我尝试使用CJX编译器从XSD架构生成Java JAXB模型。
现在我想创建一个从 Connection 到特定主机的关系。 因此，当您选择连接时，您还会收到特定的主机。
如果我们使用以下示例：
问题：
当你查询时我想要那个; SELECT主机FROM连接WHERE id = 1 您将Host作为对象（就像在SQL中一样？），现在您只需获取一个ID，我必须再次循环才能找到主机。
我错了什么，或者我该怎么办？我猜我的主要密钥和外键不起作用。所以XSD文件中有问题。
欢迎所有反馈，建议等。提前谢谢！
project.xsd
<xs:schema targetNamespace="http://www.nberlijn.nl/project/persistence/models"
xmlns="http://www.nberlijn.nl/project/persistence/models"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
elementFormDefault="qualified">
<!-- MAIN -->
<xs:element name="project">
<xs:complexType>
<xs:sequence>
<xs:element ref="hosts"/>
<xs:element ref="connections"/>
</xs:sequence>
</xs:complexType>
<!-- PRIMARY KEY'S -->
<xs:key name="PKHost">
<xs:selector xpath="hosts/host"/>
<xs:field xpath="id"/>
</xs:key>
<xs:key name="PKConnection">
<xs:selector xpath="connections/connection"/>
<xs:field xpath="id"/>
</xs:key>
<!-- FOREIGN KEY'S -->
<xs:keyref name="FKConnectionToHost" refer="PKHost">
<xs:selector xpath="connections/connection"/>
<xs:field xpath="host"/>
</xs:keyref>
</xs:element>
<!-- REFERENCES -->
<xs:element name="hosts">
<xs:complexType>
<xs:sequence>
<xs:element ref="host" maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:element name="connections">
<xs:complexType>
<xs:sequence>
<xs:element ref="connection" maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
</xs:element>
<!-- REFERENCES -->
<xs:element name="host">
<xs:complexType>
<xs:sequence>
<xs:element name="name" type="xs:string"/>
<xs:element name="address" type="xs:string"/>
<xs:element name="port" type="xs:long"/>
<xs:element name="timeout" type="xs:long"/>
</xs:sequence>
<xs:attribute name="id" type="xs:int"/>
</xs:complexType>
</xs:element>
<xs:element name="connection">
<xs:complexType>
<xs:sequence>
<xs:element name="host" type="xs:int"/>
<xs:element name="username" type="xs:string"/>
<xs:element name="password" type="xs:string"/>
</xs:sequence>
<xs:attribute name="id" type="xs:int"/>
</xs:complexType>
</xs:element>
</xs:schema>
xjc.bat
"C:\Program Files\Java\jdk1.8.0_51\bin\xjc.exe" -d src project.xsd
pause
Main.java
import nl.nberlijn.project.persistence.models.*;
import javax.xml.bind.*;
import java.io.File;
import java.util.List;
public class Main {
public static void main(String[] args) throws Exception {
marshaller();
unmarshaller();
}
private static void marshaller() throws JAXBException {
ObjectFactory objectFactory = new ObjectFactory();
Project project = objectFactory.createProject();
Hosts hosts = objectFactory.createHosts();
Connections connections = objectFactory.createConnections();
List<Host> hostList = hosts.getHost();
List<Connection> connectionList = connections.getConnection();
Host host = objectFactory.createHost();
Host host2 = objectFactory.createHost();
Connection connection = objectFactory.createConnection();
Connection connection2 = objectFactory.createConnection();
host.setId(1);
host.setName("Host");
host.setAddress("host.com");
host.setPort(22);
host.setTimeout(10000);
host2.setId(2);
host2.setName("Host 2");
host2.setAddress("host2.com");
host2.setPort(22);
host2.setTimeout(10000);
connection.setId(1);
connection.setHost(2);
connection.setUsername("user");
connection.setPassword("pass");
connection2.setId(233223231);
connection2.setHost(1);
connection2.setUsername("user2");
connection2.setPassword("pass2");
hostList.add(host);
hostList.add(host2);
connectionList.add(connection);
connectionList.add(connection2);
project.setHosts(hosts);
project.setConnections(connections);
File file = new File(System.getProperty("user.dir") + "/project.xml");
JAXBContext jaxbContext = JAXBContext.newInstance(Project.class);
Marshaller marshaller = jaxbContext.createMarshaller();
marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
marshaller.marshal(project, System.out);
marshaller.marshal(project, file);
}
private static void unmarshaller() throws JAXBException {
File file = new File(System.getProperty("user.dir") + "/project.xml");
JAXBContext jaxbContext = JAXBContext.newInstance(Project.class);
Unmarshaller unmarshaller = jaxbContext.createUnmarshaller();
Object object = unmarshaller.unmarshal(file);
Project project = (Project) object;
Connections connections = project.getConnections();
List<Connection> connectionList = connections.getConnection();
int id = 1;
System.out.println("\nSearch for a connection with id: " + id);
for (Connection connection : connectionList) {
if (connection.getId().equals(id)) {
System.out.println("Connection with id: " + connection.getId() + " found!");
Hosts hosts = project.getHosts();
List<Host> hostList = hosts.getHost();
System.out.println("Search for a host with id: " + connection.getHost());
for (Host host : hostList) {
if (host.getId() == connection.getHost()) {
System.out.println("Host found: " + host.getName());
} else {
System.out.println("Host not found!");
}
}
}
}
}
}
输出继电器：
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<project xmlns="http://www.nberlijn.nl/project/persistence/models">
<hosts>
<host id="1">
<name>Host</name>
<address>host.com</address>
<port>22</port>
<timeout>10000</timeout>
</host>
<host id="2">
<name>Host 2</name>
<address>host2.com</address>
<port>22</port>
<timeout>10000</timeout>
</host>
</hosts>
<connections>
<connection id="1">
<host>2</host>
<username>user</username>
<password>pass</password>
</connection>
<connection id="233223231">
<host>1</host>
<username>user2</username>
<password>pass2</password>
</connection>
</connections>
</project>
Search for a connection with id: 1
Connection with id: 1 found!
Search for a host with id: 2
Host not found!
Host found: Host 2