JAVA对象和XML文件绑定

深藏阁楼爱情的钟 2022-03-11 14:22 176阅读 0赞

目的

在日常工作中，我们经常处理这些编组关系：JAVA对象 <--> XML文件；JAVA对象 <--> 数据库表。本文简单介绍一下JAVA对象和XML文件之间的绑定。虽然代码简单，但解决问题的广度与思路也是非常重要的。

首先，在Maven中引入要用到的jar包。

<dependency>
    			<groupId>castor</groupId>
    			<artifactId>castor</artifactId>
    			<version>1.0</version>
    		</dependency>
    		<dependency>
    			<groupId>xerces</groupId>
    			<artifactId>xerces</artifactId>
    			<version>2.4.0</version>
    		</dependency>

1. 写两个有包含关系的Bean

package shuai.study.castor.bean;
    
    import java.util.Collection;
    import java.util.LinkedList;
    
    public class CompanyBean {
    	private String type;
    	private String name;
    	private String address;
    	private Collection<EmployeeBean> employeeBeanCollection;
    
    	public CompanyBean() {
    		this.employeeBeanCollection = new LinkedList<EmployeeBean>();
    	}
    
    	public String getType() {
    		return this.type;
    	}
    
    	public void setType(String type) {
    		this.type = type;
    	}
    
    	public String getName() {
    		return this.name;
    	}
    
    	public void setName(String name) {
    		this.name = name;
    	}
    
    	public String getAddress() {
    		return this.address;
    	}
    
    	public void setAddress(String address) {
    		this.address = address;
    	}
    
    	public Collection<EmployeeBean> getEmployeeBeanCollection() {
    		return this.employeeBeanCollection;
    	}
    
    	public void setEmployeeBeanCollection(Collection<EmployeeBean> employeeBeanCollection) {
    		this.employeeBeanCollection = employeeBeanCollection;
    	}
    
    	public void addEmployeeBean(EmployeeBean employeeBean) {
    		this.employeeBeanCollection.add(employeeBean);
    	}
    }

package shuai.study.castor.bean;
    
    public class EmployeeBean {
    	private String id;
    	private String name;
    	private String sex;
    	private int age;
    	private String address;
    
    	public String getId() {
    		return this.id;
    	}
    
    	public void setId(String id) {
    		this.id = id;
    	}
    
    	public String getName() {
    		return this.name;
    	}
    
    	public void setName(String name) {
    		this.name = name;
    	}
    
    	public String getSex() {
    		return this.sex;
    	}
    
    	public void setSex(String sex) {
    		this.sex = sex;
    	}
    
    	public int getAge() {
    		return this.age;
    	}
    
    	public void setAge(int age) {
    		this.age = age;
    	}
    
    	public String getAddress() {
    		return this.address;
    	}
    
    	public void setAddress(String address) {
    		this.address = address;
    	}
    }

2. 我们定义一个mapping文件，阐述JAVA对象和XML文件之间的关系。

<!DOCTYPE databases PUBLIC
    "-//EXOLAB/Castor Mapping DTD Version 1.0//EN"
    "http://castor.exolab.org/mapping.dtd">
    <mapping>
    	<description>Flight Route Mapping</description>
    	<class name="shuai.study.castor.bean.CompanyBean">
    		<map-to xml="company" />
    		<field name="type">
    			<bind-xml name="type" node="attribute" />
    		</field>
    		<field name="name">
    			<bind-xml name="name" />
    		</field>
    		<field name="address">
    			<bind-xml name="address" />
    		</field>
    		<field name="employeeBeanCollection" collection="collection"
    			type="shuai.study.castor.bean.EmployeeBean">
    			<bind-xml name="employee" />
    		</field>
    	</class>
    	<class name="shuai.study.castor.bean.EmployeeBean" auto-complete="true">
    		<field name="id">
    			<bind-xml name="id" node="attribute" />
    		</field>
    		<field name="name">
    			<bind-xml name="name" />
    		</field>
    		<field name="sex">
    			<bind-xml name="sex" />
    		</field>
    		<field name="age">
    			<bind-xml name="age" />
    		</field>
    		<field name="address">
    			<bind-xml name="address" />
    		</field>
    	</class>
    </mapping>

3. 写一个测试类，处理JAVA对象与XML文件之间的编组与反编组。

package shuai.study.castor;
    
    import java.io.File;
    import java.io.FileReader;
    import java.io.FileWriter;
    import java.io.IOException;
    import java.io.Reader;
    import java.io.Writer;
    
    import org.exolab.castor.mapping.Mapping;
    import org.exolab.castor.mapping.MappingException;
    import org.exolab.castor.xml.MarshalException;
    import org.exolab.castor.xml.Marshaller;
    import org.exolab.castor.xml.Unmarshaller;
    import org.exolab.castor.xml.ValidationException;
    
    import shuai.study.castor.bean.CompanyBean;
    import shuai.study.castor.bean.EmployeeBean;
    
    public class CastorDemo {
    
    	public static void main(String[] args) {
    		EmployeeBean employeeBean = new EmployeeBean();
    		employeeBean.setId("37");
    		employeeBean.setName("shuai");
    		employeeBean.setSex("male");
    		employeeBean.setAge(30);
    		employeeBean.setAddress("Ronghua South Road, Hi-Tech Zone, Chengdu");
    
    		CompanyBean companyBean = new CompanyBean();
    		companyBean.setType("foreign-owned");
    		companyBean.setName("Tieto");
    		companyBean.setAddress("Tianfu Software Park, Tianfu Avenue, Hi-Tech Zone, Chengdu");
    		companyBean.addEmployeeBean(employeeBean);
    
    		try {
    			// Mapping file path
    			String companyEmployeeMapPath = CastorDemo.class.getResource("/file/map/company_employee_map.xml").getPath();
    			Mapping companyEmployeeMapping = new Mapping();
    			// Loading Mapping file
    			companyEmployeeMapping.loadMapping(companyEmployeeMapPath);
    
    			// Output file path, make sure this path exist
    			String companyEmployeeOutputPath = CastorDemo.class.getResource("/file/output/company_employee_output.xml").getPath();
    			File companyEmployeeOutputFile = new File(companyEmployeeOutputPath);
    
    			Writer companyEmployeeWriter = new FileWriter(companyEmployeeOutputFile);
    
    			// Marshal Object to XML
    			Marshaller marshaller = new Marshaller(companyEmployeeWriter);
    			marshaller.setMapping(companyEmployeeMapping);
    			marshaller.marshal(companyBean);
    
    			// Un-Marshal XML to Object
    			Reader companyEmployeeReader = new FileReader(companyEmployeeOutputFile);
    			Unmarshaller unmarshaller = new Unmarshaller(companyEmployeeMapping);
    			CompanyBean companyEmployeeBean = (CompanyBean) unmarshaller.unmarshal(companyEmployeeReader);
    
    			System.out.println("Company is " + companyEmployeeBean.getName() + " at " + companyEmployeeBean.getAddress());
    		} catch (IOException ioe) {
    			ioe.printStackTrace(System.err);
    		} catch (MarshalException me) {
    			me.printStackTrace(System.err);
    		} catch (ValidationException ve) {
    			ve.printStackTrace(System.err);
    		} catch (MappingException me) {
    			me.printStackTrace(System.err);
    		}
    	}
    }