TextRank算法是一种用于提取文本中关键词的算法。它的基本思想是：对于每个词，计算其与其他词的相似度，然后根据相似度对词进行排序，得到一个关键词列表。

以下是一个简单的Java实现：

```java
import java.util.;

public class TextRank {
private static final int MAX_SAMPLES = 10;
private static final double MIN_SAMPLE_SIZE = 2;
private static final double MIN_DOUBLE = 0.5;
private static final double MAX_DOUBLE = 1.0;

public static void main(String[] args) {
String text = "这是一个关于计算机科学的有趣话题，包括人工智能、机器学习和深度学习等。";
System.out.println(getKeywords(text));
}

public static List getKeywords(String text) {
List keywords = new ArrayList();
int[] counts = new int[MAX_SAMPLES];
Map wordCounts = new HashMap();

for (int i = 0; i < text.length(); i++) {
char ch = text.charAt(i);
if (ch == ' ') {
break;
}

if (!wordCounts.containsKey(ch)) {
wordCounts.put(ch, 1);
} else {
counts[wordCounts.get(ch)]++;
}
}

for (int i = 0; i < MAX_SAMPLES; i++) {
double sum = 0;
for (int j = 0; j < MAX_SAMPLES; j++) {
if (counts[j] > 0 && i != j) {
sum += Math.log((double) (1 - (double) (1 - counts[j])) (double) (1 + counts[j]));
}
}
if (sum >= MIN_DOUBLE && sum