使用Java从XML文件读取功能值

Question

I have 2 XML file . In one XML file is the form which contains x and y coordinate values . In second XML file contains all the functioning/operation related to first XML which gives an output as an graph image .

I need to know how can I read the function XML file specially for functioning in java program on button click ? I know to parse , but just normal parsing will work for the operation. What libraries do I have to pass for this ?

The functioning part is already there in XML . I just need to call it to show output.

part of form XML which will be used to save x and y coordinate:-

<cont format="%9.2f" hotlink="true" name="cont_2" refvar="gud/_ZSFR[29]" type="float" width="20" xpos="545" ypos="454">
            <PROPERTY min="0"/>
            <PROPERTY max="5000"/>
        </cont>

part of function xml file which will actually do operation of generating image by passing those form xml x and y values:-

<function name="string.length" return="filenamelength">file_name</function>
    <IF>
        <CONDITION>filenamelength>=1</CONDITION>
        <THEN>
            <op>new1content=new1content+_T"\\nR250="+_F%.3f"gud/_ZSFR[29]"</op>
            <op>new1content=new1content+_T"\\nR251="+_F%.3f"gud/_ZSFR[28]"</op>
<function name="doc.exist" return="mpf1ok">_T"\mpf\1.mpf" </function>

Answer 1

There are two kinds of Libraries in java for parsing XML files. Streaming based and Tree based. If you just need to parse XML (Not concerned with generating XML) you can use Streaming API's are memory efficient. Stax is recommended in your case.

Answer 2

It sounds like what you need is a combination of:

• javax.xml.parsers ...
• org.w3c.dom. ...

there is a good tutorial on extracting data from XML here at tutorialspoint their basic example shows the use of a method called Document.getElementByTagName(String tagName) which returns an Element object. depending on how specific your element is you can also check attributes using:

• Element.getAttribute(String attrName)
• Element.hasAttribute(String attrName)

this should allow you to pinpoint the tag that you need after which you can use the methods shown in the tutorial to extract the content of the tags.

Another simple XML tutorial in Java