使用JDBC的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
Java代码
- /**
- *
- */
- 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','[email protected]','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;
-
- /**
- * @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','[email protected]','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, "[email protected]");
- 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jdbc的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;
- }
- }
- }
- }