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JDBC連接MySQL
加載及注冊JDBC驅動程序
Class.forName("com.mysql.jdbc.Driver");
Class.forName("com.mysql.jdbc.Driver").newInstance();
JDBC URL 定義驅動程序與數據源之間的連接
標準語法:
<protocol(主要通訊協議)>:<subprotocol(次要通訊協議,即驅動程序名稱)>:<data source identifier(數據源)>
MySQL的JDBC URL格式:
jdbc:mysql//[hostname][:port]/[dbname][?param1=value1][¶m2=value2]….
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示例:jdbc:mysql://localhost:3306/sample_db?user=root&password=your_password
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常見參數:
user?????????????????????? 用戶名
password????????????????? 密碼
autoReconnect????????????????? 聯機失敗,是否重新聯機(true/false)
maxReconnect????????????? 嘗試重新聯機次數
initialTimeout?????????????? 嘗試重新聯機間隔
maxRows?????????????????? 傳回最大行數
useUnicode???????????????? 是否使用Unicode字體編碼(true/false)
characterEncoding????????? 何種編碼(GB2312/UTF-8/…)
relaxAutocommit??????????? 是否自動提交(true/false)
capitalizeTypeNames??????? 數據定義的名稱以大寫表示
建立連接對象
String url="jdbc:mysql://localhost:3306/sample_db?user=root&password=your_password";
Connection con = DriverManager.getConnection(url);
建立SQL陳述式對象(Statement Object)
Statement stmt = con.createStatement();
執行SQL語句
executeQuery()
String query = "select * from test";
ResultSet rs=stmt.executeQuery(query);
結果集ResultSet
while(rs.next())
{rs.getString(1);rs.getInt(2);}
executeUpdate()
String upd="insert into test (id,name) values(1001,xuzhaori)";
int con=stmt.executeUpdate(upd);
execute()
示例:
try
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{
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}
catch(SQLException sqle)
{
}
finally
{
}
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Java類型和SQL類型技術手冊P421
PreparedStatement(預編語句)
PreparedStatement stmt = conn.prepareStatement("insert into test(id,name)values(?,?)");
stmt.setInt(1,id);
stmt.setString(2,name);
注:一旦設定語句的參數值后,就可以多次執行改語句,直到調用clearParameters()方法將他清除為止
CallableStatement(預儲程序)技術手冊P430
JDBC2.0使用
ResultSet對象中的光標上下自由移動
Statement stmt = con.createStatement (ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_READ_ONLY);
ResultSet rs=stmt.executeQuery("select * from test");
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public Statement createStatement(int resultSetType,int resultSetConcuttency) throws SQLException
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resultSetType
TYPE_FORWARD_ONLY??????????? 只能使用next()方法。
TYPE_SCROLL_SENSITIVE?????? ?可以上下移動,可以取得改變后的值。
TYPE_SCROLL_INSENSITIVE???? ?可以上下移動。
resultSetConcuttency
CONCUR_READ_ONLY??????? 只讀
CONCUR_UPDATABLE??????? ResultSet對象可以執行數據庫的新增、修改、和移除
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直接使用ResultSet對象執行更新數據
新增數據
Statement stmt=con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_PUDATABLE);
ResultSet uprs=stmt.executeQuery("select * from test");
uprs.moveToInsertRow();
uprs.updateInt(1,1001);
uprs.updateString(2,"許召日");
uprs.insertRow;
更新數據
Statement stmt=con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_PUDATABLE);
ResultSet uprs=stmt.executeQuery("select * from test");
uprs.last();
uprs.updateString("name","xuzhaori");
uprs.updateRow;
刪除數據
Statement stmt=con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_PUDATABLE);
ResultSet uprs=stmt.executeQuery("select * from test");
uprs.absolute(4);
uprs.deleteRow();
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批處理
con.setAutoCommit(false);? 關閉自動認可模式
Statement stmt=con.createStatement();
int[] rows;
stmt.addBatch("insert into test values(1001,xuzhaori)");
stmt.addBatch("insert into test values(1002,xuyalin)");
rows=stmt.executeBatch();
con.commit();? 沒有任何錯誤,執行批處理stmt.executeBatch();
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JNDI-數據源(Data Source)與連接池(Connection Pool)
Tomcat的JDBC數據源設置? 技術手冊P439
連接池工具-Proxool Var 0.8.3 技術手冊P446
設置web.xml
<?xml version="1.0" encoding="ISO-8859-1"?>
<!--<?xml version="1.0" encoding="GB2312"?>-->
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<web-app xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
version="2.4">
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<servlet>
<servlet-name>ServletConfigurator</servlet-name>
<servlet-class>org.logicalcobwebs.proxool.configuration.ServletConfigurator</servlet-class>
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<init-param>
<param-name>propertyFile</param-name>
<param-value>WEB-INF/classes/Proxool.properties</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
后端統計端口添加下列
<servlet>
<servlet-name>Admin</servlet-name>
<servlet-class>org.logicalcobwebs.proxool.admin.servlet.AdminServlet</servlet-class>
</servlet>
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<servlet-mapping>
<servlet-name>Admin</servlet-name>
<url-pattern>/Admin</url-pattern>
</servlet-mapping>
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….
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</web-app>
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配置Proxool.properties
jdbc-0.proxool.alias=JSPBook
jdbc-0.proxool.driver-class=com.mysql.jdbc.Driver
jdbc-0.proxool.driver-url=jdbc:mysql://localhost:3306/sample_db?user=root&password=browser&useUnicode=true&characterEncoding=UTF-8
jdbc-0.proxool.maximum-connection-count=10
jdbc-0.proxool.prototype-count=4
jdbc-0.proxool.house-keeping-test-sql=select CURRENT_DATE
jdbc-0.proxool.verbose=true
jdbc-0.proxool.statistics=10s,1m,1d?? ?后端統計接口添加此行
jdbc-0.proxool.statistics-log-level=DEBUG
使用Proxool連接池
Connectioncon = DriverManager.getConnection("proxool.JSPBook");
Statementstmt = con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
String query = "SELECT * FROM employee";
ResultSetrs = stmt.executeQuery(query);