JDBC常用API小結

建立數據庫鏈接的三種方式：

package com.victor_01;

import java.sql.Connection;
import java.sql.Driver;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;

import org.junit.Test;

public class Test1 {
	private String url = "jdbc:mysql://192.168.244.144:3306/test";
	private String user = "root";
	private String password = "123456";

	@Test
	public void test1() throws Exception {
		Driver driver = new com.mysql.jdbc.Driver();
		Properties prop = new Properties();
		prop.setProperty("user", user);
		prop.setProperty("password", password);
		Connection conn = driver.connect(url, prop);
		System.out.println(conn);
	}
	
	@Test
	public void test2() throws SQLException{
		Driver driver = new com.mysql.jdbc.Driver();
		DriverManager.registerDriver(driver);
		Connection conn = DriverManager.getConnection(url, user, password);
		System.out.println(conn);
	}
	
	@Test
	public void test3() throws Exception {
		Class.forName("com.mysql.jdbc.Driver");
		Connection conn = DriverManager.getConnection(url, user, password);
		System.out.println(conn);
		
	}

}

推薦使用第三種，其實第二種和第三種本質上是一種，后者是前者的優化版。

 

JDBC接口核心的API

 JDBC接口核心的API
                java.sql.*   和  javax.sql.*

            |- Driver接口： 表示java驅動程序接口。所有的具體的數據庫廠商要來實現此接口。
                |- connect(url, properties):  連接數據庫的方法。
                        url: 連接數據庫的URL 
                            URL語法： jdbc協議:數據庫子協議://主機:端口/數據庫
                            user： 數據庫的用戶名
                            password： 數據庫用戶密碼
            |- DriverManager類： 驅動管理器類，用於管理所有注冊的驅動程序
                |-registerDriver(driver)  : 注冊驅動類對象
                |-Connection getConnection(url,user,password);  獲取連接對象

            |- Connection接口： 表示java程序和數據庫的連接對象。
                    |- Statement createStatement() ： 創建Statement對象
                    |- PreparedStatement prepareStatement(String sql)  創建PreparedStatement對象
                    |- CallableStatement prepareCall(String sql) 創建CallableStatement對象

            |- Statement接口： 用於執行靜態的sql語句
                    |- int executeUpdate(String sql)  ： 執行靜態的更新sql語句（DDL，DML）
                    |- ResultSet executeQuery(String sql)  ：執行的靜態的查詢sql語句（DQL）

                |-PreparedStatement接口：用於執行預編譯sql語句
                        |- int executeUpdate() ： 執行預編譯的更新sql語句（DDL，DML）
                        |-ResultSet executeQuery()  ： 執行預編譯的查詢sql語句（DQL）

                    |-CallableStatement接口：用於執行存儲過程的sql語句（call xxx）
                            |-ResultSet executeQuery()  ： 調用存儲過程的方法


            |- ResultSet接口：用於封裝查詢出來的數據
                    |- boolean next() ： 將光標移動到下一行
                    |-getXX() : 獲取列的值

 

Statement接口

package com.victor_01;

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

import org.junit.Test;

public class Demo2 {
	private String url = "jdbc:mysql://192.168.244.144:3306/test";
	private String user = "root";
	private String password = "123456";

	@Test
	public void Test1() {
		Connection conn = null;
		Statement stmt = null;
		ResultSet rs = null;
		try {
			Class.forName("com.mysql.jdbc.Driver");
			conn = DriverManager.getConnection(url, user, password);
			stmt = conn.createStatement();

			String sql = "drop table if exists jdbc_test";
			int result = stmt.executeUpdate(sql);
			System.out.println("Drop table:" + result);

			sql = "create table jdbc_test(id int,name varchar(10))";
			result = stmt.executeUpdate(sql);
			System.out.println("Create result:" + result);

			sql = "insert into jdbc_test values(1,'hello')";
			result = stmt.executeUpdate(sql);
			System.out.println("Insert result:" + result);

			int id = 2;
			String name = "world";
			sql = "insert into jdbc_test values(" + id + ",'" + name + "')";
			result = stmt.executeUpdate(sql);
			System.out.println("Insert result2:" + result);

			name = "java";
			sql = "update jdbc_test set name='" + name + "' where id=" + id
					+ "";
			result = stmt.executeUpdate(sql);
			System.out.println("Update result:" + result);

			sql = "select * from jdbc_test";
			rs = stmt.executeQuery(sql);
			while (rs.next()) {
				System.out
						.println(rs.getInt("id") + " " + rs.getString("name"));
			}
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			if (rs != null) {
				try {
					rs.close();
				} catch (SQLException e) {
					e.printStackTrace();
				}
			}
			if (stmt != null)
				try {
					stmt.close();
				} catch (SQLException e) {
					e.printStackTrace();
				}
			if (conn != null)
				try {
					conn.close();
				} catch (SQLException e) {
					e.printStackTrace();
				}
		}

	}

}

 

PreparedStatement接口

package com.victor_01;


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

import org.junit.Test;


public class Demo3 {
	private String url="jdbc:mysql://192.168.244.144:3306/test";
	private String user="root";
	private String password="123456";
	@Test
	public void PreparedStatementTest() throws Exception{
	   Class.forName("com.mysql.jdbc.Driver");
	   Connection conn=DriverManager.getConnection(url, user, password);
	   
	   String sql="insert into jdbc_test(id,name) values(?,?)";
	   PreparedStatement prestmt =conn.prepareStatement(sql);
	   prestmt.setInt(1, 3);
	   prestmt.setString(2,"tom");
	   int result=prestmt.executeUpdate();
	   System.out.println(result);
	   
	   sql="update jdbc_test set name=? where id=?";
	   prestmt=conn.prepareStatement(sql);
	   prestmt.setString(1, "steve");
	   prestmt.setInt(2, 3);
	   result=prestmt.executeUpdate();
	   System.out.println(result);
	   
	   sql="select * from jdbc_test where id=?";
	   prestmt=conn.prepareStatement(sql);
	   prestmt.setInt(1, 3);
	   ResultSet rs= prestmt.executeQuery();
	   while(rs.next()){
		   System.out.println("id="+rs.getInt(1)+";name="+rs.getString(2));
	   }
	   rs.close();
	   prestmt.close();
	   conn.close();
	   }
	   
		
	}

 

CallableStatement接口

package com.victor_01;


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

import org.junit.Test;


public class Demo3 {
	private String url="jdbc:mysql://192.168.244.144:3306/test";
	private String user="root";
	private String password="123456";
	@Test
	public void PreparedStatementTest() throws Exception{
	   Class.forName("com.mysql.jdbc.Driver");
	   Connection conn=DriverManager.getConnection(url, user, password);
       String sql="drop procedure findById";
	   Statement stmt=conn.createStatement();
	   int result=stmt.executeUpdate(sql);
	   System.out.println("drop result:="+result);
	   
	   sql=" CREATE PROCEDURE findById(IN sid INT) BEGIN select * from jdbc_test where id=sid; end";
	   stmt=conn.createStatement();
	   result=stmt.executeUpdate(sql);
	   System.out.println("create result:="+result);
	   
	   //直接調用存儲過程
	   sql="call findById(2)";
	   CallableStatement stmt1=conn.prepareCall(sql);
	   ResultSet rs=stmt1.executeQuery();
	   while(rs.next()){
		   System.out.println("id="+rs.getInt(1)+",name="+rs.getString(2));
	   }
	   
	   //傳參調用存儲過程
	   sql="call findById(?)";
	   stmt1=conn.prepareCall(sql);
	   stmt1.setInt(1, 4);
	   rs=stmt1.executeQuery();
	   while(rs.next()){
		   System.out.println("id="+rs.getInt(1)+",name="+rs.getString(2));
	   }
	   
	   //帶有輸出參數的存儲過程
	   sql="drop procedure findById1";
	   stmt=conn.createStatement();
	   result=stmt.executeUpdate(sql);
	   System.out.println("drop findById1 result:"+result);
	   
	   sql=" CREATE PROCEDURE findById1(IN sid INT,OUT sname VARCHAR(10)) BEGIN select name into sname from jdbc_test where id=sid; end";
	   stmt=conn.createStatement();
	   result=stmt.executeUpdate(sql);
	   System.out.println("create result:="+result);
	   
	   sql="call findById1(?,?)";
	   stmt1=conn.prepareCall(sql);
	   stmt1.setInt(1, 4);
	   stmt1.registerOutParameter(2, java.sql.Types.VARCHAR);
	   stmt1.executeQuery(); //注意：結果不是返回到ResultSet中，而是返回到輸出參數中。   
	   String sname=stmt1.getString(2);
	   System.out.println(sname);
	   
	   rs.close();
	   stmt1.close();
	   stmt.close();
	   conn.close();
	   }
	   
		
	}