JDBC連接MySQL
JDBC連接MySQL
加載及注冊JDBC驅(qū)動程序
Class.forName(“com.mysql.jdbc.Driver”);
Class.forName(“com.mysql.jdbc.Driver”).newInstance();
JDBC URL 定義驅(qū)動程序與數(shù)據(jù)源之間的連接
標(biāo)準(zhǔn)語法:
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?
常見參數(shù):
user?????????????????????? 用戶名
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??????????? 是否自動提交(true/false)
capitalizeTypeNames??????? 數(shù)據(jù)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(zhí)行SQL語句
executeQuery() String query = "select * from test"; ResultSet rs=stmt.executeQuery(query); 結(jié)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 { } catch(SQLException sqle) { } finally { }
?Java類型和SQL類型 技術(shù)手冊P421
PreparedStatement(預(yù)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(shè)定語句的參數(shù)值后,就可以多次執(zhí)行改語句,直到調(diào)用clearParameters()方法將他清除為止
CallableStatement(預(yù)儲程序)技術(shù)手冊P430
JDBC2.0使用
ResultSet對象中的光標(biāo)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”);
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,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(zhí)行數(shù)據(jù)庫的新增、修改、和移除?
直接使用ResultSet對象執(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(); 沒有任何錯誤,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P439
連接池工具-Proxool Var 0.8.3 技術(shù)手冊P446
設(shè)置web.xml
<!--<?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=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(tǒng)計接口添加此行 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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