albert's blog: January 2018

2018/01/31

2018/01/30

2018/01/13

[Win 10] 如何解決磁碟使用率常 100% 的情況

Problem
當我在使用 Windows 10 的時候，從工作管理員發現，磁碟使用率常滿載，一直 90 ~ 100%，嚴重影響整體效能

How-To
解決方式分成兩方面:

在 C 槽按右鍵，將以下 checkbox uncheck，按下確定即可

到控制台 -> 服務，找到 Windows Search 此服務，將其 Stop 並將啟動類型設為手動

2018/01/12

[JSON] Jackson Annotations for JSON

Assume I have two Java beans:

  package test.albert.jackson;
    
  import lombok.Builder;
  import lombok.Data;
    
  @Data
  @Builder
  public class Employee {
    
      private Integer id;
    
      private String name;
    
      private String email;
    
      private String phone;
        
      private Address address;
   
  }

  package test.albert.jackson;
    
  import lombok.Builder;
  import lombok.Data;
    
  @Data
  @Builder
  public class Address {
    
      private String streetAddress;
      private String city;
      private String zipCode;
    
  }

I am using ObjectMapper to convert object into JSON string, the example code is as bellows:

  package test.albert.jackson;
    
  import com.fasterxml.jackson.core.JsonProcessingException;
  import com.fasterxml.jackson.databind.ObjectMapper;
    
  import lombok.extern.slf4j.Slf4j;
    
  @Slf4j
  public class JacksonTest {
    
      public static void main(String[] args) throws JsonProcessingException {
          Address address = Address.builder().zipCode("110").city("台北市").streetAddress("信義區信義路五段7號").build();
          Employee albert = Employee.builder().id(1).name("Albert").email("albert@gmail.com").phone("0900123456")
                  .address(address).build();
    
          ObjectMapper mapper = new ObjectMapper();
          String json = mapper.writeValueAsString(albert);
          log.debug(json);
      }
    
  }

The generated JSON looks like:

{
 "id": 1,
 "name": "Albert",
 "email": "albert@gmail.com",
 "phone": "0900123456",
 "address": {
  "streetAddress": "信義區信義路五段7號",
  "city": "台北市",
  "zipCode": "110"
 }
}

If I would like to ignore id, just add @JsonIgnore to id

  package test.albert.jackson;
  
  import lombok.Builder;
  import lombok.Data;
  
  @Data
  @Builder
  public class Employee {
  
      @JsonIgnore
      private Integer id;
  
      private String name;
  
      private String email;
  
      private String phone;
  
      private Address address;
  
  }

If I would like to get rid of id and phone in Employee, add @JsonIgnoreProperties({"id", "phone"}) to Employee class:

  package test.albert.jackson;
  
  import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
  
  import lombok.Builder;
  import lombok.Data;
  
  @Data
  @Builder
  @JsonIgnoreProperties({"id", "phone"})
  public class Employee {
  
      private Integer id;
  
      private String name;
  
      private String email;
  
      private String phone;
  
      private Address address;
  
  }

If I want to remove address from Employee class, just add @JsonIgnoreType to Address class.

  package test.albert.jackson;
  
  import com.fasterxml.jackson.annotation.JsonIgnoreType;
  
  import lombok.Builder;
  import lombok.Data;
  
  @Data
  @Builder
  @JsonIgnoreType
  public class Address {
  
      private String streetAddress;
      private String city;
      private String zipCode;
  
  }

2018/01/11

[Win 10] 如何解決憑證匯入失敗， "權限不足" 的錯誤

Problem
當我要將國泰證券的憑證匯入到新電腦時，IE 瀏覽出現 "權限不足" 的錯誤訊息

How-To
以系統管理員身分執行即可以解決此權限不足的問題

2018/01/10

[Maven] How to use local repository?

Problem
How to use local repository in Maven?

How-To

Approach 1. Add localRepository tag in your settings.xml

<settings xmlns="http://maven.apache.org/SETTINGS/1.0.0" 
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
        xsi:SchemaLocation="http://maven.apache.org/SETTINGS/1.0.0 
                      http://maven.apache.org/xsd/settings-1.0.0.xsd">
          
   <localRepository>C:\Users\albert\.m2</localRepository>
   
</settings>

Approach 2. Assign -Dmaven.repo.local in command line

1	mvn -o -Dmaven.repo.local=”C:\Users\albert\.m2" clean install -Dmaven.test.skip=true -X

Reference
[1] https://stackoverflow.com/questions/9123004/maven-is-it-possible-to-override-location-of-local-repository-via-the-use-of-co

2018/01/09

[GitLab] How to build jar file automatically

Problem
If I hope GitLab can build a jar file when I commit source code, how to do it?
I am using Maven 3.3.3 and JDK 7 in eclipse, and using mvn clean install -Dmaven.test.skip=true to build WAR file in eclipse.

How-To
Step 1. Add .gitlab-ci.yml to the root directory of my project, the content looks like:

image: maven:3.3.3-jdk-7
    
build:
  stage: build
  script:
   - "mvn clean install -Dmaven.test.skip=true"
  artifacts:
    expire_in: 1 week
    when: on_success
    paths:
    - target/*.jar

Step 2. Add, commit and push .gitlab-ci.yml to GitLab
Step 3. Seeing the status of your pipeline and jobs

Reference
[1] https://docs.gitlab.com/ce/ci/quick_start/README.html

2018/01/08

[GitLab] How to build WAR file automatically

Problem
If I hope GitLab can build a WAR file when I commit source code, how to do it?
I am using Maven 3 and JDK 7 in eclipse, and using mvn clean package -U to build WAR file in eclipse.

How-To
Step 1. Add .gitlab-ci.yml to the root directory of my project, the content looks like:

image: maven:3-jdk-7

build:
  stage: build
  script: "mvn clean package -U"
  artifacts:
    expire_in: 1 week
    when: always
    paths:
    - target/*.war

Step 2. Add, commit and Push .gitlab-ci.yml to GitLab
Step 3. Seeing the status of your pipeline and jobs

Reference
[1] https://docs.gitlab.com/ce/ci/quick_start/README.html
[2] https://hub.docker.com/r/library/maven/tags/

2018/01/07

[Maven] Cannot find IBM-related jar files in Maven Central Repository

Problem
If I would like to use some proprietorial jar files (i.e. IBM DB2 jdbc jar file, IBM MessageQueue jar files) in my Maven project, and add them into dependency.
How to do it?

How-To
Step 1. Download jar files, ex. DB2 jdbc jar file
Step 2. Launch command prompt, change directorty to db2 jar file and execute the following command:

mvn install:install-file -Dfile=db2jcc4-4.22.29.jar -DgroupId="com.ibm.db2.jcc" -DartifactId="db2jcc4" -Dversion="4.22.29" -Dpackaging="jar"

Step 3. Add dependency to pom.xml

    <dependency>
        <groupId>com.ibm.db2.jcc</groupId>
        <artifactId>db2jcc4</artifactId>
        <version>4.22.29</version>
    </dependency>

Step 4. Go to .m2 folder and copy com/ibm/db2/jcc/db2jcc4 to your project, for example:

Step 5. Add repository setting in your pom.xml

    <repositories>
        <repository>
            <id>my-local-repo</id>
            <!-- ${basedir} represents the directory containing pom.xml -->
            <url>file://${basedir}/local-repo</url> 
        </repository>
    </repositories>

2018/01/06

[Git] fatal:LF would be replaced by CRLF

Problem
As I try to use the git add command adds a change in the working directory to the staging area, it show the error:

fatal: LF would be replaced by CRLF

Here has a post to solve this problem: https://albert-kuo.blogspot.tw/2016/12/git-fatal-lf-would-be-replaced-by-crlf.html

But if I have hundreds of file have this problem, how to solve this problem?

Solution
Step 1. download file from http://www.bastet.com/uddu.zip

Step 2. Unzip and copy UNIX2DOS.EXE and UNIX2DOS.C to the root directory of your project.

Step 3. Assign the file extension you would like to do replacement in the command and execute this command:

for /f %f IN ( 'dir /b /s *.xml *.pom *.sha1' ) DO @unix2dos %f

Step 4. Remove UNIX2DOS.EXE and UNIX2DOS.C from your project.

2018/01/05

[Fortify] Fix Unreleased Resource: Database

Before

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.apache.commons.dbutils.QueryRunner;

public class DaoBase {

    public Connection getConnection() throws SQLException {
        return MyDataSource.getInstance().getDatasource().getConnection();
    }

    public List<Map<String, Object>> find(String sql) throws SQLException {
        List<Map<String, Object>> datas = new ArrayList<Map<String, Object>>();

        Connection con = null;
        Statement stmt = null;
        ResultSet rs = null;

        try {
            con = getConnection();
            stmt = con.createStatement();
            rs = stmt.executeQuery(sql);

            // ...
        } catch (SQLException e) {
            throw e;
        } finally {
            if(rs != null) {
                rs.close();
            }
            if(stmt != null) {
                stmt.close();
            }
            if(con != null) {
                con.close();
            }
        }

        return datas;
    }
}

After

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.apache.commons.dbutils.QueryRunner;

public class DaoBase {

    public Connection getConnection() throws SQLException {
        return MyDataSource.getInstance().getDatasource().getConnection();
    }

    public List<Map<String, Object>> find(String sql) throws SQLException {
        List<Map<String, Object>> datas = new ArrayList<Map<String, Object>>();

        Connection con = null;
        Statement stmt = null;
        ResultSet rs = null;

        try {
            con = getConnection();
            stmt = con.createStatement();
            rs = stmt.executeQuery(sql);

            // ignore...
        } catch (SQLException e) {
            throw e;
        } finally {
            close(rs);
            close(stmt);
            close(con);
        }

        return datas;
    }

    public void close(ResultSet rs) {
        if (rs != null) {
            try {
                rs.close();
            } catch (SQLException e) {
            }
        }
    }

    public void close(Statement stmt) {
        if (stmt != null) {
            try {
                stmt.close();
            } catch (SQLException e) {
            }
        }
    }

    public void close(Connection con)  {
        if (con != null) {
            try {
                con.close();
            } catch (SQLException e) {
            }
        }
    }
}

2018/01/04

[Fortify] Fix SQL Injection