Go语言视频零基础入门到精通

五菱

这里介绍两种验证机制:
[1]更新文档(xml)后,收集验证错误信息;
[2]更新文档(xml)时,直接抛出错误验证异常.
    实例中使用的xml和xsd(注:此实例为xmlbeans下载包中samples中代码,笔者做了简单修改,使之在自定义环境下运行,该代码遵循Apache License V2.)
todolist.xml

<?xml version="1.0" encoding="UTF-8"?>

<todolist xmlns="http://xmlbeans.apache.org/samples/validation/todolist">

<item id="001">

<name>Buy a south Pacific island.</name>

<description>Contingent on inheriting lots of money.</description>

<due_by>2005-05-01T23:36:28</due_by>

<action>someday_maybe_defer</action>

</item>

<item id="002">

<name>Get that new PowerBook I've been eyeing.</name>

<description>Resulting productivity increase will be exponential!</description>

<due_by>2005-05-01T23:36:28</due_by>

<action>do</action>

</item>

<item id="003">

<name>Clean the garage.</name>

<description>Remove at least enough junk so that my bicycle fits.</description>

<due_by>2005-05-30T23:36:28</due_by>

<action>delegate</action>

</item>

</todolist>

todolist.xsd

<?xml version="1.0" encoding="UTF-8"?>

<xs:schema targetNamespace="http://xmlbeans.apache.org/samples/validation/todolist" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns="http://xmlbeans.apache.org/samples/validation/todolist" elementFormDefault="qualified">

<xs:element name="todolist">

<xs:complexType>

<xs:sequence>

<xs:element name="item" type="itemType" maxOccurs="unbounded"/>

</xs:sequence>

</xs:complexType>

</xs:element>

<xs:complexType name="itemType">

<xs:sequence>

<xs:element name="name" type="xs:string"/>

<xs:element name="description" type="xs:string" minOccurs="0"/>

<xs:element name="due_by" type="xs:dateTime" minOccurs="0"/>

<xs:element name="action" type="actionType"/>

</xs:sequence>

<xs:attribute name="id" type="idType"/>

</xs:complexType>

<xs:simpleType name="nameType">

<xs:restriction base="xs:string">

<xs:maxLength value="50"/>

</xs:restriction>

</xs:simpleType>

<xs:simpleType name="idType">

<xs:restriction base="xs:int">

<xs:maxExclusive value="100"/>

</xs:restriction>

</xs:simpleType>

<xs:simpleType name="actionType">

<xs:restriction base="xs:string">

<xs:enumeration value="do"/>

<xs:enumeration value="delegate"/>

<xs:enumeration value="someday_maybe_defer"/>

<xs:enumeration value="toss"/>

<xs:enumeration value="incubate"/>

<xs:enumeration value="file"/>

</xs:restriction>

</xs:simpleType>

</xs:schema>

    使用的用于验证的java类如下所示.
    其中isValidAfterChanges()方法在更新xml时,如果发现更新的数据不符合相应的xsd,则会将验证失败的信息保存在一个ArrayList中,可以自由选择输出这些信息或忽略;
    isValidOnTheFly()方法在更新xml时,如果发现更新的数据不符合相应的xsd,则会立即抛出验证错误异常.
Validation.java

package net.zj.xmlbeans.validation;

import java.io.File;

import java.io.IOException;

import java.util.ArrayList;

import java.util.Iterator;

import org.apache.xmlbeans.XmlException;

import org.apache.xmlbeans.XmlObject;

import org.apache.xmlbeans.XmlOptions;

import org.apache.xmlbeans.samples.validation.todolist.ItemType;

import org.apache.xmlbeans.samples.validation.todolist.TodolistDocument;

import org.apache.xmlbeans.samples.validation.todolist.TodolistDocument.Todolist;

public class Validation {

private static XmlOptions m_validationOptions;

public boolean isValidAfterChanges(String xmlPath) {

System.out.println("Validating after changes:");

// Set up the validation error listener.

ArrayList<String> validationErrors = new ArrayList<String>();

m_validationOptions = new XmlOptions();

m_validationOptions.setErrorListener(validationErrors);

TodolistDocument todoList = (TodolistDocument) parseXml(xmlPath, null);

// Schema defines the <name> element as required (minOccurs = '1').

// Add an error.

todoList.getTodolist().getItemArray(0).setName(null);

// During validation, errors are added to the ArrayList for

// retrieval and printing by the printErrors method.

boolean isValid = todoList.validate(m_validationOptions);

if (!isValid) {

printErrors(validationErrors);

}

return isValid;

}

public boolean isValidOnTheFly(String xmlPath) {

System.out.println("Validating on-the-fly:");

m_validationOptions = new XmlOptions();

m_validationOptions.setValidateOnSet();

TodolistDocument todoList = (TodolistDocument) parseXml(xmlPath,

m_validationOptions);

Todolist list = todoList.getTodolist();

ItemType firstItem = list.getItemArray(0);

// Schema defines the <id> element as allowing values up to 100.

// Add an error.

firstItem.setId(8587);

// This line will not be reached.

return todoList.validate();

}

public void printErrors(ArrayList<String> validationErrors) {

System.out.println("Errors discovered during validation:");

Iterator<String> iter = validationErrors.iterator();

while (iter.hasNext()) {

System.out.println(">> " + iter.next() + " ");

}

}

public XmlObject parseXml(String xmlFilePath, XmlOptions validationOptions) {

File xmlFile = new File(xmlFilePath);

XmlObject xml = null;

try {

xml = XmlObject.Factory.parse(xmlFile, validationOptions);

} catch (XmlException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}

return xml;

}

public static void main(String[] args) {

Validation thisSample = new Validation();

String xmlPath = "docs/todolist.xml";

// Use the validate method to validate an instance after

// updates.

thisSample.isValidAfterChanges(xmlPath);

// Use the VALIDATE_ON_SET option to validate an instance

// as updates are made.

thisSample.isValidOnTheFly(xmlPath);

}

}

结果:
Validating after changes:
Errors discovered during validation:
>> /root/dev_home/workspace/[ct]XmlBeans/docs/todolist.xml:0: error: cvc-elt.3.1: Element has xsi:nil attribute but is not nillable in element item@http://xmlbeans.apache.org/samples/validation/todolist

Validating on-the-fly:
Exception in thread "main" org.apache.xmlbeans.impl.values.XmlValueOutOfRangeException: int value (8,587) is greater than or equal to maxExclusive facet (100) for idType in namespace http://xmlbeans.apache.org/samples/validation/todolist
    at org.apache.xmlbeans.impl.values.XmlObjectBase$ValueOutOfRangeValidationContext.invalid(XmlObjectBase.java:285)
    at org.apache.xmlbeans.impl.values.JavaIntHolderEx.validateValue(JavaIntHolderEx.java:140)
    at org.apache.xmlbeans.impl.values.JavaIntHolderEx.set_int(JavaIntHolderEx.java:55)
    at org.apache.xmlbeans.impl.values.XmlObjectBase.set(XmlObjectBase.java:1609)
    at org.apache.xmlbeans.impl.values.XmlObjectBase.setIntValue(XmlObjectBase.java:1541)
    at org.apache.xmlbeans.samples.validation.todolist.impl.ItemTypeImpl.setId(Unknown Source)
    at net.zj.xmlbeans.validation.Validation.isValidOnTheFly(Validation.java:85)
    at net.zj.xmlbeans.validation.ValidationTest.main(ValidationTest.java:36)