JAVA對象轉換成XML()

編者小結：將java對象轉換成xml檔案很簡單，但是將java對象轉換成<![CDATA[常值內容]]>輸出結果不轉義的形式就相當不易。大家都知道在XML 元素中，"<" 和 "&" 是非法的。"<" 會產生錯誤，因為解析器會把該字元解釋為新元素的開始。"&" 也會產生錯誤，因為解析器會把該字元解釋為字元實體的開始。某些文本，比如 JavaScript 代碼，包含大量 "<" 或"&" 字元。為了避免錯誤，可以將指令碼代碼定義為 CDATA。

CDATA：在標記CDATA下，所有的標記、實體引用都被忽略，而被XML處理常式一視同仁地當作字元資料看待，CDATA的形式如下：

<![CDATA[常值內容]]>

CDATA的常值內容中不能出現字串“]]>”，另外，CDATA不能嵌套。

 

具體實現過程如下：

Java實體類：

publicclassJavaDocu {    privateintid;    private String text;    publicint getId() {        returnid;    }    publicvoid setId(int id) {        this.id = id;    }    public String getText() {        returntext;    }    publicvoid setText(String text) {        this.text = text;    }}

MyXppDriver類：

publicclassMyXppDriver extends XppDriver {    public HierarchicalStreamWritercreateWriter(Writer out){        returnnew MyPrettyPrintWriter(out);    }}

 

MyPrettyPrintWriter類：

publicclassMyPrettyPrintWriterimplementsExtendedHierarchicalStreamWriter {    privatefinal QuickWriter writer;    privatefinal FastStack elementStack = new FastStack(16);    privatefinalchar[] lineIndenter;     privatebooleantagInProgress;    privateintdepth;    privatebooleanreadyForNewLine;    privatebooleantagIsEmpty;     privatestaticfinalchar[] AMP = "&".toCharArray();    privatestaticfinalchar[] LT = "<".toCharArray();    privatestaticfinalchar[] GT = ">".toCharArray();    privatestaticfinalchar[] SLASH_R = " ".toCharArray();    privatestaticfinalchar[] QUOT = """.toCharArray();    privatestaticfinalchar[] APOS = "'".toCharArray();    privatestaticfinalchar[] CLOSE = "</".toCharArray();     publicMyPrettyPrintWriter(Writer writer, char[] lineIndenter) {        this.writer = new QuickWriter(writer);        this.lineIndenter = lineIndenter;    }     publicMyPrettyPrintWriter(Writer writer, String lineIndenter) {        this(writer,lineIndenter.toCharArray());    }     public MyPrettyPrintWriter(PrintWriterwriter) {        this(writer, newchar[] { ' ', ' ' });    }     publicMyPrettyPrintWriter(Writer writer) {        this(new PrintWriter(writer));    }     @Override    publicvoid addAttribute(Stringkey, String value) {        writer.write(' ');        writer.write(key);        writer.write('=');        writer.write('\"');        writeAttributeValue(writer, value);        writer.write('\"');    }     protectedvoidwriteAttributeValue(QuickWriter writer, String text) {        int length = text.length();        for (int i = 0; i < length;i++) {            char c = text.charAt(i);            switch (c) {            case'&':                this.writer.write(AMP);                break;            case'<':                this.writer.write(LT);                break;            case'>':                this.writer.write(GT);                break;            case'"':                this.writer.write(QUOT);                break;            case'\'':                this.writer.write(APOS);                break;            case'\r':                this.writer.write(SLASH_R);                break;            default:                this.writer.write(c);            }        }    }     @Override    publicvoid endNode() {        depth--;        if (tagIsEmpty) {            writer.write('/');            readyForNewLine = false;            finishTag();            elementStack.popSilently();        }else{            finishTag();            writer.write(CLOSE);            writer.write((String) elementStack.pop());            writer.write('>');        }        readyForNewLine = true;        if (depth == 0) {            writer.flush();        }    }     @Override    publicvoid setValue(String text) {        readyForNewLine = false;        tagIsEmpty = false;        finishTag();        writeText(writer, text);    }     protectedvoid writeText(QuickWriterwriter, String text) {        int length = text.length();        StringCDATAPrefix = "<![CDATA[";         if(!text.startsWith(CDATAPrefix)) {            for (int i = 0; i < length;i++) {                char c = text.charAt(i);                switch (c) {                case'&':                    this.writer.write(AMP);                    break;                case'<':                    this.writer.write(LT);                    break;                case'>':                    this.writer.write(GT);                    break;                case'"':                    this.writer.write(QUOT);                    break;                case'\'':                    this.writer.write(APOS);                    break;                case'\r':                    this.writer.write(SLASH_R);                    break;                default:                    this.writer.write(c);                }            }        }         else {            for (int i = 0; i < length;i++) {                char c = text.charAt(i);                this.writer.write(c);            }        }    }     @Override    publicvoid startNode(String name){        tagIsEmpty = false;        finishTag();        writer.write('<');        writer.write(name);        elementStack.push(name);        tagInProgress = true;        depth++;        readyForNewLine = true;        tagIsEmpty = true;    }     privatevoid finishTag() {        if (tagInProgress) {            writer.write('>');        }        tagInProgress = false;        if (readyForNewLine) {            endOfLine();        }        readyForNewLine = false;        tagIsEmpty = false;    }     protectedvoid endOfLine() {        writer.write('\n');        for (int i = 0; i < depth; i++) {            writer.write(lineIndenter);        }    }     publicvoid flush() {        writer.flush();    }     publicvoid close() {        writer.close();    }     @Override    publicHierarchicalStreamWriter underlyingWriter() {        returnthis;    }     @Override    publicvoid startNode(String name, @SuppressWarnings("rawtypes")Class arg1) {        // TODO Auto-generated method stub        tagIsEmpty = false;        finishTag();        writer.write('<');        writer.write(name);        elementStack.push(name);        tagInProgress = true;        depth++;        readyForNewLine = true;        tagIsEmpty = true;    }} 

 

Java測試類別：

publicclassJavaDocuTest {     publicstaticvoid main(String[] args) throws IOException,JAXBException {        Long t1 = System.currentTimeMillis();        StringCDATAPrefix = "<![CDATA[";        StringCDATABackfix = "]]>";        JavaDocujavadocu = newJavaDocu();        JavaDocujavadocu2 = newJavaDocu();        javadocu.setText(CDATAPrefix+ "這是一個測試" + CDATABackfix);        javadocu2.setText(CDATAPrefix+ "這又是一個測試" + CDATABackfix);        List<JavaDocu>list = newArrayList<JavaDocu>();        list.add(javadocu);        list.add(javadocu2);        XStreamxstream = newXStream(newMyXppDriver());        for (int i = 0; i <list.size(); i++) {            list.get(i).setId(i);            xstream.alias("javatoxml",JavaDocu.class);            xstream.useAttributeFor(JavaDocu.class, "id");            // xstream.useAttributeFor("id",String.class);        }        System.out.println(xstream.toXML(list));        xstream.toXML(list, new PrintWriter("c:\\測試.xml", "utf-8"));}}

以上代碼可實現將javabean轉換成包含<![CDATA[常值內容]]>的xml檔案。

 

溫馨提示：此過程使用xstream.1.3.1.jar，請到http://download.csdn.net/detail/yaohucaizi/5120422下載所需jar包（免費）。

 

本文原創yhcz  由於總結過程實屬不易如需轉載請註明出處，謝謝。