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使用JAVA进行数据库部分知识的操作代码...

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本周首先暂时结束了java高级知识,进入到了数据库的学习:

java高级部分:
1.多线程:线程并发(多个线程操作共享变量);
锁机制,关键字有synchronize(并发线程安全,可锁对象和方法),wait,notify
(悲观)死锁,,wait,notify,notifyAll;
2.网络编程:UDP数据广播(数据发送者只需向交换机发送一个拷贝,交换机负责将这个信息制作n个拷贝发送给所有机器)
Http协议(HyperText Transfer Protocol)
Json数据格式,语法规则:JSON对象{"属性名":"属性值"}
JSON数组["元素1","元素2"...]
JSON插件:- Json-lib
- Gson
- Jackson
- FastJSON - alibaba

数据库部分:(采用mysql5.5数据库,以及navicat图形工具对其操作)
3.系统以及mysql常用命令
系统命令(以管理员身份运行)

: #启动服务
net start mysql

#停止服务
net stop mysql


#进入mysql命令行
mysql -uroot -p密码

#退出mysql命令行
exit


#修改密码
mysqladmin -uroot -p123456 password 密码
#备份数据库实例 mysqldump -uroot -proot mydb > d:/mydb.sql
#备份表 mysqldump -uroot -proot mydb tbuser > d:/tbuser.sql

Mysql常用命令

: --显示数据库实例
show databases;

--创建数据库实例
create database mydb;

--使用数据库实例
user mydb;

--显示实例中所有数据库表
show tables;

SQL语句

auto_increment:设置列自增,可用于主键列以及非空唯一列(not null unique)


unsigned:设置无符号列(列值不允许为负数)


zerofill:设置零填充列(当列数据长度不到定义长度时,数值前补0)

4.SQL语句:
DDL(数据库定义语言:用来建立数据库、数据库对象和定义其列):create、desc(查看表结构)、alter、drop
DML (数据库操纵语言:增删改查):select、insert、delete、update;
DCL(数据库控制语言:控制权限)revork,grant;
5.(完整性条件)约束:1. 主键约束
2. 外键约束
3. 不为空约束
4. 唯一约束
5. 检查约束(mysql暂不支持)

6.数据类型、运算符
7.查询(重点):SELECT 查询列1,查询列2,...
FROM 目标表


【WHERE 查询条件】

【GROUP BY 列名称】


【HAVING 查询条件】

【ORDER BY 列名称 ASCDESC】


【LIMIT [偏移行,]记录行数】

单表查询:模糊查询(“%”,“_”),聚合函数
多表查询:等值连接,外连接
mysql函数的使用。

import java.io.Serializable;

/**
 * 工作详情类
 * @author NIUXUYUAN
 */
public class Jobs implements Serializable{

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;
	private String id;          //id
	private String experience;  //工作经验
	private String city;        //工作地点
	private String industry;    //行业
	private String detail;      //工作详情
	private String company;     //公司
	private String jobname;     //职位
	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");
	
	/**
	 * 输入数据
	 * @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();
	}

	/**
	 * 将数据变为Jobs对象存入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,将数据导入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("请输入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("结果");
		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();
	}
}



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