Use XMLBean to easily read and write XML

1. About xml parsing

XML is becoming more and more important in java applications and is widely used in data storage and exchange. For example, our common configuration files are all stored in XML. XML is also used in technologies such as Java Message Service and Web Services for data exchange. Therefore, correctly reading and writing XML documents is the basis for XML applications.

Java provides two methods, SAX and DOM, for parsing XML, but Even so, it is not an easy task to read and write a slightly complex XML.

2. Introduction to XMLBean

Hibernate has become a popular object/relational database for Java environments. Mapping tools. Before the emergence of object/relational database mapping tools such as Hibernate, operations on the database were implemented through JDBC. For any operation on the database, developers had to write SQL statements themselves. The emergence of object/relational database mapping tools Finally, the operations on the database are converted into operations on JavaBeans, which greatly facilitates database development. Therefore, if there is a similar tool that can convert the reading and writing of XML into operations on JavaBeans, it will simplify the reading and writing of XML. Even developers who are not familiar with XML can easily read and write XML. This tool is XMLBean.

3. Prepare XMLBean and XML documents

XMLBean is an open source project of Apache, which can be downloaded from Download from http://www.apache.org, the latest version is 2.0. The directory after decompression is as follows:

xmlbean2.0.0
     +---bin
     +---docs
     +---lib
     +---samples
     +---schemas

In addition, you must prepare an XML document (customers.xml),

In this article In the example, we will read and write this document. The document source code is as follows:

    
            1
            female
            Jessica
            Lim
            1234567
            

                
                        350106
                        #25-1
                        SHINSAYAMA 2-CHOME
                
                
                        Ms Danielle
                        350107
                        #167
                        NORTH TOWER HARBOUR CITY
                
            
    
    
            2
            male
            David
            Bill
            808182
            

                
                        319087
                        1033 WS St.
                        Tima Road
                
                
                        Mr William
                        672993
                        1033 WS St.
                        Tima Road
                
            
    

This is a customer data model. Each customer has a customer number (ID), name, and gender. , phone number (phoneNumber) and address, of which there are two addresses: primary address (PrimaryAddress) and billing address (BillingAddress). Each address consists of zip code, address 1, and address 2. The billing address also has the recipient Person (receiver). In addition, you must also prepare a configuration file (file name customer.xsdconfig). I will talk about the function of this file later. Its content is as follows:

  
    sample.xmlbean
  

4. XMLBean usage steps

The steps for using other object/relational database mapping tools for Java environments are the same. Before officially using XMLBean, we need to make two preparations.

1. Generate XML Schema file

　What is an XML Schema file? Normally, each XML file has a Schema file. The XML Schema file is an XML constraint file, which defines the structure and elements of the XML file, as well as the constraints on the elements and structure. Popular To put it simply, if an XML file is a record in a database, then Schema is a table structure definition.

Why is this file needed? XMLBean needs to know the structure and constraints of an XML file through this file, such as data types, etc. Using this Schema file, XMLBean will generate a series of related Java Classes to implement operations on XML. As a developer, you use the Java Classes generated by XMLBean to complete operations on XML without the need for SAX or DOM. How to generate What about this Schema file? For developers who are familiar with XML, they can write this Schema file themselves. For developers who are not familiar with XML, they can use some tools to complete it. The more famous ones such as XMLSPY and Stylus Studio can use XML files to write it. Generate Schema file. Add the Schema file (customer.xsd) we have generated:

2. Use scomp to generate Java Classes

scomp is a compilation tool provided by XMLBean, it is in bin directory. Through this tool, we can generate Java Classes.scomp from the above Schema file. The syntax of scomp is as follows:-

　　scomp [options] [dirs]* [schemaFile.xsd]* [service.wsdl]* [config.xsdconfig]*

Main parameter description:

-src [dir] -- 生成的Java Classes存放目录
　　-srconly -- 不编译Java Classes,不产生Jar文件
　　-out [jarFileName] -- 生成的Jar文件,缺省是xmltypes.jar
　　-compiler -- Java编译器的路径,即Javac的位置
　　schemaFile.xsd -- XML Schema文件位置

　config.xsdconfig -- xsdconfig file The location of this file is mainly used to formulate some file name rules for the generated Java Class and the name of the Package. In this article, the package is sample.xmlbean

In this article, I ran it like this:

 scomp -src build\src  -out build\customerXmlBean.jar schema\customer.xsd
             -compiler C:\jdk142_04\bin\javac customer.xsdconfig

The meaning of this command line is to tell scomp to generate customerXmlBean.jar and place it in the build directory. At the same time, the source code is generated and placed under build\src. The Schema file is customer.xsd and the xsdconfig file is customer.xsdconfig. In fact, generate The Java source code is of little use, what we want is the jar file. Let's first take a look at the Classes generated under build\src\sample\xmlbean.

CustomersDocument.java -- 整个XML文档的Java Class映射
　　CustomerType.java -- 节点sustomer的映射
　　AddressType.java -- 节点address的映射
　　BillingAddressType.java -- 节点billingAddress的映射
　　PrimaryAddressType.java -- 节点primaryAddress的映射

Okay, now all our preparations have been completed Now let’s get to the point: using the jar file just generated to read and write XML.

5. Use XMLBean to read XML files

Create a new Java Project and download XMLBean2.0.0\lib\ The Jar file and the customerXmlBean.jar we just generated are added to the Project's ClassPath.

Create a new Java Class: CustomerXMLBean. The source code is as follows:

 package com.sample.reader;
    import java.io.File;
    
    import sample.xmlbean.*;
    import org.apache.commons.beanutils.BeanUtils;
    import org.apache.xmlbeans.XmlOptions;
    public class CustomerXMLBean {
    private String filename = null;
    
    public CustomerXMLBean(String filename) {
            super();
            this.filename = filename;
    }
    public void customerReader() {
            try {
              File xmlFile = new File(filename);
              CustomersDocument doc = CustomersDocument.Factory.parse(xmlFile);
              CustomerType[] customers = doc.getCustomers().getCustomerArray();
          
              for (int i = 0; i < customers.length; i++) {
                CustomerType customer = customers[i];
                println("Customer#" + i);
                println("Customer ID:" + customer.getId());
                println("First name:" + customer.getFirstname());
                println("Last name:" + customer.getLastname());
                println("Gender:" + customer.getGender());
                println("PhoneNumber:" + customer.getPhoneNumber());
                // Primary address
                PrimaryAddressType primaryAddress = customer.getAddress().getPrimaryAddress();
                println("PrimaryAddress:");
                println("PostalCode:" + primaryAddress.getPostalCode());
                println("AddressLine1:" + primaryAddress.getAddressLine1());
                println("AddressLine2:" + primaryAddress.getAddressLine2());
                // Billing address
                BillingAddressType billingAddress = customer.getAddress().getBillingAddress();
                println("BillingAddress:");
                println("Receiver:" + billingAddress.getReceiver());
                println("PostalCode:" + billingAddress.getPostalCode());
                println("AddressLine1:" + billingAddress.getAddressLine1());
                println("AddressLine2:" + billingAddress.getAddressLine2());
            
              }
            } catch (Exception ex) {
                    ex.printStackTrace();
            }
    }
    private void println(String str) {
          System.out.println(str);
    }
   public static void main(String[] args) {
      String filename = "F://JavaTest//Eclipse//XMLBean//xml//customers.xml";
                   
     CustomerXMLBean customerXMLBean = new CustomerXMLBean(filename);
                   customerXMLBean.customerReader();
    }
    }

Run it and see the output result:

How about

  Customer#0
       Customer ID:1
       First name:Jessica
       Last name:Lim
       Gender:female
       PhoneNumber:1234567
       PrimaryAddress:
       PostalCode:350106
       AddressLine1:#25-1
       AddressLine2:SHINSAYAMA 2-CHOME
       BillingAddress:
       Receiver:Ms Danielle
       PostalCode:350107
       AddressLine1:#167
       AddressLine2:NORTH TOWER HARBOUR CITY
       Customer#1
       Customer ID:2
       First name:David
       Last name:Bill
       Gender:male
       PhoneNumber:808182
       PrimaryAddress:
       PostalCode:319087
       AddressLine1:1033 WS St.
       AddressLine2:Tima Road
       BillingAddress:
       Receiver:Mr William
       PostalCode:672993
       AddressLine1:1033 WS St.
       AddressLine2:Tima Road

, is it very easy? The power of XMLBean.

6. Use XMLBean to write XML files

Using XMLBean to create an XML document is also a piece of cake. Let’s go back to Add a Method,

Please take a look at the Java Class:

 public void createCustomer() {
    try {
        // Create Document
        CustomersDocument doc = CustomersDocument.Factory.newInstance();
        // Add new customer
        CustomerType customer = doc.addNewCustomers().addNewCustomer();
        // set customer info
        customer.setId(3);
        customer.setFirstname("Jessica");
        customer.setLastname("Lim");
        customer.setGender("female");
        customer.setPhoneNumber("1234567");
        // Add new address
        AddressType address = customer.addNewAddress();
        // Add new PrimaryAddress
        PrimaryAddressType primaryAddress = address.addNewPrimaryAddress();
        primaryAddress.setPostalCode("350106");
        primaryAddress.setAddressLine1("#25-1");
        primaryAddress.setAddressLine2("SHINSAYAMA 2-CHOME");
        // Add new BillingAddress
        BillingAddressType billingAddress = address.addNewBillingAddress();
        billingAddress.setReceiver("Ms Danielle");
        billingAddress.setPostalCode("350107");
        billingAddress.setAddressLine1("#167");
        billingAddress.setAddressLine2("NORTH TOWER HARBOUR CITY");
        File xmlFile = new File(filename);
        doc.save(xmlFile);
        } catch (Exception ex) {
                ex.printStackTrace();
        }
  }

Modify the main method.

   public static void main(String[] args) {
    String filename = "F://JavaTest//Eclipse//XMLBean//xml//customers_new.xml";
        CustomerXMLBean customerXMLBean = new CustomerXMLBean(filename);
        customerXMLBean.createCustomer();
    }

Run, open customers_new.xml:

 
    
    
            3
            female
            Jessica
            Lim
            1234567
            

                    
                         350106
                         #25-1
                                       SHINSAYAMA 2-CHOME
                    
                    
                        Ms Danielle
                        350107
                       #167
                       NORTH TOWER HARBOUR CITY
                    
                    
            
    

Seven , Use XMLBean to modify the XML file

We add another Method:

public void updateCustomer(int id,String lastname) {
         try {
        File xmlFile = new File(filename);
        CustomersDocument doc = CustomersDocument.Factory.parse(xmlFile);
        CustomerType[] customers = doc.getCustomers().getCustomerArray();
      
        for (int i = 0; i < customers.length; i++) {
           CustomerType customer = customers[i];
          if(customer.getId()==id){
                customer.setLastname(lastname);
                break;
            }
        }
        doc.save(xmlFile);
         } catch (Exception ex) {
          ex.printStackTrace();
         }
           }
　　main method:
    public static void main(String[] args) {
     String filename = "F://JavaTest//Eclipse//XMLBean//xml//customers_new.xml";
                    
    CustomerXMLBean customerXMLBean = new CustomerXMLBean(filename);
                    
    customerXMLBean.updateCustomer(3,"last");
    }

After running, we will see that the lastname of the customer with customer number 3 has been changed to last.

8. Use XMLBean to delete a customer

Add another Method:

public void deleteCustomer(int id) {
     try {
      File xmlFile = new File(filename);
     CustomersDocument doc = CustomersDocument.Factory.parse(xmlFile);
    CustomerType[] customers = doc.getCustomers().getCustomerArray();
   for (int i = 0; i < customers.length; i++) {
        CustomerType customer = customers[i];
        if(customer.getId()==id){
                        customer.setNil() ;
                        break;
               }
   }
   doc.save(xmlFile);
   } catch (Exception ex) {
        ex.printStackTrace();
        }
   }
　　main method:
    public static void main(String[] args) {
    String filename = "F://JavaTest//Eclipse//XMLBean//xml//customers_new.xml";
                    
    CustomerXMLBean customerXMLBean = new CustomerXMLBean(filename);
                    
    customerXMLBean.deleteCustomer(3);
    }

运行,我们将会看到客户编号为3的客户的资料已经被删除.

　　九、查询XML

　　除了本文在以上讲述的,利用XMLBean能轻轻松松完成XML的读写操作外,结合XPath和XQuery,XMLBean还能完成象SQL查询数据库一样方便地查询XML数据. 关于XML查询以及如何创建XML数据库, 我将在另一篇文章里讨论.

　　十、结束语

　　XMLBean能帮助我们轻易读写XML,这将有助于我们降低XML的学习和使用,有了这个基础,开发人员将为学习更多地XML相关技术和Web Services,JMS等其他J2EE技术打下良好地基础.

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