Tag Archives: java

[Solved] Nacos offline service error: errCode: 500

Error Messages:

caused: errCode: 500, errMsg: do metadata operation failed ;caused: com.alibaba.nacos.consistency.exception.ConsistencyException: com.alibaba.nacos.core.distributed.raft.exception.NoLeaderException: The Raft Group [naming_instance_metadata] did not find the Leader node;caused: com.alibaba.nacos.core.distributed.raft.exception.NoLeaderException: The Raft Group [naming_instance_metadata] did not find the Leader node;

 

Solution:
The reason for the error is the registered Ip or something confusing
1. Stop nacos first,
2. Delete the protocol folder in the data directory,
3. reboot. Done!

How to Solve mybatis-plus Paging Plug-in PaginationInnerInterceptor error

Questions

mybatis-plus using PaginationInnerInterceptor paging plugin, when calling the paging query method (****Service.page(new Page(param.getPage(),param.getPageSize()),queryWrapper )) reports the following error:

 2022-07-22 17:07:20.699 [TID: N/A]  WARN 12444 --- [io-18080-exec-1] c.b.m.e.p.i.PaginationInnerInterceptor   : optimize this sql to a count sql has exception, sql:"sql语句略", exception:
net.sf.jsqlparser.parser.ParseException: Encountered unexpected token: "," ","
    at line 1, column 191.

Was expecting one of:

    "&"
    "::"
    ";"
    "<<"
    ">>"
    "ACTION"
    "ACTIVE"
    "ALGORITHM"
    "ARCHIVE"
    "ARRAY" 
    ***略****

reason

The paging plugin will default to sql optimization when processing count, and will throw an exception if optimization fails. The sql that cannot be optimized will be downgraded to the non-optimized count method.
The code summary is as follows.
where Select select = (Select) CCJSqlParserUtil.parse(sql); This line of code reports error:

    protected String autoCountSql(IPage<?> page, String sql) {
        if (!page.optimizeCountSql()) {
            return lowLevelCountSql(sql);
        }
        try {
            Select select = (Select) CCJSqlParserUtil.parse(sql);
            **************Optimization Logic*********************
            return select.toString();
        } catch (JSQLParserException e) {
            // Unable to optimize the use of the original SQL
            logger.warn("optimize this sql to a count sql has exception, sql:\"" + sql + "\", exception:\n" + e.getCause());
        } catch (Exception e) {
            logger.warn("optimize this sql to a count sql has error, sql:\"" + sql + "\", exception:\n" + e);
        }
        return lowLevelCountSql(sql);
    }

Solution:

Add the following codes before your codes:

if (!page.optimizeCountSql()) {
return lowLevelCountSql(sql);
}

just set optimizeCountSql to false, as follows

Page page = new Page(param.getPage(),param.getPageSize()),queryWrapper)
page.setOptimizeCountSql(false);

You can also redefine a class to inherit Page, and set optimizeCountSql default to =false

 

How to Solve Spring Boot Maven Build Error

Error 1:

[ERROR]Failed to execute goal org.apache.maven.plugins:maven-surefire-plugin:2.21.0:test (default-test) on project motherBuyBoot: There are test failures.
[ERROR] Please refer to D:\web\motherbuy\target\surefire-reports for the individual test results. [ERROR] Please refer to dump files (if any exist) [date]-jvmRun[N].dump, [date].dumpstream and [date]-jvmRun[N].dumpstream.

Solution:

the pom.xml file has the wrong version of Junit, or for some other reason, the junit dependency is commented out and the compilation passes.

 

Error 2:

Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.7.0:compile (default-compile) on project motherBuyBoot: Compilation failure
[ERROR] No compiler is provided in this environment. Perhaps you are running on a JRE rather than a JDK?

Solution:

Method: Compile compile environment problems, that are not configured; see the screenshot below to solve, do not forget to update maven.

[Solved] Project Error: Could not found sun.misc.BASE64Encoder

1. Questions

The project reported an error: could not found sun.misc.BASE64Encoder

2. Reason

Classes such as sun.misc.BASE64Encoder are not part of the JDK standard library, but the class is included in the JDK and can be used directly.

3. Solution

Replace sun.misc.BASE64Encoder with java.util.Base64

Example:

//import sun.misc.BASE64Encoder;
import java.util.Base64;//how to solve could not found sun.misc.BASE64Encoder error
...
// return new BASE64Encoder().encodeBuffer(bytes).trim().replaceAll("\r|\n", "");
return Base64.getEncoder().encodeToString(bytes);

[Solved] Failed to start bean ‘documentationPluginsBootstrapper’; nested exception is java.lang.NullPointerException

# org.springframework.context.ApplicationContextException: Failed to start bean ‘documentationPluginsBootstrapper’; nested exception is java.lang.NullPointerException

First, The relevant configurations in my pom.xml are as follows

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.7.1</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <!--swagger-->
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger2</artifactId>
            <version>2.9.2</version>
        </dependency>
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger-ui</artifactId>
            <version>2.9.2</version>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

At this point, my spring-boot-starter version may not match the swagger version, and the following error is reported

org.springframework.context.ApplicationContextException: Failed to start bean 'documentationPluginsBootstrapper'; nested exception is java.lang.NullPointerException

Because Springfox uses path matching based on AntPathMatcher, while Spring Boot 2.6.X uses PathPatternMatcher.

Solution:

Configurate in application.properties:

spring.mvc.pathmatch.matching-strategy=ANT_PATH_MATCHER

The problem can be solved.

[Solved] M1 Chip MacBook Pro Error: snappy-java FAILED_TO_LOAD_NATIVE_LIBRARY

Solution:

Directly find the xml file that introduces the dependency (I am the xml file of spark-core), change the version of snappy-java in it to 1.1.8.4. just reload it.

    <dependency>
      <groupId>org.xerial.snappy</groupId>
      <artifactId>snappy-java</artifactId>
      <version>1.1.8.4</version>
      <scope>compile</scope>
    </dependency>

 

How to Solve: (Detailed exploration process)

The MacBook Pro with the new M1 pro chip arrived a few days ago, and I couldn’t wait to try it out. Because the chip uses the ARM instruction set, the previous Intel chip computers used the X86 instruction set, so there were inevitably some problems. However, after a year of adaptation, there are basically no major problems, so after a few days of trying, I decided to use the machine for work production.

Because I want to install Java, at first I used the traditional Intel version of jdk (because the main use is jdk1.8, and Oracle only did the adaptation of jdk17 for the arm version), and I feel that some programs in the development will not be executed so fast (and 18 MacBook Pro execution speed is about the same), because after all, it has to go through Rosetta2 translate. Therefore, after using it for a few days, I replaced the Intel version of jdk with the ARM version of jdk, but there is a problem in the documentation, the direct download link given in the documentation is not the ARM version, I found that the execution has been using the intel version of java after installation, then I found that the download link is wrong, you need to manually download the real ARM version of jdk from the official website.

After installing the arm version of jdk, the compilation speed is really improved, but when executing the spark program locally, I encountered such a problem, the detailed log is as follows:

Caused by: org.xerial.snappy.SnappyError: [FAILED_TO_LOAD_NATIVE_LIBRARY] no native library is found for os.name=Mac and os.arch=aarch64
	at org.xerial.snappy.SnappyLoader.findNativeLibrary(SnappyLoader.java:331)
	at org.xerial.snappy.SnappyLoader.loadNativeLibrary(SnappyLoader.java:171)
	at org.xerial.snappy.SnappyLoader.load(SnappyLoader.java:152)
	at org.xerial.snappy.Snappy.<clinit>(Snappy.java:47)
	at org.apache.parquet.hadoop.codec.SnappyDecompressor.decompress(SnappyDecompressor.java:62)
	at org.apache.parquet.hadoop.codec.NonBlockedDecompressorStream.read(NonBlockedDecompressorStream.java:51)
	at java.io.DataInputStream.readFully(DataInputStream.java:195)
	at java.io.DataInputStream.readFully(DataInputStream.java:169)
	at org.apache.parquet.bytes.BytesInput$StreamBytesInput.toByteArray(BytesInput.java:205)
	at org.apache.parquet.column.values.dictionary.PlainValuesDictionary$PlainBinaryDictionary.<init>(PlainValuesDictionary.java:89)
	at org.apache.parquet.column.values.dictionary.PlainValuesDictionary$PlainBinaryDictionary.<init>(PlainValuesDictionary.java:72)
	at org.apache.parquet.column.Encoding$1.initDictionary(Encoding.java:90)
	at org.apache.parquet.column.Encoding$4.initDictionary(Encoding.java:149)
	at org.apache.spark.sql.execution.datasources.parquet.VectorizedColumnReader.<init>(VectorizedColumnReader.java:103)
	at org.apache.spark.sql.execution.datasources.parquet.VectorizedParquetRecordReader.checkEndOfRowGroup(VectorizedParquetRecordReader.java:280)
	at org.apache.spark.sql.execution.datasources.parquet.VectorizedParquetRecordReader.nextBatch(VectorizedParquetRecordReader.java:225)
	at org.apache.spark.sql.execution.datasources.parquet.VectorizedParquetRecordReader.nextKeyValue(VectorizedParquetRecordReader.java:137)
	at org.apache.spark.sql.execution.datasources.RecordReaderIterator.hasNext(RecordReaderIterator.scala:39)
	at org.apache.spark.sql.execution.datasources.FileScanRDD$$anon$1.hasNext(FileScanRDD.scala:105)
	at org.apache.spark.sql.execution.datasources.FileScanRDD$$anon$1.nextIterator(FileScanRDD.scala:177)
	at org.apache.spark.sql.execution.datasources.FileScanRDD$$anon$1.hasNext(FileScanRDD.scala:105)
	at org.apache.spark.sql.catalyst.expressions.GeneratedClass$GeneratedIterator.scan_nextBatch$(Unknown Source)
	at org.apache.spark.sql.catalyst.expressions.GeneratedClass$GeneratedIterator.processNext(Unknown Source)
	at org.apache.spark.sql.execution.BufferedRowIterator.hasNext(BufferedRowIterator.java:43)
	at org.apache.spark.sql.execution.WholeStageCodegenExec$$anonfun$8$$anon$1.hasNext(WholeStageCodegenExec.scala:395)
	at org.apache.spark.sql.catalyst.expressions.GeneratedClass$GeneratedIterator.agg_doAggregateWithKeys$(Unknown Source)
	at org.apache.spark.sql.catalyst.expressions.GeneratedClass$GeneratedIterator.processNext(Unknown Source)
	at org.apache.spark.sql.execution.BufferedRowIterator.hasNext(BufferedRowIterator.java:43)
	at org.apache.spark.sql.execution.WholeStageCodegenExec$$anonfun$8$$anon$1.hasNext(WholeStageCodegenExec.scala:395)
	at scala.collection.Iterator$$anon$11.hasNext(Iterator.scala:408)
	at org.apache.spark.shuffle.sort.BypassMergeSortShuffleWriter.write(BypassMergeSortShuffleWriter.java:125)
	at org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:96)
	at org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:53)
	at org.apache.spark.scheduler.Task.run(Task.scala:108)
	at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:335)
	... 3 more

org.xerial.snappy is a compressed/uncompressed library, I am using spark version 2.2.0, which depends on snappy 1.1.2.6. The contents of this version are as follows:

As you can see, this version of snappy only supports x86 and x86_64 for Mac systems, not arm64. Just find the dependency that introduces snappy-java and upgrade its version directly to the latest version.

Searching through IDEA’s dependency graph, I found that the library was imported by spark-core, my version of spark-core is 2.2.0 and the snappy-java introduced is 1.1.2.6. As shown in the figure:

The latest version of snappy-java is 1.1.8.4 in the mvnrepository, so replace the original version in the spark-core xml file directly, as shown in the figure

Reload the dependency and execute it again. The code executes smoothly and the problem is solved.

[Solved] JAVA HttpClient Send Https request certificate error:PKIX path building failed:

Recently, when using httpclient to connect with the third-party SMS interface, a certificate invalidation error was reported during the local test.

1. Post request of Encapsulated HttpClient:

public static Map<String, Object> postReq(String URL, Map<String, Object> paramMap, Map<String, String> headers) throws Exception {
        Map<String, Object> map = new HashMap<String, Object>();

        RequestConfig requestConfig = RequestConfig.custom()
                .setConnectTimeout(2000) // Set the connection timeout, in milliseconds
                .setConnectionRequestTimeout(1000)
                .setSocketTimeout(5000) // timeout for requesting data, in milliseconds
                .build();
        HttpRequestRetryHandler myRetryHandler = new HttpRequestRetryHandler() {
            @Override
            public boolean retryRequest(IOException exception, int executionCount, HttpContext context) {
                return false;
            }
        };

        try (CloseableHttpClient client = HttpClients.custom()
                .setDefaultRequestConfig(requestConfig)
                .setRetryHandler(myRetryHandler)
                .build()) {

            HttpPost httpPost = new HttpPost(URL);
            if (paramMap != null) {
                JSONObject paramJson = new JSONObject(paramMap);
                StringEntity paramEntity = new StringEntity(paramJson.toString(), "UTF-8");
                paramEntity.setContentType("application/json; charset=utf-8");
                httpPost.setEntity(paramEntity);
            }
            httpPost.setConfig(requestConfig);

            if (headers != null && !headers.isEmpty()) {
                for (String key : headers.keySet()) {
                    String value = headers.get(key);
                    httpPost.setHeader(key, value);
                }
            }

            CloseableHttpResponse response = client.execute(httpPost);

            HttpEntity entity = response.getEntity();

            if (entity != null) {
                String responseStr = EntityUtils.toString(entity, "UTF-8");
                if (responseStr.isEmpty()) {
                    responseStr = "{}";
                }

                int statusCode = response.getStatusLine().getStatusCode();
                if (HttpServletResponse.SC_OK == statusCode) {
                    try {
                        JSONObject dataJson = (JSONObject) JSONObject.parse(responseStr);
                        map = new HashMap<>(dataJson);
                    } catch (Exception e) {
                        map.put("reponse", responseStr);
                    }
                } else {
                    return map;
                }
            }
            response.close();
        }
        return map;
    }

However, an error will be reported when accessing some self signed HTTPS requests. This problem is caused by the invalid link certificate, because the self signed certificate will be recognized as an unsafe link.

sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target

2. Solutions

  1. Set the security certificate of jdk according to the online method -> No work
  2. Set maven to ignore the certificate checksum -> no work
  3. Yml file configuration httpclient ignore SSL checksum, seems to have no effect.
  4. Finally used the method of modifying the code, the principle is also to ignore the certificate checksum, but the code produced the effect, it is estimated that the construction is related to the Httpclient.

 

Modify the original code

// Ignore SSL Security Certification
**SSLConnectionSocketFactory scsf = new SSLConnectionSocketFactory(
        SSLContexts.custom().loadTrustMaterial(null, new TrustSelfSignedStrategy()).build(),
        NoopHostnameVerifier.INSTANCE);**

try (CloseableHttpClient client = **HttpClients.custom().setSSLSocketFactory(scsf)**
        .setDefaultRequestConfig(requestConfig)
        .setRetryHandler(myRetryHandler)
        .build()) {

[Solved] socket failed: EPERM (Operation not permitted)

Reason & Solution:

1. The network permission is not enabled
2 HTTP is not supported

Add network permissions to AndroidManifest.xml

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

If the error is still reported, add the following to the Application in the AndroidManifest.xml file

android:usesCleartextTraffic="true"

Reason: On Android 9.0 machines, http access is not supported by default, all network access must use https. of course Android has supported https in several earlier versions, except that http is not supported by default using https on 9.0.

If the above operation can not be solved, please uninstall the application first, and then run it again.

[Solved] Linux Error: Failed to start bean ‘webServerStartStop‘; nested exception is org.springframework.

💛 Environment: windows10, centos7.5.1804

linux_debug：Failed to start bean ‘webServerStartStop’; nested exception is org. springframework. boot.

1. Error information

2022-07-08 18:12:25.088 ERROR 33600 --- [           main] o.s.boot.SpringApplication               : Application run failed

org.springframework.context.ApplicationContextException: Failed to start bean 'webServerStartStop'; nested exception is org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat server
	at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:181) ~[spring-context-5.3.21.jar!/:5.3.21]
	at org.springframework.context.support.DefaultLifecycleProcessor.access$200(DefaultLifecycleProcessor.java:54) ~[spring-context-5.3.21.jar!/:5.3.21]
	at org.springframework.context.support.DefaultLifecycleProcessor$LifecycleGroup.start(DefaultLifecycleProcessor.java:356) ~[spring-context-5.3.21.jar!/:5.3.21]
	at java.lang.Iterable.forEach(Iterable.java:75) ~[na:1.8.0_333]
	at org.springframework.context.support.DefaultLifecycleProcessor.startBeans(DefaultLifecycleProcessor.java:155) ~[spring-context-5.3.21.jar!/:5.3.21]
	at org.springframework.context.support.DefaultLifecycleProcessor.onRefresh(DefaultLifecycleProcessor.java:123) ~[spring-context-5.3.21.jar!/:5.3.21]

2. Problem description

When running the jar package made by springboot project on Linux;

If the above problem occurs, port 8080 is occupied;

3. Solutions

Close the occupied 8080 port;

3.1 windows

Enter in CMD

# Find the corresponding pid
netstat -ano | findstr 8080

## out：TCP 0.0.0.0:8080 0.0.0.0:0 LISTENING 6148

Close the PID number corresponding to the port, assuming that port 8080 corresponds to the process number with process number 123

taskkill /pid 6148 -t -f

3.2 linux

Enter in CMD

# Find the corresponding pid
netstat -ano | grep 8080

## out：TCP 0.0.0.0:8080 0.0.0.0:0 LISTENING 6148

Close the PID number corresponding to the port, assuming that port 8080 corresponds to the process number with process number 123

kill -9 PID 123

[Solved] Failed to load resource: the server responded with a status of 404 ()

Failed to load resource: the server responded with a status of 404 ()

There is a problem with server compilation. Some resources are not compiled in the server compilation and packaging, resulting in no accessed resources in the server.

Solution:

1. Put the resources that cannot be scanned into the corresponding location of the out folder

For example:

Put the folder at (1) on (2)

Method 2:

Repackage

[Solved] JPA Create Sheet error at the First time: Cant DROP [xxx]；check that column/key exists

Main contents of error reporting information:

        Cant DROP [xxx]; check that column/key exists

Error reporting information reference data:

A configuration as follows:

package org.hibernate.tool.schema.internal;

public abstract class AbstractSchemaMigrator implements SchemaMigrator {
    …………

    private UniqueConstraintSchemaUpdateStrategy uniqueConstraintStrategy;
}

The reason for the locking problem is that the default configuration is: delete + first and then create.

Then the solution of the problem should consider using the second one: RECREATE_QUIETLY, try to create it directly and ignore the exception.

Problem-solving:

Configure the above mentioned configuration in application.yml, but since this configuration was not prompted, after a query, it was found in.

package org.hibernate.cfg;


public interface AvailableSettings extends org.hibernate.jpa.AvailableSettings {
    ……
    /*
        In most dialects, unique constraints are used for unique columns and unique keys. SchemaUpdate needs to create these constraints, but DB support for finding existing constraints is extremely inconsistent. In addition, non-explicitly named unique constraints use randomly generated characters. Therefore, choose from these strategies. org.hibernate.tool.hbm2ddl.UniqueConstraintSchemaUpdateStrategy.DROP_RECREATE_QUIETLY (default): Attempt to delete and then (re)create each unique constraint. Ignore any exceptions thrown. org.hibernate.tool.hbm2ddl.UniqueConstraintSchemaUpdateStrategy.RECREATE_QUIETLY : Attempts to (re)create the unique constraint, ignoring any exceptions thrown if the constraint already exists org.hibernate.tool. hbm2ddl.UniqueConstraintSchemaUpdateStrategy.SKIP : Don't try to create unique constraint structure updates
    */
    String UNIQUE_CONSTRAINT_SCHEMA_UPDATE_STRATEGY = "hibernate.schema_update.unique_constraint_strategy";

    ……
}

Configurate in application.yml:

spring:
  ## jpa configuration
  jpa:
    hibernate:
      ddl-auto: ${JPA_HIBERNATE_DDL_AUTO:update}
    open-in-view: ${JPA_OPEN_IN_VIEW:true}
    show-sql: ${JPA_SHOW_SQL:false}
    properties:
      hibernate:
        schema_update:
          ## This configuration is the focus of this blog post, after setting, the error report no longer appears
          unique_constraint_strategy: RECREATE_QUIETLY