Lombok优雅编码(三)

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六、使用:@Log

        Lombok 为我们内置了各种日志组件的支持, 通常我们在SpringBoot项目开发中添加日志记录的功能, 而无论什么日志记录, 其添加时候都要先初始化, 然后才开始使用, 比如说如下的Log4j的初始化:

private static final org.apache.logging.log4j.Logger log = org.apache.logging.log4j.LogManager.getLogger(LogExample.class);

        虽然说每个项目的初始化操作都比较简单，但是也架不住数量众多，所以说为了简化起见，lombok推出了@Log注解，该注解就是帮助我们在日志中进行初始化操作的。其具体的使用方式为在所需要添加@Log的类名上添加如下注解：

@Slf4j

        然后我们就可以像普通的已经初始化的日志程序一样, 通过log.的方式进行调用了，例如打印 info信息: 

log.info("");

注解API

CommonsLog
Creates private static final org.apache.commons.logging.Log log = org.apache.commons.logging.LogFactory.getLog(LogExample.class);
@Flogger
Creates private static final com.google.common.flogger.FluentLogger log = com.google.common.flogger.FluentLogger.forEnclosingClass();
@JBossLog
Creates private static final org.jboss.logging.Logger log = org.jboss.logging.Logger.getLogger(LogExample.class);
@Log
Creates private static final java.util.logging.Logger log = java.util.logging.Logger.getLogger(LogExample.class.getName());
@Log4j
Creates private static final org.apache.log4j.Logger log = org.apache.log4j.Logger.getLogger(LogExample.class);
@Log4j2
Creates private static final org.apache.logging.log4j.Logger log = org.apache.logging.log4j.LogManager.getLogger(LogExample.class);
@Slf4j
Creates private static final org.slf4j.Logger log = org.slf4j.LoggerFactory.getLogger(LogExample.class);
@XSlf4j
Creates private static final org.slf4j.ext.XLogger log = org.slf4j.ext.XLoggerFactory.getXLogger(LogExample.class);

With Lombok

@Slf4j
public class Lesson29ApplicationTests {

    @Test
    public void testLombok(){
        // 测试Getter/Setter
        UserBean user = new UserBean();
        user.setName("测试lombok");
        user.setAge(10);
        user.setAddress("测试地址");
        System.out.println(user.toString());

        log.info(user.toString());
    }

}

Vanilla Java

public class Lesson29ApplicationTests {

    private static final org.slf4j.Logger log = org.slf4j.LoggerFactory.getLogger(Lesson29ApplicationTests.class);

    @Test
    public void testLombok(){
        // 测试Getter/Setter
        UserBean user = new UserBean();
        user.setName("测试lombok");
        user.setAge(10);
        user.setAddress("测试地址");
        System.out.println(user.toString());

        log.info(user.toString());
    }

}

七、使用:@NonNull

        使用@NonNull 生成一个非空的检查

With Lombok

public class NonNullExample extends Something {
  private String name;
  
  public NonNullExample(@NonNull Person person) {
    super("Hello");
    this.name = person.getName();
  }
}

Vanilla Java

public class NonNullExample extends Something {
  private String name;
  
  public NonNullExample(@NonNull Person person) {
    super("Hello");
    if (person == null) {
      throw new NullPointerException("person is marked @NonNull but is null");
    }
    this.name = person.getName();
  }
}

八、使用:@SneakyThrows

        @SneakyThrows的用法比较简单, 其实就是对异常的一个整理, 不处理, 直接扔掉. 减少到处写catch的不便利性. 比如在线程中，catch所有异常，再比如在一些不太可能发生异常的地方，但是你又必须cache checked exception的地方使用这个annotation会显得代码比较规整，易读。或许也会显得高大上一点吧. 但是这样的写法存在争议, 谨慎使用!

With Lombok

public class SneakyThrowsExample implements Runnable {
  @SneakyThrows(UnsupportedEncodingException.class)
  public String utf8ToString(byte[] bytes) {
    return new String(bytes, "UTF-8");
  }
  
  @SneakyThrows
  public void run() {
    throw new Throwable();
  }
}

Vanilla Java

public class SneakyThrowsExample implements Runnable {
  public String utf8ToString(byte[] bytes) {
    try {
      return new String(bytes, "UTF-8");
    } catch (UnsupportedEncodingException e) {
      throw Lombok.sneakyThrow(e);
    }
  }
  
  public void run() {
    try {
      throw new Throwable();
    } catch (Throwable t) {
      throw Lombok.sneakyThrow(t);
    }
  }
}