java web: 简单登录页面-java-火龙果软件工程

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java web: 简单登录页面

作者：哲人善思来源：博客园发布于 2015-11-10

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第一次接触java web开发，花费了一天半的时间，写了个简单的登录页面，以此文为记。

开发工具

Eclipse Luna Release (4.4.0) 已集成maven，maven目前的体会就是管理各种依赖

jetty为maven提供的一个插件，类似tomcat

struts2框架，MVC，action，jsp

mysql server 5.6

开发过程

1. 新建Maven web工程

Group Id: org.apache.maven.archetypes

Artifact Id: maven-archetype-webapp

2. 使用maven添加依赖及插件

在pom.xml的<dependencies></dependencies>间添加，或者是右键工程选择Maven->Add Dependency

jsp页面支持

<dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>servlet-api</artifactId>
    <version>2.5</version>
    <scope>provided</scope>
</dependency>

struts2

<dependency>
    <groupId>org.apache.struts</groupId>
    <artifactId>struts2-core</artifactId>
    <version>2.3.

mysql connector

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.31</version>
</dependency>

jetty

为插件，在<plugins></plugins>间添加，或者是右键工程选择Maven->Add Plugin，接着在pom.xml中写配置

<plugin>
    <groupId>org.mortbay.jetty</groupId>
    <artifactId>maven-jetty-plugin</artifactId>
    <version>6.1.10</version>
    
    <configuration>
        <scanIntervalSeconds>10</scanIntervalSeconds>
        <stopKey>foo</stopKey>
        <stopPort>9999</stopPort>
    </configuration>
                
    <executions>
        <execution>
            <id>start-jetty</id>
            <phase>pre-integration-test</phase>
            <goals>
                <goal>run</goal>
            </goals>
            
            <configuration>
                <scanIntervalSeconds>0</scanIntervalSeconds>
                <daemon>true</daemon>
            </configuration>
        </execution>
        
        <execution>
            <id>stop-jetty</id>
            <phase>post-integration-test</phase>
            <goals>
                <goal>stop</goal>
            </goals>
        </execution>
    </executions>
</plugin>

编译源码的插件

<plugin>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>2.3.2</version>
    
    <configuration>
        <source>1.6</source>
        <target>1.6</target>
    </configuration>
</plugin>

注意plugin的层次

<build>
    <plugins>
    <plugin>...</plugin>
    </plugins>
</build>

3. maven命令行

网上搜索资料，得知命令mvn jetty:run，可以启动jetty。

请教杨学长后，知道在Eclipse中，右键工程，选择run as中的run configurations，打开界面如下

红框部分，即是maven命令输入的地方，如jetty:run

4. struts2框架开发登录页面

4.1 web.xml中添加struts2过滤器

<filter>
    <filter-name>struts2</filter-name>
    <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
</filter>

<filter-mapping>
<filter-name>struts2</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>

4.2 struts.xml中添加action

<package name="struts2demo" namespace="/" extends="struts-default">
    <action name="Login">
        <result>login.jsp</result> 
    </action>
    
    <action name="Welcome" class="struts2demo.WelcomeUserAction">
        <result name="SUCCESS">welcome_user.jsp</result>
        <result name="ERROR">error.jsp</result>
    </action>
</package>

4.3 MVC

V->login.jsp

<%@ page contentType="text/html; charset=UTF-8"%>
<%@ taglib prefix="s" uri="/struts-tags"%>

M->WelcomeUserAction.java

package struts2demo;

import java.sql.*;

public class WelcomeUserAction {
//<s:textfield name="username"> you can get it from <s:property value="username">
private String username;
private String password;

//get and set method for struts2 fill in
//Username is the label name
public String getUsername() {
return username;
}

public void setUsername(String username) {
this.username = username;
}

public String getPassword() {
return password;
}

public void setPassword(String password) {
this.password = password;
}

//"all struts logic here"
public String execute() {
//
try {
Class.forName("com.mysql.jdbc.Driver");
//System.out.println("Success loading Mysql Driver!");
}
catch (Exception e) {
//System.out.println("Error loading Mysql Driver!");
e.printStackTrace();
}

//
try {
Connection connect = DriverManager.getConnection("jdbc:mysql://localhost:3306/zrss", "root", "1234");

String sql = "select * from user where name = ?";
PreparedStatement ps = connect.prepareStatement(sql);
ps.setString(1, username);
ResultSet rs = ps.executeQuery();

while (rs.next()) {
if (rs.getString("password").equals(password)) {
return "SUCCESS";
}
}
}
catch (Exception e) {
e.printStackTrace();
}

return "ERROR";
}
}

C->forward to SUCCESS(welcome_user.jsp) or ERROR(error.jsp)

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