[SpringMVC starts from 0] SpringMVC RESTFul actual case -- implementation of modification function

1, Echo function

Before the actual modification, you need to have an echo function, that is, you can see the data after clicking the edit page.

1. Modify operation hyperlink

The request address here is the same as the deleted address. You need to bring the id because you want to echo the data of this id.

  <td>
      <a @click="deleteEmployee" th:href="@{/employee/} + ${employee.id}">delete</a>
      <a th:href="${/employee/} + ${employee.id}">to update</a>
  </td>

After redeployment, move the mouse over the update button, and the requested address can also be displayed in the lower left corner of the browser.

2. Method of processing controller

Because this ECHO operation request is not only to return the view, but also to obtain the information under the id, it cannot be realized by configuring the view controller, and the controller method needs to be written.

Continue to add methods under class EmployeeController:

    @RequestMapping(value = "/employee/{id}", method = RequestMethod.GET)
    public String getEmployeeById(@PathVariable("id") Integer id, Model model) {
        Employee employee = employeeDao.get(id);
        model.addAttribute("employee", employee);
        return "employee_update";
    }

Besides id, there is also a formal parameter model, because the queried data needs to be shared in the request field. Finally, return to the modification page.

3. Create and modify page

New employee_update.html, you can copy the new page and modify it:

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>Update employee</title>
</head>
<body>

<form th:action="@{/employee}" method="post">
    <input type="hidden" name="_method" value="put">
    <input type="hidden" name="id" th:value="${employee.id}">
    lastName:<input type="text" name="lastName" th:value="${employee.lastName}"><br>
    email:<input type="text" name="email" th:value="${employee.email}"><br>
    gender:<input type="radio" name="gender" value="1" th:field="${employee.gender}">male
    <input type="radio" name="gender" value="0" th:field="${employee.gender}">female<br>
    <input type="submit" value="to update"><br>
</form>

</body>
</html>

Because echo is required, value should be added, such as th:value="${employee.id}".

In addition, there are 2 hidden fields:

< input type = "hidden" name = "id" th: value = "${employee. id}" >, used to store id.
< input type = "hidden" name = "_method" value = "put" >, used to send put requests.

Redeploy the test and click the update button:

Echo succeeded.

2, Modify function

1. Add controller method

    @RequestMapping(value = "/employee", method = RequestMethod.PUT)
    public String updateEmployee(Employee employee) {
        employeeDao.save(employee);
        return "redirect:/employee";
    }

Call the save() method in dao, and finally redirect to the list page.

2. Test effect

After redeployment, click Update to modify 3 data to test the effect.

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