1.get

@RequestMapping(value = "/user",method = RequestMethod.GET)
public String user(){
    System.out.println("查询所有用户信息");
    return "success";
}
@RequestMapping(value = "/user/{id}",method = RequestMethod.GET)
public String getUserById(){
    System.out.println("查询单个用户信息");
    return "success";
}

<a th:href="@{/user}" >查询所有用户</a>
<a th:href="@{/user/1}">查询单个用户</a>

2 post

@RequestMapping(value = "/user",method = RequestMethod.POST)
public String addUser(){
    System.out.println("添加单个用户信息");
    return "success";
}

<form th:action="@{/user}" method="post">
    用户名：<input type="text" name="username">
    年龄：<input type="text" name="age">
    <input type="submit" value="添加单个用户">
</form>