（1）连接mysql的工具类：DBUtil.java
package com.xuliugen.util;import java.sql.Connection;import java.sql.DriverManager;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;{public static Connection getConn() {Connection conn = null;try {Class.forName(“com.mysql.jdbc.Driver”);conn = DriverManager.getConnection(“jdbc:mysql://localhost:3306/你的数据库名称”, “你的账号”, “你的密码”);} catch (ClassNotFoundException e) {e.printStackTrace();} catch (SQLException e) {e.printStackTrace();}return conn;}public static PreparedStatement prepareStmt(Connection conn, String sql) {PreparedStatement pstmt = null;try {pstmt = conn.prepareStatement(sql);} catch (SQLException e) {e.printStackTrace();}return pstmt;}public static ResultSet executeQuery(Statement stmt, String sql) {ResultSet rs = null;try {rs = stmt.executeQuery(sql);} catch (SQLException e) {e.printStackTrace();}return rs;}(Connection conn, Statement stmt,PreparedStatement preStatement, ResultSet rs) {if (conn != null) {try {conn.close();} catch (SQLException e) {e.printStackTrace();}conn = null;}if (stmt != null) {try {stmt.close();} catch (SQLException e) {e.printStackTrace();}stmt = null;}if (preStatement != null) {try {preStatement.close();} catch (SQLException e) {e.printStackTrace();}preStatement = null;}if (rs != null) {try {rs.close();} catch (SQLException e) {e.printStackTrace();}rs = null;}}}
（2）使用preparedStatement插入数据的数据库：
(Comment comment) {Connection connection = DBUtil.getConn();String sql = “insert into comment values (null,?,?,?,?)”;PreparedStatement preparedStatement = null;boolean flag = false;try {preparedStatement = connection.prepareStatement(sql);preparedStatement.setString(1, comment.getCommenttext() + “”);preparedStatement.setString(2, comment.getCommenttime() + “”);preparedStatement.setString(3, comment.getUserid() + “”);preparedStatement.setString(4, comment.getArticleid() + “”);int isOk = preparedStatement.executeUpdate();if (isOk > 0) {return !flag;} else {return flag;}} catch (SQLException e) {e.printStackTrace();}DBUtil.close(connection, null, preparedStatement, null);return flag;}
（3）使用preparedStatement选择数据，读取数据：
public List<Comment> getCommentDetail(int userid, int articleid) {Connection connection = DBUtil.getConn();String sql = “select * from comment c where c.userid=? and c.articleid=?”;// 编写sql语句，第一个字段不需要插入，是自动增加的PreparedStatement preparedStatement = null;List<Comment> commentList = new ArrayList<Comment>();try {preparedStatement = connection.prepareStatement(sql);preparedStatement.setInt(1, userid);preparedStatement.setInt(2, articleid);//这里的产讯不需要传入sql语句ResultSet rs = preparedStatement.executeQuery();// 判断是否为空if (rs.next()) {while (rs.next()) {// 将信息迭代到list中Comment comment = new Comment();comment.setCommentid(rs.getInt(“commentid”));comment.setCommenttext(rs.getString(“commenttext”));comment.setCommenttime(rs.getString(“commenttime”));comment.setUserid(rs.getInt(“userid”));comment.setArticleid(rs.getInt(“articleid”));commentList.add(comment);}} else {return null;}} catch (SQLException e) {e.printStackTrace();}DBUtil.close(connection, null, preparedStatement, null);return commentList;}
（4）使用Statement操作数据库：
public List<Article> getArticleMessage() {Connection connection = DBUtil.getConn();String sql = “select * from article”;// 编写sql语句，第一个字段不需要插入，，是自动增加的Statement statement = null;List<Article> articleList = new ArrayList<Article>();try {statement = connection.createStatement();ResultSet rs = statement.executeQuery(sql);//判断是否为空if (rs.next()) {while (rs.next()) {//将信息迭代到list中Article article = new Article();article.setTitle(rs.getString(“title”));article.setContext(rs.getString(“context”));article.setArticleTime(rs.getString(“articletime”));article.setUserid(rs.getInt(“userid”));article.setArticleid(rs.getInt(“articleid”));articleList.add(article);}} else {return null;}} catch (SQLException e) {e.printStackTrace();}DBUtil.close(connection, statement, null, null);return articleList;}
期待遇上一位撑着油纸伞，结着忧愁丁香一样的姑娘;或者在春暖花开时，
