文章目录
- 前言
- I 、 DEBUG 宏的应用
- 1.1 发布模式关闭NSLog
- II、 NSLog调试技巧
- 2.1 Where to find NSLog's output
- 2.2 Improved logging in Objective-C
- 2.1 Objective-C's boxing capability (`装箱`快速构造数字对象)
- 2.2 知识补充：装箱和拆箱
- see also
- Log facility 和level的关系
- 常见的日志文件
- 配置【生成/存储日志】策略: `vim /etc/rsyslog.conf`
- 配置IP
前言
今天周末时间关系，此文只完成了部分内容，后续完整内容请移步到博客（kunnan.blog.csdn.net）
- 本文demo（请到博客看链接：kunnan.blog.csdn.net）
I 、 DEBUG 宏的应用
- 应用场景：区分调试模式和发布模式进行特殊处理
- 自定义preprocessor macro：
The DEBUG preprocessor macro setting in an Xcode project
1.1 发布模式关闭NSLog
//调试模式 #ifdef DEBUG #define NSLog(...) NSLog(__VA_ARGS__) #define KisDebug 1 //#define NSLog(fmt, ...) NSLog((@"[文件名:%s]\n" "[函数名:%s]\n" "[行号:%d] \n" fmt), __FILE__, __FUNCTION__, __LINE__, ##__VA_ARGS__); #else//发布模式 #define NSLog(...) #define KisDebug 0 #endif
II、 NSLog调试技巧
2.1 Where to find NSLog’s output
NSLog outputs messages to the Apple System Log facility or to the Console app
2.2 Improved logging in Objective-C
- Improved logging in Objective-C
- Format specifiers for data types
2.1 Objective-C’s boxing capability (装箱快速构造数字对象)
The printf function NSLog offers a number of substitution tokens for printing numbers (%d, %ld, %f, %d, for example). As a convenience, you can use Objective-C’s boxing capability to save time and avoid compiler warnings.
- For example
平常也可以使用@ 来快速包装数字类型以对象的形式进行存储和传参
[discountArray addObject:[[ self class] mj_objectWithKeyValues:@{@"placeholder":QCTLocal(@"please_input_card_num"),@"btnContent":QCTLocal(@"member_see"),@"EnterModelType":@2,@"isEnabled":@1,@"isLast":@1,@"block":block}]];
2.2 知识补充：装箱和拆箱
- Java包装类(装箱和拆箱)
全部被final修饰，顺便提一下，java.lang.Math,System,String也被final修饰
包装类是使用面向对象的思想把简单的数据类型封装成类。
1.特点
包装类把简单的数据类型包装成类。
注：简单数据类型不是类，使用简单数据类型主要为了提高代码的运行效率
2.
装箱和拆箱
把简单数据类型包装成对应的包装类称为boxing(示例：Integer i=1;将1包装成Integer再使用Object引用Integer对象)
把包装类型转换成简单数据类型称为unboxing（示例：Integer i=1，int p=i;//将包装类Integer转化成简单数据类型int）注：Integer的拆箱方法为 int intValue()，其他的包装类以此类推
1）包装类都重写了toString方法，equals方法，hashCode方法
2）Integer的API:
String toBinaryString(int i); 将int类型的数据以二进制字符串形式返回
int parseInt(String) 将字符串转化成int类型
int parseInt(Stringstr,int i ) 将字符串转化成对应的进制 类型,str为被转换的字符串，i为进制类型（10,8,16）
Integer valueof(String str) 将字符串转换成Integer类型。
see also
- String Format Specifiers
| Specifier | Description |
%@ |
Objective-C object, printed as the string returned by descriptionWithLocale: if available, or descriptionotherwise. Also works with CFTypeRef objects, returning the result of the CFCopyDescription function. |
%% |
'%' character. |
%d, %D |
Signed 32-bit integer (int). |
%u, %U |
Unsigned 32-bit integer (unsigned int). |
%x |
Unsigned 32-bit integer (unsigned int), printed in hexadecimal using the digits 0–9 and lowercase a–f. |
%X |
Unsigned 32-bit integer (unsigned int), printed in hexadecimal using the digits 0–9 and uppercase A–F. |
%o, %O |
Unsigned 32-bit integer (unsigned int), printed in octal. |
%f |
64-bit floating-point number (double). |
%e |
64-bit floating-point number (double), printed in scientific notation using a lowercase e to introduce the exponent. |
%E |
64-bit floating-point number (double), printed in scientific notation using an uppercase E to introduce the exponent. |
%g |
64-bit floating-point number (double), printed in the style of %e if the exponent is less than –4 or greater than or equal to the precision, in the style of %f otherwise. |
%G |
64-bit floating-point number (double), printed in the style of %E if the exponent is less than –4 or greater than or equal to the precision, in the style of %f otherwise. |
%c |
8-bit unsigned character (unsigned char). |
%C |
16-bit UTF-16 code unit (unichar). |
%s |
Null-terminated array of 8-bit unsigned characters. Because the %s specifier causes the characters to be interpreted in the system default encoding, the results can be variable, especially with right-to-left languages. For example, with RTL, %s inserts direction markers when the characters are not strongly directional. For this reason, it’s best to avoid %s and specify encodings explicitly. |
%S |
Null-terminated array of 16-bit UTF-16 code units. |
%p |
Void pointer (void *), printed in hexadecimal with the digits 0–9 and lowercase a–f, with a leading 0x. |
%a |
64-bit floating-point number (double), printed in scientific notation with a leading 0x and one hexadecimal digit before the decimal point using a lowercase p to introduce the exponent. |
%A |
64-bit floating-point number (double), printed in scientific notation with a leading 0X and one hexadecimal digit before the decimal point using a uppercase P to introduce the exponent. |
%F |
64-bit floating-point number (double), printed in decimal notation. |
- Format specifiers for data types
| Type | Format specifier | Considerations |
NSInteger |
%ld or %lx |
Cast the value to long. |
NSUInteger |
%lu or %lx |
Cast the value to unsigned long. |
CGFloat |
%f or %g |
%f works for floats and doubles when formatting; but note the technique described below for scanning. |
CFIndex |
%ld or %lx |
The same as NSInteger. |
| pointer | %p or %zx |
%p adds 0x to the beginning of the output. If you don’t want that, use %zx and no typecast. |
- Basic debugging
Log facility 和level的关系
NSLog outputs messages to the Apple System Log facility or to the Console app
- facility：是系统对某种类型事件的定义。
LOG_AUTH
LOG_AUTHPRIV 安全认证
LOG_CRON clock daemon (cron and at) 计划任务事件
LOG_DAEMON 后台进程
LOG_FTP ftp daemon
LOG_KERN kernel messages
LOG_LOCAL0 through LOG_LOCAL7 用户自定义设备
LOG_LPR printer subsystem
LOG_MAIL 邮件系统mail subsystem
LOG_NEWS news subsystem
LOG_SYSLOG syslogd自身产生的日志
LOG_USER (default)
- level :指遇到何种情况才记录日志
从下到上，级别从低到高，记录的信息越来越少
LOG_EMERG 紧急，致命，服务无法继续运行，如配置文件丢失
LOG_ALERT 报警，需要立即处理，如磁盘空使用95%
LOG_CRIT 致命行为
LOG_ERR 错误行为
LOG_WARNING 警告信息
LOG_NOTICE 普通，重要的标准信息
LOG_INFO 标准信息
LOG_DEBUG 调试信息，排错所需，一般不建议使用
常见的日志文件
tail /var/log/messages //系统主日志文件
tail -20 /var/log/messages
tail -f /var/log/messages //动态查看日志文件的尾部
tailf /var/log/secure //认证、安全
tail /var/log/maillog //跟邮件postfix相关
tail /var/log/cron //crond、at进程产生的日志
tail /var/log/dmesg //和系统启动相关
tail /var/log/audit/audit.log //系统审计日志
tail /var/log/yum.log //yum
tail /var/log/mysqld.log //MySQL
tail /var/log/xferlog //和访问FTP服务器相关
w //当前登录的用户 /var/log/wtmp
last //最近登录的用户 /var/log/btmp
lastlog //所有用户的登录情况 /var/log/lastlog
配置【生成/存储日志】策略: vim /etc/rsyslog.conf
由设备+级别+存放位置组成
FACILITY+LEVEL+FILE组成:
authpriv.* /var/log/secure（SSH信息）
mail.* -/var/log/maillog（发邮件）
cron.* /var/log/cron（创建任务）
authpriv.* * <代表所有终端>
authpriv. @192.168.10.230authpriv.* @@192.168.10.230
配置IP
- /etc/sysconfig/network-scripts/ifcfg-enp2s0中各个参数的意义
vim /etc/sysconfig/network-scripts/ifcfg-enp2s0
NAME=“enp2s0”
DEVICE=“enp2s0”
ONBOOT=yes //是否启用该设备
BOOTPROTO=none //手动(none/static)还是自动(dhcp)
IPADDR=172.16.120.246 //地址
PREFIX=24 //掩码
IPADDR1=192.168.200.246 //额外地址
PREFIX1=24 //额外掩码，注意编号
GATEWAY=172.16.120.254 //网关
DNS1=8.8.8.8 //DNS
DNS2=114.114.114.114 //DNS2
