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MySQL_(Java)使用JDBC向数据库发起查询请求 传送门
MySQL_(Java)使用JDBC向数据库中插入(insert)数据 传送门
MySQL_(Java)使用JDBC向数据库中删除(delete)数据 传送门
MySQL_(Java)使用JDBC向数据库中修改(update)数据 传送门
MySQL数据库中的数据，数据库名garysql，表名garytb
import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; public class JDBC01 { public static void main(String[] args) throws SQLException { insert("插入Garyy4","123456"); } public static void selectAll() throws SQLException { //注册驱动 使用驱动连接数据库 Connection con = null; Statement stmt = null; ResultSet rs = null; try { //数据库的连接 con = JDBCUtils.getConnection(); //数据库的增删改查 stmt = con.createStatement(); //返回一个结果集 rs =stmt.executeQuery("select * from garytb"); while(rs.next()) { //System.out.println(rs.getString(1)+","+rs.getString(2)+","+rs.getString(3)); System.out.println(rs.getString("id")+","+rs.getString("username")+","+rs.getString("password")); } } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); }finally { JDBCUtils.close(rs, stmt, con); } } //校验用户 public static boolean selectByUernamePassword(String username,String password) throws SQLException { Connection con=null; Statement stmt = null; ResultSet rs = null; try { Class.forName("com.mysql.jdbc.Driver"); String url ="jdbc:mysql://localhost:3306/garysql?useUnicode=true&characterEncoding=UTF8&useSSL=false"; con = DriverManager.getConnection(url,"root","123456"); stmt =con.createStatement(); String sql = "select * from garytb where username = '"+username+"' and password = '"+password+"'"; //System.out.println(sql); rs = stmt.executeQuery(sql); if(rs.next()) { return true; }else { return false; } } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); }finally { if(rs!=null) rs.close(); if(stmt!=null) stmt.close(); if(con!=null) con.close(); } return false; } public static boolean selectByUP2(String username,String password) throws SQLException{ Connection con=null; Statement stmt = null; ResultSet rs = null; try { Class.forName("com.mysql.jdbc.Driver"); String url ="jdbc:mysql://localhost:3306/garysql?useUnicode=true&characterEncoding=UTF8&useSSL=false"; con = DriverManager.getConnection(url,"root","123456"); String sql = "select * from garytb where username = ? and password = ?"; PreparedStatement pstmt = con.prepareStatement(sql); //添加参数 pstmt.setString(1, username); pstmt.setString(2, password); //进行查询 rs = pstmt.executeQuery(); if(rs.next()) { return true; }else { return false; } } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); }finally { if(rs!=null) rs.close(); if(stmt!=null) stmt.close(); if(con!=null) con.close(); } return false; } //pageNumber是页数，第几页，pageCount是每页显示多少个数据 public static void selectUserByPage(int pageNumber,int pageCount) throws SQLException { //注册驱动 使用驱动连接数据库 Connection con = null; PreparedStatement stmt = null; ResultSet rs = null; try { Class.forName("com.mysql.jdbc.Driver"); //String url ="jdbc:mysql://localhost:3306/garysql"; //指定编码查询数据库 String url ="jdbc:mysql://localhost:3306/garysql?useUnicode=true&characterEncoding=UTF8&useSSL=false"; String user = "root"; String password = "123456"; //建立和数据库的连接 con = DriverManager.getConnection(url,user,password); stmt = con.prepareStatement("select * from garytb limit ?,?"); stmt.setInt(1, (pageNumber-1)*pageCount ); stmt.setInt(2, pageCount); rs = stmt.executeQuery(); while(rs.next()) { //System.out.println(rs.getString(1)+","+rs.getString(2)+","+rs.getString(3)); System.out.println(rs.getString("id")+","+rs.getString("username")+","+rs.getString("password")); } } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); }finally { if(rs!=null) rs.close(); if(stmt!=null) stmt.close(); if(con!=null) con.close(); } } //crud: create read updata delete //插入语句 public static void insert(String username,String password) throws SQLException { //注册驱动 使用驱动连接数据库 Connection con = null; PreparedStatement stmt = null; ResultSet rs = null; try { con = JDBCUtils.getConnection(); String sql = "insert into garytb(username,password) values(?,?)"; stmt = con.prepareStatement(sql); stmt.setString(1, username); stmt.setString(2, password); int result =stmt.executeUpdate();// 返回值代表收到影响的行数 System.out.println("插入成功"+username); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); }finally { JDBCUtils.close(rs, stmt, con); } } }
JDBC01.java
import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; public class JDBCUtils { private static final String connectionURL = "jdbc:mysql://localhost:3306/garysql?useUnicode=true&characterEncoding=UTF8&useSSL=false"; private static final String username = "root"; private static final String password = "123456"; //创建数据库的连接 public static Connection getConnection() { try { Class.forName("com.mysql.jdbc.Driver"); return DriverManager.getConnection(connectionURL,username,password); } catch (Exception e) { e.printStackTrace(); } return null; } //关闭数据库的连接 public static void close(ResultSet rs,Statement stmt,Connection con) throws SQLException { if(rs!=null) rs.close(); if(stmt!=null) stmt.close(); if(con!=null) con.close(); } }
JDBCUtils.java
向数据库中添加用户名和密码
public static void insert(String username,String password) throws SQLException { //注册驱动 使用驱动连接数据库 Connection con = null; PreparedStatement stmt = null; ResultSet rs = null; try { con = JDBCUtils.getConnection(); String sql = "insert into garytb(username,password) values(?,?)"; stmt = con.prepareStatement(sql); stmt.setString(1, username); stmt.setString(2, password); int result =stmt.executeUpdate();// 返回值代表收到影响的行数 System.out.println("插入成功"+username); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); }finally { JDBCUtils.close(rs, stmt, con); } }
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