Spring为什么返回String而不是HTML视图

huangapple
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英文:

Why is Spring returning a String instead of HTML view

问题

  1. 我只会翻译代码部分，不包括代码注释和文件名。
  3. Actor.java：
  5. ```java
  6. package com.dbtest.dbTest;
  8. import jakarta.persistence.Entity;
  9. import jakarta.persistence.Id;
  11. @Entity
  12. public class Actor {
  14.     @Id
  15.     private Integer actor_id;
  16.     private String first_name;
  17.     private String last_name;
  19.     private String last_update;
  21.     public Actor(Integer actor_id, String first_name, String last_name, String last_update) {
  22.         this.actor_id = actor_id;
  23.         this.first_name = first_name;
  24.         this.last_name = last_name;
  25.         this.last_update = last_update;
  26.     }
  28.     public Actor() {}
  30.     public Integer getActor_id() {
  31.         return actor_id;
  32.     }
  34.     public void setActor_id(Integer actor_id) {
  35.         this.actor_id = actor_id;
  36.     }
  38.     public String getFirst_name() {
  39.         return first_name;
  40.     }
  42.     public void setFirst_name(String first_name) {
  43.         this.first_name = first_name;
  44.     }
  46.     public String getLast_name() {
  47.         return last_name;
  48.     }
  50.     public void setLast_name(String last_name) {
  51.         this.last_name = last_name;
  52.     }
  54.     public String getLast_update() {
  55.         return last_update;
  56.     }
  58.     public void setLast_update(String last_update) {
  59.         this.last_update = last_update;
  60.     }
  62. }

ActorRepository.java：

  1. package com.dbtest.dbTest;
  3. import org.springframework.data.repository.CrudRepository;
  5. public interface ActorRepository extends CrudRepository<Actor, Integer> {
  6. }

MainController.java：

  1. package com.dbtest.dbTest;
  3. import java.util.Date;
  4. import java.text.SimpleDateFormat;
  5. import org.springframework.beans.factory.annotation.Autowired;
  6. import org.springframework.ui.Model;
  7. import org.springframework.web.bind.annotation.*;
  9. @RestController
  10. @RequestMapping(path="/actor")
  11. public class MainController {
  12.     @Autowired
  13.     private ActorRepository actorRepository;
  15.     @PostMapping(path="/add")
  16.     public @ResponseBody String addNewActor(@RequestParam String first_name, @RequestParam String last_name) {
  17.         Actor a = new Actor();
  18.         a.setActor_id(this.getMaxId()+1);
  19.         a.setFirst_name(first_name);
  20.         a.setLast_name(last_name);
  21.         Date date = new Date(System.currentTimeMillis());
  22.         SimpleDateFormat sdf = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
  23.         String formattedDate = sdf.format(date);
  24.         a.setLast_update(formattedDate);
  25.         actorRepository.save(a);
  26.         return "OK!";
  27.     }
  29.     @PostMapping(path="/delete")
  30.     public @ResponseBody String deleteActorById(@RequestParam int id) {
  31.         for(Actor a : this.actorRepository.findAll()) {
  32.             if(a.getActor_id() == id) {
  33.                 this.actorRepository.deleteById(id);
  34.                 return "DELETED!";
  35.             }
  36.         }
  37.         return "USER NOT FOUND " + id;
  38.     }
  40.     public int getMaxId() {
  41.         int max = 0;
  42.         for(Actor a : actorRepository.findAll()) {
  43.             if(a.getActor_id() > max) {
  44.                 max = a.getActor_id();
  45.             }
  46.         }
  47.         return max;
  48.     }
  50.     @GetMapping(path="/all")
  51.     public String showActor(Model model) {
  52.         model.addAttribute("actors", this.actorRepository.findAll());
  53.         return "actor";
  54.     }
  55. }

DbTestApplication.java：

  1. package com.dbtest.dbTest;
  3. import org.springframework.boot.SpringApplication;
  4. import org.springframework.boot.autoconfigure.SpringBootApplication;
  6. @SpringBootApplication
  7. public class DbTestApplication {
  9.     public static void main(String[] args) {
  10.         SpringApplication.run(DbTestApplication.class, args);
  11.     }
  13. }

actor.html：

  1. <!DOCTYPE html>
  2. <html xmlns:th="http://www.thymeleaf.org">
  3. <head>
  4. <meta charset="UTF-8">
  5. <title th:text="Listado de actores"></title>
  6. </head>
  7. <body>
  8.     <table>
  9.         <thead>
  10.             <tr>
  11.                 <th>ID</th>
  12.                 <th>Nombre</th>
  13.                 <th>Apellido</th>
  14.                 <th>&Uacute;ltima actualizaci&oacute;n</th>
  15.             </tr>
  16.         </thead>
  17.         <tbody>
  18.             <tr th:each="actor : ${actors}">
  19.                 <td th:text="${actor.actor_id}"></td>
  20.                 <td th:text="${actor.first_name}"></td>
  21.                 <td th:text="${actor.last_name}"></td>
  22.                 <td th:text="${actor.last_update}"></td>
  23.             </tr>
  24.         </tbody>
  25.     </table>
  26. </body>
  27. </html>

application.properties：

  1. spring.jpa.hibernate.ddl-auto=update
  2. spring.datasource.url=jdbc:mysql://${MYSQL_HOST:localhost}:3306/sakila
  3. spring.datasource.username=root
  4. spring.datasource.password=root
  5. spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
  6. logging.level.root=INFO
  7. logging.file.name=spring.log
  2. <details>
  3. <summary>英文:</summary>
  4. I&#180;m just learning Spring framework and recently founded the mentioned problem doing a simple app which tries to connect with a mysql database.
  5. [Here is a screen capture][1]
  6. My code is here also:
  7. Actor.java:
  8. package com.dbtest.dbTest;
  9. import jakarta.persistence.Entity;
  10. import jakarta.persistence.Id;
  11. @Entity
  12. public class Actor {
  13. @Id
  14. private Integer actor_id;
  15. private String first_name;
  16. private String last_name;
  17. private String last_update;
  18. public Actor(Integer actor_id, String first_name, String last_name, String last_update) {
  19. this.actor_id = actor_id;
  20. this.first_name = first_name;
  21. this.last_name = last_name;
  22. this.last_update = last_update;
  23. }
  24. public Actor() {}
  25. public Integer getActor_id() {
  26. return actor_id;
  27. }
  28. public void setActor_id(Integer actor_id) {
  29. this.actor_id = actor_id;
  30. }
  31. public String getFirst_name() {
  32. return first_name;
  33. }
  34. public void setFirst_name(String first_name) {
  35. this.first_name = first_name;
  36. }
  37. public String getLast_name() {
  38. return last_name;
  39. }
  40. public void setLast_name(String last_name) {
  41. this.last_name = last_name;
  42. }
  43. public String getLast_update() {
  44. return last_update;
  45. }
  46. public void setLast_update(String last_update) {
  47. this.last_update = last_update;
  48. }
  49. }
  50. ActorRepository.java:
  51. package com.dbtest.dbTest;
  52. import org.springframework.data.repository.CrudRepository;
  53. //This will be AUTO IMPLEMENTED by Spring into a Bean called userRepository
  54. //CRUD refers Create, Read, Update, Delete
  55. public interface ActorRepository extends CrudRepository&lt;Actor, Integer&gt; {
  56. }
  57. MainController.java:
  58. package com.dbtest.dbTest;
  59. import java.util.Date;
  60. import java.text.SimpleDateFormat;  
  61. import org.springframework.beans.factory.annotation.Autowired;
  62. import org.springframework.ui.Model;
  63. import org.springframework.web.bind.annotation.GetMapping;
  64. import org.springframework.web.bind.annotation.PostMapping;
  65. import org.springframework.web.bind.annotation.RequestMapping;
  66. import org.springframework.web.bind.annotation.RequestParam;
  67. import org.springframework.web.bind.annotation.ResponseBody;
  68. import org.springframework.web.bind.annotation.RestController;
  69. @RestController
  70. @RequestMapping(path=&quot;/actor&quot;)
  71. public class MainController {
  72. @Autowired
  73. private ActorRepository actorRepository;
  74. @PostMapping(path=&quot;/add&quot;) 
  75. public @ResponseBody String addNewActor(@RequestParam String first_name, @RequestParam String last_name) {
  76. Actor a = new Actor();
  77. a.setActor_id(this.getMaxId()+1);
  78. a.setFirst_name(first_name);
  79. a.setLast_name(last_name);
  80. Date date = new Date(System.currentTimeMillis());
  81. SimpleDateFormat sdf = new SimpleDateFormat(&quot;yyyy/MM/dd HH:mm:ss&quot;);
  82. String formattedDate = sdf.format(date);
  83. a.setLast_update(formattedDate);
  84. actorRepository.save(a);
  85. return &quot;OK!&quot;;
  86. }
  87. @PostMapping(path=&quot;/delete&quot;)
  88. public @ResponseBody String deleteActorById(@RequestParam int id) {
  89. for(Actor a : this.actorRepository.findAll()) {
  90. if(a.getActor_id() == id) {
  91. this.actorRepository.deleteById(id);
  92. return &quot;DELETED!&quot;;
  93. }
  94. }
  95. return &quot;USER NOT FOUND &quot;+id;
  96. }
  97. public int getMaxId() {
  98. int max = 0;
  99. for(Actor a :actorRepository.findAll()) {
  100. if(a.getActor_id() &gt; max) {
  101. max = a.getActor_id();
  102. }
  103. }
  104. return max;
  105. }
  106. @GetMapping(path=&quot;/all&quot;)
  107. public String showActor(Model model) {
  108. model.addAttribute(&quot;actors&quot;, this.actorRepository.findAll());
  109. return &quot;actor&quot;;
  110. }
  111. }
  112. DbTestApplication.java:
  113. package com.dbtest.dbTest;
  114. import org.springframework.boot.SpringApplication;
  115. import org.springframework.boot.autoconfigure.SpringBootApplication;
  116. @SpringBootApplication
  117. public class DbTestApplication {
  118. public static void main(String[] args) {
  119. SpringApplication.run(DbTestApplication.class, args);
  120. }
  121. }
  122. actor.html:
  123. &lt;!DOCTYPE html&gt;
  124. &lt;html xmlns:th=&quot;http://www.thymeleaf.org&quot;&gt;
  125. &lt;head&gt;
  126. &lt;meta charset=&quot;UTF-8&quot;&gt;
  127. &lt;title th:text=&quot;Listado de actores&quot;&gt;&lt;/title&gt;
  128. &lt;/head&gt;
  129. &lt;body&gt;
  130. &lt;table&gt;
  131. &lt;thead&gt;
  132. &lt;tr&gt;
  133. &lt;th&gt;ID&lt;/th&gt;
  134. &lt;th&gt;Nombre&lt;/th&gt;
  135. &lt;th&gt;Apellido&lt;/th&gt;
  136. &lt;th&gt;&#218;ltima actualizaci&#243;n&lt;/th&gt;
  137. &lt;/tr&gt;
  138. &lt;/thead&gt;
  139. &lt;tbody&gt;
  140. &lt;tr th:each=&quot;actor : ${actors}&quot;&gt;
  141. &lt;td th:each=&quot;${actor.actor_id}&quot;&gt;&lt;/td&gt;
  142. &lt;td th:each=&quot;${actor.first_name}&quot;&gt;&lt;/td&gt;
  143. &lt;td th:each=&quot;${actor.last_name}&quot;&gt;&lt;/td&gt;
  144. &lt;td th:each=&quot;${actor.last_update}&quot;&gt;&lt;/td&gt;
  145. &lt;/tr&gt;
  146. &lt;/tbody&gt;
  147. &lt;/table&gt;
  148. &lt;/body&gt;
  149. &lt;/html&gt;
  150. application.properties:
  151. spring.jpa.hibernate.ddl-auto=update
  152. spring.datasource.url=jdbc:mysql://${MYSQL_HOST:localhost}:3306/sakila
  153. spring.datasource.username=root
  154. spring.datasource.password=root
  155. spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
  156. logging.level.root=INFO
  157. logging.file.name=spring.log
  158. [Directory hierarchy here][2]
  159. Thanks in advance :)
  160. [1]: https://i.stack.imgur.com/fMGLc.png
  161. [2]: https://i.stack.imgur.com/AcZqK.png
  162. </details>
  163. # 答案1
  164. **得分**: 1
  165. `@Controller` 用于返回视图，`@RestController` 用于返回 JSON 响应。如果你想在 Thymeleaf 和 MVC 项目中使用，应该使用 `@Controller`。只需记住，在其他地方需要返回一个视图，而不是 `return &quot;OK!&quot;;`，因为这可能不是你的 HTML 页面的名称。
  166. <details>
  167. <summary>英文:</summary>
  168. `@Controller` is used to return a view, `@RestController` is used to return a JSON response. If you want to use thymeleaf and MVC project, you should be using `@Controller`
  169. Just keep in mind that that you need to return a view in other places not `return &quot;OK!&quot;;` because that is not probably a name of html page that you have.
  170. </details>

huangapple
  • 本文由 发表于 2023年4月19日 23:27:28
  • 转载请务必保留本文链接：https://go.coder-hub.com/76056298.html
  • html
  • java
  • spring
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