How EL gets context parameter values ​​(code attached)

This time I will show you how EL obtains the context parameter value (with code). What are the precautions for EL to obtain the context parameter value? The following is a practical case, let's take a look.

1. actionReturn parameters to the page

/**
 * 测试js中获取后台传值
 * @param model
 * @param req
 * @return	String
 */
@RequestMapping("getValue")
public String getValue(Model model, HttpServletRequest req){
	model.addAttribute("stringValue", "测试在js中取值...");
	model.addAttribute("numberValue", 111);
	List<String> list = new ArrayList<String>();
	list.add("aaa");
	list.add("bbb");
	list.add("ccc");
	model.addAttribute("arrayValue", list);
	model.addAttribute("jsonStringValue", JSON.toJSONString(list));
	User user = new User();
	user.setUserID("1");
	user.setUserName("test");
	user.setMobile("13800000000");
	user.setEmail("test@163.com");
	user.setNickName("test");
	model.addAttribute("objJsonString", JSON.toJSONString(user));
	return "/getValue.htm";
}

2. Use EL in js ExpressionGet the parameter value

<script type="text/javascript">
	$(function(){
		var stringValue = '${stringValue}';
		console.log('stringValue-------------' + stringValue);
				
		var numberValue = ${numberValue};
		console.log('numberValue-------------' + numberValue);
				
		var jsonStringValue = ${jsonStringValue};
		console.log('jsonValue---------------' + jsonStringValue);
				
		var jsonStringValue1 = '${jsonStringValue}';
		console.log('jsonValue1---------------' + jsonStringValue1); 
				
		var objJsonString = '${objJsonString}';
		console.log("objJsonString------------------- " + objJsonString);
		var obj = JSON.parse(objJsonString);
		console.log("userName ------------ " + obj.userName);
	});
</script>

Remarks: Get the numeric parameter value, not used in EL expressions in js Add quotation marks; take the string type parameter value. EL expressions in js need to be quoted; object and collection type parameter values ​​need to be converted using JSON.toJSONString() in the background.

I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website!

Recommended reading:

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