3.1 執行DDL語句

/**
	 * 執行DDL語句(建立表)
	 */
	@Test
	public void test1(){
		Statement stmt = null;
		Connection conn = null;
		try {
			//1.驅動註冊程式
			Class.forName("com.mysql.jdbc.Driver");
			
			//2.獲取連線物件
			conn = DriverManager.getConnection(url, user, password);
			
			//3.建立Statement
			stmt = conn.createStatement();
			
			//4.準備sql
			String sql = "CREATE TABLE student(id INT PRIMARY KEY AUTO_INCREMENT,NAME VARCHAR(20),gender VARCHAR(2))";
			
			//5.傳送sql語句，執行sql語句,得到返回結果
			int count = stmt.executeUpdate(sql);
			
			//6.輸出
			System.out.println("影響了"+count+"行！");
		} catch (Exception e) {
			e.printStackTrace();
			throw new RuntimeException(e);
		} finally{
			//7.關閉連線(順序:後開啟的先關閉)
			if(stmt!=null)
				try {
					stmt.close();
				} catch (SQLException e) {
					e.printStackTrace();
					throw new RuntimeException(e);
				}
			if(conn!=null)
				try {
					conn.close();
				} catch (SQLException e) {
					e.printStackTrace();
					throw new RuntimeException(e);
				}
		}
	}
 

3.2 執行DML語句

/**
 * 使用Statement執行DML語句
 * @author APPle
 *
 */
public class Demo2 {
private String url = "jdbc:mysql://localhost:3306/day17";
private String user = "root";
private String password = "root";
 
/**
 * 增加
 */
@Test
public void testInsert(){
Connection conn = null;
Statement stmt = null;
try {
//通過工具類獲取連線物件
conn = JdbcUtil.getConnection();
//3.建立Statement物件
stmt = conn.createStatement();
//4.sql語句
String sql = "INSERT INTO student(NAME,gender) VALUES('李四','女')";
//5.執行sql
int count = stmt.executeUpdate(sql);
System.out.println("影響了"+count+"行");
} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException(e);
} finally{
//關閉資源
/*if(stmt!=null)
try {
stmt.close();
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException(e);
}
if(conn!=null)
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException(e);
}*/
JdbcUtil.close(conn, stmt);
}
}
/**
 * 修改
 */
@Test
public void testUpdate(){
Connection conn = null;
Statement stmt = null;
//模擬使用者輸入
String name = "陳六";
int id = 3;
try {
/*//1.註冊驅動
Class.forName("com.mysql.jdbc.Driver");
//2.獲取連線物件
conn = DriverManager.getConnection(url, user, password);*/
//通過工具類獲取連線物件
conn = JdbcUtil.getConnection();
//3.建立Statement物件
stmt = conn.createStatement();
//4.sql語句
String sql = "UPDATE student SET NAME='"+name+"' WHERE id="+id+"";
System.out.println(sql);
//5.執行sql
int count = stmt.executeUpdate(sql);
System.out.println("影響了"+count+"行");
} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException(e);
} finally{
//關閉資源
/*if(stmt!=null)
try {
stmt.close();
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException(e);
}
if(conn!=null)
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException(e);
}*/
JdbcUtil.close(conn, stmt);
}
}
/**
 * 刪除
 */
@Test
public void testDelete(){
Connection conn = null;
Statement stmt = null;
//模擬使用者輸入
int id = 3;
try {
/*//1.註冊驅動
Class.forName("com.mysql.jdbc.Driver");
//2.獲取連線物件
conn = DriverManager.getConnection(url, user, password);*/
//通過工具類獲取連線物件
conn = JdbcUtil.getConnection();
//3.建立Statement物件
stmt = conn.createStatement();
//4.sql語句
String sql = "DELETE FROM student WHERE id="+id+"";
System.out.println(sql);
//5.執行sql
int count = stmt.executeUpdate(sql);
System.out.println("影響了"+count+"行");
} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException(e);
} finally{
//關閉資源
/*if(stmt!=null)
try {
stmt.close();
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException(e);
}
if(conn!=null)
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException(e);
}*/
JdbcUtil.close(conn, stmt);
}
}
}
 

3.3 執行DQL語句

/**
 * 使用Statement執行DQL語句（查詢操作）
 * @author APPle
 */
public class Demo3 {

	@Test
	public void test1(){
		Connection conn = null;
		Statement stmt = null;
		try{
			//獲取連線
			conn = JdbcUtil.getConnection();
			//建立Statement
			stmt = conn.createStatement();
			//準備sql
			String sql = "SELECT * FROM student";
			//執行sql
			ResultSet rs = stmt.executeQuery(sql);
			
			//移動游標
			/*boolean flag = rs.next();
			
			flag = rs.next();
			flag = rs.next();
			if(flag){
				//取出列值
				//索引
				int id = rs.getInt(1);
				String name = rs.getString(2);
				String gender = rs.getString(3);
				System.out.println(id+","+name+","+gender);
				
				//列名稱
				int id = rs.getInt("id");
				String name = rs.getString("name");
				String gender = rs.getString("gender");
				System.out.println(id+","+name+","+gender);
			}*/
			
			//遍歷結果
			while(rs.next()){
				int id = rs.getInt("id");
				String name = rs.getString("name");
				String gender = rs.getString("gender");
				System.out.println(id+","+name+","+gender);
			}
			
		}catch(Exception e){
			e.printStackTrace();
			throw new RuntimeException(e);
		}finally{
			JdbcUtil.close(conn, stmt);
		}
	}
}