

TestEntity te = new TestEntity();

BigDecimal decTest = new BigDecimal(1.2);

te.setDecTest(decTest.setScale(3,RoundingMode.HALF_UP);

TestEntityService.save(te);

通过这种解决方法，我们将BigDecimals精度手动降低为数据库之一.

With this workaround we reduce the BigDecimals precicsion manually to the one of the database.

但是，如果数据模型发生更改，我们将不得不手动调整比例.有没有办法让我们的jpa/hibernate实现为我们自动进行转换?例如.与设置属性.无论如何，在一个正在创建bean的位置执行该操作将是错误的操作.

However if the data model changes we would have to adjust the scale there manually. Is there a way to get our jpa / hibernate implementation to do that conversion for us automatically? E.g. with setting a property. Doing it at the spot where one is creating the bean would be the wrong spot to do it anyways.

推荐答案

您可以使用自定义用户类型，也可以像这样简单地实现属性的setter:

You could use a custom user type, or you could simply implement the setter of the property like this:

public void setDecTest(BigDecimal decTest) {
    this.decTest = decTest.setScale(3, RoundingMode.HALF_UP));
}

因此，此舍入将封装在实体中.

This rounding would thus be encapsulated in the entity.

请注意，使用双精度型初始化BigDecimal有点奇怪.如果要将1.2存储在BigDecimal中，请使用new BigDecimal("1.2")，并且不会使用1.1999999999999999555910790149937383830547332763671875初始化BigDecimal.

Note that using a double to initialize a BigDecimal is a bit strange. If you want 1.2 to be stored in the BigDecimal, use new BigDecimal("1.2"), and you won't have a BigDecimal initialized with 1.1999999999999999555910790149937383830547332763671875.

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