Spring boot 拦截器中的应用程序属性值

Question

有人可以帮我读取 Spring Boot 拦截器中的应用程序属性值（

preHandle

方法）吗？

我正在尝试在

preHandle

中写一些逻辑。该逻辑需要从

application.properties

文件中获取一些值。我使用

@Value

注释，但它始终为空。

谢谢

Answer 1

我建议以下解决方案

   @Configuration
public class XYZWebappWebConfig extends WebMvcConfigurerAdapter{



@Autowired
private XYZCustomWebappInterceptor xyzCustomWebappInterceptor;

 @Override
 public void addInterceptors(InterceptorRegistry registry){

    registry.addInterceptor(xyzCustomWebappInterceptor).addPathPatterns("/**");
   }

}

在实际课堂上你会做以下事情

// Custom interceptor class
@Component
public class XYZCustomInterceptor implements HandlerInterceptor{
@Value("${JWT.secret}")
private String jwtSecret;

@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse 
                           response, Object arg2) throws Exception {
//use the secret key
}
}

Answer 2

我解决了这个问题。这是详细信息。

解决前：

// Custom interceptor class
public class XYZCustomInterceptor implements HandlerInterceptor{
@Value("${JWT.secret}")
private String jwtSecret;

@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse 
                               response, Object arg2) throws Exception {

 // I am using the jwtSecret in this method for parsing the JWT
 // jwtSecret is NULL

  }
}


 //To Register (another class)

 @Configuration
 public class XYZWebappWebConfig extends WebMvcConfigurerAdapter{

 @Override
 public void addInterceptors(InterceptorRegistry registry){

    registry.addInterceptor(new                         
                 XYZCustomWebappInterceptor()).addPathPatterns("/**");
   }

}

当通过使用“new”关键字创建类来添加拦截器（XYZCustomWebappInterceptor）时，Spring boot将无法理解这些注释。这就是为什么当我在 XYZCustomWebappInterceptor 中读取这些值（来自 application.properties 的 jwtSecret）时，它为空。

我是如何解决的：

//Read those properties values in this class and pass it to interceptor's 
//constructor method. 

 @Configuration
 public class XYZWebappWebConfig extends WebMvcConfigurerAdapter{

 @Value("${JWT.secret}")
 private String jwtSecret;

 @Override
 public void addInterceptors(InterceptorRegistry registry){

    registry.addInterceptor(new                         

    XYZCustomWebappInterceptor(jwtSecret)).addPathPatterns("/**");
   }

}


// Custom interceptor class
public class XYZCustomInterceptor implements HandlerInterceptor{

private String jwtSecret;

RbsCustomWebappInterceptor(String secret){
    this.jwtSecret = secret;
}

@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse 
                               response, Object arg2) throws Exception {


 // I am using the jwtSecret in this method for parsing the JWT
 // Now, jwtSecret is NOT NULL

  }
}

谢谢大家对我的帮助。

Answer 3

对于非webmvc springboot应用。

如果您的要求是从属性文件中读取表名称，请使用下面的代码片段。

  @Slf4j
  @Component
  public class HibernateInterceptor extends EmptyInterceptor {

    private static final long serialVersionUID = 1L;
    
    @Value(value = "${user.documents.table.name}")
    private String targetTableName;
    
    private static String FINAL_TABLE_NAME;
    
    @PostConstruct
    public void init() {
        FINAL_TABLE_NAME = targetTableName;
    }
   
    @Override
    public String onPrepareStatement(String sql) {
          log.info("tagetTableName::"+FINAL_TABLE_NAME);
          //String prepedStatement = super.onPrepareStatement(sql);
          sql = sql.replaceAll("filenet_tfa_documents", FINAL_TABLE_NAME);
          //log.info("new table name:"+sql);
          return sql;
    }
    
}