使用servlet和Java Bean訪問MySQL

2019-11-18 13:43:26

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　　使用servlet和java Bean訪問MySQL

運(yùn)行環(huán)境: JDK 5.0 + Tomcat 5.5.4

JDK安裝路徑: D:/Java/jdk1.5.0_01
Tomcat安裝路徑:D:/Tomcat 5.5

設(shè)置環(huán)境變量(控制面板->系統(tǒng)->高級(jí)):
java_home=D:/Java/jdk1.5.0_01
path=%JAVA_HOME%/bin
classpath=.;D:/Java/jdk1.5.0_01/lib/dt.jar;D:/Java/jdk1.5.0_01/lib/tools.jar;D:/Tomcat 5.5/common/lib/servlet-api.jar;D:/Tomcat 5.5/common/lib/mysql-connector-java-3.1.6-bin.jar;

其中D:/Tomcat 5.5/common/lib/servlet-api.jar為Tomcat的servlet API實(shí)現(xiàn),一定要加上,不如無法編譯servlet
D:/Tomcat 5.5/common/lib/mysql-connector-java-3.1.6-bin.jar;是MySQL的JDBC驅(qū)動(dòng),connect/J 3.1.6,可到MySQL官方網(wǎng)站下載

Tomcat5.5虛擬目錄設(shè)定:
D:/Tomcat 5.5/conf/Catalina/localhost下新加一test.xml
內(nèi)容如下:
<Context path="/test" docBase="d:/www" reloadable="true" crossContext="true" debug="0" >
</Context>

d:/www路徑將是我們測試網(wǎng)站的根目錄,通過http://localhost:8080/test訪問該虛擬目錄
d:/www下建有目錄WEB-INF,下有web.xml設(shè)置文件(可參考D:/Tomcat 5.5/webapps/ROOT/WEB-INF/web.xml),classes目錄和lib目錄

//連接數(shù)據(jù)庫的Java Bean文件名dbconn.java
package NinGoo;
import java.sql.*;
public class dbconn {
public dbconn() {
}
//declare variable
PRivate Connection conn = null;
ResultSet rs = null;
private String server = "127.0.0.1";
private String port = "3306";
private String db = "test";
private String user = "root";
private String pass = "passWord";
private String drivername="com.mysql.jdbc.Driver";
private String URL="jdbc:mysql://"+server+":"+port+"/"+db+"?user="+user+"&password="+pass;

public Connection getConn(){//get database connection
try{
Class.forName(drivername).newInstance();
conn = DriverManager.getConnection(URL);
}
catch(Exception e){
e.printStackTrace();
}
return this.conn ;
}

public ResultSet executeSQL(String str) {
try{
Statement stmt = conn.createStatement();
rs = stmt.executeQuery(str);
}
catch(Exception e){
e.printStackTrace();
}
return this.rs;
}
}

編譯javac welcome.java,將編譯后的文件welcome.class放到目錄D:/www/WEB-INF/classes/NinGoo/下

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