简单的Java连接MySQL和基本语法

Java连接MySQL需要jdbc驱动，文件为mysql-connector-java-x.x.xx.jar和mysql-connector-java-x.x.xx-bin.jar

建议用phpmyadmin来管理数据库，在写Java操作数据库的代码之前先到phpmyadmin上面操作一下，不会的MySQL指令也可以根据提示在phpmyadmin上得到答案。

下面是Java部分的代码

package application;import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;public class ConfigMySQL {static final String DB_URL = "jdbc:mysql://localhost:3306/resemblance";  //路径的最后一部分resemblance是数据库名，注意按需更改static final String USER = "root"; //数据库登陆账号static final String PASS = "12345678c";  //数据库登陆密码public static boolean login(String user, String psd) throws SQLException {Connection conn = null;Statement stmt = null;try{Class.forName("com.mysql.jdbc.Driver");System.out.println("连接数据库...");conn = DriverManager.getConnection(DB_URL,USER,PASS);stmt = conn.createStatement();String sql;sql = "SELECT * FROM `user` WHERE username='" + user + "'and password='" + psd + "'";ResultSet rs = stmt.executeQuery(sql);if(rs.next()) {  //对于登陆来说rs.next()为真的话代表账号密码匹配，不用做处理直接返回真就可以rs.close();stmt.close();conn.close();return true;}else {rs.close();stmt.close();conn.close();return false;}}catch(SQLException se){// 处理 JDBC 错误se.printStackTrace();}catch(Exception e){// 处理 Class.forName 错误e.printStackTrace();}finally{// 关闭资源try{if(stmt!=null) stmt.close();}catch(SQLException se2){}// 什么都不做try{if(conn!=null) conn.close();}catch(SQLException se){se.printStackTrace();}}return false;}public static void creatTable(String user, int cols, double[][] res) throws ClassNotFoundException {Connection conn = null;Statement stmt = null;String create = "CREATE TABLE `resemblance`.`" + user + "` ( `CODE` VARCHAR(10) NOT NULL , "; //创建表要确定列头的信息，不能创建空表for(int i = 1;  i <= cols; i++) {create = create + "`Gl-" + i + "` DOUBLE NOT NULL ";if(i != cols) {create = create + ", ";}else {create = create + ") ENGINE = InnoDB;";}}Class.forName("com.mysql.jdbc.Driver");System.out.println("连接数据库...");try {conn = DriverManager.getConnection(DB_URL,USER,PASS);stmt = conn.createStatement();stmt.executeLargeUpdate("DROP TABLE IF EXISTS " + user);stmt = conn.createStatement();if(0 == stmt.executeLargeUpdate(create)){System.out.println("成功创建表！");String insert = "INSERT INTO `" + user + "` (`CODE`, ";  //对数据表进行写入for(int j = 1; j <= cols; j++) {insert = insert + "`Gl-" + j + "`";if(j != cols) {insert = insert + ", ";}else {insert = insert + ") VALUES ";}}for(int i = 1; i <= cols; i++) {if(i != 1) {insert = insert + ", ";}insert = insert + "('Gl-" + i + "', ";for(int j = 1; j <= cols; j++) {insert = insert + "'" + res[j - 1][i - 1] + "'";if(j != cols) {insert = insert + ", ";}else {insert = insert + ")";}}}stmt = conn.createStatement();stmt.executeLargeUpdate(insert);}else{System.out.println("创建表失败！");}stmt.close();conn.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}}
}

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