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    1. 明輝手游網中心:是一個免費提供流行視頻軟件教程、在線學習分享的學習平臺!

      使用JAVA進行數據庫局部知識的設置代碼

      [摘要]本周首先暫時結束了java高級知識,進入到了數據庫的學習:java高級部分: 1.多線程:線程并發(多個線程操作共享變量); ...
      本周首先暫時結束了java高級知識,進入到了數據庫的學習:

      java高級部分:
      1.多線程:線程并發(多個線程操作共享變量);
      鎖機制,關鍵字有synchronize(并發線程安全,可鎖對象和方法),wait,notify
      (悲觀)死鎖,,wait,notify,notifyAll;
      2.網絡編程:UDP數據廣播(數據發送者只需向交換機發送一個拷貝,交換機負責將這個信息制作n個拷貝發送給所有機器)
      Http協議(HyperText Transfer Protocol)
      Json數據格式,語法規則:JSON對象{"屬性名":"屬性值"}
      JSON數組["元素1","元素2"...]
      JSON插件:- Json-lib
      - Gson
      - Jackson
      - FastJSON - alibaba
      ;
      數據庫部分:(采用mysql5.5數據庫,以及navicat圖形工具對其操作)
      3.系統以及mysql常用命令
      系統命令(以管理員身份運行)

      : #啟動服務
      net start mysql

      #停止服務
      net stop mysql


      #進入mysql命令行
      mysql -uroot -p密碼

      #退出mysql命令行
      exit


      #修改密碼
      mysqladmin -uroot -p123456 password 密碼
      #備份數據庫實例 mysqldump -uroot -proot mydb > d:/mydb.sql
      #備份表 mysqldump -uroot -proot mydb tbuser > d:/tbuser.sql

      Mysql常用命令

      : --顯示數據庫實例
      show databases;

      --創建數據庫實例
      create database mydb;

      --使用數據庫實例
      user mydb;

      --顯示實例中所有數據庫表
      show tables;

      SQL語句

      auto_increment:設置列自增,可用于主鍵列以及非空唯一列(not null unique)


      unsigned:設置無符號列(列值不允許為負數)


      zerofill:設置零填充列(當列數據長度不到定義長度時,數值前補0)

      4.SQL語句:
      DDL(數據庫定義語言:用來建立數據庫、數據庫對象和定義其列):create、desc(查看表結構)、alter、drop
      DML (數據庫操縱語言:增刪改查):select、insert、delete、update;
      DCL(數據庫控制語言:控制權限)revork,grant;
      5.(完整性條件)約束:1. 主鍵約束
      2. 外鍵約束
      3. 不為空約束
      4. 唯一約束
      5. 檢查約束(mysql暫不支持)

      6.數據類型、運算符
      7.查詢(重點):SELECT 查詢列1,查詢列2,...
      FROM 目標表


      【WHERE 查詢條件】

      【GROUP BY 列名稱】


      【HAVING 查詢條件】

      【ORDER BY 列名稱 ASC DESC】


      【LIMIT [偏移行,]記錄行數】

      單表查詢:模糊查詢(“%”,“_”),聚合函數
      多表查詢:等值連接,外連接
      mysql函數的使用。

      import java.io.Serializable;
      
      /**
       * 工作詳情類
       * @author NIUXUYUAN
       */
      public class Jobs implements Serializable{
      
      	/**
      	 * 
      	 */
      	private static final long serialVersionUID = 1L;
      	private String id;          //id
      	private String experience;  //工作經驗
      	private String city;        //工作地點
      	private String industry;    //行業
      	private String detail;      //工作詳情
      	private String company;     //公司
      	private String jobname;     //職位
      	public Jobs(String id, String experience, String city, String industry, String detail, String company,
      			String jobname) {
      		super();
      		this.id = id;
      		this.experience = experience;
      		this.city = city;
      		this.industry = industry;
      		this.detail = detail;
      		this.company = company;
      		this.jobname = jobname;
      	}
      	
      	@Override
      	public String toString() {
      		return "Jobs [id=" + id + ", experience=" + experience + ", city=" + city + ", industry=" + industry
      				+ ", detail=" + detail + ", company=" + company + ", jobname=" + jobname + "]";
      	}
      	
      	public String toString(int i) {
      		return experience+city+industry+detail+company+jobname;
      	}
      
      	public Jobs() {
      		// TODO Auto-generated constructor stub
      	}
      
      	public String getId() {
      		return id;
      	}
      
      	public void setId(String id) {
      		this.id = id;
      	}
      
      	public String getExperience() {
      		return experience;
      	}
      
      	public void setExperience(String experience) {
      		this.experience = experience;
      	}
      
      	public String getCity() {
      		return city;
      	}
      
      	public void setCity(String city) {
      		this.city = city;
      	}
      
      	public String getIndustry() {
      		return industry;
      	}
      
      	public void setIndustry(String industry) {
      		this.industry = industry;
      	}
      
      	public String getDetail() {
      		return detail;
      	}
      
      	public void setDetail(String detail) {
      		this.detail = detail;
      	}
      
      	public String getCompany() {
      		return company;
      	}
      
      	public void setCompany(String company) {
      		this.company = company;
      	}
      
      	public String getJobname() {
      		return jobname;
      	}
      
      	public void setJobname(String jobname) {
      		this.jobname = jobname;
      	}
      	
      }
      import java.io.BufferedReader;
      import java.io.File;
      import java.io.FileInputStream;
      import java.io.FileNotFoundException;
      import java.io.FileOutputStream;
      import java.io.IOException;
      import java.io.InputStreamReader;
      import java.io.ObjectInputStream;
      import java.io.ObjectOutputStream;
      import java.util.ArrayList;
      import java.util.List;
      
      public class AddJobs {
      
      	static List<Jobs> list = new ArrayList<>();
      	File file = new File("jobs");
      	
      	/**
      	 * 輸入數據
      	 * @throws IOException
      	 */
      	public void input() throws IOException {
      	     BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
      	     System.out.println("以id/experience/education/city/industry/detail/company/jobname格式填入:");
      	     String msg = "";
      	     while(!(msg = br.readLine()).equalsIgnoreCase("quit")) {
      	    	 add(msg);
      	     }
      	     br.close();
      	}
      
      	/**
      	 * 將數據變為Jobs對象存入list集合
      	 * @param msg
      	 */
      	private void add(String msg) {
      		String[] s = msg.split("/");
      		Jobs job = new Jobs(s[0], s[1], s[2], s[3], s[4], s[5], s[6]);
      		list.add(job);
      	}
      	
      	private void checkFile() throws FileNotFoundException, IOException, ClassNotFoundException {
      		if(file.length()>0) {
      		ObjectInputStream ois = new ObjectInputStream(new FileInputStream(file));
      		List<Jobs> temp = (List<Jobs>)ois.readObject();
      		if(temp!=null) {
      			list.clear();
      			for(Jobs t:temp) {
      				list.add(t);
      			}
      		}
      		ois.close();
      		}
      	}
      	public static void main(String[] args) throws FileNotFoundException, IOException, ClassNotFoundException {
      		AddJobs aj = new AddJobs();
      		if(!aj.file.exists()) {
      			aj.file.createNewFile();
      		}
      		aj.checkFile();
      		aj.input();
      		ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(aj.file));
      		oos.writeObject(list);
      		oos.close();
      	}
      
      }
      import java.io.BufferedReader;
      import java.io.File;
      import java.io.FileInputStream;
      import java.io.FileNotFoundException;
      import java.io.IOException;
      import java.io.InputStreamReader;
      import java.io.ObjectInputStream;
      import java.util.ArrayList;
      import java.util.List;
      
      public class Query {
      
      	static List<Jobs> list = new ArrayList<>();
      	File file = new File("jobs");
      
      	/**
      	 * 查看file文件,將數據導入list集合
      	 * @throws FileNotFoundException
      	 * @throws IOException
      	 * @throws ClassNotFoundException
      	 */
      	private void checkFile() throws FileNotFoundException, IOException, ClassNotFoundException {
      		if(file.length()>0) {
      		ObjectInputStream ois = new ObjectInputStream(new FileInputStream(file));
      		List<Jobs> temp = (List<Jobs>)ois.readObject();
      		if(temp!=null) {
      			list.clear();
      			for(Jobs t:temp) {
      				list.add(t);
      			}
      		}
      		ois.close();
      		}
      	}
      	
      	public void check() throws IOException {
      		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
      		System.out.println("請輸入experience/education/city/industry/detail/company/jobname的某些信息");
      		String msg = br.readLine();
      		String[] s = msg.split("/");
      		String regex = "";
      		for (String str : s) {
      			regex += "[\\s\\S]*" + str + "[\\s\\S]*";
      		}
      		List<Jobs> temp = new ArrayList<>();
      		for (Jobs j : list) {
      			msg = j.toString(1);
      			if(msg.matches(regex)) {
      				temp.add(j);
      			}
      		}
      		System.out.println("結果");
      		for (Jobs jobs : temp) {
      			System.out.println(jobs);
      		}
      	}
      	public static void main(String[] args) throws FileNotFoundException, ClassNotFoundException, IOException {
      		Query q = new Query();
      		q.checkFile();
      		q.check();
      	}
      }

      相關文章:

      Java連接MySQL數據庫及簡單操作代碼

      數據庫基礎知識

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