How to inject spring-managed bean into servlet

Idea: configure the servlet as a spring bean to inject other beans, and then use the proxy servlet to assist in configuration and operation:

 

I. Proxy servlet writing:

 

View sourceprint? 01 import javax. servlet. ServletException;

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03 import javax. servlet. http. HttpServlet;

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05 import javax. servlet. http. HttpServletRequest;

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07 import javax. servlet. http. HttpServletResponse;

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09

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11 import org. apache. commons. logging. Log;

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13 import org. apache. commons. logging. LogFactory;

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15 import org. springframework. web. context. WebApplicationContext;

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17 import org. springframework. web. context. support. WebApplicationContextUtils;

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19

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21 /**

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23 * HttpServlet proxy

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25 * @ author lwei

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27 * @ since 2011-03-17

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29 * @ version 1.0

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31 */

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33 public class HttpServletProxy extends HttpServlet {

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35 /**

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37 * random serialVersionUID

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39 */

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41 private static final long serialVersionUID =-7208519469035631940L;

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43 Log logger = LogFactory. getLog (HttpServletProxy. class );

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45 private String targetServlet;

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47 private HttpServlet proxy;

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49

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51 public void init () throws ServletException {

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53 this.tar getServlet = getInitParameter ("targetServlet ");

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55 getServletBean ();

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57 proxy. init (getServletConfig ());

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59 logger.info (targetServlet + "was inited by HttpServletProxy successfully ......");

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61}

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63

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65 private void getServletBean (){

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67 WebApplicationContext wac =

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69 WebApplicationContextUtils. getRequiredWebApplicationContext (getServletContext ());

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71 this. proxy = (HttpServlet) wac. getBean (targetServlet );

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73}

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75

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77 @ Override

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79 public void service (HttpServletRequest request, HttpServletResponse response)

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81 throws ServletException, IOException, RuntimeException {

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83 proxy. service (request, response );

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85}

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87}

Ii. Business servlet writing:

 

 

View sourceprint? 01 import java. io. IOException;

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03

04

05 import javax. servlet. ServletException;

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07 import javax. servlet. ServletOutputStream;

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09 import javax. servlet. http. HttpServlet;

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11 import javax. servlet. http. HttpServletRequest;

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13 import javax. servlet. http. HttpServletResponse;

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15

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17 /**

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19 * @ author lwei

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21 */

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23 public class UserCheckServlet extends HttpServlet {

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25

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27 /**

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29 * random serialVersionUID

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31 */

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33 private static final long serialVersionUID = 307563511351_22929l;

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35

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37 private UserService userService; (UserService is a spring-hosted bean that is injected using the set method)

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39

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41 // If configured directly in the spring configuration file, the set method is not required.

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43 // how to inject beans depends on my habits of using spring

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45 public void setUserService (UserService userService ){

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47 this. userService = userService;

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49}

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51

52

53 public UserCheckServlet (){

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55 super ();

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57}

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59

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61 public void init () throws ServletException {

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63 super. init ();

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65}

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67

68

69 @ Override

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71 public void service (HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse)

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73 throws ServletException, IOException, RuntimeException {

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75 ....

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77 ....

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79 userService. getUserByCode (); (use of bean after injection)

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81 ....

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83 ....

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85}

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87}

 

 

3. bean configured as spring in serlvet:

<Bean id = "userCheckServlet" class = "com. XXX. xxxxx. web. UserCheckServlet"/>

4. Configure the service servlet in web. xml:

 

View sourceprint? 01 <servlet>

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03 <servlet-name> UserCheckProxy </servlet-name>

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05 <servlet-class> com. XXX. xxxx. web. HttpServletProxy </servlet-class>

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07 <init-param>

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09 <param-name> targetServlet </param-name>

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11 <param-value> userCheckServlet </param-value> (name of the bean configured as spring in the business servlet)

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13 </init-param>

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15 </servlet>

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17 <servlet-mapping>

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19 <servlet-name> UserCheckProxy </servlet-name>

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21 <url-pattern>/UserCheck </url-pattern>

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23 </servlet-mapping>

Author: "lwei's blog"