Spring Boot Thymeleaf 星號語法*{...}用法如下。
參考「Spring Boot + Thymeleaf 簡單範例」搭建好Spring Boot Thymeleaf專案，下面依此進行修改。
*{...}作用和${...}用法類似皆用來從環境中取得變數，差別在於*{...}在有th:object選定物件的情況下只會取得該物件的屬性。
建立一個Employee類，此物件的屬性將在hello.html中以${...}及*{...}取得。
Employee
package com.abc.demo.model;
public class Employee {
private long id;
private String name;
private int age;
// getters and setters
}
在導向hello.html的DemoController.hello()建立Employee物件並設為model attribute名稱為"employee"。
DemoController
package com.abc.demo.controller;
import com.abc.demo.model.Employee;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
@Controller
public class DemoController {
@GetMapping("/hello")
public String hello(
@RequestParam(name = "name", required = false, defaultValue = "World") String name,
Model model) {
model.addAttribute("name", name); // set request attribute
Employee employee = new Employee();
employee.setId(1);
employee.setName("John");
employee.setAge(29);
model.addAttribute("employee", employee);
return "hello"; // forward to hello.html
}
}
在thymeleaf模板hello.html使用${...}及*{...}取得Employee的屬性。在<div>使用th:object="${employee}"獲取"employee"的物件，所以子標籤<li>的*{id}相當於${employee.id}。此即為星號語法的效果。
hello.html
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>Hello Thymeleaf</title>
</head>
<body>
<p th:text="'Hello, ' + ${name} + '!'"/>
<h3>Employee</h3>
<div th:object="${employee}">
<ul>
<li>ID:<span th:text="*{id}"></span></li> <!-- 相當於${emloyee.id} -->
<li>Name:<span th:text="${employee.name}"></span></li>
<li>Age:<span th:text="${#object.age}"></span></li>
</ul>
</div>
</body>
</html>
啟動專案在瀏覽器輸入http://localhost:8080/demo/hello顯示結果如下。
參考github。
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