JDBC初步

JDBC

 1 import java.sql.*;
 2 
 3 public class TestJDBC {
 4     public static void main(String[] args) {
 5         ResultSet rs = null;
 6         Statement stmt = null;
 7         Connection conn = null;
 8         try {
 9             // Class是java.lang的包， 给名子把类的实例new出来 可能找不到类 抛异常ClassNotFoundException
10             // 自动向drivermanager注册
11             Class.forName("com.mysql.jdbc.Driver");
12             String url = "jdbc:mysql://127.0.0.1:3307/world";
13             conn = DriverManager.getConnection(url, "hill", "hill");
14             stmt = conn.createStatement();
15             rs = stmt.executeQuery("select * from city");
16             while (rs.next()) {
17                 System.out.println(rs.getString("Name"));
18             }
19         } catch (ClassNotFoundException e) {
20             e.printStackTrace();
21         } catch (SQLException e) {
22             e.printStackTrace();
23         } finally {
24             try {
25                 if (rs != null) {
26                     rs.close();
27                 }
28                 if (stmt != null) {
29                     stmt.close();
30                 }
31                 if (conn != null) {
32                     conn.close();
33                 }
34             } catch (SQLException e) {
35                 e.printStackTrace();
36             }
37         }
38 
39     }
40 
41 }

DML1

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

public class TestDML {
	public static void main(String[] args) {

		Statement stmt = null;
		Connection conn = null;
		try {
			// Class是java.lang的包， 给名子把类的实例new出来 可能找不到类 抛异常ClassNotFoundException
			// 自动向drivermanager注册
			Class.forName("com.mysql.jdbc.Driver");
			String url = "jdbc:mysql://127.0.0.1:3307/samp_db";
			conn = DriverManager.getConnection(url, "hill", "hill");
			stmt = conn.createStatement();
			String sql = "insert into tab_user values (02,‘hehe‘)";
			stmt.executeUpdate(sql);
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		} catch (SQLException e) {
			e.printStackTrace();
		} finally {
			try {

				if (stmt != null) {
					stmt.close();
				}
				if (conn != null) {
					conn.close();
				}
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}

	}

}

DML2

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

public class TestDML2 {
	public static void main(String[] args) {
		if (args.length != 2) {
			System.out.println("Parameter Error!");
			System.exit(-1);
		}
		int num = 0;
		try {
			num = Integer.parseInt(args[0]);
		} catch (NumberFormatException e) {
			System.out.println("Parameter Error! NumberFormatException!");
			System.exit(-1);
		}
		String name = args[1];
		Statement stmt = null;
		Connection conn = null;
		try {
			// Class是java.lang的包， 给名子把类的实例new出来 可能找不到类 抛异常ClassNotFoundException
			// 自动向drivermanager注册
			Class.forName("com.mysql.jdbc.Driver");
			String url = "jdbc:mysql://127.0.0.1:3307/samp_db";
			conn = DriverManager.getConnection(url, "hill", "hill");
			stmt = conn.createStatement();
			String sql = "insert into tab_user values " + "(" + num + ",‘"
					+ name + "‘)";
			System.out.println(sql);
			stmt.executeUpdate(sql);
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		} catch (SQLException e) {
			e.printStackTrace();
		} finally {
			try {

				if (stmt != null) {
					stmt.close();
				}
				if (conn != null) {
					conn.close();
				}
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}

	}
}

PreparedStatement

import java.sql.*;

public class TestPrepStmt {
	public static void main(String[] args) {
		if (args.length != 2) {
			System.out.println("Parameter Error!");
			System.exit(-1);
		}
		int num = 0;
		try {
			num = Integer.parseInt(args[0]);
		} catch (NumberFormatException e) {
			System.out.println("Parameter Error! NumberFormatException!");
			System.exit(-1);
		}
		String name = args[1];
		PreparedStatement pstmt = null;
		Connection conn = null;
		try {
			// Class是java.lang的包， 给名子把类的实例new出来 可能找不到类 抛异常ClassNotFoundException
			// 自动向drivermanager注册
			Class.forName("com.mysql.jdbc.Driver");
			String url = "jdbc:mysql://127.0.0.1:3307/samp_db";
			conn = DriverManager.getConnection(url, "hill", "hill");
			pstmt = conn.prepareStatement("inset into tab_user values(?,?,?)");
			pstmt.setInt(1,num);
			pstmt.setString(2,name);
			pstmt.executeUpdate();
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		} catch (SQLException e) {
			e.printStackTrace();
		} finally {
			try {

				if (pstmt != null) {
					pstmt.close();
				}
				if (conn != null) {
					conn.close();
				}
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}

	}
}

批处理

Transaction

可滚动的结果集