使用JAVA进行数据库部分知识的操作代码

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、dropDML （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 ASC|DESC】

【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;//idprivate 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;}@Overridepublic 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();}} 相关文章：

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