jdbc学习(三): 使用statement, preparedStatment进行数据操作

使用statement进行数据的查询，基本步骤如下：
* 1. 初始化simpleDbSource对象
* 2. 获得getconnection
* 3. createStatement 获得查询语句
* 4. executeUpdate, 执行更新语句
* 5. 关闭使用的statement, connection, 注意次序不要弄错
*
* 注意：更新语句，执行过一次后，column需要递增，否则报错

/**
 * 
 */
package db;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;

/**
 * @author sean
 * 
 * 1. 初始化simpleDbSource对象
 * 2. 获得getconnection
 * 3. createStatement 获得查询语句
 * 4. executeUpdate, 执行更新语句
 * 5. 关闭使用的statement, connection, 注意次序不要弄错
 * 
 * 注意：更新语句，执行过一次后，column需要递增，否则报错
 */
public class StatementDemo {

	private static String insertSql="insert into user values('7','sean','sean@mail.com','hellofromsean')";
	private static String querySql ="select * from user";

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		DBSource dbSource;
		Connection conn = null;
		java.sql.Statement stmt = null;

		try {
			dbSource = new SimpleDBSource();
			conn = dbSource.getConnect();
			stmt = conn.createStatement();

			//数据库更新工作,包括create, drop, update, insert etc.
			stmt.executeUpdate(insertSql);
			System.out.println("执行成功"+ insertSql);

			//进行数据库查询
			ResultSet rs = stmt.executeQuery(querySql);

			//进行遍历
			while(rs.next()){
				System.out.println(rs.getInt(1)+ "\t");
				System.out.println(rs.getString(2)+ "\t");
				System.out.println(rs.getString(3)+ "\t");
				System.out.println(rs.getString(4)+ "\t");
				System.out.println("**********************");
			}



		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

		//依次关闭statement和conn数据库连接对象，清空资源
		finally{
			if(stmt!= null){
				try {
					stmt.close();
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
				stmt= null;
			}
			if(conn!=null){
				try {
					conn.close();
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
				conn= null;
			}
		}
	}
}

/**
*
*/
package db;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

/**
* @author sean
*
* 1. 初始化simpleDbSource对象
* 2. 获得getconnection
* 3. createPreparedStatement 获得查询语句
* 4. 设置具体更新内容,setInt(colIndex, value), setString(colIndex,value)
* 4. executeUpdate, 执行更新语句
* 5. 关闭使用的PreparedStatementstatement, connection, 注意次序不要弄错
*
* 注意：更新语句，执行过一次后，column需要递增，否则报错
*/
public class PreparedStatementDemo {

private static String querySql ="select * from user";
private static String pstmtSql = "insert into user values(?,?,?,?)";

Connection conn1;
static Statement stmt;
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
DBSource dbSource;
Connection conn = null;
java.sql.PreparedStatement pstmt = null;

try {
dbSource = new SimpleDBSource();
conn = dbSource.getConnect();
pstmt = conn.prepareStatement(pstmtSql);

pstmt.setInt(1, 9);
pstmt.setString(2, "sean");
pstmt.setString(3, "my@hotmail.com");
pstmt.setString(4, "add some comments");

//数据库更新工作,包括create, drop, update, insert etc.
pstmt.executeUpdate();

//清空设置的参数，为后续更新准备
pstmt.clearParameters();

System.out.println("执行成功"+ pstmtSql);

//进行数据库查询
Connection conn1 = dbSource.getConnect();
Statement stmt = conn1.createStatement();
ResultSet rs = stmt.executeQuery(querySql);

//进行遍历
while(rs.next()){
System.out.println(rs.getInt(1)+ "\t");
System.out.println(rs.getString(2)+ "\t");
System.out.println(rs.getString(3)+ "\t");
System.out.println(rs.getString(4)+ "\t");
System.out.println("**********************");
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

//依次关闭statement和conn数据库连接对象，清空资源
finally{
if(stmt!= null){
try {
stmt.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
stmt= null;
}

if(pstmt!= null){
try {
pstmt.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
pstmt= null;
}

if(conn!=null){
try {
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
conn= null;
}
}
}
}