正则表达式获取img的src内容

如果我们有如下一段数据，我们想获取img中src的内容。

<p>桥边姑娘，我把你放心上</p><p><img src="https://n.sinaimg.cn/news/transform/20171113/puY7-fynship2141885.jpg" _src="https://n.sinaimg.cn/news/transform/20171113/puY7-fynship2141885.jpg" style="width: 550px; height: 317px;"/></p>

具体实现

这里我们分两步走，先匹配img标签，然后再获取src后面的内容。具体代码如下：

private static final Pattern IMAGE_TAG_PATTERN = Pattern.compile("<(img|IMG)(.*?)>");
private static Pattern IMAGE_SRC_PATTERN = Pattern.compile("(src|SRC)=\"(.*?)\"");
private static Pattern IMAGE__SRC_PATTERN = Pattern.compile("(_src|_SRC)=\"(.*?)\"");

public static void matchImgSrcTag(String srcStr) {

    List<String> targets = new ArrayList<>();

    // 针对src标签
    // 先匹配img标签
    Matcher imageTagMatcher = IMAGE_TAG_PATTERN.matcher(srcStr);
    while (imageTagMatcher.find()) {
        String image = imageTagMatcher.group(2).trim();
        // 获取src后面的内容
        Matcher imageSrcMatcher = IMAGE_SRC_PATTERN.matcher(image);
        String src = null;
        if (imageSrcMatcher.find()) {
            src = imageSrcMatcher.group(2).trim();
        }
        if (src == null || src.isEmpty()) {
            continue;
        }
        System.out.println("src:" + src);
        targets.add(src);
    }

    // 针对_src标签
    while (imageTagMatcher.find()) {
        String image = imageTagMatcher.group(2).trim();
        Matcher imageSrcMatcher = IMAGE__SRC_PATTERN.matcher(image);
        String src = null;
        if (imageSrcMatcher.find()) {
            src = imageSrcMatcher.group(2).trim();
        }
        if (src == null || src.isEmpty()) {
            continue;
        }
        System.out.println("_src_:" + src);
        targets.add(src);
    }
}

测试验证

public static void main(String[] args) {
    String src = "<p>桥边姑娘，我把你放心上</p><p><img src=\"https://n.sinaimg.cn/news/transform/20171113/puY7-fynship2141885.jpg\" _src=\"https://n.sinaimg.cn/news/transform/20171113/puY7-fynship2141885.jpg\" style=\"width: 550px; height: 317px;\"/></p>";
    matchImgSrcTag(src);
}

output:

src:https://n.sinaimg.cn/news/transform/20171113/puY7-fynship2141885.jpg
_src_:https://n.sinaimg.cn/news/transform/20171113/puY7-fynship2141885.jpg