歷史趨勢：以往，因性能問題，中間層都用 C 或 C++ 編寫，隨著優(yōu)化編譯器（將 Java 字節(jié)碼轉(zhuǎn)為高效的特定機(jī)器碼）和技術(shù)的發(fā)展，如EJB，Java 開始用于中間層的開發(fā)這也讓 Java 的優(yōu)勢突顯出現(xiàn)出來，使用 Java 作為服務(wù)器代碼語言，JDBC隨之被重視。

JDBC 編程步驟

加載驅(qū)動程序：

Class.forName(driverClass)
//加載MySql驅(qū)動
Class.forName("com.mysql.jdbc.Driver")
//加載Oracle驅(qū)動
Class.forName("oracle.jdbc.driver.OracleDriver")

獲得數(shù)據(jù)庫連接：

復(fù)制代碼代碼如下:

DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/imooc", "root", "root");

創(chuàng)建Statement\PreparedStatement對象：

復(fù)制代碼代碼如下:

conn.createStatement();

conn.prepareStatement(sql);

完整實(shí)例

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

public class DbUtil {

 public static final String URL = "jdbc:mysql://localhost:3306/imooc";
 public static final String USER = "liulx";
 public static final String PASSWORD = "123456";

 public static void main(String[] args) throws Exception {
  //1.加載驅(qū)動程序
  Class.forName("com.mysql.jdbc.Driver");
  //2. 獲得數(shù)據(jù)庫連接
  Connection conn = DriverManager.getConnection(URL, USER, PASSWORD);
  //3.操作數(shù)據(jù)庫，實(shí)現(xiàn)增刪改查
  Statement stmt = conn.createStatement();
  ResultSet rs = stmt.executeQuery("SELECT user_name, age FROM imooc_goddess");
  //如果有數(shù)據(jù)，rs.next()返回true
  while(rs.next()){
   System.out.println(rs.getString("user_name")+" 年齡："+rs.getInt("age"));
  }
 }
}

增刪改查

public class DbUtil {
 public static final String URL = "jdbc:mysql://localhost:3306/imooc";
 public static final String USER = "liulx";
 public static final String PASSWORD = "123456";
 private static Connection conn = null;
 static{
  try {
   //1.加載驅(qū)動程序
   Class.forName("com.mysql.jdbc.Driver");
   //2. 獲得數(shù)據(jù)庫連接
   conn = DriverManager.getConnection(URL, USER, PASSWORD);
  } catch (ClassNotFoundException e) {
   e.printStackTrace();
  } catch (SQLException e) {
   e.printStackTrace();
  }
 }

 public static Connection getConnection(){
  return conn;
 }
}

//模型
package liulx.model;

import java.util.Date;

public class Goddess {

 private Integer id;
 private String user_name;
 private Integer sex;
 private Integer age;
 private Date birthday; //注意用的是java.util.Date
 private String email;
 private String mobile;
 private String create_user;
 private String update_user;
 private Date create_date;
 private Date update_date;
 private Integer isDel;
 //getter setter方法。。。
}

//---------dao層--------------
package liulx.dao;

import liulx.db.DbUtil;
import liulx.model.Goddess;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

public class GoddessDao {
 //增加
 public void addGoddess(Goddess g) throws SQLException {
  //獲取連接
  Connection conn = DbUtil.getConnection();
  //sql
  String sql = "INSERT INTO imooc_goddess(user_name, sex, age, birthday, email, mobile,"+
   "create_user, create_date, update_user, update_date, isdel)"
    +"values("+"?,?,?,?,?,?,?,CURRENT_DATE(),?,CURRENT_DATE(),?)";
  //預(yù)編譯
  PreparedStatement ptmt = conn.prepareStatement(sql); //預(yù)編譯SQL，減少sql執(zhí)行

  //傳參
  ptmt.setString(1, g.getUser_name());
  ptmt.setInt(2, g.getSex());
  ptmt.setInt(3, g.getAge());
  ptmt.setDate(4, new Date(g.getBirthday().getTime()));
  ptmt.setString(5, g.getEmail());
  ptmt.setString(6, g.getMobile());
  ptmt.setString(7, g.getCreate_user());
  ptmt.setString(8, g.getUpdate_user());
  ptmt.setInt(9, g.getIsDel());

  //執(zhí)行
  ptmt.execute();
 }

 public void updateGoddess(){
  //獲取連接
  Connection conn = DbUtil.getConnection();
  //sql, 每行加空格
  String sql = "UPDATE imooc_goddess" +
    " set user_name=?, sex=?, age=?, birthday=?, email=?, mobile=?,"+
    " update_user=?, update_date=CURRENT_DATE(), isdel=? "+
    " where id=?";
  //預(yù)編譯
  PreparedStatement ptmt = conn.prepareStatement(sql); //預(yù)編譯SQL，減少sql執(zhí)行

  //傳參
  ptmt.setString(1, g.getUser_name());
  ptmt.setInt(2, g.getSex());
  ptmt.setInt(3, g.getAge());
  ptmt.setDate(4, new Date(g.getBirthday().getTime()));
  ptmt.setString(5, g.getEmail());
  ptmt.setString(6, g.getMobile());
  ptmt.setString(7, g.getUpdate_user());
  ptmt.setInt(8, g.getIsDel());
  ptmt.setInt(9, g.getId());

  //執(zhí)行
  ptmt.execute();
 }

 public void delGoddess(){
  //獲取連接
  Connection conn = DbUtil.getConnection();
  //sql, 每行加空格
  String sql = "delete from imooc_goddess where id=?";
  //預(yù)編譯SQL，減少sql執(zhí)行
  PreparedStatement ptmt = conn.prepareStatement(sql);

  //傳參
  ptmt.setInt(1, id);

  //執(zhí)行
  ptmt.execute();
 }

 public List<Goddess> query() throws SQLException {
  Connection conn = DbUtil.getConnection();
  Statement stmt = conn.createStatement();
  ResultSet rs = stmt.executeQuery("SELECT user_name, age FROM imooc_goddess");

  List<Goddess> gs = new ArrayList<Goddess>();
  Goddess g = null;
  while(rs.next()){
   g = new Goddess();
   g.setUser_name(rs.getString("user_name"));
   g.setAge(rs.getInt("age"));

   gs.add(g);
  }
  return gs;
 }

 public Goddess get(){
  Goddess g = null;
  //獲取連接
  Connection conn = DbUtil.getConnection();
  //sql, 每行加空格
  String sql = "select * from imooc_goddess where id=?";
  //預(yù)編譯SQL，減少sql執(zhí)行
  PreparedStatement ptmt = conn.prepareStatement(sql);
  //傳參
  ptmt.setInt(1, id);
  //執(zhí)行
  ResultSet rs = ptmt.executeQuery();
  while(rs.next()){
   g = new Goddess();
   g.setId(rs.getInt("id"));
   g.setUser_name(rs.getString("user_name"));
   g.setAge(rs.getInt("age"));
   g.setSex(rs.getInt("sex"));
   g.setBirthday(rs.getDate("birthday"));
   g.setEmail(rs.getString("email"));
   g.setMobile(rs.getString("mobile"));
   g.setCreate_date(rs.getDate("create_date"));
   g.setCreate_user(rs.getString("create_user"));
   g.setUpdate_date(rs.getDate("update_date"));
   g.setUpdate_user(rs.getString("update_user"));
   g.setIsDel(rs.getInt("isdel"));
  }
  return g;
 }
}

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