📄 jdbcpiedataset.html
字号:
<HTML><BODY BGCOLOR="white"><PRE><FONT color="green">001</FONT> /* ===========================================================<a name="line.1"></a><FONT color="green">002</FONT> * JFreeChart : a free chart library for the Java(tm) platform<a name="line.2"></a><FONT color="green">003</FONT> * ===========================================================<a name="line.3"></a><FONT color="green">004</FONT> *<a name="line.4"></a><FONT color="green">005</FONT> * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.<a name="line.5"></a><FONT color="green">006</FONT> *<a name="line.6"></a><FONT color="green">007</FONT> * Project Info: http://www.jfree.org/jfreechart/index.html<a name="line.7"></a><FONT color="green">008</FONT> *<a name="line.8"></a><FONT color="green">009</FONT> * This library is free software; you can redistribute it and/or modify it <a name="line.9"></a><FONT color="green">010</FONT> * under the terms of the GNU Lesser General Public License as published by <a name="line.10"></a><FONT color="green">011</FONT> * the Free Software Foundation; either version 2.1 of the License, or <a name="line.11"></a><FONT color="green">012</FONT> * (at your option) any later version.<a name="line.12"></a><FONT color="green">013</FONT> *<a name="line.13"></a><FONT color="green">014</FONT> * This library is distributed in the hope that it will be useful, but <a name="line.14"></a><FONT color="green">015</FONT> * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY <a name="line.15"></a><FONT color="green">016</FONT> * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public <a name="line.16"></a><FONT color="green">017</FONT> * License for more details.<a name="line.17"></a><FONT color="green">018</FONT> *<a name="line.18"></a><FONT color="green">019</FONT> * You should have received a copy of the GNU Lesser General Public<a name="line.19"></a><FONT color="green">020</FONT> * License along with this library; if not, write to the Free Software<a name="line.20"></a><FONT color="green">021</FONT> * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, <a name="line.21"></a><FONT color="green">022</FONT> * USA. <a name="line.22"></a><FONT color="green">023</FONT> *<a name="line.23"></a><FONT color="green">024</FONT> * [Java is a trademark or registered trademark of Sun Microsystems, Inc. <a name="line.24"></a><FONT color="green">025</FONT> * in the United States and other countries.]<a name="line.25"></a><FONT color="green">026</FONT> *<a name="line.26"></a><FONT color="green">027</FONT> * -------------------<a name="line.27"></a><FONT color="green">028</FONT> * JDBCPieDataset.java<a name="line.28"></a><FONT color="green">029</FONT> * -------------------<a name="line.29"></a><FONT color="green">030</FONT> * (C) Copyright 2002-2004, by Bryan Scott and Contributors.<a name="line.30"></a><FONT color="green">031</FONT> *<a name="line.31"></a><FONT color="green">032</FONT> * Original Author: Bryan Scott; Andy<a name="line.32"></a><FONT color="green">033</FONT> * Contributor(s): David Gilbert (for Object Refinery Limited);<a name="line.33"></a><FONT color="green">034</FONT> * Thomas Morgner;<a name="line.34"></a><FONT color="green">035</FONT> * <a name="line.35"></a><FONT color="green">036</FONT> * $ Id: $<a name="line.36"></a><FONT color="green">037</FONT> *<a name="line.37"></a><FONT color="green">038</FONT> * Changes<a name="line.38"></a><FONT color="green">039</FONT> * -------<a name="line.39"></a><FONT color="green">040</FONT> * 26-Apr-2002 : Creation based on JdbcXYDataSet, but extending <a name="line.40"></a><FONT color="green">041</FONT> * DefaultPieDataset (BS);<a name="line.41"></a><FONT color="green">042</FONT> * 24-Jun-2002 : Removed unnecessary import and local variable (DG);<a name="line.42"></a><FONT color="green">043</FONT> * 13-Aug-2002 : Updated Javadoc comments and imports, removed default <a name="line.43"></a><FONT color="green">044</FONT> * constructor (DG);<a name="line.44"></a><FONT color="green">045</FONT> * 18-Sep-2002 : Updated to support BIGINT (BS);<a name="line.45"></a><FONT color="green">046</FONT> * 21-Jan-2003 : Renamed JdbcPieDataset --> JDBCPieDataset (DG);<a name="line.46"></a><FONT color="green">047</FONT> * 03-Feb-2003 : Added Types.DECIMAL (see bug report 677814) (DG);<a name="line.47"></a><FONT color="green">048</FONT> * 05-Jun-2003 : Updated to support TIME, optimised executeQuery method (BS);<a name="line.48"></a><FONT color="green">049</FONT> * 30-Jul-2003 : Added empty contructor and executeQuery(connection,string) <a name="line.49"></a><FONT color="green">050</FONT> * method (BS);<a name="line.50"></a><FONT color="green">051</FONT> * 02-Dec-2003 : Throwing exceptions allows to handle errors, removed default <a name="line.51"></a><FONT color="green">052</FONT> * constructor, as without a connection, a query can never be <a name="line.52"></a><FONT color="green">053</FONT> * executed (TM);<a name="line.53"></a><FONT color="green">054</FONT> * 04-Dec-2003 : Added missing Javadocs (DG);<a name="line.54"></a><FONT color="green">055</FONT> */<a name="line.55"></a><FONT color="green">056</FONT> <a name="line.56"></a><FONT color="green">057</FONT> package org.jfree.data.jdbc;<a name="line.57"></a><FONT color="green">058</FONT> <a name="line.58"></a><FONT color="green">059</FONT> import java.sql.Connection;<a name="line.59"></a><FONT color="green">060</FONT> import java.sql.DriverManager;<a name="line.60"></a><FONT color="green">061</FONT> import java.sql.SQLException;<a name="line.61"></a><FONT color="green">062</FONT> import java.sql.Timestamp;<a name="line.62"></a><FONT color="green">063</FONT> import java.sql.Types;<a name="line.63"></a><FONT color="green">064</FONT> import java.sql.ResultSet;<a name="line.64"></a><FONT color="green">065</FONT> import java.sql.ResultSetMetaData;<a name="line.65"></a><FONT color="green">066</FONT> import java.sql.Statement;<a name="line.66"></a><FONT color="green">067</FONT> <a name="line.67"></a><FONT color="green">068</FONT> import org.jfree.data.general.DefaultPieDataset;<a name="line.68"></a><FONT color="green">069</FONT> import org.jfree.data.general.PieDataset;<a name="line.69"></a><FONT color="green">070</FONT> <a name="line.70"></a><FONT color="green">071</FONT> /**<a name="line.71"></a><FONT color="green">072</FONT> * A {@link PieDataset} that reads data from a database via JDBC.<a name="line.72"></a><FONT color="green">073</FONT> * <P><a name="line.73"></a><FONT color="green">074</FONT> * A query should be supplied that returns data in two columns, the first <a name="line.74"></a><FONT color="green">075</FONT> * containing VARCHAR data, and the second containing numerical data. The <a name="line.75"></a><FONT color="green">076</FONT> * data is cached in-memory and can be refreshed at any time.<a name="line.76"></a><FONT color="green">077</FONT> *<a name="line.77"></a><FONT color="green">078</FONT> * @author Bryan Scott.<a name="line.78"></a><FONT color="green">079</FONT> */<a name="line.79"></a><FONT color="green">080</FONT> public class JDBCPieDataset extends DefaultPieDataset {<a name="line.80"></a><FONT color="green">081</FONT> <a name="line.81"></a><FONT color="green">082</FONT> /** The database connection. */<a name="line.82"></a><FONT color="green">083</FONT> private transient Connection connection;<a name="line.83"></a><FONT color="green">084</FONT> <a name="line.84"></a><FONT color="green">085</FONT> /**<a name="line.85"></a><FONT color="green">086</FONT> * Creates a new JDBCPieDataset and establishes a new database connection.<a name="line.86"></a><FONT color="green">087</FONT> *<a name="line.87"></a><FONT color="green">088</FONT> * @param url the URL of the database connection.<a name="line.88"></a><FONT color="green">089</FONT> * @param driverName the database driver class name.<a name="line.89"></a><FONT color="green">090</FONT> * @param user the database user.<a name="line.90"></a><FONT color="green">091</FONT> * @param password the database users password.<a name="line.91"></a><FONT color="green">092</FONT> * <a name="line.92"></a><FONT color="green">093</FONT> * @throws ClassNotFoundException if the driver cannot be found.<a name="line.93"></a><FONT color="green">094</FONT> * @throws SQLException if there is a problem obtaining a database <a name="line.94"></a><FONT color="green">095</FONT> * connection.<a name="line.95"></a><FONT color="green">096</FONT> */<a name="line.96"></a><FONT color="green">097</FONT> public JDBCPieDataset(String url,<a name="line.97"></a><FONT color="green">098</FONT> String driverName,<a name="line.98"></a><FONT color="green">099</FONT> String user,<a name="line.99"></a><FONT color="green">100</FONT> String password)<a name="line.100"></a><FONT color="green">101</FONT> throws SQLException, ClassNotFoundException {<a name="line.101"></a><FONT color="green">102</FONT> <a name="line.102"></a><FONT color="green">103</FONT> Class.forName(driverName);<a name="line.103"></a><FONT color="green">104</FONT> this.connection = DriverManager.getConnection(url, user, password);<a name="line.104"></a><FONT color="green">105</FONT> }<a name="line.105"></a><FONT color="green">106</FONT> <a name="line.106"></a><FONT color="green">107</FONT> /**<a name="line.107"></a><FONT color="green">108</FONT> * Creates a new JDBCPieDataset using a pre-existing database connection.<a name="line.108"></a><FONT color="green">109</FONT> * <P><a name="line.109"></a><FONT color="green">110</FONT> * The dataset is initially empty, since no query has been supplied yet.<a name="line.110"></a><FONT color="green">111</FONT> *<a name="line.111"></a><FONT color="green">112</FONT> * @param con the database connection.<a name="line.112"></a><FONT color="green">113</FONT> */<a name="line.113"></a><FONT color="green">114</FONT> public JDBCPieDataset(Connection con) {<a name="line.114"></a><FONT color="green">115</FONT> if (con == null) {<a name="line.115"></a><FONT color="green">116</FONT> throw new NullPointerException("A connection must be supplied.");<a name="line.116"></a><FONT color="green">117</FONT> }<a name="line.117"></a><FONT color="green">118</FONT> this.connection = con;<a name="line.118"></a><FONT color="green">119</FONT> }<a name="line.119"></a><FONT color="green">120</FONT> <a name="line.120"></a><FONT color="green">121</FONT> <a name="line.121"></a><FONT color="green">122</FONT> /**<a name="line.122"></a><FONT color="green">123</FONT> * Creates a new JDBCPieDataset using a pre-existing database connection.<a name="line.123"></a><FONT color="green">124</FONT> * <P><a name="line.124"></a><FONT color="green">125</FONT> * The dataset is initialised with the supplied query.<a name="line.125"></a><FONT color="green">126</FONT> *<a name="line.126"></a><FONT color="green">127</FONT> * @param con the database connection.<a name="line.127"></a><FONT color="green">128</FONT> * @param query the database connection.<a name="line.128"></a><FONT color="green">129</FONT> * <a name="line.129"></a><FONT color="green">130</FONT> * @throws SQLException if there is a problem executing the query.<a name="line.130"></a><FONT color="green">131</FONT> */<a name="line.131"></a><FONT color="green">132</FONT> public JDBCPieDataset(Connection con, String query) throws SQLException {<a name="line.132"></a><FONT color="green">133</FONT> this(con);<a name="line.133"></a><FONT color="green">134</FONT> executeQuery(query);<a name="line.134"></a><FONT color="green">135</FONT> }<a name="line.135"></a><FONT color="green">136</FONT> <a name="line.136"></a><FONT color="green">137</FONT> /**<a name="line.137"></a><FONT color="green">138</FONT> * ExecuteQuery will attempt execute the query passed to it against the<a name="line.138"></a><FONT color="green">139</FONT> * existing database connection. If no connection exists then no action<a name="line.139"></a><FONT color="green">140</FONT> * is taken.<a name="line.140"></a><FONT color="green">141</FONT> * The results from the query are extracted and cached locally, thus<a name="line.141"></a><FONT color="green">142</FONT> * applying an upper limit on how many rows can be retrieved successfully.<a name="line.142"></a><FONT color="green">143</FONT> *<a name="line.143"></a><FONT color="green">144</FONT> * @param query the query to be executed.<a name="line.144"></a><FONT color="green">145</FONT> * <a name="line.145"></a><FONT color="green">146</FONT> * @throws SQLException if there is a problem executing the query.<a name="line.146"></a><FONT color="green">147</FONT> */<a name="line.147"></a><FONT color="green">148</FONT> public void executeQuery(String query) throws SQLException {<a name="line.148"></a><FONT color="green">149</FONT> executeQuery(this.connection, query);<a name="line.149"></a><FONT color="green">150</FONT> }<a name="line.150"></a><FONT color="green">151</FONT> <a name="line.151"></a><FONT color="green">152</FONT> /**<a name="line.152"></a><FONT color="green">153</FONT> * ExecuteQuery will attempt execute the query passed to it against the<a name="line.153"></a><FONT color="green">154</FONT> * existing database connection. If no connection exists then no action<a name="line.154"></a><FONT color="green">155</FONT> * is taken.<a name="line.155"></a>⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -