johnnian

package com.shishu.service;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.RenderingHints;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileOutputStream;

johnnian

```
/**
 * 根据经纬度计算距离 
 * @author Johnnian
 *
 */
public class LocationUtils {  
	
    private static double EARTH_RADIUS = 6378.137;  
  

johnnian

#!/bin/sh 
#description: release memory
free -m|awk  '/^Mem/ {if($4<512) {system("sync&&echo 3 > /proc/sys/vm/drop_caches");}}'

johnnian

- hAdmin： [https://github.com/huangyaoxin/hAdmin](https://github.com/huangyaoxin/hAdmin)

johnnian

打开终端，执行     /usr/libexec/java_home -V

johnnian

#查询当前目录下的子目录占用空间大小 du -h --max-depth=1

johnnian

ssh-keygen -t rsa
ssh-copy-id -i /root/.ssh/id_rsa.pub root@x.x.x.x

johnnian

# Docker command
alias dec="docker exec -it "
alias dim="docker images"
alias dps="docker ps -l"
alias dpsa="docker ps -a"
alias dstart="docker start "
alias dstop="docker stop "
alias dkill="docker kill "
alias drm="docker rm "
alias drmi="docker rmi "

johnnian

## 命令行工具

H2数据库提供了一组命令行工具，如果你需要了解这些工具，使用参数`-?`，如：

	java -cp h2*.jar org.h2.tools.Backup -?

命令行工具有：

* Backup 创建数据库备份
* ChangeFileEncryption 允许改变文件加密密码和数据库的加密算法

johnnian

[root@localhost ~]$ rpm -qa|grep jdk  
jdk-1.6.0_45-fcs.x86_64
java-1.6.0-openjdk-1.6.0.0-1.66.1.13.0.el6.x86_64
java-1.7.0-openjdk-1.7.0.45-2.4.3.3.el6.x86_64

[root@localhost ~]$ yum -y remove jdk-1.6.0_45-fcs.x86_64
[root@localhost ~]$ yum -y remove java-1.6.0-openjdk-1.6.0.0-1.66.1.13.0.el6.x86_64
[root@localhost ~]$ yum -y remove java-1.7.0-openjdk-1.7.0.45-2.4.3.3.el6.x86_64

rpm -e --nodeps jdk-1.6.0_45-fcs.x86_64