Struts2连接MySQL数据库

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按照如下步骤连接MySQL数据库 :

第一步 : 创建struts.xml并向其中添加如下xml代码 :

Xml代码
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts
 Configuration 2.0//EN"
"http://struts.apache.org/dtds/struts-2.0.dtd">

<struts>


<constant name="struts.enable.DynamicMethodInvocation"
 value="false" />
<constant name="struts.devMode" value="true" />
<include file="struts-default.xml"/>




 <package name="roseindia" namespace="/roseindia"
extends="struts-default">



<action name="insert">
 <result>/pages/insertData.jsp</result>
</action>

<action name="insertData" class="net.roseindia.insert">
 <result name="error">/pages/insertData.jsp</result>
 <result>/pages/insertSuccess.jsp</result>
</action>

</package>


</struts>

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts
 Configuration 2.0//EN"
"http://struts.apache.org/dtds/struts-2.0.dtd">

<struts>


<constant name="struts.enable.DynamicMethodInvocation"
 value="false" />
<constant name="struts.devMode" value="true" />
<include file="struts-default.xml"/>



 <package name="roseindia" namespace="/roseindia"
extends="struts-default">



<action name="insert">
 <result>/pages/insertData.jsp</result>
</action>

<action name="insertData" class="net.roseindia.insert">
 <result name="error">/pages/insertData.jsp</result>
 <result>/pages/insertSuccess.jsp</result>
</action>

</package>

</struts>
第二步 : 创建一个JSP输入表单 :

insertData.jsp

Html代码
<%@ taglib prefix="s" uri="/struts-tags" %>
<html>
<head>
<title>Struts 2 Insert Data Application!</title>

<link href="<s:url value="/css/main.css"/>" rel="stylesheet"
type="text/css"/>

</head>
<body>


<s:form action="insertData" method="POST" validate="true">

<tr>
<td colspan="2">
Please enter
</td>

</tr>

<s:actionerror />
<s:fielderror />

<s:textfield name="username" label="User Name"/>
<s:password name="password" label="Password"/>
<s:submit value="Save" align="center"/>

</s:form>

</body>

</html>

<%@ taglib prefix="s" uri="/struts-tags" %>
<html>
<head>
<title>Struts 2 Insert Data Application!</title>

<link href="<s:url value="/css/main.css"/>" rel="stylesheet"
type="text/css"/>

</head>
<body>

<s:form action="insertData" method="POST" validate="true">

<tr>
<td colspan="2">
Please enter
</td>

</tr>

<s:actionerror />
<s:fielderror />

<s:textfield name="username" label="User Name"/>
<s:password name="password" label="Password"/>
<s:submit value="Save" align="center"/>

</s:form>

</body>

</html>第三步 : 创建一个Action类.

首先通过MySQL驱动的帮助("org.gjt.mm.mysql.Driver")建立一个MySQL数据库连接.现在,在MySQL数据库中创建一个账户以连接数据库.创建连接后,你可以向MySQL数据库的表中检索,添加,更新数据.

下面的Action类通过方法适当的类型的帮助和API接口建立了与MySQL数据库的连接.如果建立了连接输入的数据会添加到MySQL数据库表中否则显示错误信息.

insert.java

Java代码
package net.roseindia;
import com.opensymphony.xwork2.ActionSupport;
import java.util.Date;
import java.sql.*;


/**
* Validate a user login. 
*/
public class insert extends ActionSupport {

 public String execute() throws Exception {
String url = "jdbc:mysql://localhost:3306/";
String dbName = "taskproject";
String driverName = "org.gjt.mm.mysql.Driver";
String userName = "root";
String password = "root";
Connection con=null;
Statement stmt=null;
try{
 Class.forName(driverName).newInstance();
 con=DriverManager.getConnection(url+dbName, userName,
 password);
 stmt=con.createStatement();
}
catch(Exception e){
 System.out.println(e.getMessage());
}
String uname=getUsername();
String pws=getPassword();
stmt = con.createStatement();
 int val = stmt.executeUpdate("INSERT employee VALUES
 ('"+uname+"','"+pws+"')");
if(val == 0){
 return ERROR;
}
else{
 return SUCCESS;
}
 }
 // ---- Username property ----

/**
 * Field to store User username.
 * 
 */
private String username = null;


/**
 * Provide User username.
 *
 * @return Returns the User username.
 */
public String getUsername() {
 return username;
}

/**
 * Store new User username
 *
 * @param value The username to set.
 */
public void setUsername(String value) {
 username = value;
}

// ---- Username property ----

/**
 * Field to store User password.
 * 
 */
private String password = null;


/**
 * Provide User password.
 *
 * @return Returns the User password.
 */
public String getPassword() {
 return password;
}

/**
 * Store new User password
 *
 * @param value The password to set.
 */
public void setPassword(String value) {
 password = value;
}

}

package net.roseindia;
import com.opensymphony.xwork2.ActionSupport;
import java.util.Date;
import java.sql.*;

/**
* Validate a user login. 
*/
public class insert extends ActionSupport {

 public String execute() throws Exception {
String url = "jdbc:mysql://localhost:3306/";
String dbName = "taskproject";
String driverName = "org.gjt.mm.mysql.Driver";
String userName = "root";
String password = "root";
Connection con=null;
Statement stmt=null;
try{
 Class.forName(driverName).newInstance();
 con=DriverManager.getConnection(url+dbName, userName,
 password);
 stmt=con.createStatement();
}
catch(Exception e){
 System.out.println(e.getMessage());
}
String uname=getUsername();
String pws=getPassword();
stmt = con.createStatement();
 int val = stmt.executeUpdate("INSERT employee VALUES
 ('"+uname+"','"+pws+"')");
if(val == 0){
 return ERROR;
}
else{
 return SUCCESS;
}
 }
 // ---- Username property ----

/**
 * Field to store User username.
 * 
 */
private String username = null;

/**
 * Provide User username.
 *
 * @return Returns the User username.
 */
public String getUsername() {
 return username;
}

/**
 * Store new User username
 *
 * @param value The username to set.
 */
public void setUsername(String value) {
 username = value;
}

// ---- Username property ----

/**
 * Field to store User password.
 * 
 */
private String password = null;

/**
 * Provide User password.
 *
 * @return Returns the User password.
 */
public String getPassword() {
 return password;
}

/**
 * Store new User password
 *
 * @param value The password to set.
 */
public void setPassword(String value) {
 password = value;
}

}

代码的描述 :

Connection :

这是java.sql包中的一个接口,通过指定的数据库像MySQL, Ms-Access, Oracle等和java文件建立连接.SQL语句执行于Connection接口的上下文中.

Class.forName(String driver):

该方法是static的.它试图动态加载类并返回类实例.当它匹配类的指定string时,它获得String类型值(driver).

DriverManager:

它是java.sql包中的一个类,管理一系列JDBC的驱动.每个驱动都通过该类注册.

getConnection(String url, String userName, String password):

该方法通过指定的数据库url建立数据库连接.它需要三个String类型的参数如 :

url: - 需要连接的数据库url

userName: - 数据库用户名

password: - 数据库密码

con.close():

该方法用来断开连接.它释放了数据库占用的所有资源.

第四步 : 创建验证器.

验证文件的格式应该是<ActionClassName>-validation.xml或<ActionClassName>-<ActionAliasName>-validation.xml.

insert-validation.xml

Xml代码
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE validators PUBLIC
 "-//OpenSymphony Group//XWork Validator 1.0.2//EN"
 "http://www.opensymphony.com/xwork/xwork-validator-1.0.2.dtd">

<validators>
 <field name="username">
<field-validator type="requiredstring">
 <param name="trim">true</param>
 <message>User name is required</message>
</field-validator>
 </field>
 <field name="password">
<field-validator type="requiredstring">
 <param name="trim">true</param>
 <message>Password is required</message>
</field-validator>
 </field>
</validators>

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE validators PUBLIC
 "-//OpenSymphony Group//XWork Validator 1.0.2//EN"
 "http://www.opensymphony.com/xwork/xwork-validator-1.0.2.dtd">

<validators>
 <field name="username">
<field-validator type="requiredstring">
 <param name="trim">true</param>
 <message>User name is required</message>
</field-validator>
 </field>
 <field name="password">
<field-validator type="requiredstring">
 <param name="trim">true</param>
 <message>Password is required</message>
</field-validator>
 </field>
</validators>

当在文本域中输入正确的数据后,用户将在insertSuccess.jsp页面得到输入的数据.

insertSuccess.jsp

Html代码
<html>

<head>

<title>Inserted Data List</title>

</head>

<body>
 Inserted Data: 
User name = <%=request.getParameter("username") %>!
Password = <%=request.getParameter("password") %>!
</body>

</html>

<html>

<head>

<title>Inserted Data List</title>

</head>

<body>
 Inserted Data: 
User name = <%=request.getParameter("username") %>!
Password = <%=request.getParameter("password") %>!
</body>

</html>

输出 :

当程序执行时用户得到如下页面 :

不填写任何字段并点击"Save"按钮,你将得到如下输出页面 :

如果你只输入"Password"并不输入其它字段并点击"Save"按钮,你将得到该输出页面 :

如果你只输入"User Name"并不输入其它字段并点击"Save"按钮,你将得到该输出页面 :