将POJO转化成符合XML格式的字符串http://my.oschina.net/jeffli1993/blog/376846

可以使用Java自带的JAXB库来将POJO转化成符合XML格式的字符串。

首先，需要在POJO类上添加JAXB注解，例如：

@XmlRootElement
public class User {
    private String name;
    private int age;

    public User() {}

    public User(String name, int age) {
        this.name = name;
        this.age = age;
    }

    @XmlElement
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @XmlElement
    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
}

然后，可以使用JAXBContext和Marshaller将POJO转化成XML格式的字符串：

public static String convertToXml(Object obj) throws JAXBException {
    JAXBContext context = JAXBContext.newInstance(obj.getClass());
    Marshaller marshaller = context.createMarshaller();
    marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
    StringWriter writer = new StringWriter();
    marshaller.marshal(obj, writer);
    return writer.toString();
}

调用方式如下：

User user = new User("Tom", 30);
String xml = convertToXml(user);
System.out.println(xml);

输出结果如下：

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<user>
    <age>30</age>
    <name>Tom</name>
</user>

注意：需要添加以下依赖：

<dependency>
    <groupId>javax.xml.bind</groupId>
    <artifactId>jaxb-api</artifactId>
    <version>2.3.1</version>
</dependency>
<dependency>
    <groupId>com.sun.xml.bind</groupId>
    <artifactId>jaxb-core</artifactId>
    <version>2.3.0.1</version>
</dependency>
<dependency>
    <groupId>com.sun.xml.bind</groupId>
    <artifactId>jaxb-impl</artifactId>
    <version>2.3.1</version>
</dependency>