第一部分数据的增删改查。
@1 查看表的结构。
DESC student studentt为数据库
@2 增一条记录。
@3改记录
@4删除记录
#查表的结构 DESC student SELECT *FROM student; INSERT INTO `students`.`student`(`stuId`, `stuName`, `stuSex`, `stuAge`) VALUES (1001, '毛毛', '男', 12); INSERT INTO `students`.`student`(`stuId`, `stuName`, `stuSex`, `stuAge`) VALUES (1002, '毛二', '男', 30); INSERT INTO `students`.`student`(`stuId`, `stuName`, `stuSex`, `stuAge`) VALUES (1003, '胡滨', '男', 20); INSERT INTO `students`.`student`(`stuId`, `stuName`, `stuSex`, `stuAge`) VALUES (1004, '集合', '男', 20); DESC studenta; INSERT INTO `students`.`studenta`(`stuId`, `stuSex`, `stuHeight`, `stuAge`) VALUES (1008, '674', 56, '79'); INSERT INTO `students`.`studenta`(`stuId`, `stuName`, `stuSex`, `stuHeight`, `stuAge`) VALUES (1009, '欣慰', '456', 34, '78'); INSERT INTO `students`.`studenta`(`stuId`, `stuName`, `stuSex`, `stuHeight`, `stuAge`) VALUES (1010, 'ok', '456', 34, '78'); SELECT *FROM studenta; select * FROM student; INSERT INTO `students`.`studenta`(`stuId`, `stuName`, `stuSex`, `stuHeight`, `stuAge`) VALUES (1011, '三体', '456', 34, '78'); INSERT INTO `students`.`studenta`(`stuId`, `stuName`, `stuSex`, `stuHeight`, `stuAge`) VALUES (10012, '学Java很快哦', '345', 34, '67') INSERT INTO `students`.`student`(`stuId`, `stuName`, `stuSex`, `stuAge`) VALUES (1007, 'hellows', '男', 24) INSERT INTO `students`.`stu`(`stuId`, `stuName`, `stuSex`, `stuAge`) VALUES (1007, '胡期', '男', 35); INSERT INTO `students`.`stu`(`stuId`, `stuName`, `stuSex`, `stuAge`) VALUES (10071, '分解', '男', 35); INSERT INTO `students`.`stu`(`stuId`, `stuName`, `stuSex`, `stuAge`) VALUES (10072, '信他', '男', 35); INSERT INTO `students`.`stu`(`stuId`, `stuName`, `stuSex`, `stuAge`) VALUES (10073, 'comon', '男', 35); INSERT INTO `students`.`stu`(`stuId`, `stuName`, `stuSex`, `stuAge`) VALUES (10074, '自由', '男', 35); DESC stu; SELECT * FROM stu; INSERT INTO `students`.`student`(`stuId`, `stuName`, `stuSex`, `stuAge`) VALUES (1006, 'hellow', '男', 24) INSERT INTO `students`.`stu`(`stuId`, `stuName`, `stuSex`, `stuAge`) VALUES (1075, '小王', '女', 23); DESC stu; DESC student select * FROM student; UPDATE `students`.`student` SET `stuName` = 'need' WHERE `stuId` = 1007 DELETE FROM `students`.`student` WHERE `stuId` = 1006
回顾了一下mysql的基本语法。
java代码。
@1导入构架包
package jdbc; import java.sql.Connection; import java.sql.DriverManager; public class JDBCDamo1 { public static void main(String[] args) throws Exception{ // 加载驱动类 Class.forName("com.mysql.cj.jdbc.Driver"); System.out.println("加载驱动类成功"); //地址 String url ="jdbc:mysql://127.0.0.1:3306/students"; System.out.println("mysql连接成功"); String username="root"; String password="123456"; Connection conn=DriverManager.getConnection(url,username,password); System.out.println(conn); System.out.println(url); System.out.println(username); System.out.println(password); System.out.println(conn.getHoldability()); System.out.println(conn.getAutoCommit()); System.out.println(conn.getCatalog()); System.out.println(conn.getClientInfo(password)); System.out.println(conn.isClosed()); System.out.println(conn.isReadOnly()); System.out.println(conn.isValid(conn.getHoldability())); System.out.println(conn.toString()); System.out.println(conn.equals(username)); System.out.println(conn.prepareCall(username)); System.out.println(conn.prepareCall(url)); System.out.println(conn.prepareCall(password)); System.out.println(conn.getWarnings()); System.out.println(conn.setSavepoint()); System.out.println(conn.createStatement()); System.out.println(conn.setSavepoint()); System.out.println(conn.createBlob()); System.out.print(conn.createSQLXML()); System.out.println(conn.hashCode()); } }
package Gradation; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.Statement; public class Tran { static Connection con; static Statement sql; static ResultSet res; public Connection getConnection() { return con; } public static void main(String[] args) throws Exception { Class.forName("com.mysql.cj.jdbc.Driver"); System.out.println("加载驱动类成功"); //地址 String url ="jdbc:mysql://127.0.0.1:3306/student"; System.out.println("mysql连接成功"); String username="root"; String password="123456"; Connection conn=DriverManager.getConnection(url,username,password); System.out.println(conn); Gradation c=new Gradation(); con=c.getConnection(); try { sql=con.createStatement(); res=sql.executeQuery("select*from tb_stu where"+"name like '胡%'"); while(res.next()) { String id =res.getString("id"); String name=res.getString("name"); String sex=res.getString("sex"); String birthday=res.getString("birthday"); System.out.println(id); System.out.println(name); System.out.println(sex); System.out.println(birthday); } } catch (Exception e) { //e.printStackTrace(); } } }
package jdbc; import java.sql.*; //查询学生信息 //查询信息 public class JDBCCha { public static void main(String[] args) throws Exception { // 建立链接 Connection conn = DBUtil.getConnection(); //创建statement对象 Statement stmt =conn.createStatement(); //执行mysql语句 String sql="select *from student"; ResultSet rs =stmt.executeQuery(sql); //遍历集合 while(rs.next()) { int stuId=rs.getInt("stuId"); String stuName=rs.getString("stuName"); String stuSex=rs.getString("stuSex"); int stuAge=rs.getInt("stuAge"); System.out.println(stuId+"---------"+stuName+"-----------"+stuSex+"---------"+stuAge); } //关闭数据库连接 DBUtil.getClose(conn); } }
package jdbc; import java.sql.*; //查询学生信息 //删除信息 public class JDBCDelect { public static void main(String[] args) throws Exception { // 建立链接 Connection conn = DBUtil.getConnection(); //创建statement对象 Statement stmt =conn.createStatement(); //执行mysql语句 String sql="delect from student"; ResultSet rs =stmt.executeQuery(sql); //遍历集合 /* * while(rs.next()) { * * int stuId=rs.getInt("stuId"); String stuName=rs.getString("stuName"); String * stuSex=rs.getString("stuSex"); int stuAge=rs.getInt("stuAge"); * System.out.println(stuId+"---------"+stuName+"-----------"+stuSex+"---------" * +stuAge); * * } * * //关闭数据库连接 DBUtil.getClose(conn); * * * } */ } }
package jdbc; import java.sql.*; public class JDBCShan { //修改信息 public static void main(String[] args) throws Exception { // 建立链接 Connection conn = DBUtil.getConnection(); // Statement stmt =conn.createStatement(); String sql="update student set stuSex='女'"; stmt.executeLargeUpdate(sql); DBUtil.getClose(conn); } }
package jdbc; import java.sql.*; import java.sql.Connection; import java.sql.DriverManager; //增加信息 public class JDBCZeng { public static void main(String[] args) throws Exception{ Connection conn=DBUtil.getConnection(); System.out.println(conn); //获取 statement对象 Statement stmt =conn.createStatement(); //增加 String sql="insert into student (stuId,stuName,stuSex,stuAge) values(1003,'sanmao','女',20)"; //4 执行语句 int count= stmt.executeUpdate(sql); if(count>0) { System.out.println("学生插入成功"); }else { System.out.println("in the end"); } //5 int the end //conn.close(); DBUtil.getClose(conn); // 加载驱动类 //Class.forName("com.mysql.cj.jdbc.Driver"); //System.out.println("加载驱动类成功"); //建立数据库 //String url ="jdbc:mysql://127.0.0.1:3306/students"; //System.out.println("mysql连接成功"); //String username="root"; //String password="123456"; //Connection conn=DriverManager.getConnection(url,username,password); //System.out.println(conn); } }
package jdbc; public class Student { private int stuId; private String stuName; private String stuSex; private int stuAge; public Student() { super(); // TODO Auto-generated constructor stub } public Student(int stuId, String stuName, String stuSex, int stuAge) { super(); this.stuId = stuId; this.stuName = stuName; this.stuSex = stuSex; this.stuAge = stuAge; } /** * @return the stuId */ public int getStuId() { return stuId; } /** * @param stuId the stuId to set */ public void setStuId(int stuId) { this.stuId = stuId; } /** * @return the stuName */ public String getStuName() { return stuName; } /** * @param stuName the stuName to set */ public void setStuName(String stuName) { this.stuName = stuName; } /** * @return the stuAge */ public int getStuAge() { return stuAge; } /** * @param stuAge the stuAge to set */ public void setStuAge(int stuAge) { this.stuAge = stuAge; } @Override public String toString() { return "Student [stuId=" + stuId + ", stuName=" + stuName + ", stuSex=" + stuSex + ", stuAge=" + stuAge + "]"; } }
package Code; /** * java的转码格式 * @author MZFAITHDREAM * */ public class CodeDemo1 { public static void main(String[] args) throws Exception { // TODO Auto-generated method stub String str="我爱距离100km江西南字符昌学lookforyou江西区的学院"; //将字符串转成编码 byte [] by =str.getBytes("utf-8"); //将数据给用户看 String str1 =new String(by,"utf-8"); System.out.println(str1); //网页定义utf-8 String str2="我爱距离100km温州瓯江"; //将字符串转成编码 byte [] by1 =str1.getBytes("gbk"); //将数据给用户看 String str3 =new String(by,"gbk"); System.out.println(str2); System.out.println(str.getBytes()); System.out.println(str); System.out.println(str2); } }
package readingrandwriter; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.OutputStreamWriter; public class CopeFile { public static void main(String[] args) throws IOException { //创建字节输入 FileInputStream fis= new FileInputStream("C:\\Users\\MZFAITHDREAM\\Desktop\\Javaday1_9.zip"); //创建字节输出 FileOutputStream fos =new FileOutputStream("D:\\Day"); //字符输入 InputStreamReader isr=new InputStreamReader(fis,"utf-8"); //字符输出 OutputStreamWriter osr=new OutputStreamWriter(fos,"utf-8"); //创建一个数组去放入取到的数据 char[] cr=new char[1024]; int num=0; //while while((num=isr.read(cr))!=-1) { //reading osr.write( cr,0,num); } isr.close(); osr.close(); } }
package readingrandwriter; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.FileReader; import java.io.FileWriter; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.OutputStreamWriter; public class CopeFile2 { public static void main(String[] args) throws IOException { //创建字节输入 //FileInputStream fis= new FileInputStream("C:\\Users\\MZFAITHDREAM\\Desktop\\Javaday1_9.zip"); //创建字节输出 //FileOutputStream fos =new FileOutputStream("D:\\Day"); //字符输入 //InputStreamReader isr=new InputStreamReader(fis,"utf-8"); //字符输出 //OutputStreamWriter osr=new OutputStreamWriter(fos,"utf-8"); FileReader fr=new FileReader("C:\\Users\\MZFAITHDREAM\\Desktop\\青年大学习第10期.xlsx"); FileWriter fw=new FileWriter("D:\\dayop1"); //创建一个数组去放入取到的数据 char[] cr=new char[1024]; int num=0; //while while((num=fr.read(cr))!=-1) { //reading fw.write( cr,0,num); } fr.close(); fw.close(); } }
package repeat; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; public class Copy1 { public static void main(String[] args) throws IOException{ // TODO Auto-generated method stub FileInputStream fis= new FileInputStream("C:\\Users\\MZFAITHDREAM\\Desktop\\1.jpg"); FileOutputStream fos =new FileOutputStream("D:\\胡滨.jpg" ,true); byte[] by =new byte[1024]; //int read(byte[]) by) int num=0; while((num=fis.read(by))!=-1) { //reading fos.write(by, 0, num); } //关闭流 fis.close(); fos.close(); } }
package repeat; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; public class Copy2 { public static void main(String[] args) throws IOException{ // TODO Auto-generated method stub FileInputStream fis= new FileInputStream("C:\\Users\\MZFAITHDREAM\\Desktop\\1.png"); FileOutputStream fos =new FileOutputStream("D:\\hu.png" ,true); byte[] by =new byte[1024]; //int read(byte[]) by) int num=0; while((num=fis.read(by))!=-1) { //reading fos.write(by, 0, num); } //关闭流 fis.close(); fos.close(); } }
Exception in thread "main" java.io.FileNotFoundException: C:\Users\MZFAITHDREAM\Desktop\1.jpg (系统找不到指定的文件。) at java.io.FileInputStream.open0(Native Method) at java.io.FileInputStream.open(FileInputStream.java:195) at java.io.FileInputStream.<init>(FileInputStream.java:138) at java.io.FileInputStream.<init>(FileInputStream.java:93) at repeat.Copy1.main(Copy1.java:13)