为什么保存之后找不到ppt了呢(保存的ppt找不到)
821
2022-05-30
SAX解析XML采用的是从上而下的基于事件驱动的解析方式,在解析过程中会视情况自动调用startDocument()、startElement()、characters()、endElement()、endDocument()等相关的方法。
由编译执行的结果来看:
startDocument()方法只会在文档开始解析的时候被调用,每次解析只会调用一次。
startElement()方法每次在开始解析一个元素,即遇到元素标签开始的时候都会调用。
characters()方法也是在每次解析到元素标签携带的内容时都会调用,即使该元素标签的内容为空或换行。而且如果元素内嵌套元素,在父元素结束标签前, characters()方法会再次被调用,此处需要注意。
endElement()方法每次在结束解析一个元素,即遇到元素标签结束的时候都会调用。
endDocument() startDocument()方法只会在文档解析结束的时候被调用,每次解析只会调用一次。
oracle官方解析教程 http://docs.oracle.com/javase/tutorial/jaxp/sax/parsing.html
package com.demo.test; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import javax.xml.parsers.ParserConfigurationException; import javax.xml.parsers.SAXParser; import javax.xml.parsers.SAXParserFactory; import javax.xml.transform.OutputKeys; import javax.xml.transform.Result; import javax.xml.transform.Transformer; import javax.xml.transform.TransformerConfigurationException; import javax.xml.transform.sax.SAXTransformerFactory; import javax.xml.transform.sax.TransformerHandler; import javax.xml.transform.stream.StreamResult; import org.xml.sax.Attributes; import org.xml.sax.InputSource; import org.xml.sax.SAXException; import org.xml.sax.helpers.AttributesImpl; import org.xml.sax.helpers.DefaultHandler; public class XmlDemo { private static class SAXHandler extends DefaultHandler { @Override public void startDocument() throws SAXException { System.out.println("startDocument"); } @Override public void endDocument() throws SAXException { System.out.println("endDocument"); } @Override public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException { System.out.println("startElement, uri=" + uri + ", localName=" + localName + ", qName=" + qName + ", attributes.getLength()=" + attributes.getLength()); if (attributes.getLength() > 0) { for (int i = 0; i < attributes.getLength(); i++) { System.out.println("startElement attributes(" + i + "): " + attributes.getQName(i) + "=" + attributes.getValue(i)); } } } @Override public void endElement(String uri, String localName, String qName) throws SAXException { System.out.println("endElement, uri=" + uri + ", localName=" + localName + ", qName=" + qName); } @Override public void characters(char[] ch, int start, int length) throws SAXException { System.out.println("characters, start=" + start + ", length=" + length + ", ch=" + new String(ch, start, length)); } } private static void parseXml(String xmlPath) { SAXParserFactory saxParserFactory = SAXParserFactory.newInstance(); FileInputStream fis = null; try { fis = new FileInputStream(xmlPath); InputSource is = new InputSource(fis); // SAX会自动从流中检测正确的字符编码,但是如果流中没有明确指定编码,可能会导致转换错误 is.setEncoding("UTF-8"); SAXParser saxParser = saxParserFactory.newSAXParser(); saxParser.parse(is, new SAXHandler()); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (ParserConfigurationException e) { e.printStackTrace(); } catch (SAXException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } finally { if (fis != null) { try { fis.close(); } catch (IOException e) { e.printStackTrace(); } } } } private static void generateXml(String filePath) { SAXTransformerFactory saxTransformerFactory = (SAXTransformerFactory) SAXTransformerFactory.newInstance(); FileOutputStream fos = null; try { TransformerHandler transformerHandler = saxTransformerFactory.newTransformerHandler(); Transformer transformer = transformerHandler.getTransformer(); transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8"); // 如果是yes,那么会自动换行但不会缩进;如果是no,则不会换行。默认是no // transformer.setOutputProperty(OutputKeys.INDENT, "no"); //不省略的话,会自动添加。默认是no transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "no"); fos = new FileOutputStream(filePath); Result result = new StreamResult(fos); transformerHandler.setResult(result); transformerHandler.startDocument(); AttributesImpl attr = new AttributesImpl(); attr.addAttribute(null, null, "class", String.class.getName(), "value"); startElement(transformerHandler, "html", null); startElement(transformerHandler, "head", null); endElement(transformerHandler, "head"); startElement(transformerHandler, "body", null); selfEndElement(transformerHandler, "p", attr, "characters"); endElement(transformerHandler, "body"); endElement(transformerHandler, "html"); transformerHandler.endDocument(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (TransformerConfigurationException e) { e.printStackTrace(); } catch (SAXException e) { e.printStackTrace(); } finally { if (fos != null) { try { fos.close(); } catch (IOException e) { e.printStackTrace(); } } } } // SAX默认不自动缩进,因此需要手动根据元素层次进行缩进控制 private static int indent = 0; private static String uri = "http://www.chy.uri"; private static String localname = "localname"; // private static String uri = null; // private static String localname = null; private static void startElement(TransformerHandler transformerHandler, String qName, Attributes atts) throws SAXException { System.out.println("startElement " + qName); indent++; addTabs(transformerHandler); transformerHandler.startElement(uri, localname, qName, atts); } private static void endElement(TransformerHandler transformerHandler, String qName) throws SAXException { System.out.println("endElement " + qName); addTabs(transformerHandler); indent--; transformerHandler.endElement(uri, localname, qName); } /** * 自封闭式标签 */ private static void selfEndElement(TransformerHandler transformerHandler, String qName, Attributes atts, String str) throws SAXException { System.out.println("endElement " + qName); indent++; addTabs(transformerHandler); indent--; transformerHandler.startElement(uri, localname, qName, atts); if (str != null) { char[] charArr = str.toCharArray(); transformerHandler.characters(charArr, 0, charArr.length); } transformerHandler.endElement(uri, localname, qName); } /** * SAX不会添加缩进,要自己添加 */ private static void addTabs(TransformerHandler transformerHandler) throws SAXException { System.out.println("addTabs " + indent); char[] ch = new char[indent]; ch[0] = '\n'; if (indent > 1) { for (int i = 1; i < ch.length; i++) { ch[i] = '\t'; } } transformerHandler.characters(ch, 0, ch.length); } public static void main(String[] args) { String xmlPath = "test.xml"; parseXml(xmlPath); generateXml("test.xml"); } }
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
179
180
181
182
183
184
185
186
187
188
189
生成的XML如下
characters
1
2
3
4
5
6
7
8
这里如果uri变量设置为空,会自动生成一个无结束标签的META标签,并且indent设置为no也无效,还是会自动换行
characters
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
右击项目 –> Properties(Alt + Enter)–> Java Build Path –> Libraries –> 双击JRE System Library
注意:这里如果选择OSGi/Minimum-1.2是找不到”javax.xml.“或”org.xml.sax.”的相关包的。最低版本必须是J2SE-1.5。
Java XML
版权声明:本文内容由网络用户投稿,版权归原作者所有,本站不拥有其著作权,亦不承担相应法律责任。如果您发现本站中有涉嫌抄袭或描述失实的内容,请联系我们jiasou666@gmail.com 处理,核实后本网站将在24小时内删除侵权内容。