删除BASE64字符串JAVA的开始和结束

在java中，如何删除附加到BASE64字符串的基本信息。我收到xml，其中一个元素包含BASE64图片，但在字符串的开头，我得到了以下内容：

<![CDATA[Content-type: image/jpeg
Content-transfer-encoding: base64

begin-base64 644 Billede installation_2818.jpg

我尝试将conent转换为java字符串类型，并使用一些正则表达式调用replace，如

".*.jpg"

但这是行不通的，我想这是因为画面太大了，但我不确定，我已经没有想法了。我甚至做了一个像这样的小测试程序：

public class Base64RegExExample {

public static void main(String[] args) {
    // TODO Auto-generated method stub
    String xml = "<![CDATA[Content-type: image/jpeg Content-transfer-encoding: base-64begin-base64 644 Billede installation_2818.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]]>";

    xml = xml.replaceFirst(".*\\.jpg","").replaceFirst("]]>", "");
    xml = xml.replaceFirst("]]>", "");
    /*byte[] bytes = javax.xml.bind.DatatypeConverter.parseBase64Binary(imageData);
    System.out.println(new String(bytes));*/
}

---

将DOTALL修改器添加到第一个正则表达式：

.replaceFirst（（？s）。*？\\.jpg“，”）

如果您向我们显示希望结束的确切字符串，也会有助于您的问题。请明确指定要从整个字符串中删除的字符串，以便我们能够正确理解。

public class Base64RegExExample {

public static void main(String[] args) {
    // TODO Auto-generated method stub
    String xml = "<![CDATA[Content-type: image/jpeg Content-transfer-encoding: base-64begin-base64 644 Billede installation_2818.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]]>";

    xml = xml.replaceFirst(".*\\.jpg","").replaceFirst("]]>", "");
    xml = xml.replaceFirst("]]>", "");
    /*byte[] bytes = javax.xml.bind.DatatypeConverter.parseBase64Binary(imageData);
    System.out.println(new String(bytes));*/
}

<![CDATA[Content-type: image/jpeg
Content-transfer-encoding: base64

begin-base64 644 Billede installation_2818.jpg
/9j/4QtCRXhpZgAASUkqAAgAAAAMAAABBAABAAAAIAoAAAEBBAABAAAAmAcAAA8BAgAIAAAAngAA
ABABAgAJAAAApgAAABIBAwABAAAAAQAAABoBBQABAAAAsAAAABsBBQABAAAAuAAAACgBAwABAAAA
AgAAADEBAgAOAAAAwAAAADIBAgAUAAAAzgAAABMCAwABAAAAAQAAAGmHBAABAAAA4gAAAHwDAABT
QU1TVU5HAFNNLUczODhGAABIAAAAAQAAAEgAAAABAAAARzM4OEZYWFUxQU9IMwAyMDE1OjExOjE4
IDEyOjI4OjIzACIAmoIFAAEAAACAAgAAnYIFAAEAAACIAgAAIogDAAEAAAACAAAAJ4gDAAEAAAC0
AAAAAJAHAAQAAAAwMjIwA5ACABQAAACQAgAABJACABQAAACkAgAAAZEHAAQAAAABAgMAAZIKAAEA...]]>

/9j/4QtCRXhpZgAASUkqAAgAAAAMAAABBAABAAAAIAoAAAEBBAABAAAAmAcAAA8BAgAIAAAAngAA
ABABAgAJAAAApgAAABIBAwABAAAAAQAAABoBBQABAAAAsAAAABsBBQABAAAAuAAAACgBAwABAAAA
AgAAADEBAgAOAAAAwAAAADIBAgAUAAAAzgAAABMCAwABAAAAAQAAAGmHBAABAAAA4gAAAHwDAABT
QU1TVU5HAFNNLUczODhGAABIAAAAAQAAAEgAAAABAAAARzM4OEZYWFUxQU9IMwAyMDE1OjExOjE4
IDEyOjI4OjIzACIAmoIFAAEAAACAAgAAnYIFAAEAAACIAgAAIogDAAEAAAACAAAAJ4gDAAEAAAC0
AAAAAJAHAAQAAAAwMjIwA5ACABQAAACQAgAABJACABQAAACkAgAAAZEHAAQAAAABAgMAAZIKAAEA...