/**
     * 读取xml文件的所有属性返回Properties对象
     * 这里用到了输入流
     */
    public void readFileToXML() {
        FileInputStream  fis =null;
        try {
            fis = new FileInputStream(MY_PROJECT_FILE_XML);
            Properties p=new Properties();
            p.loadFromXML(fis);
            System.out.println(p);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            try {
                if(fis!=null){
                    fis.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

<pre><code class="lang-">/** * 读取xml文件的所有属性返回Properties对象 * 这里用到了输入流 */ public void readFileToXML() { FileInputStream fis =null; try { fis = new FileInputStream(MY_PROJECT_FILE_XML); Properties p=new Properties(); p.loadFromXML(fis); System.out.println(p); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); }finally { try { if(fis!=null){ fis.close(); } } catch (IOException e) { e.printStackTrace(); } } } </code></pre> <h1><a id="_29"></a>报错</h1> <p>“C:\Program Files\Java\jdk1.8.0_131\bin\java.exe” “-javaagent:D:\Program Files\JetBrains\IntelliJ IDEA 2021.2.2\lib\idea_rt.jar=59042:D:\Program Files\JetBrains\IntelliJ IDEA 2021.2.2\bin” -Dfile.encoding=UTF-8 -classpath “C:\Program Files\Java\jdk1.8.0_131\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\rt.jar;D:\idea_workspace\java-basic\target\classes;D:\rep\org\springframework\boot\spring-boot-starter-web\2.7.0\spring-boot-starter-web-2.7.0.jar;D:\rep\org\springframework\boot\spring-boot-starter\2.7.0\spring-boot-starter-2.7.0.jar;D:\rep\org\springframework\boot\spring-boot\2.7.0\spring-boot-2.7.0.jar;D:\rep\org\springframework\boot\spring-boot-autoconfigure\2.7.0\spring-boot-autoconfigure-2.7.0.jar;D:\rep\org\springframework\boot\spring-boot-starter-logging\2.7.0\spring-boot-starter-logging-2.7.0.jar;D:\rep\ch\qos\logback\logback-classic\1.2.11\logback-classic-1.2.11.jar;D:\rep\ch\qos\logback\logback-core\1.2.11\logback-core-1.2.11.jar;D:\rep\org\apache\logging\log4j\log4j-to-slf4j\2.17.2\log4j-to-slf4j-2.17.2.jar;D:\rep\org\apache\logging\log4j\log4j-api\2.17.2\log4j-api-2.17.2.jar;D:\rep\org\slf4j\jul-to-slf4j\1.7.36\jul-to-slf4j-1.7.36.jar;D:\rep\jakarta\annotation\jakarta.annotation-api\1.3.5\jakarta.annotation-api-1.3.5.jar;D:\rep\org\yaml\snakeyaml\1.30\snakeyaml-1.30.jar;D:\rep\org\springframework\boot\spring-boot-starter-json\2.7.0\spring-boot-starter-json-2.7.0.jar;D:\rep\com\fasterxml\jackson\core\jackson-databind\2.13.3\jackson-databind-2.13.3.jar;D:\rep\com\fasterxml\jackson\core\jackson-annotations\2.13.3\jackson-annotations-2.13.3.jar;D:\rep\com\fasterxml\jackson\core\jackson-core\2.13.3\jackson-core-2.13.3.jar;D:\rep\com\fasterxml\jackson\datatype\jackson-datatype-jdk8\2.13.3\jackson-datatype-jdk8-2.13.3.jar;D:\rep\com\fasterxml\jackson\datatype\jackson-datatype-jsr310\2.13.3\jackson-datatype-jsr310-2.13.3.jar;D:\rep\com\fasterxml\jackson\module\jackson-module-parameter-names\2.13.3\jackson-module-parameter-names-2.13.3.jar;D:\rep\org\springframework\boot\spring-boot-starter-tomcat\2.7.0\spring-boot-starter-tomcat-2.7.0.jar;D:\rep\org\apache\tomcat\embed\tomcat-embed-core\9.0.63\tomcat-embed-core-9.0.63.jar;D:\rep\org\apache\tomcat\embed\tomcat-embed-el\9.0.63\tomcat-embed-el-9.0.63.jar;D:\rep\org\apache\tomcat\embed\tomcat-embed-websocket\9.0.63\tomcat-embed-websocket-9.0.63.jar;D:\rep\org\springframework\spring-web\5.3.20\spring-web-5.3.20.jar;D:\rep\org\springframework\spring-beans\5.3.20\spring-beans-5.3.20.jar;D:\rep\org\springframework\spring-webmvc\5.3.20\spring-webmvc-5.3.20.jar;D:\rep\org\springframework\spring-aop\5.3.20\spring-aop-5.3.20.jar;D:\rep\org\springframework\spring-context\5.3.20\spring-context-5.3.20.jar;D:\rep\org\springframework\spring-expression\5.3.20\spring-expression-5.3.20.jar;D:\rep\org\projectlombok\lombok\1.18.24\lombok-1.18.24.jar;D:\rep\org\slf4j\slf4j-api\1.7.36\slf4j-api-1.7.36.jar;D:\rep\org\springframework\spring-core\5.3.20\spring-core-5.3.20.jar;D:\rep\org\springframework\spring-jcl\5.3.20\spring-jcl-5.3.20.jar” com.basic.io.PropertiesDemo<br /> java.util.InvalidPropertiesFormatException: org.xml.sax.SAXParseException; lineNumber: 3; columnNumber: 164; 文档根元素 “project” 必须匹配 DOCTYPE 根 “null”。<br /> at sun.util.xml.PlatformXmlPropertiesProvider.load(PlatformXmlPropertiesProvider.java:80)<br /> at java.util.PropertiesXmlSupport.load(Properties.java:1201) at java.util.Properties.loadFromXML(Properties.java:881) at com.basic.io.PropertiesDemo.readFileToXML(PropertiesDemo.java:105) at com.basic.io.PropertiesDemo.main(PropertiesDemo.java:17) Caused by: org.xml.sax.SAXParseException; lineNumber: 3; columnNumber: 164; 文档根元素 "project" 必须匹配 DOCTYPE 根 "null"。 at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:203) at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.error(ErrorHandlerWrapper.java:134) at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:396) at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:327) at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:284) at com.sun.org.apache.xerces.internal.impl.dtd.XMLDTDValidator.rootElementSpecified(XMLDTDValidator.java:1599) at com.sun.org.apache.xerces.internal.impl.dtd.XMLDTDValidator.handleStartElement(XMLDTDValidator.java:1877) at com.sun.org.apache.xerces.internal.impl.dtd.XMLDTDValidator.startElement(XMLDTDValidator.java:742) at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanStartElement(XMLDocumentFragmentScannerImpl.java:1359) at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImplContentDriver.scanRootElementHook(XMLDocumentScannerImpl.java:1289)<br /> at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl<span class="katex"><span class="katex-mathml"><math><semantics><mrow><mi>F</mi><mi>r</mi><mi>a</mi><mi>g</mi><mi>m</mi><mi>e</mi><mi>n</mi><mi>t</mi><mi>C</mi><mi>o</mi><mi>n</mi><mi>t</mi><mi>e</mi><mi>n</mi><mi>t</mi><mi>D</mi><mi>r</mi><mi>i</mi><mi>v</mi><mi>e</mi><mi>r</mi><mi mathvariant="normal">.</mi><mi>n</mi><mi>e</mi><mi>x</mi><mi>t</mi><mo>(</mo><mi>X</mi><mi>M</mi><mi>L</mi><mi>D</mi><mi>o</mi><mi>c</mi><mi>u</mi><mi>m</mi><mi>e</mi><mi>n</mi><mi>t</mi><mi>F</mi><mi>r</mi><mi>a</mi><mi>g</mi><mi>m</mi><mi>e</mi><mi>n</mi><mi>t</mi><mi>S</mi><mi>c</mi><mi>a</mi><mi>n</mi><mi>n</mi><mi>e</mi><mi>r</mi><mi>I</mi><mi>m</mi><mi>p</mi><mi>l</mi><mi mathvariant="normal">.</mi><mi>j</mi><mi>a</mi><mi>v</mi><mi>a</mi><mo>:</mo><mn>3</mn><mn>1</mn><mn>3</mn><mn>2</mn><mo>)</mo><mi>a</mi><mi>t</mi><mi>c</mi><mi>o</mi><mi>m</mi><mi mathvariant="normal">.</mi><mi>s</mi><mi>u</mi><mi>n</mi><mi mathvariant="normal">.</mi><mi>o</mi><mi>r</mi><mi>g</mi><mi mathvariant="normal">.</mi><mi>a</mi><mi>p</mi><mi>a</mi><mi>c</mi><mi>h</mi><mi>e</mi><mi mathvariant="normal">.</mi><mi>x</mi><mi>e</mi><mi>r</mi><mi>c</mi><mi>e</mi><mi>s</mi><mi mathvariant="normal">.</mi><mi>i</mi><mi>n</mi><mi>t</mi><mi>e</mi><mi>r</mi><mi>n</mi><mi>a</mi><mi>l</mi><mi mathvariant="normal">.</mi><mi>i</mi><mi>m</mi><mi>p</mi><mi>l</mi><mi mathvariant="normal">.</mi><mi>X</mi><mi>M</mi><mi>L</mi><mi>D</mi><mi>o</mi><mi>c</mi><mi>u</mi><mi>m</mi><mi>e</mi><mi>n</mi><mi>t</mi><mi>S</mi><mi>c</mi><mi>a</mi><mi>n</mi><mi>n</mi><mi>e</mi><mi>r</mi><mi>I</mi><mi>m</mi><mi>p</mi><mi>l</mi></mrow><annotation encoding="application/x-tex">FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:3132) at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="strut" style="height:0.75em;"></span><span class="strut bottom" style="height:1em;vertical-align:-0.25em;"></span><span class="base"><span class="mord mathit" style="margin-right:0.13889em;">F</span><span class="mord mathit" style="margin-right:0.02778em;">r</span><span class="mord mathit">a</span><span class="mord mathit" style="margin-right:0.03588em;">g</span><span class="mord mathit">m</span><span class="mord mathit">e</span><span class="mord mathit">n</span><span class="mord mathit">t</span><span class="mord mathit" style="margin-right:0.07153em;">C</span><span class="mord mathit">o</span><span class="mord mathit">n</span><span class="mord mathit">t</span><span class="mord mathit">e</span><span class="mord mathit">n</span><span class="mord mathit">t</span><span class="mord mathit" style="margin-right:0.02778em;">D</span><span class="mord mathit" style="margin-right:0.02778em;">r</span><span class="mord mathit">i</span><span class="mord mathit" style="margin-right:0.03588em;">v</span><span class="mord mathit">e</span><span class="mord mathit" style="margin-right:0.02778em;">r</span><span class="mord mathrm">.</span><span class="mord mathit">n</span><span class="mord mathit">e</span><span class="mord mathit">x</span><span class="mord mathit">t</span><span class="mopen">(</span><span class="mord mathit" style="margin-right:0.07847em;">X</span><span class="mord mathit" style="margin-right:0.10903em;">M</span><span class="mord mathit">L</span><span class="mord mathit" style="margin-right:0.02778em;">D</span><span class="mord mathit">o</span><span class="mord mathit">c</span><span class="mord mathit">u</span><span class="mord mathit">m</span><span class="mord mathit">e</span><span class="mord mathit">n</span><span class="mord mathit">t</span><span class="mord mathit" style="margin-right:0.13889em;">F</span><span class="mord mathit" style="margin-right:0.02778em;">r</span><span class="mord mathit">a</span><span class="mord mathit" style="margin-right:0.03588em;">g</span><span class="mord mathit">m</span><span class="mord mathit">e</span><span class="mord mathit">n</span><span class="mord mathit">t</span><span class="mord mathit" style="margin-right:0.05764em;">S</span><span class="mord mathit">c</span><span class="mord mathit">a</span><span class="mord mathit">n</span><span class="mord mathit">n</span><span class="mord mathit">e</span><span class="mord mathit" style="margin-right:0.02778em;">r</span><span class="mord mathit" style="margin-right:0.07847em;">I</span><span class="mord mathit">m</span><span class="mord mathit">p</span><span class="mord mathit" style="margin-right:0.01968em;">l</span><span class="mord mathrm">.</span><span class="mord mathit" style="margin-right:0.05724em;">j</span><span class="mord mathit">a</span><span class="mord mathit" style="margin-right:0.03588em;">v</span><span class="mord mathit">a</span><span class="mrel">:</span><span class="mord mathrm">3</span><span class="mord mathrm">1</span><span class="mord mathrm">3</span><span class="mord mathrm">2</span><span class="mclose">)</span><span class="mord mathit">a</span><span class="mord mathit">t</span><span class="mord mathit">c</span><span class="mord mathit">o</span><span class="mord mathit">m</span><span class="mord mathrm">.</span><span class="mord mathit">s</span><span class="mord mathit">u</span><span class="mord mathit">n</span><span class="mord mathrm">.</span><span class="mord mathit">o</span><span class="mord mathit" style="margin-right:0.02778em;">r</span><span class="mord mathit" style="margin-right:0.03588em;">g</span><span class="mord mathrm">.</span><span class="mord mathit">a</span><span class="mord mathit">p</span><span class="mord mathit">a</span><span class="mord mathit">c</span><span class="mord mathit">h</span><span class="mord mathit">e</span><span class="mord mathrm">.</span><span class="mord mathit">x</span><span class="mord mathit">e</span><span class="mord mathit" style="margin-right:0.02778em;">r</span><span class="mord mathit">c</span><span class="mord mathit">e</span><span class="mord mathit">s</span><span class="mord mathrm">.</span><span class="mord mathit">i</span><span class="mord mathit">n</span><span class="mord mathit">t</span><span class="mord mathit">e</span><span class="mord mathit" style="margin-right:0.02778em;">r</span><span class="mord mathit">n</span><span class="mord mathit">a</span><span class="mord mathit" style="margin-right:0.01968em;">l</span><span class="mord mathrm">.</span><span class="mord mathit">i</span><span class="mord mathit">m</span><span class="mord mathit">p</span><span class="mord mathit" style="margin-right:0.01968em;">l</span><span class="mord mathrm">.</span><span class="mord mathit" style="margin-right:0.07847em;">X</span><span class="mord mathit" style="margin-right:0.10903em;">M</span><span class="mord mathit">L</span><span class="mord mathit" style="margin-right:0.02778em;">D</span><span class="mord mathit">o</span><span class="mord mathit">c</span><span class="mord mathit">u</span><span class="mord mathit">m</span><span class="mord mathit">e</span><span class="mord mathit">n</span><span class="mord mathit">t</span><span class="mord mathit" style="margin-right:0.05764em;">S</span><span class="mord mathit">c</span><span class="mord mathit">a</span><span class="mord mathit">n</span><span class="mord mathit">n</span><span class="mord mathit">e</span><span class="mord mathit" style="margin-right:0.02778em;">r</span><span class="mord mathit" style="margin-right:0.07847em;">I</span><span class="mord mathit">m</span><span class="mord mathit">p</span><span class="mord mathit" style="margin-right:0.01968em;">l</span></span></span></span>PrologDriver.next(XMLDocumentScannerImpl.java:852)<br /> at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:602)<br /> at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:505)<br /> at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:841)<br /> at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:770)<br /> at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:141)<br /> at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:243)<br /> at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:339)<br /> at sun.util.xml.PlatformXmlPropertiesProvider.getLoadingDoc(PlatformXmlPropertiesProvider.java:106)<br /> at sun.util.xml.PlatformXmlPropertiesProvider.load(PlatformXmlPropertiesProvider.java:78)<br /> … 4 more</p> <p>Process finished with exit code 0</p>