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/lib64/libstdc++.so.6: version `CXXABI’1.3.8′ not found `36733;

Explain the function of static keyword and final keyword in Java in detail>>>

original address : https://blog.csdn.net/EI__ Nino/article/details/100086157

the ultimate war

Death Strike

1 ImportError: /lib64/libstdc++.so.6: version `CXXABI_1.3.8’ not found

Libstdc + +. So. 6 is too low, which leads to
see if your libstdc + +. So. 6 contains cxxabi_ 1.3.8

 1 # strings /usr/lib64/libstdc++.so.6 | grep CXXABI
 2 CXXABI_1.3
 3 CXXABI_1.3.1
 4 CXXABI_1.3.2
 5 CXXABI_1.3.3
 6 CXXABI_1.3.4
 7 CXXABI_1.3.5
 8 CXXABI_1.3.6
 9 CXXABI_1.3.7
10 CXXABI_TM_1

Sure enough, No
note that the GCC version is not necessarily too low. Use SCL (about SCL) https://linux.cn/article-6776-1.html ）It’s useless to upgrade GCC. We can’t upgrade libstdc + +. So. 6 at all
so we need to upgrade libstdc + +. So. 6 and upgrade GCC by the way. If you only upgrade GCC (through SCL), it is invalid, because the version of GCC is higher, but its libstdc + + is the original libstdc + +. So. 6 of require

If you don’t believe it, look

1 # cat /opt/rh/devtoolset-7/root/usr/lib/gcc/x86_64-redhat-linux/7/libstdc++.so
2 
3 /* GNU ld script
4 Use the shared library, but some functions are only in
5 the static library, so try that secondarily. */
6 OUTPUT_FORMAT(elf64-x86-64)
7 INPUT ( /usr/lib64/libstdc++.so.6 -lstdc++_nonshared )

So does the egg hurt

The only solution is to recompile GCC

compile GCC

Install dependency library Yum install – y GMP devel mpfr devel libmpc devel

Download source code package ftp://ftp.gnu.org/gnu/gcc/gcc-9.2.0/

Decompress

configure

(note that this is very time-consuming. Adding – J4 means 4-thread compilation. If you have 4 cores, it will be full, leading to CPU full and service alarm. So it depends on the situation. I’m direct nohup make & amp; Then go home to sleep)

The orders are as follows

1 sudo yum install gmp-devel mpfr-devel libmpc-devel -y
2 cd download
3 wget ftp://ftp.gnu.org/gnu/gcc/gcc-9.2.0/gcc-9.2.0.tar.xz
4 xz -d gcc-9.2.0.tar.xz
5 tar -xf gcc-9.2.0.tar
6 cd gcc-9.2.0
7 ./configure --disable-multilib --enable-languages=c,c++ --prefix=$HOME/local
8 make -j4
9 make -j install

After installation, add the newly installed path to the environment variable

1 export LD_LIBRARY_PATH=$HOME/local/lib64

It can be found in ~ /. Bash_ Add path = $home/local/bin in the profile: $path
put the local in the front, in case there are bin with the same name at the same time, you can call the local bin file
to save LD_ LIBRARY_ Path = $home/local/lib64 is also added to. Base_ Profile, which can be used in the future
done.

Unable to open thread: http request failed! (4 pesos, PHP 4)

After chopping hands, the fraud call came before the express delivery was received. How to improve the privacy and security of e-commerce>>>

When using PHP5’s own file_ get_ When the contents method is used to get remote files, sometimes the file will appear_ get_ contents(): failed to open stream: HTTP request failed! This is a warning message

Google or Baidu, a lot of such problems, the solution is to modify PHP. Ini, allow_ url_ Fopen is enabled and changed to allow_ url_ fopen = On

This can solve some people’s problems. Some people say that in php.ini, there are two options: allow_ url_ Fopen = on (indicates that the remote file can be opened through URL), user_ Agent = “PHP” (indicates which script is used to access the network. By default, there is a “;” Remove it.) Restart the server

However, some of them still have this warning message. If you want to solve it perfectly, you still need to set the user in php.ini_ Agent, PHP’s default user_ The agent is PHP, we changed it to Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0) to simulate the browser

user_ agent=”Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0)”

In the work of this problem, after the perfect solution, so share with you

<?php
ini_set("user_agent","Mozilla/4.0(compatible;MSIE5.00;Windows98)");
$data_content=file_get_contents($url);

But the best way is to use curl to grab it. It seems that curl is more powerful

Original address:

Failed to open stream: http request failed（ file_ get_ (caused by contents)

Label:

php

file_ get_ contents

failed

Intelligent recommendation

php Only variables can be passed by reference

ntpdate[16603]: the NTP socket is in use

How to view the source code of Google Chrome plug-in

Learn more about PHP opcode caching

[No.5 ionic] modify the application name, icon and start interface

Solution to the problem of bash: gulp: command not found after installing gulp in Windows system

Why are there a series of technical challenges behind “OMG buy it”>>>

When using the gulp server command, bash: gulp: command not found appears
first of all, when I saw this command, I doubted that my gulp was not installed properly. I executed it again NPM install - G gulp , but the command ran smoothly, and the result still appeared: bash: gulp: command not found
then I found the following article on the Internet
I feel that the direction to solve the problem is right. The command of gulp is invalid. It should be the configuration problem. Then I go to the global directory (C: program files/nodejsnode)_ modules/npm/node_ Modules) to see if my gulp package is installed, and it is not! My bag succeeded, but it was in the wrong place

1. Use the command to check: NPM config get prefix , and the following figure is obtained

looking at the location, it seems that it is the address that I configured when I used the lower version of node.. But now NPM has been integrated into node. I can’t find the configuration address myself. Anyway, there is absolutely no environment variable. Now I just want to correct the address and go to the new path I follow C:// program files/nodejs/node_ modules\npm。

2. Use the command to modify the configuration

npm config set prefix C:\Program Files\nodejs\node_ As we all know, the file name of the program files in the middle is very hollow, which causes the command to be interrupted in this way. So I went to the configuration file to modify it manually (this is a simple and direct way). The file location is here C:// users/administrator (see the figure below)

3. Check the configuration of NPM again

as can be seen from the above figure, the configuration address now points to NPM in node, and then install gulp to see
running commands: NPM install - G gulp and gulp - V

HDFS problem set (1), use the command to report an error: com.google.protobuf.servicee xception:java.lang.OutOfMemoryError :java heap space

Why are there a series of technical challenges behind “OMG buy it”>>>

Only personal practice, if there is something wrong, welcome to exchange

I. causes

Execute the following two basic HDFS commands to report an error

1 hdfs dfs -get /home/mr/data/* ./
2 hdfs dfs -ls /home/mr/data/*

These are two normal HDFS commands. How can I report an error?Then open the HDFS command to see the problem

Second, analysis

1) Use the following command to find the path of the HDFS command

1 which hdfs

Open the script with VIM HDFS, and find that Hadoop will be used when executing with HDFS DFS_ CLIENT_ Opts configuration item. The configuration item is usually set in the directory/etc/Hadoop/conf/hadoop-env.sh by searching

Open hadoop-env.sh script and find that the configuration item adopts the default configuration, namely 256M

2) After checking, there are 1W + small files in the/home/MR/data directory, but the size is only about 100m. It is speculated that the metadata is too large due to the size of the file data, resulting in insufficient memory when loading to the client ( guess may not be correct, you are welcome to give a correct explanation )

Third, solutions

Increase Hadoop_ CLIENT_ The configuration of opts can solve the problem in both forms

1 export HADOOP_CLIENT_OPTS="-Xmx1024m $HADOOP_CLIENT_OPTS"
2 hdfs dfs -get /home/mr/data/* ./
3 
4 HADOOP_CLIENT_OPTS="-Xmx1024m" hdfs dfs -get /home/mr/data/* ./

In addition, you can modify the configuration permanently by modifying the value in hadoop-env.sh

An error occurred when the idea was compiled: java.io.ioexception: cannot create empty file:

Open source software supply chain lighting plan, waiting for you>>>

A few days ago, after the computer was updated, this problem appeared when I opened the idea. At that time, I thought I had changed the configuration file of idea

Problem solving:

1. Problems after updating the computer: (you may not update it, but you have changed the coding format of the computer)

A) open the control panel to find the clock and area

　　　　　　　　

　　　　

B) find the area

　　　　　　

C) management > Change system locale

　　　　　　

D) cancel the bate version of Unicode – UTF-8 (if it has been cancelled, you can also check it)

　　　　　　

2. Code format configuration in idea: (if problem 1 is not solved)

　　　　　　a) File > Settings…

　　　　　　　　

　　　　　　b) Editor > File encodings to configure tuf-8 character encoding

Step 4, transparent native… Can be checked or not. It is only used for serialization

　　　　　　　　

　　　　　　　　　　

Java.net.noroutetohostexception: cannot assign requested address

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Question:

Error reason: because the client connection port allocated by Linux is exhausted, the socket connection cannot be established. Although the socket is closed normally, the port is not released immediately, but is in time_ Wait status. By default, wait for 60s and release
check the range of client connection ports supported by Linux, that is, 28232 portscat /proc/sys/net/ipv4/ip_ local_ port_ range
32768 - 61000

Solution:
1. Reduce the waiting time after port release, which is 60 s by default and 15 ~ 30 s by modificationecho 30 >/proc/sys/net/ipv4/tcp_ fin_ Timeout
2. Modify the TCP/IP protocol configuration by configuring /proc/sys/net/IPv4/TCP_ tw_ Reuse , default to 0, modify to 1, release time_ Wait port for new connectionecho 1 >/proc/sys/net/ipv4/tcp_ tw_ Reuse
3. Modify CTP/IP protocol configuration to recycle socket resources quickly. The default value is 0. Modify to 1echo 1 >/proc/sys/net/ipv4/tcp_ tw_ recycle

https://blog.csdn.net/weixin_ 43757847/article/details/88188091

https://my.oschina.net/shichangcheng/blog/1560864

https://stackoverflow.com/questions/32282112/error-setting-net-ipv4-tcp-tw-reuse-net-ipv4-tcp-tw-recycle-in-sysctl-conf

Wei Chengjun helped to find it

Postscript:

There’s a solution

Modify httpclient4. Idletimeout = & lt; in JMeter. Properties; timeinms> Set the time you think is reasonable. Generally, it can be set to 10-60s (it means the connection will be disconnected after 10s of free time). Note that the unit here is Ms

Reference: https://blog.csdn.net/Stesthu/article/details/87968927

Postscript:

I misunderstood this concept a little. After establishing a long connection, httpclient4.idletimeout means that the long link port will be disconnected as soon as it is idle. For example, the server will be disconnected directly when it is idle before it responds, resulting in an error. Here, the time should be set a little longer, keep a long connection, keep a connection all the time

Reference: https://www.cnblogs.com/kaibindirver/p/11957645.html To use a long connection, you need to configure the requester. See the connection section

Check whether the port is used up. Netstat – an check whether there is a port in timewait

https://i-beta.cnblogs.com/posts/edit-done; postId=11956755

Postscript:

After configuring a long connection, there will still be an error. Finally, you need to modify the release time of the port on the Mac https://www.cnblogs.com/kaibindirver/p/11958506.html

Moreover, when JMeter simulates sending a request, remember to add

C onnection:keep-alive Stay connected

Failed to create webapp project with Maven in idea (without SRC and other file directory): received fatal Alert: Protocol_ Version solution

Geeks, please accept the hero post of 2021 Microsoft x Intel hacking contest>>>

Specific steps:

1. First, add a configuration to Maven Runtime: – dhttps. Protocols = tlsv1.2, as shown in the following figure

2. Create project or module

3. When selecting a webapp template, use the Maven below instead of the coco above

3. The rest is the normal flow of things, not to repeat

Created web project structure:

explain why :

Due to the insecurity of tlsv1.1 protocol and the PCI security standard, maven sonatype central warehouse no longer supports tlsv1.1 and the following protocol versions from June 18, 2018

For the original text, please refer to the official explanation of no longer supports tlsv1.1 and below

The JDK I use is 1.7. Although jdk1.7 supports TLS 1.2, it is disabled by default, so the received fatal Alert: protocol above will appear_ Version exception

The following table shows the default TLS protocol used by JDK in different versions of Oracle documents:

solutions:

scheme 1: upgrade JDK to 1.8

JDK1.8 TLS 1.2 is enabled by default, and this exception will not occur

PS: the price can be a bit high, especially for some old projects, which can not be upgraded just by upgrading

scheme 2: enable TLS 1.2 by adding – dhttps. Protocols = tlsv1.2 and configuring the Java runtime parameter

summary: if you are JDK 1.7, both schemes are OK (this article uses the second scheme). If you are 1.6 or below, it is recommended to upgrade JDK

Android studio real machine test failed — “no target device found”

Reference article:

https://blog.csdn.net/chang_ sir/article/details/51755572

Today, I want to test a program with a real machine, but I report such a error “no target device found” . After checking, the machine has been successfully connected. And my edit configurations.. — > Deployment Target Option –> Target has been set to USB device. Why did it report that the target device was not found

1. It is preliminarily estimated that the last time I modified the project, it may not be closed normally, or there may be a conflict when modifying the configuration. In short, it can’t be used. There is a problem. Refer to the article mentioned above, and finally it is solved. The first step is to ensure the physical connection between the mobile phone and the computer

2. Click the Android device monitor button

Make sure that your device is online. If your device is not displayed, it means that the Android monitor program has not been started and cannot recognize the device connected by the USB cable. Don’t worry at this time. This is a normal phenomenon. The solution is also very simple. Find the View menu button, which is a small inverted triangle. There is a Reset ADB option in the drop-down menu. Click it and you will find that your device is online

For my project, I can operate normally when I return to the main interface, which proves that the error has been fixed

Failed to install node with. MSI, rolling back action (Reprint)

Reprint address: https://blog.csdn.net/qq_ 33295622/article/details/52956369
the situation shown in the figure above appears when the node is reinstalled, and the solutions are as follows:
1. Download the stable version of node.exe from the official website, and select 32bit or 64bit according to the actual situation

here I choose 64bit, After downloading, get node.exe
2 http://nodejs.org/dist/npm/ Download the latest version of NPM
3. Create the node.js folder under the C:: program files file, and put the node.exe and the unzipped NPM in it
4. Configure environment variables, right-click computer – properties – advanced system settings – environment variables, and add C:: program files – node.js to the user variable path, Add a new variable node to the system variable_ Path, and the value of the variable is C:// program files \ \ node. JS \ \ node_ Modules


5. At this time, you can enter CMD in windows search, open cmd.exe, enter node – V and NPM – V respectively

the NPM version I download here is 1.4.9, enter NPM install [email protected] -g. You can download the NPM of the specified version to get the result above
so far, node.js and NPM have been successfully installed

Ora-01653: table a cannot be extended by 1024 (in table space ABC)

JavaScript implementation: how to write beautiful conditional expression>>>

Oracle ora-01653: error of unable to extend table

Today, when PL SQL developer was used to import data into Oracle database, an error was suddenly reported, which can only be terminated. The specific contents of the error are as follows:

ORA-01653: unable to extend table USER_ DATA.JKHDFXJL by 128 in tablespace MSMS

It means user_ The data table space is insufficient, so Google has a look, and it has some features. There are two kinds of problems: one is that the automatic expansion function of the table space is not on; The other is that the space is really not enough, which has reached the upper limit of automatic expansion

So the step to solve the problem is to check the table space size of Oracle database first, and then check whether the automatic expansion function of all data files under the table space is turned on; If the table space is not enough, then we need to expand the table space

The specific steps are as follows:

execute the following SQL statements in PL SQL developer

SELECTa.tablespace_ Name “table space name”,

a.bytes/1024/1024 “table space size (m)”,

(a.bytes – b.bytes)/1024/1024 “used space (m)”,

b.bytes/1024/1024 “free space (m)”,

round (((a.bytes – b.bytes)/a.bytes) * 100,2) “usage ratio”

from (select table space)_ name,sum(bytes) bytes

FROMdba_ data_ files

GROUPBYtablespace_ name) a,

(SELECTtablespace_ name,sum(bytes) bytes,max(bytes) largest

FROMdba_ free_ space

GROUPBYtablespace_ name) b

WHEREa.tablespace_ name = b.tablespace_ name

ORDERBY((a.bytes – b.bytes)/a.bytes)DESC

“table space size (m)” indicates the total disk space occupied by all data files in the table space in the operating system

For example: User_ Data table space has two data files, datafile1 is 300MB, datafile2 is 400MB, then User_ The “table space size” of data table space is 700MB

“used space (m)” indicates how much table space has been used

“free space (m)” indicates how much table space is left

“usage ratio” indicates the percentage that has been used

for example, view user from step 1_ Data table space has been used by more than 90% . You can view the total number of data files in the table space, whether each data file is automatically expanded, and the maximum value of automatic expansion

SELECTfile_ name,

tablespace_ name,

bytes /1024/1024″bytes MB”,

maxbytes /1024/1024″maxbytes MB”

FROMdba_ data_ files

WHEREtablespace_ name =’USER_ DATA‘;

check whether the MSMS table space is automatically expanded

SELECTfile_ id, file_ name, tablespace_ name, autoextensible, increment_ by

FROMdba_ data_ files

WHEREtablespace_ name =’USER_ DATA‘

ORDERBYfile_ iddesc;

Check whether the corresponding value of “ autoextensible ” is yes or no. if it is no, it means that the automatic expansion function of MSMS table space is not on. Just change it to yes

for example, the current size of MSMS table space is 0.9gb, but the maximum size of each data file can only be 1GB, and the data file is almost full, so we need to expand the table space

there are two ways to expand the table space: one is to increase the size of data files, the other is to increase the number of data files

first, find out the data file and path corresponding to the table space

SELECT*FROMdba_ data_ files tWHEREt.tablespace_ Name =’table space name ‘

–Find the full path of the data file in the corresponding table space, which corresponds to file_ Name field

solution 1: increase data file

alter database datafile ‘full path data file name’ resize * * m

–Increase the size of a data file in the corresponding table space to * * M

solution 2: add data file

Get the statement that creates the table space:

SELECTdbms_ metadata.get_ ddl(‘TABLESPACE’,’USER_ DATA‘)FROMdual;

confirm that the disk space is sufficient, and add a data file [use DF – G command in UNIX and Linux operating system (check the available disk space)]

alter table space name adddatafile ‘full path data file name’ size * * m

autoextension maxsize20g

–Add a new data file, and the full path data file name is the full path file name of the new data file. The size is * * m, the automatic expansion function is on, and the maximum expansion value of the data file is 20g

verify the added data files

SELECTfile_ name, file_ id, tablespace_ name

FROMdba_ data_ files

WHEREtablespace_ Name =’table space name ‘

0

if you delete a table space data file

alter table space name

drop datafile ‘/ u01/APP/Oracle/product/10.2.0/oradata/orcl/ User_ DATA.dbf’

ps : table space generally keeps the idle percentage above 10%, and the data file size should not exceed 2G. When the table space is insufficient, you can either reset the datafile or add the datafile