JDBC連接MySQL
JDBC連接MySQL
加載及注冊(cè)JDBC驅(qū)動(dòng)程序
Class.forName("com.mysql.jdbc.Driver");
Class.forName("com.mysql.jdbc.Driver").newInstance();
JDBC URL 定義驅(qū)動(dòng)程序與數(shù)據(jù)源之間的連接
標(biāo)準(zhǔn)語(yǔ)法:
<protocol(主要通訊協(xié)議)>:<subprotocol(次要通訊協(xié)議,即驅(qū)動(dòng)程序名稱(chēng))>:<data source identifier(數(shù)據(jù)源)>
MySQL的JDBC URL格式:
jdbc:mysql//[hostname][:port]/[dbname][?param1=value1][¶m2=value2]….
示例:jdbc:mysql://localhost:3306/sample_db?user=root&password=your_password
常見(jiàn)參數(shù):
user 用戶(hù)名
password 密碼
autoReconnect 聯(lián)機(jī)失敗,是否重新聯(lián)機(jī)(true/false)
maxReconnect 嘗試重新聯(lián)機(jī)次數(shù)
initialTimeout 嘗試重新聯(lián)機(jī)間隔
maxRows 傳回最大行數(shù)
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(dòng)提交(true/false)
capitalizeTypeNames 數(shù)據(jù)定義的名稱(chēng)以大寫(xiě)表示
建立連接對(duì)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(duì)象(Statement Object)
Statement stmt = con.createStatement();
執(zhí)行SQL語(yǔ)句
executeQuery()String query = "select * from test";ResultSet rs=stmt.executeQuery(query);結(jié)果集ResultSetwhile(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{ }catch(SQLException sqle){}finally{}
Java類(lèi)型和SQL類(lèi)型 技術(shù)手冊(cè)P421
PreparedStatement(預(yù)編語(yǔ)句)
PreparedStatement stmt = conn.prepareStatement("insert into test(id,name)values(?,?)");
stmt.setInt(1,id);
stmt.setString(2,name);
注:一旦設(shè)定語(yǔ)句的參數(shù)值后,就可以多次執(zhí)行改語(yǔ)句,直到調(diào)用clearParameters()方法將他清除為止
CallableStatement(預(yù)儲(chǔ)程序)技術(shù)手冊(cè)P430
JDBC2.0使用
ResultSet對(duì)象中的光標(biāo)上下自由移動(dòng)
Statement stmt = con.createStatement (ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_READ_ONLY);
ResultSet rs=stmt.executeQuery("select * from test");
public Statement createStatement(int resultSetType,int resultSetConcuttency) throws SQLException
resultSetType
TYPE_FORWARD_ONLY 只能使用next()方法。
TYPE_SCROLL_SENSITIVE 可以上下移動(dòng),可以取得改變后的值。
TYPE_SCROLL_INSENSITIVE 可以上下移動(dòng)。
resultSetConcuttency
CONCUR_READ_ONLY 只讀
CONCUR_UPDATABLE ResultSet對(duì)象可以執(zhí)行數(shù)據(jù)庫(kù)的新增、修改、和移除
直接使用ResultSet對(duì)象執(zhí)行更新數(shù)據(jù)
新增數(shù)據(jù)
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(shù)據(jù)
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(shù)據(jù)
Statement stmt=con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_PUDATABLE);ResultSet uprs=stmt.executeQuery("select * from test");uprs.absolute(4);uprs.deleteRow();
批處理
con.setAutoCommit(false); 關(guān)閉自動(dòng)認(rèn)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(méi)有任何錯(cuò)誤,執(zhí)行批處理stmt.executeBatch();
JNDI-數(shù)據(jù)源(Data Source)與連接池(Connection Pool)
Tomcat的JDBC數(shù)據(jù)源設(shè)置 技術(shù)手冊(cè)P439
連接池工具-Proxool Var 0.8.3 技術(shù)手冊(cè)P446
設(shè)置web.xml
<?xml version="1.0" encoding="ISO-8859-1"?><!--<?xml version="1.0" encoding="GB2312"?>--> <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">….<servlet><servlet-name>ServletConfigurator</servlet-name><servlet-class>org.logicalcobwebs.proxool.configuration.ServletConfigurator</servlet-class> <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(tǒng)計(jì)端口添加下列<servlet><servlet-name>Admin</servlet-name><servlet-class>org.logicalcobwebs.proxool.admin.servlet.AdminServlet</servlet-class></servlet> <servlet-mapping><servlet-name>Admin</servlet-name><url-pattern>/Admin</url-pattern></servlet-mapping> …. </web-app>
配置Proxool.properties
jdbc-0.proxool.alias=JSPBookjdbc-0.proxool.driver-class=com.mysql.jdbc.Driverjdbc-0.proxool.driver-url=jdbc:mysql://localhost:3306/sample_db?user=root&password=browser&useUnicode=true&characterEncoding=UTF-8jdbc-0.proxool.maximum-connection-count=10jdbc-0.proxool.prototype-count=4jdbc-0.proxool.house-keeping-test-sql=select CURRENT_DATEjdbc-0.proxool.verbose=truejdbc-0.proxool.statistics=10s,1m,1d 后端統(tǒng)計(jì)接口添加此行jdbc-0.proxool.statistics-log-level=DEBUG
使用Proxool連接池
Connection con = DriverManager.getConnection("proxool.JSPBook");Statement stmt = con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);String query = "SELECT * FROM employee";ResultSet rs = stmt.executeQuery(query);
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