Spring Boot JDBC连接

Question

我将尝试配置Spring Boot，以便将Tomcat连接池连接到我的生产数据库。我的应用程序不是Web应用程序（我也很难向Spring表达这一点）。我有一个启动类和另外3个类。 代码：

@Configuration

@EnableAutoConfiguration(exclude = DataSourceAutoConfiguration.class)

public class Starter {

private static Logger logger;

@Autowired
private static MyController controller;

public static void main(String[] args) {

//      SpringApplication.setWebEnvironment(false);

    SpringApplication.run(Starter.class, args);

    LogbackConfigLoader lcl = new LogbackConfigLoader();
    if (lcl.init()) {
        logger = LoggerFactory.getLogger(Starter.class);
        logger.debug("Initialized....");
    }
    else{
        logger = LoggerFactory.getLogger(Starter.class);
    }


    logger.info(controller.getProva());

}


}

这是配置信息： `

`

@Configuration

@ConfigurationProperties(prefix="datasource.NIS")

public class NISDBConfiguration {

private String jdbcInterceptors;
private long validationInterval = 30000;

private org.apache.tomcat.jdbc.pool.DataSource pool;

@Value("${driver-class-name}")
private String driverClassName;

@Value("${url}")
private String url;

@Value("${username}")
private String username;

@Value("${password}")
private String password;

@Value("${maxActive}")
private int maxActive = 30;

@Value("${maxIdle}")
private int maxIdle = 8;

@Value("${minIdle}")
private int minIdle = 8;

@Value("${initialSize}")
private int initialSize = 10;

private String validationQuery;

private boolean testOnBorrow;

private boolean testOnReturn;

private boolean testWhileIdle;

private Integer timeBetweenEvictionRunsMillis;

private Integer minEvictableIdleTimeMillis;

private Integer maxWaitMillis;

public String getJdbcInterceptors() {
    return jdbcInterceptors;
}

public void setJdbcInterceptors(String jdbcInterceptors) {
    this.jdbcInterceptors = jdbcInterceptors;
}

public long getValidationInterval() {
    return validationInterval;
}

public void setValidationInterval(long validationInterval) {
    this.validationInterval = validationInterval;
}

public org.apache.tomcat.jdbc.pool.DataSource getPool() {
    return pool;
}

public void setPool(org.apache.tomcat.jdbc.pool.DataSource pool) {
    this.pool = pool;
}

public String getDriverClassName() {
    return driverClassName;
}

public void setDriverClassName(String driverClassName) {
    this.driverClassName = driverClassName;
}

public String getUrl() {
    return url;
}

public void setUrl(String url) {
    this.url = url;
}

public String getUsername() {
    return username;
}

public void setUsername(String username) {
    this.username = username;
}

public String getPassword() {
    return password;
}

public void setPassword(String password) {
    this.password = password;
}

public int getMaxActive() {
    return maxActive;
}

public void setMaxActive(int maxActive) {
    this.maxActive = maxActive;
}

public int getMaxIdle() {
    return maxIdle;
}

public void setMaxIdle(int maxIdle) {
    this.maxIdle = maxIdle;
}

public int getMinIdle() {
    return minIdle;
}

public void setMinIdle(int minIdle) {
    this.minIdle = minIdle;
}

public int getInitialSize() {
    return initialSize;
}

public void setInitialSize(int initialSize) {
    this.initialSize = initialSize;
}

public String getValidationQuery() {
    return validationQuery;
}

public void setValidationQuery(String validationQuery) {
    this.validationQuery = validationQuery;
}

public boolean isTestOnBorrow() {
    return testOnBorrow;
}

public void setTestOnBorrow(boolean testOnBorrow) {
    this.testOnBorrow = testOnBorrow;
}

public boolean isTestOnReturn() {
    return testOnReturn;
}

public void setTestOnReturn(boolean testOnReturn) {
    this.testOnReturn = testOnReturn;
}

public boolean isTestWhileIdle() {
    return testWhileIdle;
}

public void setTestWhileIdle(boolean testWhileIdle) {
    this.testWhileIdle = testWhileIdle;
}

public Integer getTimeBetweenEvictionRunsMillis() {
    return timeBetweenEvictionRunsMillis;
}

public void setTimeBetweenEvictionRunsMillis(
        Integer timeBetweenEvictionRunsMillis) {
    this.timeBetweenEvictionRunsMillis = timeBetweenEvictionRunsMillis;
}

public Integer getMinEvictableIdleTimeMillis() {
    return minEvictableIdleTimeMillis;
}

public void setMinEvictableIdleTimeMillis(Integer minEvictableIdleTimeMillis) {
    this.minEvictableIdleTimeMillis = minEvictableIdleTimeMillis;
}

public Integer getMaxWaitMillis() {
    return maxWaitMillis;
}

public void setMaxWaitMillis(Integer maxWaitMillis) {
    this.maxWaitMillis = maxWaitMillis;
} 

@Bean(name = "dsNIS") 
public DataSource dataSource() { 
    this.pool = new org.apache.tomcat.jdbc.pool.DataSource();
    this.pool.setDriverClassName(getDriverClassName());
    this.pool.setUrl(getUrl());
    this.pool.setUsername(getUsername());
    this.pool.setPassword(getPassword());
    this.pool.setInitialSize(getInitialSize());
    this.pool.setMaxActive(getMaxActive());
    this.pool.setMaxIdle(getMaxIdle());
    this.pool.setMinIdle(getMinIdle());
    this.pool.setTestOnBorrow(isTestOnBorrow());
    this.pool.setTestOnReturn(isTestOnReturn());
    this.pool.setTestWhileIdle(isTestWhileIdle());

    if (getTimeBetweenEvictionRunsMillis() != null) {
        this.pool
                .setTimeBetweenEvictionRunsMillis(getTimeBetweenEvictionRunsMillis());
    }
    if (getMinEvictableIdleTimeMillis() != null) {
        this.pool.setMinEvictableIdleTimeMillis(getMinEvictableIdleTimeMillis());
    }
    this.pool.setValidationQuery(getValidationQuery());
    this.pool.setValidationInterval(this.validationInterval);
    if (getMaxWaitMillis() != null) {
        this.pool.setMaxWait(getMaxWaitMillis());
    }
    if (this.jdbcInterceptors != null) {
        this.pool.setJdbcInterceptors(this.jdbcInterceptors);
    }
    return this.pool;

} 

@PreDestroy
public void close() {
    if (this.pool != null) {
        this.pool.close();
    }
}

@Bean(name = "jdbcNIS") 
public JdbcTemplate jdbcTemplate(DataSource dsNIS) { 
    return new JdbcTemplate(dsNIS); 
}

} `

the repository

package org.hp.data;

@Repository

public class NisRepository {

protected final Logger log = LoggerFactory.getLogger(getClass()); 


@Autowired 
@Qualifier("jdbcNIS") 
protected JdbcTemplate jdbc; 


public String getItem(long id) { 
    return jdbc.queryForObject("SELECT * FROM sb_item WHERE id=?", itemMapper, id); 
} 

private static final RowMapper<String> itemMapper = new RowMapper<String>() {
    @Override
    public String mapRow(ResultSet rs, int rowNum) throws SQLException { 
        String item = rs.getString("title"); 
        return item; 
    } 
};


public JdbcTemplate getJdbc() {
    return jdbc;
}

public void setJdbc(JdbcTemplate jdbc) {
    this.jdbc = jdbc;
} 

}

控制器

@Controller
public class MyController {


@Autowired 
private NisRepository items; 

public NisRepository getItems() {
    return items;
}

public void setItems(NisRepository items) {
    this.items = items;
}

public String getProva(){
    return items.getItem(10);
}

但是当我运行应用程序时，总是会出现NullPointerException异常，因为MyController没有自动装配并且始终为空。

我也尝试使用new创建一个新实例（但我相信这不正确，因为这与Spring MVC模式不符）。

问题在哪里？

提前致谢。

- Raffaele

---

Spring不会自动装配静态字段，它只会自动装配Spring Bean的实例字段。如果您不希望将您的应用程序视为Web应用程序，为什么要使用@Controller注解来注释Spring MVC（即Web）控制器？ - JB Nizet

我对Spring还很陌生，所以对于我的显而易见的问题感到抱歉。实际上，我在这里需要的唯一一件事就是连接池，以便并行执行一些任务。 - Raffaele

我尝试修改MyController类，删除@Controller注释。我还从Starter类中删除了静态字段，并添加了以下内容：MyController controller = new MyController(); logger.info(controller.getProva()); - Raffaele

但是在MyController中，NisRepository自动装配变量仍然会出现NullPointer错误。 - Raffaele

Answer 1

您正在使用Spring Boot，但非常努力地试图不使用它。您还声明您没有使用Web应用程序，但是为什么您有一个@Controller？

要解决您的问题，请删除DataSource和JdbcTemplate的配置，Spring Boot将为您配置这些内容。这基本上意味着删除您的NISDBConfiguration类。只需将正确的属性添加到application.properties文件中即可。

spring.datasource.driver-class-name=<your-driver-here>
spring.datasource.url=<your-url>
spring.datasource.username=<your-username>
spring.datasource.password=<your-password>

当然，您需要的其他属性，请查看参考指南以获取更多属性。

从您的存储库中删除JdbcTemplate属性中的@Qualifier，您也不需要getter和setter。我建议使用基于构造函数的注入。

package org.hp.data;

@Repository
public class NisRepository {

    protected final Logger log = LoggerFactory.getLogger(getClass()); 

    protected final JdbcTemplate jdbc; 

    @Autowired
    public NisRepository(JdbcTemplate jbc) {
        this.jdbc=jdbc;
    }

    public String getItem(long id) { 
        return jdbc.queryForObject("SELECT * FROM sb_item WHERE id=?", itemMapper, id); 
    } 


    private static final RowMapper<String> itemMapper = new RowMapper<String>() {
        @Override
        public String mapRow(ResultSet rs, int rowNum) throws SQLException { 
            String item = rs.getString("title"); 
            return item; 
        } 
    };

}

如果您没有网络应用程序，请将@Controller替换为@Service。

然后重新编写您的启动类。

@SpringBootApplication
public class Starter {

    private static Logger logger;

    public static void main(String[] args) {

    //      SpringApplication.setWebEnvironment(false);

        ApplicationContext ctx = SpringApplication.run(Starter.class, args);

        LogbackConfigLoader lcl = new LogbackConfigLoader();
        if (lcl.init()) {
            logger = LoggerFactory.getLogger(Starter.class);
            logger.debug("Initialized....");
        }
        else{
            logger = LoggerFactory.getLogger(Starter.class);
        }

        MyController controller = ctx.getBean(MyController.class);
        logger.info(controller.getProva());

    }


}

看起来你也在尝试规避Spring Boot的配置加载？试着与框架合作而不是反对它。

如果你没有web应用程序，请不要将spring-boot-starter-web包含在你的依赖项中，并确保你没有任何其他与Web相关的内容。Spring Boot自动检测Web环境并尝试引导那些类，如果它们不存在，它将只运行为普通的Java应用程序。

- M. Deinum

---

我需要配置两个不同的数据源。通过更好地学习框架，特别是Spring Boot，我解决了我的问题。我为每个数据源配置使用了单个Bean类，并通过使用application.properties（具有不同的前缀）注入了配置。之后，我为应用程序中的每个DAO创建了一个JDBCTemplate，一切都运行良好。感谢您的帮助和建议。 - Raffaele