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[数据库]java连接数据库步骤


* Connection : 连接数据库并担任传送数据的任务* Statement : 执行SQL语句* ResultSet :保存Statement执行后产生的查询结果1.注册驱动Class.forName(JDBC驱动类);2.获取数据库连接Connection con=DriverManager.getConnection(JDBC url,数据库用户名,密码);3.获得 Statement对象Statement stmt=con.createStatement();4.执行SQL语句ResultSet rs=stmt.executeQuery(select a,b from table);5.处理执行结果while(rs.next()){  int x=rs.getInt("a"); String s=rs.getString("b");  *数据类型要相匹配}6.释放资源1.rs.close();2.stmt.close();3.con.close();*顺序倒过来依次关闭实例:Java使用PreparedStatement接口插入数据库信息public class PreparedStatementDemo01 {  public static final String DBDRIVER = "org.gjt.mm.mysql.Driver";  public static final String DBURL = "jdbc:mysql://localhost:3306/";  public static final String DBUSER = "root";  public static final String DBPASS = "root";  public static void main(String args[]) throws ParseException, ClassNotFoundException, SQLException  {    Connection conn = null;  //数据库连接    PreparedStatement pstmt = null;  //数据库操作    Statement stmt = null;    ResultSet rs = null; //Rs接口    String name = "黄鹏";    String password = "1598741";    int age = 21;    String sex = "男";    String birthday ="1992-04-30";    Date temp = null;    temp = new SimpleDateFormat("yyyy-MM-dd").parse(birthday);    java.sql.Date bri = new java.sql.Date(temp.getTime());    //创建数据库操作语句    String sql1 = "CREATE DATABASE MyDemo;";     //选择使用哪个数据库的语句    String sql2 = "USE MyDemo;";    //创建数据库表操作语句    String sql3 = "CREATE TABLE user(name varchar(20) primary key,password varchar(20),age int,sex varchar(10),birthday Date);";    //查询数据库语句    String sql5 = "select * from user;";              //用PreparedStatement执行的插入语句    String sql4 = "INSERT INTO user(name,password,age,sex,birthday) VALUES(?,?,?,?,?);";        //加载驱动程序    Class.forName(DBDRIVER);    //连接mysql数据库    conn = DriverManager.getConnection(DBURL,DBUSER,DBPASS);      //实例化PreparedStatement    pstmt = conn.prepareStatement(sql4);    //设置第一个?内容    pstmt.setString(1, name);    //设置第二个?内容    pstmt.setString(2, password);    //设置第三个?内容    pstmt.setInt(3, age);    //设置第四个?内容    pstmt.setString(4,sex);    //设置第五个?内容    pstmt.setDate(5, bri);    //执行数据库更新,不需要sql        stmt = conn.createStatement();     stmt.execute(sql1);    stmt.execute(sql2);    stmt.execute(sql3);        pstmt.executeUpdate();    rs = stmt.executeQuery(sql5);    //向控制台输出信息    while(rs.next())     {      String QueryName = rs.getString("name");      String QueryPwd = rs.getString("password");      int QueryAge = rs.getInt("age");      String QuerySex = rs.getString("sex");      Date QueryDate = rs.getDate("birthday");      System.out.println("name:"+QueryName+" pwd:"+QueryPwd+" "+QueryAge+" sex:"+QueryPwd+" date:"+QueryDate);          }                      pstmt.close();    conn.close();          }}