Detailed explanation of the steps for EL to obtain context parameters

This time I will give you a detailed explanation of the steps for EL to obtain context parameters. What are the precautions for EL to obtain context parameters? 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!

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