1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178
|
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import java.io.OutputStreamWriter;
import javax.xml.namespace.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import javax.xml.xpath.*;
import org.xml.sax.*;
import org.w3c.dom.*;
/**
* JAXP 1.3 XPath API sample.
*
* Basic utility for applying an XPath expression to an input xml file and printing
* the evaluation result, using JAXP 1.3 XPath API.
*
* Takes 3 arguments:
* (1) an xml file name
* (2) an XPath expression to apply to the input document
* (3) the return type, which is one of the following Strings:
* num, bool, str, node, nodeset
*
* Examples:
* java ApplyXPathJAXP foo.xml /doc/name[1]/@last str
* java ApplyXPathJAXP foo.xml /doc/name nodeset
*/
public class ApplyXPathJAXP
{
public static void main(String[] args)
{
QName returnType = null;
if (args.length != 3)
{
System.err.println("Usage: java ApplyXPathAPI xml_file xpath_expression type");
}
InputSource xml = new InputSource(args[0]);
String expr = args[1];
// set the return type
if (args[2].equals("num")) returnType = XPathConstants.NUMBER;
else if (args[2].equals("bool")) returnType = XPathConstants.BOOLEAN;
else if (args[2].equals("str")) returnType = XPathConstants.STRING;
else if (args[2].equals("node")) returnType = XPathConstants.NODE;
else if (args[2].equals("nodeset")) returnType = XPathConstants.NODESET;
else
System.err.println("Invalid return type: " + args[2]);
// Create a new XPath
XPathFactory factory = XPathFactory.newInstance();
XPath xpath = factory.newXPath();
Object result = null;
try {
// compile the XPath expression
XPathExpression xpathExpr = xpath.compile(expr);
// Evaluate the XPath expression against the input document
result = xpathExpr.evaluate(xml, returnType);
// Print the result to System.out.
printResult(result);
}
catch (Exception e) {
e.printStackTrace();
}
}
/**
* Print the type and value of the evaluation result.
*/
static void printResult(Object result)
throws Exception
{
if (result instanceof Double) {
System.out.println("Result type: double");
System.out.println("Value: " + result);
}
else if (result instanceof Boolean) {
System.out.println("Result type: boolean");
System.out.println("Value: " + ((Boolean)result).booleanValue());
}
else if (result instanceof String) {
System.out.println("Result type: String");
System.out.println("Value: " + result);
}
else if (result instanceof Node) {
Node node = (Node)result;
System.out.println("Result type: Node");
System.out.println("<output>");
printNode(node);
System.out.println("</output>");
}
else if (result instanceof NodeList) {
NodeList nodelist = (NodeList)result;
System.out.println("Result type: NodeList");
System.out.println("<output>");
printNodeList(nodelist);
System.out.println("</output>");
}
}
/** Decide if the node is text, and so must be handled specially */
static boolean isTextNode(Node n)
{
if (n == null)
return false;
short nodeType = n.getNodeType();
return nodeType == Node.CDATA_SECTION_NODE || nodeType == Node.TEXT_NODE;
}
static void printNode(Node node)
throws Exception
{
if (isTextNode(node)) {
System.out.println(node.getNodeValue());
}
else {
// Set up an identity transformer to use as serializer.
Transformer serializer = TransformerFactory.newInstance().newTransformer();
serializer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
serializer.transform(new DOMSource(node), new StreamResult(new OutputStreamWriter(System.out)));
}
}
static void printNodeList(NodeList nodelist)
throws Exception
{
Node n;
// Set up an identity transformer to use as serializer.
Transformer serializer = TransformerFactory.newInstance().newTransformer();
serializer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
for (int i = 0; i < nodelist.getLength(); i++)
{
n = nodelist.item(i);
if (isTextNode(n)) {
// DOM may have more than one node corresponding to a
// single XPath text node. Coalesce all contiguous text nodes
// at this level
StringBuffer sb = new StringBuffer(n.getNodeValue());
for (
Node nn = n.getNextSibling();
isTextNode(nn);
nn = nn.getNextSibling()
) {
sb.append(nn.getNodeValue());
}
System.out.print(sb);
}
else {
serializer.transform(new DOMSource(n), new StreamResult(new OutputStreamWriter(System.out)));
}
System.out.println();
}
}
}
|