Javascript:从具有相同标签名称的两个XML节点检索数据的可靠方法是什么?

Question

功能齐全的示例。

问题：某些<UNIT>节点具有多个<NAMES>子节点，而其他节点则没有子节点。如果我不知道同级节点在节点树中的位置，如何从具有相同名称标记的同级节点<NAMES>检索数据？有没有一种简单的方法来获取它们的相对位置？

例如，如何检索<NAMES>标签中包含的"加利福尼亚"属性(我只成功检索了前 2 个属性)：
California Republic The Golden State California CA The Eureka State Golden West

注意：XML 节点的格式不一致，不允许我更改 XML。

/*retrieve specific XML nodes*/
function testResults() {
const { value } = myInputId;
const foundState = [...xmlDoc.querySelectorAll('STATE')]
.find(possibleMatch => possibleMatch.textContent === value);
const unit = foundState.parentElement;
var u_state = unit.querySelector('STATE') ? unit.querySelector('STATE').textContent: "Not Found";
var u_gdp = unit.querySelector('GDP') ? unit.querySelector('GDP').textContent: "Not Found";
var u_pop = unit.querySelector('POPULATION') ? unit.querySelector('POPULATION').textContent: "Not Found";
var u_code = unit.querySelector('CODE') ? unit.querySelector('CODE').textContent: "Not Found";
/*retrieve alternate names attributes from 1st "NAMES" node*/
var u_name1 = unit.querySelector('NAMES') ? unit.querySelector('NAMES').getAttribute('name'): "Not Found";
var u_other1 = unit.querySelector('NAMES') ? unit.querySelector('NAMES').getAttribute('other'): "Not Found";
/*retrieve alternate names attributes from 2nd "NAMES" node*/
var u_name2 = unit.querySelector('NAMES') ? unit.querySelector('NAMES').getAttribute('name'): "Not Found";
var u_other2 = unit.querySelector('NAMES') ? unit.querySelector('NAMES').getAttribute('other'): "Not Found";
/*retrieve alternate names attributes from 3rd "NAMES" node*/
var u_name3 = unit.querySelector('NAMES') ? unit.querySelector('NAMES').getAttribute('name'): "Not Found";
var u_other3 = unit.querySelector('NAMES') ? unit.querySelector('NAMES').getAttribute('other'): "Not Found";
/*show retrieved XML data*/
document.getElementById("u_state").innerHTML = u_state ;
document.getElementById("u_gdp").innerHTML = u_gdp ;
document.getElementById("u_pop").innerHTML = u_pop;
document.getElementById("u_code").innerHTML = u_code;
document.getElementById("u_name1").innerHTML = u_name1;
document.getElementById("u_other1").innerHTML = u_other1;
document.getElementById("u_name2").innerHTML = u_name2;
document.getElementById("u_other2").innerHTML = u_other2;
document.getElementById("u_name3").innerHTML = u_name3;
document.getElementById("u_other3").innerHTML = u_other3;
}
/*simulate xmlDoc*/
var parser, xmlDoc, x, i;
var text = `<STATE_DATA>
<UNIT>
<STATE>California</STATE>
<GDP>2,500,000,000,000</GDP>
<POPULATION>39,600,000</POPULATION>
<NAMES name='California Republic' other='The Golden State' />
<NAMES name='California' other='CA' />
<NAMES name='The Eureka State' other='Golden West' />
<CODE>CA</CODE>
</UNIT>
<UNIT>
<STATE>Texas</STATE>
<GDP>1,600,000,000,000</GDP>
<POPULATION>28,300,000</POPULATION>
<NAMES name='Republic of Texas' other='The Lone Star State' />
<NAMES name='Texas' other='TX' />
<CODE>TX</CODE>
</UNIT>
</STATE_DATA>
`;
parser = new DOMParser();
xmlDoc = parser.parseFromString(text, "text/xml");
/*submit input on ENTER*/
var n = document.getElementById("myInputId");
n.addEventListener("keyup", function(event) {
event.preventDefault();
if (event.keyCode === 13) {
document.getElementById("myButton").click();
}
});

<input list="myInput" id="myInputId" value="">
<button id="myButton" onClick="testResults()">submit</button>
<datalist id="myInput">
<option id="CA">California</option>
<option id="TX">Texas</option>
</datalist>
<!--display XML data here-->
<p>state: <span id="u_state"></span></p>
<p>gdp: <span id="u_gdp"></span></p>
<p>pop: <span id="u_pop"></span></p>
<p>code: <span id="u_code"></span></p>
<p>name1: <span id="u_name1"></span></p>
<p>other1: <span id="u_other1"></span></p>
<p>name2: <span id="u_name2"></span></p>
<p>other2: <span id="u_other2"></span></p>
<p>name3: <span id="u_name3"></span></p>
<p>other3: <span id="u_other3"></span></p>

正如您在代码片段中看到的，这是 XML：

<STATE_DATA>
<UNIT>
<STATE>California</STATE>
<GDP>2,500,000,000,000</GDP>
<POPULATION>39,600,000</POPULATION>
<NAMES name='California Republic' other='The Golden State' />
<NAMES name='California' other='CA' />
<NAMES name='The Eureka State' other='Golden West' />
<CODE>CA</CODE>
</UNIT>
<UNIT>
<STATE>Texas</STATE>
<GDP>1,600,000,000,000</GDP>
<POPULATION>28,300,000</POPULATION>
<NAMES name='Republic of Texas' other='The Lone Star State' />
<NAMES name='Texas' other='TX' />
<CODE>TX</CODE>
</UNIT>
</STATE_DATA>

Answer 1

只需遍历所有NAMES，这些是找到的UNIT的子项。不要为此使用querySelector，因为querySelector只会返回第一个匹配项，而不会返回下一个匹配项;请改用querySelectorAll。

const [name1, name2, name3] = unit.querySelectorAll('NAMES');
var u_name1 = name1 ? name1.getAttribute('name') : 'Not Found';
var u_other1 = name1 ? name1.getAttribute('other') : 'Not Found';
var u_name2 = name2 ? name2.getAttribute('name') : 'Not Found';
var u_other2 = name2 ? name2.getAttribute('other') : 'Not Found';
var u_name3 = name3 ? name3.getAttribute('name') : 'Not Found';
var u_other3 = name3 ? name3.getAttribute('other') : 'Not Found';

/*retrieve specific XML nodes*/
function testResults() {
const {
value
} = myInputId;
const foundState = [...xmlDoc.querySelectorAll('STATE')]
.find(possibleMatch => possibleMatch.textContent === value);
const unit = foundState.parentElement;
var u_state = unit.querySelector('STATE') ? unit.querySelector('STATE').textContent : "Not Found";
var u_gdp = unit.querySelector('GDP') ? unit.querySelector('GDP').textContent : "Not Found";
var u_pop = unit.querySelector('POPULATION') ? unit.querySelector('POPULATION').textContent : "Not Found";
var u_code = unit.querySelector('CODE') ? unit.querySelector('CODE').textContent : "Not Found";
const [name1, name2, name3] = unit.querySelectorAll('NAMES');
var u_name1 = name1 ? name1.getAttribute('name') : 'Not Found';
var u_other1 = name1 ? name1.getAttribute('other') : 'Not Found';
var u_name2 = name2 ? name2.getAttribute('name') : 'Not Found';
var u_other2 = name2 ? name2.getAttribute('other') : 'Not Found';
var u_name3 = name3 ? name3.getAttribute('name') : 'Not Found';
var u_other3 = name3 ? name3.getAttribute('other') : 'Not Found';
/*show retrieved XML data*/
document.getElementById("u_state").innerHTML = u_state;
document.getElementById("u_gdp").innerHTML = u_gdp;
document.getElementById("u_pop").innerHTML = u_pop;
document.getElementById("u_code").innerHTML = u_code;
document.getElementById("u_name1").innerHTML = u_name1;
document.getElementById("u_other1").innerHTML = u_other1;
document.getElementById("u_name2").innerHTML = u_name2;
document.getElementById("u_other2").innerHTML = u_other2;
document.getElementById("u_name3").innerHTML = u_name3;
document.getElementById("u_other3").innerHTML = u_other3;
}
/*simulate xmlDoc*/
var parser, xmlDoc, x, i;
var text =
"<STATE_DATA>" +
"<UNIT>" +
"<STATE>California</STATE>" +
"<GDP>2,500,000,000,000</GDP>" +
"<POPULATION>39,600,000</POPULATION>" +
/*THREE siblings with the same element tag name "NAMES"*/
"<NAMES name='California Republic' other='The Golden State' />" +
"<NAMES name='California' other='CA'/>" +
"<NAMES name='The Eureka State' other='Golden West'/>" +
"<CODE>CA</CODE>" +
"</UNIT>" +
"<UNIT>" +
"<STATE>Texas</STATE>" +
"<GDP>1,600,000,000,000</GDP>" +
"<POPULATION>28,300,000</POPULATION>" +
/*TWO siblings with the same element tag name "NAMES"*/
"<NAMES name='Republic of Texas' other='The Lone Star State' />" +
"<NAMES name='Texas' other='TX'/>" +
"<CODE>TX</CODE>" +
"</UNIT>" +
"</STATE_DATA>";
parser = new DOMParser();
xmlDoc = parser.parseFromString(text, "text/xml");
/*submit input on ENTER*/
var n = document.getElementById("myInputId");
n.addEventListener("keyup", function(event) {
event.preventDefault();
if (event.keyCode === 13) {
document.getElementById("myButton").click();
}
});

<input list="myInput" id="myInputId" value="">
<button id="myButton" onClick="testResults()">submit</button>
<datalist id="myInput">
<option id="CA">California</option>
<option id="TX">Texas</option>
</datalist>
<!--display XML data here-->
<p>state: <span id="u_state"></span></p>
<p>gdp: <span id="u_gdp"></span></p>
<p>pop: <span id="u_pop"></span></p>
<p>code: <span id="u_code"></span></p>
<p>name1: <span id="u_name1"></span></p>
<p>other1: <span id="u_other1"></span></p>
<p>name2: <span id="u_name2"></span></p>
<p>other2: <span id="u_other2"></span></p>
<p>name3: <span id="u_name3"></span></p>
<p>other3: <span id="u_other3"></span></p>

但是，如果允许的话，最好使用数组而不是具有硬编码索引名称的变量。