安装docker(Centos 8)

yum-config-manager –add-repo https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo

yum install -y yum-utils device-mapper-persistent-data lvm2
yum install -y containerd.io

yum install -y docker-ce –nobest

这个过程借鉴博客：https://blog.csdn.net/peizhelun/article/details/104435856/

systemctl enable docker

安装mysql

docker pull mysql:5.7

docker run -d -p 3306:3306 –name mymysql -e MYSQL_ROOT_PASSWORD=123456 d589ea3123e0

安装es

docker pull elasticsearch:6.6.2

docker run -d –name elasticsearch -p 9200:9200 -p 9300:9300 -e “discovery.type=single-node” 1bca39c5a102

docker run -d –name elasticsearch -p 9200:9200 -p 9300:9300 -e ES_JAVA_OPTS=”-Xms256m -Xmx256m” 1bca39c5a102

es的分页从第0页开始，而不是第1页

es在docker里面的参数修改

find /var/lib/docker/overlay2/ -name jvm.options

在找到的路径里改

安装rabbitmq

docker pull rabbitmq:3.7.7-management

docker run -d –name rabbitmq3.7.7 -p 5672:5672 -p 15672:15672 –hostname myRabbit -e RABBITMQ_DEFAULT_VHOST=my_vhost -e RABBITMQ_DEFAULT_USER=root -e RABBITMQ_DEFAULT_PASS=jx172020 2888deb59dfc

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rabbitmqctl eval 'rabbit_amqqueue:declare({resource, <<"/">>, queue, <<"payNotify">>}, true, false, [], none).'

安装nginx

wget https://imcfile.oss-cn-beijing.aliyuncs.com/shizhan/file/liaoshixiong/nginx-1.16.1.tar.gz

tar -zxvf nginx-1.16.1.tar.gz -C /opt/module

进入目录下

cd /opt/module/nginx-1.16.1

配置安装目录

./configure –prefix=/usr/local/nginx

yum install -y zlib-devel openssl openssl-devel pcre-devel

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location / {
            root   web;
            index  index.html index.htm;
        }

location /admin {
    alias   admin;
    index  index.html index.htm;
}

Linux命令

ps - ef|grep java

查看Java进程

死锁

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/**
 * @author xixing
 * @version 1.0
 * @date 2020/7/16 10:52
 *
 * 死锁是两个及以上线程在执行过程中抢夺资源造成的现象
 *
 */
public class DeadLockDemo {

    public static void main(String[] args) {
        String resourseA="resourseA";
        String resourseB="resourseB";

        new Thread(new HoldLockThread(resourseA,resourseB),"ThreadA").start();
        new Thread(new HoldLockThread(resourseB,resourseA),"ThreadB").start();

        /**
         * linux ps -ef|grep xxx   ls -l
         *
         * windows下也有类型ps的查看进程命令，但是只要看java进程
         * 可以用 jps =java ps      jps -l
         * jstack 28087
         *
         */
    }
}

class HoldLockThread implements Runnable{

    private String resourseA;
    private String resourseB;
    Lock lock=new ReentrantLock();

    public HoldLockThread(String resourseA, String resourseB) {
        this.resourseA = resourseA;
        this.resourseB = resourseB;
    }

    @Override
    public void run() {

        synchronized (resourseA){
            System.out.println(Thread.currentThread().getName()+"\t 自己持有"+resourseA+"尝试获得\t"+resourseB);
            try {
                TimeUnit.SECONDS.sleep(2);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            synchronized (resourseB){

            }

        }


    }

}

JVM体系结构

复制算法

标记回收算法

标记-压缩算法

GC

Boolean类型

example:

​ -XX:+PrintGCDetails

KV设值类型

MetaspaceSize是元空间大小

MaxTenuringThreshold是多少次之后就是老年期

jinfo

jinfo -flags 5678

可以把5678这个进程号的全部参数打印

查看JVM初始家底

java -XX:+PrintFlagsInitial

java -XX:+PrintFlagsFinal =代表默认 :=代表修改后的值

-Xms 启动时最小内存

-Xmx 最大内存

-Xss 单个线程最大栈空间

为0则为默认值，在不同系统，默认值不一样，在linux，os x，unix的64位系统中为1024k，在windows则取决于你的虚拟内存大小。

-XX:+PrintGCDetails -XX:MetaspaceSize=128m -XX:SurvivorRatio=4 -XX:NewRatio=4

-XX:+PrintGCDetails

查看gc详情

GC在青春期，FullGC在养老区

[GC (Allocation Failure) [PSYoungGen: 1752K->488K(2560K)] 1752K->664K(9728K), 0.0018961 secs] [Times: user=0.00 sys=0.00, real=0.00 secs]
[GC (Allocation Failure) [PSYoungGen: 488K->496K(2560K)] 664K->716K(9728K), 0.0015663 secs] [Times: user=0.00 sys=0.00, real=0.00 secs]
[Full GC (Allocation Failure) [PSYoungGen: 496K->0K(2560K)] [ParOldGen: 220K->629K(7168K)] 716K->629K(9728K), [Metaspace: 3216K->3216K(1056768K)], 0.0066899 secs] [Times: user=0.02 sys=0.00, real=0.01 secs]
[GC (Allocation Failure) [PSYoungGen: 0K->0K(2560K)] 629K->629K(9728K), 0.0004493 secs] [Times: user=0.00 sys=0.00, real=0.00 secs]
[Full GC (Allocation Failure) [PSYoungGen: 0K->0K(2560K)] [ParOldGen: 629K->611K(7168K)] 629K->611K(9728K), [Metaspace: 3216K->3216K(1056768K)], 0.0068001 secs] [Times: user=0.00 sys=0.00, real=0.01 secs]
Exception in thread “main” java.lang.OutOfMemoryError: Java heap space
at tech.xixing.jvm.HelloGC.main(HelloGC.java:15)
Heap
PSYoungGen total 2560K, used 57K [0x00000000ffd00000, 0x0000000100000000, 0x0000000100000000)
eden space 2048K, 2% used [0x00000000ffd00000,0x00000000ffd0e588,0x00000000fff00000)
from space 512K, 0% used [0x00000000fff00000,0x00000000fff00000,0x00000000fff80000)
to space 512K, 0% used [0x00000000fff80000,0x00000000fff80000,0x0000000100000000)
ParOldGen total 7168K, used 611K [0x00000000ff600000, 0x00000000ffd00000, 0x00000000ffd00000)
object space 7168K, 8% used [0x00000000ff600000,0x00000000ff698f48,0x00000000ffd00000)
Metaspace used 3247K, capacity 4496K, committed 4864K, reserved 1056768K
class space used 353K, capacity 388K, committed 512K, reserved 1048576K

Process finished with exit code 1

-XX:SurvivorRatio

默认XX:SurvivorRatio=8

eden space 53248K, 8% used [0x0000000780980000,0x0000000780dab0f0,0x0000000783d80000)
from space 6144K, 0% used [0x0000000784380000,0x0000000784380000,0x0000000784980000)
to space 6144K, 0% used [0x0000000783d80000,0x0000000783d80000,0x0000000784380000)

XX:SurvivorRatio=4

PSYoungGen total 54784K, used 4404K [0x0000000780980000, 0x0000000784980000, 0x00000007c0000000)
eden space 44032K, 10% used [0x0000000780980000,0x0000000780dcd328,0x0000000783480000)
from space 10752K, 0% used [0x0000000783f00000,0x0000000783f00000,0x0000000784980000)
to space 10752K, 0% used [0x0000000783480000,0x0000000783480000,0x0000000783f00000)

-XX:NewRatio

Heap
PSYoungGen total 54784K, used 4404K [0x0000000780980000, 0x0000000784980000, 0x00000007c0000000)
eden space 44032K, 10% used [0x0000000780980000,0x0000000780dcd328,0x0000000783480000)
from space 10752K, 0% used [0x0000000783f00000,0x0000000783f00000,0x0000000784980000)
to space 10752K, 0% used [0x0000000783480000,0x0000000783480000,0x0000000783f00000)
ParOldGen total 131072K, used 0K [0x0000000701c00000, 0x0000000709c00000, 0x0000000780980000)
object space 131072K, 0% used [0x0000000701c00000,0x0000000701c00000,0x0000000709c00000)
Metaspace used 3222K, capacity 4496K, committed 4864K, reserved 1056768K
class space used 350K, capacity 388K, committed 512K, reserved 1048576K

新生代和老年代分别为54784K和131072K符合1：2

-XX:MaxTenuringThreshold

进入养老区的次数

数值必须在0-15之间

常用jvm参数

ThreadPoolExecutor

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public static ExecutorService newFixedThreadPool(int nThreads) {
    return new ThreadPoolExecutor(nThreads, nThreads,
                                  0L, TimeUnit.MILLISECONDS,
                                  new LinkedBlockingQueue<Runnable>());
}

public static ExecutorService newSingleThreadExecutor() {
        return new FinalizableDelegatedExecutorService
            (new ThreadPoolExecutor(1, 1,
                                    0L, TimeUnit.MILLISECONDS,
                                    new LinkedBlockingQueue<Runnable>()));
}
public static ExecutorService newCachedThreadPool() {
        return new ThreadPoolExecutor(0, Integer.MAX_VALUE,
                                      60L, TimeUnit.SECONDS,
                                      new SynchronousQueue<Runnable>());
}


public ThreadPoolExecutor(int corePoolSize,
                              int maximumPoolSize,
                              long keepAliveTime,
                              TimeUnit unit,
                              BlockingQueue<Runnable> workQueue,
                              ThreadFactory threadFactory,
                              RejectedExecutionHandler handler)

线程池底层工作原理

CPU密集型配线程数

IO密集型配线程数

1.尽可能配多线程，比如说CPU核数*2

2.

整合阿里云oss实现文件上传

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package tech.xixing.machineprice.service.impl;

import com.aliyun.oss.OSS;
import com.aliyun.oss.OSSClientBuilder;
import org.apache.commons.lang.StringEscapeUtils;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;
import org.springframework.web.multipart.MultipartFile;
import tech.xixing.machineprice.service.OssService;
import tech.xixing.machineprice.utils.RandomString;
import tech.xixing.machineprice.vo.ResponseVO;

import java.io.ByteArrayInputStream;
import java.io.IOException;

/**
 * @author xixing
 * @version 1.0
 * @date 2020/7/11 10:46
 */
@Service
public class OssServiceImpl implements OssService {

    @Value("${aliyun.oss.accessKeyId}")
    private String ACCESS_KEY_ID;

    @Value("${aliyun.oss.accessKeySecret}")
    private String ACCESS_KEY_SECRET;

    @Value("${aliyun.oss.endpoint}")
    private String ENDPOINT;

    @Value("${aliyun.oss.bucketName}")
    private String BUCKETNAME;


    @Override
    public ResponseVO<String> uploadFile(MultipartFile file) {
        OSS ossClient= new OSSClientBuilder().build(ENDPOINT,ACCESS_KEY_ID,ACCESS_KEY_SECRET);
        String originalFilename = file.getOriginalFilename();
        String[] split = originalFilename.split("\\.");

        String name = RandomString.getRandomString(15)+"."+split[split.length-1];
        try {
            ossClient.putObject(BUCKETNAME,"instrument/"+name,new ByteArrayInputStream(file.getBytes()));
        } catch (IOException e) {
            e.printStackTrace();
        }
        ossClient.shutdown();
        String res = StringEscapeUtils.escapeHtml("http://"+BUCKETNAME+"."+ENDPOINT+"/instrument/"+name);
        return ResponseVO.successByData(res);
    }
}

对于刚生成的id，如果需要用到的话

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<insert id="insertSelective" parameterType="tech.xixing.machineprice.pojo.Manufactor" useGeneratedKeys="true" keyProperty="id">
  insert into manufactor
  <trim prefix="(" suffix=")" suffixOverrides=",">
    <if test="id != null">
      id,
    </if>
    <if test="name != null">
      name,
    </if>
    <if test="createTime != null">
      create_time,
    </if>
    <if test="updateTime != null">
      update_time,
    </if>
    <if test="sortedOrder != null">
      sorted_order,
    </if>
  </trim>
  <trim prefix="values (" suffix=")" suffixOverrides=",">
    <if test="id != null">
      #{id,jdbcType=INTEGER},
    </if>
    <if test="name != null">
      #{name,jdbcType=VARCHAR},
    </if>
    <if test="createTime != null">
      #{createTime,jdbcType=TIMESTAMP},
    </if>
    <if test="updateTime != null">
      #{updateTime,jdbcType=TIMESTAMP},
    </if>
    <if test="sortedOrder != null">
      #{sortedOrder,jdbcType=INTEGER},
    </if>
  </trim>
</insert>

useGeneratedKeys=”true” keyProperty=”id”加上这两句，就可以在原来对象中写入这个id。

#{}使用的是预编译对应JDBC中的PreparedStatement

${}mybatis不会修改或者转义字符串，直接输出变量值

使用#{}可以防止sql注入

使用#{}包裹的语句会加上单引号

会使得部分语句失效

如创建mysql表的时候,只能使用${}

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<update id="createByTableName" >
    create table ${CreateTable.tableName} (
        id int(11) ,
        <foreach collection="CreateTable.tableList" index="index" item="item">
            ${ item }  varchar(64) ,
        </foreach>
        PRIMARY KEY (id)

    );
</update>