如何在spring-boot中用application.properties制作config类？6金钱.anslist

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我有两个问题。首先，我在spring-boot中测试了db连接，如下图所示。

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• @RunWith(SpringJUnit4ClassRunner.class)
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• public class OracleConnectionTest {
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•     private static final Logger LOGGER = LoggerFactory.getLogger(OracleConnectionTest.class);
  
• 
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•     private static final String DRIVER = "oracle.jdbc.driver.OracleDriver";
  
•     private static final String URL = "jdbcracle:thin127.0.0.1:1521rcl";
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•     private static final String USER = "user1";
  
•     private static final String PW = "user1";
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• 
  
•     @Test
  
•     public void testConnection() throws ClassNotFoundException {
  
•         Class.forName(DRIVER);
  
• 
  
•         try (Connection connection = DriverManager.getConnection(URL, USER, PW)) {
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•             LOGGER.info(String.valueOf(connection));
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•         } catch (SQLException e) {
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•             LOGGER.error(String.valueOf(e));
  
•         }
  
•     }}
  

但是我想把DB信息分离到application.properties文件(resourcesapplication.properties)中去，所以我需要制作JdbcConfig文件(java Bean)。所以我需要制作JdbcConfig文件(java bean)，如下图所示(含测试代码)。

• @Getter
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• @Setter
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• @Configuration
  
• @ConfigurationProperties(prefix = "spring.datasource")
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• public class JdbcConfig {
  
•     @Value("${driver-class-name}")
  
•     private String driverClassName;
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•     @Value("${url}")
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•     private String url;
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•     @Value("${username}")
  
•     private String username;
  
•     @Value("${password}")
  
•     private String password;
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• 
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•     @Override
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•     public String toString() {
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•         return "JdbcConfig[" +
  
•                 "driverClassName=" + driverClassName
  
•                 + ", url=" + url
  
•                 + ", username=" + username
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•                 + ", password=" + password
  
•                 + "]";
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•     }}
  

• @RunWith(SpringJUnit4ClassRunner.class)
  
• @ContextConfiguration(classes = {JdbcConfig.class})
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• public class OracleConnectionTest {
  
•     private static final Logger LOGGER = LoggerFactory.getLogger(OracleConnectionTest.class);
  
• 
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•     @Autowired
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•     private JdbcConfig jdbcConfig;
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• 
  
•     @Test
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•     public void testConnection() throws ClassNotFoundException {
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•         LOGGER.info("Test: {}", jdbcConfig.toString());
  
• 
  
•         Class.forName(jdbcConfig.getDriverClassName());
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• 
  
•         try (Connection connection = DriverManager.getConnection(jdbcConfig.getUrl(), jdbcConfig.getUsername(), jdbcConfig.getPassword())) {
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•             LOGGER.info(String.valueOf(connection));
  
•         } catch (SQLException e) {
  
•             LOGGER.error(String.valueOf(e));
  
•         }
  
•     }}
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但是，我遇到了 NullPointerException(JdbcConfig) 运行时 testConnection(). 所以我必须这样修改JdbcConfig类。

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• @Getter
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• @Setter
  
• @Component
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• @PropertySource("classpath:application.properties")
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• public class JdbcConfig {
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•     @Value("${spring.datasource.driver-class-name}")
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•     private String driverClassName;
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•     @Value("${spring.datasource.url}")
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•     private String url;
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•     @Value("${spring.datasource.username}")
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•     private String username;
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•     @Value("${spring.datasource.password}")
  
•     private String password;
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• 
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•     @Override
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•     public String toString() {
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•         return "JdbcConfig[" +
  
•                 "driverClassName=" + driverClassName
  
•                 + ", url=" + url
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•                 + ", username=" + username
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•                 + ", password=" + password
  
•                 + "]";
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•     }}
  

我不明白为什么 @Configuration & @ConfigurationProperties 注解不适用。其次，我以为spring-boot会自动创建 DataSource(javax.sql.DataSource) 通过阅读 application.properties. 例如，我的朋友在没有创建DataSource bean(class)的情况下测试成功。但是我遇到了一个错误，就像下面的错误一样，所以我必须创建DataSource bean。

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• Unsatisfied dependency expressed through field 'ds'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'javax.sql.DataSource' available
  

所以我必须创建DataSource bean。我不知道为什么我朋友的代码不创建bean(DataSource)就能自动运行，而我却不一样。我的代码如下。

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• @RunWith(SpringJUnit4ClassRunner.class)
  
• @ContextConfiguration(classes = DataSourceConfig.class)
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• public class DataSourceTest {
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•     private static final Logger LOGGER = LoggerFactory.getLogger(DataSourceTest.class);
  
• 
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•     @Autowired
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•     private DataSource ds;  // DataSource & DriverManagerDataSource
  
• 
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•     @Test
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•     public void testConnection() throws Exception {
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•         try (Connection con = ds.getConnection()) {
  
•             LOGGER.info(String.valueOf(con));
  
•         } catch (Exception e) {
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•             e.printStackTrace();
  
•         }
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•     }
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• }
  

• @Configuration
  
• @Import(JdbcConfig.class)
  
• public class DataSourceConfig {
  
•     private static final Logger LOGGER = LoggerFactory.getLogger(DataSourceConfig.class);
  
• 
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•     @Bean
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•     public DataSource dataSource(JdbcConfig jdbcConfig) {
  
•         LOGGER.debug("Test: {}", jdbcConfig.toString());
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•         DriverManagerDataSource dataSource = new DriverManagerDataSource();
  
•         dataSource.setDriverClassName(jdbcConfig.getDriverClassName());
  
•         dataSource.setUrl(jdbcConfig.getUrl());
  
•         dataSource.setUsername(jdbcConfig.getUsername());
  
•         dataSource.setPassword(jdbcConfig.getPassword());
  
•         return dataSource;
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•     }
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• }
  

谢谢你阅读我的长文。添加一个属性文件(application.properties)

• # JSP
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• spring.mvc.view.prefix = /WEB-INF/jsp/
  
• spring.mvc.view.suffix = .jsp
  
• 
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• # language setting
  
• spring.http.encoding.charset = UTF-8
  
• spring.http.encoding.enabled = true
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• spring.http.encoding.force = true
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• 
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• # Database Info
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• spring.datasource.driver-class-name = oracle.jdbc.driver.OracleDriver
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• spring.datasource.url = jdbcracle:thin127.0.0.1:1521rcl
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• spring.datasource.username = user1spring.datasource.password = user1
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