java SAX解析器如何处理来自的错误数据。XML文件
我需要做一个程序,需要一段时间。xml文件,该文件使用Java中的SAX解析器来解析。xml文件,将其存储在arrayList中,然后调用方法以使用arrayList显示某些对象
我的程序需要能够处理给SAX解析器错误数据的用户,这样,如果它没有正在寻找的特定标记,那么它就不会中断。我需要它能够加载数据并使用“check”命令检查数据的完整性。例如,如果客户没有与其关联的帐户,程序将输出哪个客户没有帐户
下面,我为程序、处理程序和应用程序设置了任务。下面有错误数据的xml
计划的任务:
检查:此命令用于检查命名项的完整性。换句话说,它检查给定类型的所有条目是否正确。例如,如果命令为: 检查客户 该计划应列出所有没有任何帐户的客户(名字和姓氏)。相关命令包括: 检查帐户:列出任何没有关联地址的帐户号码 检查地址:列出任何没有相关仪表的地址 检查仪表:列出没有任何仪表读数的仪表id,或其读数与仪表类型不匹配的仪表id,例如,轮询仪表的推送读数
。xml文件:
<xml version="1.0" encoding="UTF-8">
<!-- Customer with no account -->
<customer lastName ="Anderson" firstName="Thomas">
</customer>
<!-- Account with no address -->
<customer lastName ="Baker" firstName="Susanne">
<account type="residential" accountNumber="999-999-99">
</account>
</customer>
<!-- Address with no meter -->
<customer lastName ="Charles" firstName="Henry">
<account type="residential" accountNumber="888-888-88">
<address type="apartment" unit="308" street="E 6th St." number="56" zipCode="13126"/>
</account>
</customer>
<!-- Meter with no readings -->
<customer lastName ="Davidson" firstName="Mary">
<account type="residential" accountNumber="666-666-66">
<address type="apartment" unit="308" street="W 9th St." number="67" zipCode="13126">
<meter id = "RM-4876-X4" brand="GE" type="poll" location = "West side of building"/>
</address>
</account>
</customer>
<!-- Meter with mismatched readings -->
<customer lastName ="Evans" firstName="Oscar">
<account type="residential" accountNumber="555-555-55">
<address type="house" street="E 10th St." number="78" zipCode="13126">
<meter id = "RM-4874-X4" brand="GE" type="poll" location = "North side">
<meterReading reading="650" date = "1413227815" flag="poll"/>
<meterReading reading="675" date = "1413314215" flag="push"/>
<meterReading reading="622" date = "1413400615" flag="poll"/>
</meter>
</address>
</account>
</customer>
</xml>
处理程序文件:
package csc241hw07;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.ZoneOffset;
import java.util.ArrayList;
import java.util.List;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
public class MyHandler extends DefaultHandler {
// Variables to hold current values
private ArrayList<Customer> customerList = new ArrayList<Customer>();
private Customer currentCustomer;
private Account currentAccount;
private Address currentAddress;
private Meter currentMeter;
//getter method for employee list
public ArrayList<Customer> getCustList() {
return customerList;
}
@Override
public void startElement(String uri, String localName, String qName, Attributes attributes)
throws SAXException {
if (qName.equalsIgnoreCase("customer")) {
//Create a customer object
String lastName = attributes.getValue("lastName");
String firstName = attributes.getValue("firstName");
currentCustomer = new Customer(lastName, firstName);
} else if (qName.equalsIgnoreCase("address")) {
// Create an Address object
String street = attributes.getValue("street");
int houseNumber = Integer.parseInt(attributes.getValue("number"));
String zipCode = attributes.getValue("zipCode");
String type = attributes.getValue("type");
String unit = attributes.getValue("unit");
if (type.equalsIgnoreCase("mailing")) {
// this is a mailing address -- assign to current customer
MailingAddress ma = new MailingAddress(street, houseNumber, zipCode, type);
currentCustomer.setMailingAddress(ma);
} else if (type.equalsIgnoreCase("house")) {
// Create a house
currentAddress = new House(street, houseNumber, zipCode, type);
} else if (type.equalsIgnoreCase("commercial")) {
// Create a commercial
currentAddress = new Commercial(street, houseNumber, zipCode, type);
} else if (unit != null) {
// Create an apartment
currentAddress = new Apartment(street, houseNumber, zipCode, type, unit);
} else {
System.out.println("Unknown address type:" + type);
}
if (currentAddress != null) {
// Assign this account to current address
currentAddress.setAccount(currentAccount);
currentAccount.addAddress(currentAddress);
}
} else if (qName.equalsIgnoreCase("meter")) {
// Create a meter object
String type = attributes.getValue("type");
String brand = attributes.getValue("brand");
String id = attributes.getValue("id");
if (type.equalsIgnoreCase("push")) {
currentMeter = new PushMeter(id, brand, type);
} else if (type.equalsIgnoreCase("poll")) {
currentMeter = new PollMeter(id, brand, type);
} else {
System.out.println("Unknown meter type: " + type);
}
if (currentMeter != null) {
// Set location
String location = attributes.getValue("location");
currentMeter.setLocation(currentAddress, location);
currentAddress.addMeter(currentMeter);
}
//System.out.println("METER:");
} else if (qName.equalsIgnoreCase("meterReading")) {
// Create a meter reading
//<meterReading reading="622" date = "1413400615" flag="push"/>
double reading = Double.parseDouble(attributes.getValue("reading"));
//System.out.println("DATE:" );
ZoneOffset z = ZoneOffset.ofHours(5);
long epoch = Long.parseLong(attributes.getValue("date"));
LocalDateTime d = LocalDateTime.ofEpochSecond(epoch,0,z);
//System.out.println("DATE:" + d.toString());
String flag = attributes.getValue("flag");
MeterReading mr = new MeterReading(reading, d, flag, currentMeter);
// Add this to current meter
currentMeter.addReading(mr);
//System.out.println("METERREADING:");
} else if (qName.equalsIgnoreCase("account")) {
// <account type="residential" accountNumber="876-543-21">
String type = attributes.getValue("type");
String acctNum = attributes.getValue("accountNumber");
if (type.equalsIgnoreCase("residential")) {
// residential account
currentAccount = new ResidentialAccount(acctNum, currentCustomer);
} else if (type.equalsIgnoreCase("commercial")) {
currentAccount = new CommercialAccount(acctNum, currentCustomer);
} else {
System.out.println("Unknown account type:" + type);
}
if (currentAccount != null) {
// Add this account to current customer
currentCustomer.addAccount(currentAccount);
}
}
}
@Override
public void endElement(String uri, String localName, String qName) throws SAXException {
if (qName.equalsIgnoreCase("customer")) {
customerList.add(currentCustomer);
currentCustomer = null;
} else if (qName.equalsIgnoreCase("meter")) {
currentMeter = null;
} else if (qName.equalsIgnoreCase("account")) {
currentAccount = null;
} else if (qName.equalsIgnoreCase("address")) {
currentAddress = null;
}
}
}
谢谢大家!
# 1 楼答案
您可以再添加一个“坏”客户列表,如:
并添加一些更改,将这些客户从“好”客户中分离出来。例如:
实际上,您可以根据需要以不同的方式实现
isCustomerGood
。现在您只需在解析结束时运行check
方法# 2 楼答案
首先,我认为坏数据并不是指导致解析异常的非良好格式的XML文件
如果上述假设是正确的,那么我认为您应该考虑使用XPath来查询数据文件并检查目标元素不存在的条件…
那么,为什么不使用XPath呢?XPath可以使代码更易于编写和维护