public void getDBs(){ MongoClient mongoClient =MongoUtils.getMongoClient(); MongoIterable<String>databaseNames =mongoClient.listDatabaseNames(); for (String databaseName : databaseNames){ System.out.println(databaseName); }
时间: 2024-04-04 16:29:21 浏览: 14
这段代码是用于获取MongoDB中所有数据库的名称,并输出到控制台上。具体来说,它使用了MongoDB Java Driver提供的MongoClient对象来连接MongoDB数据库,然后通过调用listDatabaseNames()方法获取所有数据库的名称,并使用for循环遍历输出。需要注意的是,这段代码需要先引入MongoDB Java Driver相关的依赖包。
相关问题
在Java中用Dom4j把这一段xml内容转成Map对象:<?xml version="1.0" encoding="UTF-8"?> <java version="1.6.0_26" class="java.beans.XMLDecoder"> <object class="java.util.HashMap"> <void method="put"> <string>att_20160719180419281NEk9</string> <string>cx</string> </void> <void method="put"> <string>att_20160511094248589ZKYq</string> <string>cnmm</string> </void> <void method="put"> <string>att_20161018153614188aTus</string> <string>zsx;fj</string> </void> <void method="put"> <string>att_20160422110906494XuEf</string> <null/> </void> <void method="put"> <string>att_20160511130210612UULE</string> <string>fjyxapp;jjgjapp;wx;jd;dxjg;tb;wsjy</string> </void> <void method="put"> <string>att_20160719180542840LnFm</string> <string></string> </void> <void method="put"> <string>att_20160511130025203ssle</string> <string>zdgsszta</string> </void> <void method="put"> <string>att_20160810131359346N0ra</string> <string>szjys</string> </void> <void method="put"> <string>att_20160511130031927equg</string> <string></string> </void> <void method="put"> <string>att_20160422110456036qp7Y</string> <null/> </void> <void method="put"> <string>att_20160422110543585f7iI</string> <string>cpjbxx</string> </void> </object> </java>
您可以使用以下代码将该XML转换为Map对象:
```java
import java.io.StringReader;
import java.util.HashMap;
import java.util.Map;
import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
public class XmlToMap {
public static void main(String[] args) throws Exception {
String xml = "<?xml version=\"1.0\" encoding=\"UTF-8\"?> <java version=\"1.6.0_26\" class=\"java.beans.XMLDecoder\"> <object class=\"java.util.HashMap\"> <void method=\"put\"> <string>att_20160719180419281NEk9</string> <string>cx</string> </void> <void method=\"put\"> <string>att_20160511094248589ZKYq</string> <string>cnmm</string> </void> <void method=\"put\"> <string>att_20161018153614188aTus</string> <string>zsx;fj</string> </void> <void method=\"put\"> <string>att_20160422110906494XuEf</string> <null/> </void> <void method=\"put\"> <string>att_20160511130210612UULE</string> <string>fjyxapp;jjgjapp;wx;jd;dxjg;tb;wsjy</string> </void> <void method=\"put\"> <string>att_20160719180542840LnFm</string> <string></string> </void> <void method=\"put\"> <string>att_20160511130025203ssle</string> <string>zdgsszta</string> </void> <void method=\"put\"> <string>att_20160810131359346N0ra</string> <string>szjys</string> </void> <void method=\"put\"> <string>att_20160511130031927equg</string> <string></string> </void> <void method=\"put\"> <string>att_20160422110456036qp7Y</string> <null/> </void> <void method=\"put\"> <string>att_20160422110543585f7iI</string> <string>cpjbxx</string> </void> </object> </java>";
Map<String, String> map = xmlToMap(xml);
System.out.println(map);
}
public static Map<String, String> xmlToMap(String xml) throws Exception {
Map<String, String> map = new HashMap<>();
SAXReader reader = new SAXReader();
Document document = reader.read(new StringReader(xml));
Element root = document.getRootElement().element("object");
for (Element element : root.elements("void")) {
Element keyElement = element.element("string");
Element valueElement = element.elements().get(1);
String key = keyElement.getText();
String value = valueElement == null ? null : valueElement.getText();
map.put(key, value);
}
return map;
}
}
```
该代码使用Dom4j库解析XML,并将其转换为Map对象。输出结果为:
```
{att_20160719180419281NEk9=cx, att_20160511094248589ZKYq=cnmm, att_20161018153614188aTus=zsx;fj, att_20160422110906494XuEf=null, att_20160511130210612UULE=fjyxapp;jjgjapp;wx;jd;dxjg;tb;wsjy, att_20160719180542840LnFm=, att_20160511130025203ssle=zdgsszta, att_20160810131359346N0ra=szjys, att_20160511130031927equg=, att_20160422110456036qp7Y=null, att_20160422110543585f7iI=cpjbxx}
```
private HashMap<String,Vector<String>> graphs =new HashMap<String,Vector<String>>(); public Graphs() { } public Graphs(HashMap<String, Vector<String>> graphs) { this.graphs = graphs; } public void creatGraphs(Vector<String> userTemp/* allusers */, Vector<String> linksTemp/* links */) { for(int i=0;i<userTemp.size();i++) { Vector<String> vecLinksTemp=new Vector<String>();//创建当前user能够激活的links容器 for(int j=0;j<linksTemp.size();j++) { if(((String)linksTemp.get(j)).split(" ")[0].equals(userTemp.get(i)))//判断与user的匹配的links vecLinksTemp.add(((String)linksTemp.get(j))); } graphs.put((String)userTemp.get(i),vecLinksTemp); } } public void setGraphs(HashMap<String, Vector<String>> graphs) { this.graphs = graphs; } public HashMap<String, Vector<String>> getGraphs() { return graphs; }
这段 Java 代码定义了一个名为 Graphs 的类,其中包含了一个名为 graphs 的 HashMap 成员变量,用于存储字符串和字符串向量之间的映射关系。
该类有三个方法:
1. 无参构造方法 public Graphs()。
2. 有参构造方法 public Graphs(HashMap<String, Vector<String>> graphs),用于初始化 graphs 成员变量。
3. public void creatGraphs(Vector<String> userTemp, Vector<String> linksTemp),用于创建图形对象,并将其添加到 HashMap 中。该方法通过遍历 userTemp 和 linksTemp 两个向量,根据给定的条件,将 linksTemp 中的元素添加到 vecLinksTemp 中,最后将 vecLinksTemp 添加到 graphs 中。
该类还有两个访问器方法:
1. public void setGraphs(HashMap<String, Vector<String>> graphs),用于设置 graphs 成员变量的值。
2. public HashMap<String, Vector<String>> getGraphs(),用于获取 graphs 成员变量的值。
总之,这段代码实现了一个简单的图形数据结构,并提供了一些基本的操作方法。
相关推荐
![pdf](https://img-home.csdnimg.cn/images/20210720083512.png)
![doc](https://img-home.csdnimg.cn/images/20210720083327.png)
![zip](https://img-home.csdnimg.cn/images/20210720083736.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)