java jdbc連接和使用詳細(xì)介紹

更新時(shí)間：2016年12月25日 14:11:22 投稿：lqh

這篇文章主要介紹了 java jdbc連接和使用詳細(xì)介紹的相關(guān)資料,需要的朋友可以參考下

java jdbc連接和使用

jdbc

導(dǎo)入驅(qū)動(dòng)

//jar是已經(jīng)打包好的class文件集，可以引用到其他工程中
//Build Path中add external jars導(dǎo)入

連接JDBC

1. 加載驅(qū)動(dòng)

  Class.from("com.mysql.jdbc.Driver");

創(chuàng)建連接

//導(dǎo)包使用 java.sql.*；
String jdbc="jdbc:mysql://localhost:3306/student?user=root&password=&characterEncoding=utf-8";//student是表名
Connection conn = DriverManager.getConnection(jdbc);

2. 注意數(shù)據(jù)庫(kù)打開(kāi)之后一定要記得關(guān)。

 conn.close();

1. 執(zhí)行SQL語(yǔ)句（創(chuàng)建表，插入，刪除，更新）

使用Statemant

Statemant st = conn.createStatemant();
 int row = st.executeUpdate(sql語(yǔ)句);//不能做查詢操作。

使用PrepareStatement

可以使用？占位符來(lái)代替你需要傳遞的參數(shù)

String sql = "insert into " + TABLENAME
+ "(name,subject,score) values(?,?,?)";
PrepareStatement pt = conn.prepareStatement(sql);
 //給每一位占位符設(shè)置值,下標(biāo)從1開(kāi)始
 pt.setString(1,score.getName());
 pt.setString(2.score.getSubject());
pt.setDouble(3,score.getScore());
 //使用無(wú)參的方法
pt.executeUpdate();

1.查詢操作

static List<Score> queryScore(Connection pconn, Score pScore)
      throws SQLException {
    ArrayList<Score> mlist = new ArrayList<>();
    String sql = "select * from " + TABLENAME + " where name = ?";
    PreparedStatement ps = pconn.prepareStatement(sql);
    ps.setString(1, pScore.getName());
    ResultSet rs = ps.executeQuery();

    while (rs.next()) {
      // 這里可以通過(guò)rs獲取所有結(jié)果
      String subject = rs.getString("subject");
      int id = rs.getInt("id");
      double score = rs.getDouble("score");
      mlist.add(new Score(id, pScore.getName(), subject, score));
    }
    return mlist;
  }

下面是一個(gè)小程序

//建立數(shù)據(jù)庫(kù)連接類
public class DAO {

  // 放問(wèn)數(shù)據(jù)庫(kù)的鏈接地址
  static String jdbc = "jdbc:mysql://localhost:3306/student?user=root&password=&characterEncoding=utf-8";

  // 打開(kāi)鏈接
  public static Connection connection() {
    // 使用JDBC的步驟
    // 1. 加載JDBC驅(qū)動(dòng)
    try {
      // 類的全名 包名+類名
      Class.forName("com.mysql.jdbc.Driver");
      // 2. 連接數(shù)據(jù)庫(kù)
      Connection conn = DriverManager.getConnection(jdbc);
      return conn;
    } catch (Exception e) {
      System.out.println("驅(qū)動(dòng)加載失敗");
      return null;
    }
  }



}


//分?jǐn)?shù)類
public class Score {

  String name;
  String id;
  String subject;
  double score;



  public Score(String name, String subject, double score) {
    super();
    this.name = name;
    this.subject = subject;
    this.score = score;
  }



  @Override
  public String toString() {
    return "Score [name=" + name + ", id=" + id + ", subject=" + subject
        + ", score=" + score + "]";
  }



  public Score(String name, String id, String subject, double score) {
    super();
    this.name = name;
    this.id = id;
    this.subject = subject;
    this.score = score;
  }

  public String getName() {
    return name;
  }

  public void setName(String name) {
    this.name = name;
  }

  public String getId() {
    return id;
  }

  public void setId(String id) {
    this.id = id;
  }

  public String getSubject() {
    return subject;
  }

  public void setSubject(String subject) {
    this.subject = subject;
  }

  public double getScore() {
    return score;
  }

  public void setScore(double score) {
    this.score = score;
  }

}


//實(shí)現(xiàn)類
public class Test {


  public static String TABLENAME = "score";

  public static void main(String[] args) {
    try {
      Connection conn = DAO.connection();
      if (conn != null) {
        System.out.println("鏈接上了");
        // createTable(conn);
        // 插入一條記錄
        // Score score = new Score("李四 ", "Android", 98);
        // System.out.println(addScore2(conn, score));
        // deleteScore(conn, score);
        // updateScore(conn, score);
        List<Score> list = queryScoreByName(conn, "王五"); //queryAllScore(conn);
        for (Score score : list) {
          System.out.println(score);
        }
        conn.close();
      } else {
        System.out.println("鏈接失敗 ");
      }
    } catch (SQLException e) {
      e.printStackTrace();
    }
  }

  // 創(chuàng)建一張表
  public static boolean createTable(Connection conn) {
    // 開(kāi)始執(zhí)行sql語(yǔ)句
    String sql = "create table "
        + TABLENAME
        + "(id integer primary key auto_increment,name varchar(3) not null,subject varchar(20) not null,score double)";
    // 要執(zhí)行一條語(yǔ)句，需要一個(gè)執(zhí)行的類 Statement
    try {
      Statement st = conn.createStatement();
      int result = st.executeUpdate(sql);
      System.out.println(result);
      if (result != -1)
        return true;
    } catch (SQLException e) {
      e.printStackTrace();
    }
    return false;
  }

  // 添加一條記錄
  public static boolean addScore(Connection conn, Score score)
      throws SQLException {
    String sql = "insert into " + TABLENAME
        + "(name,subject,score) values('" + score.getName() + "','"
        + score.getSubject() + "'," + score.getScore() + ")";
    System.out.println(sql);
    Statement st = conn.createStatement();
    int row = st.executeUpdate(sql);
    if (row > 0)
      return true;
    return false;
  }

  // 添加一條記錄2
  public static boolean addScore2(Connection conn, Score score)
      throws SQLException {
    // 占位符?來(lái)代替需要設(shè)置的參數(shù)
    String sql = "insert into " + TABLENAME
        + "(name,subject,score) values(?,?,?)";
    PreparedStatement ps = conn.prepareStatement(sql);
    // 必須給定？所代表的值
    ps.setString(1, score.getName());
    ps.setString(2, score.getSubject());
    ps.setDouble(3, score.getScore());
    // 調(diào)用無(wú)參的方法
    int row = ps.executeUpdate();
    if (row > 0)
      return true;
    return false;
  }

  public static boolean deleteScore(Connection conn, Score score)
      throws SQLException {
    String sql = "delete from " + TABLENAME + " where name=? and subject=?";
    // 創(chuàng)建PrepareStatement
    PreparedStatement ps = conn.prepareStatement(sql);
    ps.setString(1, score.getName());
    ps.setString(2, score.getSubject());
    // ps.setDouble(3, score.getScore());
    // 執(zhí)行
    int row = ps.executeUpdate();
    System.out.println(row);
    if (row > 0)
      return true;
    return false;
  }

  public static boolean updateScore(Connection conn, Score score)
      throws SQLException {
    // 修改 score人他的科目的成績(jī)
    String sql = "update " + TABLENAME
        + " set score=? where name=? and subject=?";
    PreparedStatement ps = conn.prepareStatement(sql);
    ps.setDouble(1, score.getScore());
    ps.setString(2, score.getName());
    ps.setString(3, score.getSubject());
    int row = ps.executeUpdate();
    System.out.println(row);
    if (row > 0)
      return true;
    return false;
  }

  public static List<Score> queryAllScore(Connection conn)
      throws SQLException {
    String sql = "select * from " + TABLENAME;
    // 開(kāi)始查詢
    Statement st = conn.createStatement();
    ResultSet rs = st.executeQuery(sql);
    List<Score> list = new ArrayList<Score>();
    while (rs.next()) {
      // 這里可以通過(guò)rs獲取所有結(jié)果
      String id = rs.getString("id");
      String name = rs.getString("name");
      String subject = rs.getString("subject");
      double score = rs.getDouble("score");
      list.add(new Score(name, id, subject, score));
    }
    // 結(jié)束
    return list;
  }

  public static List<Score> queryScoreByName(Connection conn, String name)
      throws SQLException {
    String sql = "select * from " + TABLENAME + " where name=?";
    PreparedStatement pt = conn.prepareStatement(sql);
    pt.setString(1, name);
    ResultSet rs = pt.executeQuery();
    List<Score> list = new ArrayList<>();
    while (rs.next()) {
      String subject = rs.getString("subject");
      String id = rs.getString("id");
      double score = rs.getDouble("score");
      list.add(new Score(name, id, subject, score));
    }
    return list;
  }

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