我在我的 Java 文件中硬编码了以下 JSON 对象
JSONObject notificationInfoJson = new JSONObject();
notificationInfoJson.put("title", "Payment Received");
notificationInfoJson.put("firstName", "Bhuvan");
notificationInfoJson.put("lastName", "Aggarwal");
notificationInfoJson.put("accountId", "111");
notificationInfoJson.put("paymentId", "555");
JSONArray accounts = new JSONArray();
for(int i=1; i<=2; i++) {
JSONObject account = new JSONObject();
account.put("accountId", 1000 + i);
account.put("paymentId", 1000 + i);
accounts.put(account);
}
notificationInfoJson.put("accounts", accounts);
// passing the below json in the template as input
JSONObject data = new JSONObject();
data.put("notificationInfo", notificationInfoJson);
Json 形成为:
{
"title": "Payment Received",
"firstName": "Bhuvan",
"lastName": "Aggarwal",
"accountId": "111",
"paymentId": "555",
"accounts": [
{
"accountId": 1001,
"paymentId": 1001
},
{
"accountId": 1002,
"paymentId": 1002
}
]
}
你能告诉我如何读取FTL文件中的Json数组吗？
FTL 文件:
<!doctype html>
<html lang="en">
<head>
<title>Notification</title>
</head>
<body>
<div class="page">
<p>Dear ${notificationInfo.firstName} ${notificationInfo.lastName}</p>
<p>Your payment has been received for the following accounts</p>
<#list notificationInfo.accounts?keys as account>
<p>Account ID: ${account.accountId}</p>
<p>Payment ID: ${account.paymentId}</p>
</#list>
<br>
<p>Thank you!</p>
</div>
</body>
</html>
错误:
2018-08-16 16:59:29,929 [ main] runtime ERROR Error executing FreeMarker template
FreeMarker template error:
For "." left-hand operand: Expected a hash, but this has evaluated to a string (wrapper: f.t.SimpleScalar):
==> account [in template "payment-received.ftl" at line 12, column 34]
----
FTL stack trace ("~" means nesting-related):
- Failed at: ${account.accountId} [in template "payment-received.ftl" at line 12, column 32]
----
Java stack trace (for programmers):
----
freemarker.core.NonHashException: [... Exception message was already printed; see it above ...]
at freemarker.core.Dot._eval(Dot.java:45)
at freemarker.core.Expression.eval(Expression.java:78)
at freemarker.core.Expression.evalAndCoerceToString(Expression.java:82)
at freemarker.core.DollarVariable.accept(DollarVariable.java:41)
at freemarker.core.Environment.visit(Environment.java:324)
at freemarker.core.MixedContent.accept(MixedContent.java:54)
at freemarker.core.Environment.visitByHiddingParent(Environment.java:345)
at freemarker.core.IteratorBlock$IterationContext.executeNestedBlockInner(IteratorBlock.java:240)
at freemarker.core.IteratorBlock$IterationContext.executeNestedBlock(IteratorBlock.java:220)
at freemarker.core.IteratorBlock$IterationContext.accept(IteratorBlock.java:194)
at freemarker.core.Environment.visitIteratorBlock(Environment.java:572)
at freemarker.core.IteratorBlock.acceptWithResult(IteratorBlock.java:78)
at freemarker.core.IteratorBlock.accept(IteratorBlock.java:64)
at freemarker.core.Environment.visit(Environment.java:324)
at freemarker.core.MixedContent.accept(MixedContent.java:54)
at freemarker.core.Environment.visit(Environment.java:324)
at freemarker.core.Environment.process(Environment.java:302)
at freemarker.template.Template.process(Template.java:325)
at com.amdocs.bil.notification.beans.TemplateEngine.generateMessage(TemplateEngine.java:125)
at com.amdocs.bil.notification.TestTemplateEngine.testTemplateEngine(TestTemplateEngine.java:51)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)
2018-08-16 16:59:29,936 [ main] TemplateEngine ERROR TemplateEngine.generateMessage: freemarker.core.NonHashException: For "." left-hand operand: Expected a hash, but this has evaluated to a string (wrapper: f.t.SimpleScalar):
==> account [in template "payment-received.ftl" at line 12, column 34]
----
FTL stack trace ("~" means nesting-related):
- Failed at: ${account.accountId} [in template "payment-received.ftl" at line 12, column 32]
----
最佳答案
我发现我必须在 FTL 文件中使用以下代码
notificationInfo.accounts will call JSONObject.get("accounts"), as FreeMarker knows the get(key) convention. The result of that is a JSONArray. But that doesn't implement List or anything familiar, so FreeMarker doesn't know how to list it.
使用下面的代码:
<#assign accounts = notificationInfo.accounts>
<#list 0 ..< accounts.length() as i>
<p>Account ID: ${accounts.get(i).accountId} </p>
<p>Payment ID: ${accounts.get(i).paymentId} </p>
</#list>
或者
更好的方法是编写 CustomObjectWrapper 并在配置中设置 ObjectWrapper。感谢@ddekany 的建议
cfg.setObjectWrapper(new JSONArrayObjectWrapper());
public class JSONArrayObjectWrapper extends DefaultObjectWrapper {
@Override
public TemplateModel handleUnknownType (Object obj) throws TemplateModelException {
if (obj instanceof JSONArray) {
return new JSONArraySequenceModel((JSONArray) obj);
}
return super.handleUnknownType(obj);
}
public class JSONArraySequenceModel implements TemplateSequenceModel {
private JSONArray jsonArray;
public JSONArraySequenceModel(JSONArray jsonArray) {
this.jsonArray = jsonArray;
}
@Override
public TemplateModel get(int index) throws TemplateModelException {
TemplateModel model = null;
try {
model = wrap(jsonArray.get(index));
} catch (JSONException e) {
e.printStackTrace();
}
return model;
}
@Override
public int size() throws TemplateModelException {
return jsonArray.length();
}
}
}
关于java - 如何读取FTL文件中的JSONArray？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/51875696/