groovy“ with”块用法查询

Question

I am trying to use the with block in Groovy to easily initalize my class, but I am getting the following error. Could anyone tell me what I am doing wrong?

MyXMLTemplate template = new MyXMLTemplate ().with {
    TxId = 'mnop'
    oapTxId = 'abcd'
}

The error I get is:

org.codehaus.groovy.runtime.typehandling.GroovyCastException: Cannot cast object 'abcd' with class 'java.lang.String' to class 'org.example.MyXMLTemplate'
at org.codehaus.groovy.runtime.typehandling.DefaultTypeTransformation.castToType(DefaultTypeTransformation.java:331)
at org.codehaus.groovy.runtime.ScriptBytecodeAdapter.castToType(ScriptBytecodeAdapter.java:599)

I am using groovy 1.8.0

Answer 1

You need to return the template itself from the with block:

MyXMLTemplate template = new MyXMLTemplate ().with {
    TxId = 'mnop'
    oapTxId = 'abcd'
    it
}

Answer 2

It's hard to see what the problem is without seeing the definition of your class. I'll assume that TxId and oapTxId are both properties of the class.

I suspect your error is caused by oapTxId being of type MyXMLTemplate , and so not assignable from String.

Incidetally, as your with block is just initializing class properties, you could use the more idiomatic constructor and setters approach:

MyXmlTemplate template = new MyXMLTemplate(TxId: 'mnop', oapTxId : 'abcd')