1.用java建立資料庫，但是這種動態建立資料庫是非主流的。一般不會這樣操作。

import java.sql.*;

public class Test
{
    public static void main(String[] args) throws Exception
    {
        Class.forName("com.mysql.jdbc.Driver");

        //一開始必須填一個已經存在的資料庫
        String url = "jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8"
 
;   
        Connection conn = DriverManager.getConnection(url, "root", "123456");
        Statement stat = conn.createStatement();

        //建立資料庫hello
        stat.executeUpdate("create database hello");

        //開啟建立的資料庫
        stat.close();
        conn.close();
        url = "jdbc:mysql://localhost:3306/hello?useUnicode=true&characterEncoding=utf-8"
 
;
        conn = DriverManager.getConnection(url, "root", "123456");
        stat = conn.createStatement();

        //建立表test
        stat.executeUpdate("create table test(id int, name varchar(80))");

        //新增資料
        stat.executeUpdate("insert into test values(1, '張三')");
        stat.executeUpdate
 
("insert into test values(2, '李四')");

        //查詢資料
        ResultSet result = stat.executeQuery("select * from test");
        while (result.next())
        {
            System.out.println(result.getInt("id") + " " + result.getString("name"));
        }

        //關閉資料庫
        result.close();
        stat.close();
        conn.close();
    }
}

1. 插入

public int insert()  
{  
    int i=0;  
    String sql="insert into (表名)(列名1,列明2) values(?,?)";  
    Connection cnn=getConn();  

    try{  
        PreparedStatement preStmt =cnn.prepareStement(sql);  
        preStmt.setString(1,值);  
        preStmt.setString(2,值);//或者：preStmt.setInt(1,值);  
        i=preStmt.executeUpdate();  
    }  
    catch (SQLException e)  
    {  
        e.printStackTrace();  
    }  
    return i;//返回影響的行數，1為執行成功  
}  

3.更新

public int update  
{  
    int i=0;  
    String sql="update (表名) set  (列名1)=?,列明2=? where (列名)=？";//注意要有where條件  
    Connection cnn=getConn();  


    try{  
        PreparedStatement preStmt =cnn.prepareStatement(sql);  
        preStmt.setString(1,(值));  
        preStmt.setString(2,(值));//或者：preStmt.setInt(1,值);  
        preStmt.setInt(3,(值));  
        i=preStmt.executeUpdate();  
    }  
    catch (SQLException e)  
    {  
        e.printStackTrace();  
    }  
    return i;//返回影響的行數，1為執行成功  
}  

4.查詢

public String select  
    {  
        String sql = "select * from (表名) where (列名)=(值)";  
        Connection cnn = getConn();//此處為通過自己寫的方法getConn()獲得連線  
        try  
        {  
            Statement stmt = conn.createStatement();  
            ResultSet rs = stmt.executeQuery(sql);  

            if(rs.next())  
            {  
                int m1 = rs.getInt(1);//或者為rs.getString(1)，根據資料庫中列的值型別確定，引數為第一列  
                String m2 = rs.getString(2);  
            }  
            //可以將查詢到的值寫入類，然後返回相應的物件  
        }  
        catch (SQLException e)  
        {  
            e.printStackTrace();  
        }  
        return (相應的值的變數);  
    }  

另一種，封裝好的查詢

import java.sql.SQLException;  

public class DBHelper {  
    public static final String url = "jdbc:mysql://127.0.0.1/student";  
    public static final String name = "com.mysql.jdbc.Driver";  
    public static final String user = "root";  
    public static final String password = "root";  

    public Connection conn = null;  
    public PreparedStatement pst = null;  

    public DBHelper(String sql) {  
        try {  
            Class.forName(name);//指定連線型別  
            conn = DriverManager.getConnection(url, user, password);//獲取連線  
            pst = conn.prepareStatement(sql);//準備執行語句  
        } catch (Exception e) {  
            e.printStackTrace();  
        }  
    }  

    public void close() {  
        try {  
            this.conn.close();  
            this.pst.close();  
        } catch (SQLException e) {  
            e.printStackTrace();  
        }  
    }  
}  

import java.sql.SQLException;  

public class Demo {  

    static String sql = null;  
    static DBHelper db1 = null;  
    static ResultSet ret = null;  

    public static void main(String[] args) {  
        sql = "select *from stuinfo";//SQL語句  
        db1 = new DBHelper(sql);//建立DBHelper物件  

        try {  
            ret = db1.pst.executeQuery();//執行語句，得到結果集  
            while (ret.next()) {  
                String uid = ret.getString(1);  
                String ufname = ret.getString(2);  
                String ulname = ret.getString(3);  
                String udate = ret.getString(4);  
                System.out.println(uid + "\t" + ufname + "\t" + ulname + "\t" + udate );  
            }//顯示資料  
            ret.close();  
            db1.close();//關閉連線  
        } catch (SQLException e) {  
            e.printStackTrace();  
        }  
    }  

}  

5.刪除

public int delete()  
{  
    String sql = "delete from (表名) where (列名)=(值)";  
    int i=0;  
    Connection conn = getConn();//此處為通過自己寫的方法getConn()獲得連線  
    try  
    {  
        Statement stmt = conn.createStatement();  
        i = stmt.executeUpdate(sql);  
    }  
    catch (SQLException e)  
    {  
        e.printStackTrace();  
    }  
    return i;//如果返回的是1，則執行成功;  
}