This error is a bit misleading. What it is trying to tell you is that your jdbc driver does not know how to set one of your columns to null. In the following section I will show you what causes this error and how to correct it.
First lets start with a simple POJO (Plain Old Java Object).
import java.util.Date;
public class Address {
private String line1;
private String line2;
private String city;
private String state;
private String postalCode;
private Date purchaseDate;
private Date soldDate;
... Standard mutators (getters setters) ...
}
Here is the example table that we will be using.
Address {
line1 varchar2(100),
line2 varchar2(100),
city varchar2(100),
state varchar2(100),
postal_code varchar2(25),
purchase_date date,
sold_date date
}
With this in place we can create the sqlmaps to work with it. With this error only your insert and update statements will be of concern. I will use an insert both the solution works for both.
<typeAlias alias="Address" type="com.abc.domain.Address"/>
<insert id="insertAddress" parameterClass="Address">
INSERT INTO
ADDRESS (
line1,
line2,
city,
state,
postal_code,
purchase_date,
sold_date
)
values (
#line1#,
#line2#,
#city#,
#state#,
#postal_code#,
#purchase_date#,
#sold_date#
)
</insert>
So far everything looks good and will work part of the time. In the following example the classic invalid column type error will be thrown.
Address address = new Address();
address.setLine1("123 Anywhere Street");
address.setCity("Somewhere over the Rainbow");
address.setState("Never never land");
address.setPostalCode("01234");
address.setPurcahseDate(purcahseDate);
Notice in the code above that I leave the line2 and soldDate properties as null. This is where the problem creeps in. When the insert sqlmap come to the line2 column it will throw an error. There are two solutions for this problem.
The first is to use dynamic conditions.
<typeAlias alias="Address" type="com.abc.domain.Address"/>
<insert id="insertAddress" parameterClass="Address">
INSERT INTO
ADDRESS (
line1,
line2,
city,
state,
postal_code,
purchase_date,
sold_date
)
values (
#line1#,
<isNull property="line2">
null,
</isNull>
<isNotNull property="line2">
#line2#,
</isNotNull>
#city#,
#state#,
#postal_code#,
#purchase_date#,
#sold_date#
)
</insert>
As you can see this can become a time consuming process to make sure that every column that can be null has these tags. A second and cleaner option is to define what the jdbc type is.
<typeAlias alias="Address" type="com.abc.domain.Address"/>
<insert id="insertAddress" parameterClass="Address">
INSERT INTO
ADDRESS (
line1,
line2,
city,
state,
postal_code,
purchase_date,
sold_date
)
values (
#line1#,
#line2:VARCHAR#,
#city#,
#state#,
#postal_code#,
#purchase_date#,
#sold_date:DATE#
)
</insert>
Just do this only any column that can be null! Now you may be asking yourself what are the valid jdbc types. Look no further they are posted in the Java API documents java.sql.Types.
主要原因是沒有對inline參數制定類型。