Java五大框架

2017-6-13 
Lifusen 此文章仅代表个人观点，如有问题提出请联系Q:570429601
1、Hibernate （开放源代码的对象关系映射框架） 
Hibernate是一个开放源代码的对象关系映射框架，它对JDBC进行了非常轻量级的对象封装，它将POJO与数据库表建立映射关系，是一个全自动的orm框架，hibernate可以自动生成SQL语句，自动执行，使得Java程序员可以随心所欲的使用对象编程思维来操纵数据库。 Hibernate可以应用在任何使用JDBC的场合，既可以在Java的客户端程序使用，也可以在Servlet/JSP的Web应用中使用，最具革命意义的是，Hibernate可以在应用EJB的J2EE架构中取代CMP，完成数据持久化的重任。
！（Hibernate默认用的是slf4j-nop.jar日志实现方式。
但是我们可以替换成log4j的实现。但不是简单的加上log4j-1.2.17.jar就行了。
中间还需要一个转换器slf4j-log4j12-1.5.8.jar）
1.在src目录下创建hibernate.cfg.xml配置文件（文件名字不能修改）
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC 
"-//Hibernate/Hibernate Configuration DTD 3.0//EN" 
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>

<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="connection.url">jdbc:mysql://localhost:3306/sampe_h5_db</property>
<property name="connection.username">root</property>
<property name="connection.password">root</property>
<!-- 为Hibernate指定不同数据库的方言 -->
<property name="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</property>

<property name="hibernate.show_sql">true</property>
<property name="hibernate.format_sql">true</property>

<mapping class="sample.h5.entity.User" />

　　　　<!-- create and update the database automaticlly -->
<property name="hbm2ddl.auto">update</property>

<!-- javax.persistence.validation.mode默认情况下是auto的，就是说如果不设置的话它是会自动去你的classpath下面找一个
bean-validation**包，但是找不到，所以beanvalitionFactory错误 -->
<property name="javax.persistence.validation.mode">none</property>

</session-factory>
</hibernate-configuration>

注意： hibernate.hbm2ddl.auto属性不要乱用，也可以不用
(1)<property name="hibernate.hbm2ddl.auto"> create-drop </property>

create-drop:表示在hebarinate初始化时创建表格,程序运行结束的时候会删除相应的表格，在实际项目中不用

(2)<property name="hibernate.hbm2ddl.auto">create</property>

在hibernate初始化时会创建表格，在运行结束之后不删除表格，而是在下一次运行的时候如果有旧的删掉，没有旧的，重新建表格

(3)<property name="hibernate.hbm2ddl.auto">update</property>

只是根据映射文件去和数据库中的表对应起来，如果不一致，就更新表的结构

(4)<property name="hibernate.hbm2ddl.auto">validate</property>

校验映射文件和数据库中的表是不是能对应起来，不能对应报错，实际中常用

最后一条javax.persistence.validation.mode可以不用，
加上<mapping class="sample.h5.entity.User" />
------------------------------------------------------------------------------------------------------------------------------------------
@Entity
@Table(name="tbl_book")
public class Book {

@Id @GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(name="bid")
private Integer id;

@Column(name="btitle")
private String title;

@ManyToOne    
@JoinColumn(name="bcategoryid")
private Category category;

category---    @OneToMany(mappedBy="category")    
private Set<Book> books;

@Column(name="otime")
@Temporal(TemporalType.TIMESTAMP)
private Date time;

@OneToMany(cascade=CascadeType.ALL,fetch=FetchType.EAGER, mappedBy="order")级联，紧急加载
private Set<OrderItem> items = new HashSet<OrderItem>();

//组件注解：使用Embedded注解说明，我要使用ZhangHao（组件类）类中的属性来匹配表中的列（数据库没有实体对应）
@Embedded
@AttributeOverrides({
@AttributeOverride(name="username", column=@Column(name="uloginid")),
@AttributeOverride(name="password", column=@Column(name="uloginpsw"))
})
private ZhangHao zhaoHao;

@ElementCollection(fetch=FetchType.EAGER) // 将所有集合的默认抓取策略（fetch），LAZY（延迟加载）设置成EAGER（紧急加载）
@CollectionTable(name="tbl_tel", joinColumns=@JoinColumn(name="tuid"))
@Column(name="tphone")    
@SortNatural
private SortedSet<String> phones = new TreeSet<String>();

@ElementCollection(fetch=FetchType.EAGER)
@CollectionTable(name="tbl_score", joinColumns=@JoinColumn(name="suid"))
@MapKeyColumn(name="scourse")
@Column(name="sscore")
@SortNatural

@ElementCollection(fetch=FetchType.EAGER)
@CollectionTable(name="tbl_recieve", joinColumns=@JoinColumn(name="ruid"))
@MapKeyColumn(name="rname")    
@OrderBy(clause="rid")
private Map<String, Recieve> recieves = new HashMap<String, Recieve>();
private Map<String, Integer> scores = new HashMap<String, Integer>();

@Column(name="uregistDate", updatable=false)
// 日期时间类型的注解
@Temporal(TemporalType.DATE)
private Date registDate;

// 计算列：该注解修饰的字段（count）是根据注解指定的语句查询计算出来的值，并不存在一个叫做count的列在表中
@Formula("(select count(*) from tbl_user)")
private Integer count;

// 瞬时属性的注解：表示Hibernate忽略该属性
@Transient
private String other;

hql
// 查询出一组或一个实体对象
//List<Book> list = session.createQuery("from Book b where b.title = '西游记'").list();
查出单个的对象（值）
//Object result = session.createQuery("select avg(b.price) from Book b").uniqueResult();
// hql的更新和修改
//int row = session.createQuery("update Book b set b.price = b.price * 0.8").executeUpdate();    
//System.out.println("修改了" + row +"本书的价格！");

int pageSize = 2;
int pageNO = 1;
List<Book> list = session.createQuery("from Book b where b.price >= :price")
.setParameter("price", 30.0)
.setFirstResult((pageNO-1) * pageSize)
.setMaxResults(pageSize)
.list();
//String hql = "from Book b where b.title <> '西游记' and b.price >= 50 ";
//String hql = "from Book b where b.title like '%记%'";
//String hql = "from Book b where b.price between 40 and 80";
//String hql = "from Book b where b.author in ('吴承恩', '司马迁')";
//String hql = "from Book b where b.category is not null";
//String hql = "select b from Book b, Category c where b.category = c";
//String hql = "select b.id, b.title, b.price from Book b";
//String hql = "select new list(b.id, b.title, b.price) from Book b";
//String hql = "select new map(b.id as ID, b.title as 标题, b.price as 价格) from Book b";
//String hql = "select new Book(b.id, b.title, b.price) from Book b";
//String hql = "from Book b where b.category.name = '历史'";
//String hql = "select b from Book b left join b.category c where c.name = '历史' ";
//String hql = "select distinct c from Category c left join fetch c.books b where b.price < 30.0";
//String hql = "select c from Category c where size(c.books) > 0 order by c.id";
String hql = "select new map(b.category.name as 分类, count(b) as 图书本数, avg(b.price) as 图书平均售价) from Book b group by b.category having avg(b.price) >= 40.0 order by 图书平均售价 desc";

List<Map> list = session.createQuery(hql).list();
/*
List<Order> orders = session.createCriteria(Order.class)
.add(Restrictions.ge("money", 300.0))
.setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY)
.list();
*/

连接池
hibernate.cfg.xml
<property name="hibernate.c3p0.min_size">5</property><!-- 连接池中最小连接数 -->    
<property name="hibernate.c3p0.max_size">20</property><!-- 连接池中最大连接数 -->    
<property name="hibernate.c3p0.timeout">120</property><!-- 设定数据库连接超时时间，以秒为单位。如果连接池中某个数据库连接处于空闲状态且超过timeout秒时，就会从连接池中移除-->    
<property name="hibernate.c3p0.idle_test_period">3000</property>

<property name="hibernate.cache.region.factory_class">org.hibernate.cache.ehcache.EhCacheRegionFactory</property>
<property name="hibernate.cache.use_second_level_cache">true</property>
<property name="hibernate.cache.use_query_cache">true</property>
ehcache.xml
<?xml version="1.0" encoding="UTF-8"?>
<ehcache xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../config/ehcache.xsd">

<diskStore path="D:ehcacheData"/>


<defaultCache
maxElementsInMemory="1000"
eternal="false"
overflowToDisk="true"
diskPersistent="true"
timeToIdleSeconds="120"
timeToLiveSeconds="240"
maxElementsOnDisk="10000000"
diskExpiryThreadIntervalSeconds="120"
memoryStoreEvictionPolicy="LRU">
</defaultCache>
</ehcache>

存储过程
// 创建了一个存储过程 调用器对象
ProcedureCall call = session.createStoredProcedureCall("getOrderDetails");
call.registerParameter("m", Double.class, ParameterMode.IN).bindValue(300.0);
call.registerParameter("c", Long.class, ParameterMode.OUT);

ProcedureOutputs outputs = call.getOutputs();

// 从存储过程的输出的对象组中，获取输出参数的值
Long count = (Long) outputs.getOutputParameterValue("c");

// 从存储过程的输出的对象组中获取结果集类型的输出结果
ResultSetOutput output = (ResultSetOutput) outputs.getCurrent();
// 从结果集类型的输出结果中，获取数据列表
List<Object[]> orderinfos = output.getResultList();


System.out.println("下单顾客	下单次数	总消费额");
for(Object[] orderinfo : orderinfos) {
System.out.println(orderinfo[0] + "	" + orderinfo[1] + "	" + orderinfo[2]);
}
System.out.println("
订单金额在200以上的订单数量是：" + count );
}
命名查询
// 调用session的创建命名查询对象的方法：createNamedQuery
List<Order> orders = session.createNamedQuery("getOrdersByMoney", Order.class)
.setParameter("minMoney", 300.0)
.list();

for(Order o : orders) {
System.out.println(o.getId() + ", " + o.getCustomer() + ", " + o.getMoney() + ", " + o.getTime() + ", " + o.getItems());
}
}
存储过程2
@Test
public void testSencodLevelCache() {
Category c1 = session.get(Category.class, 1);
System.out.println(c1.getId() +", " + c1.getName());

session.createQuery("from Category c").setCacheable(true).list();
}

@Test
public void testSencodLevelCache2() {
Category c1 = session.get(Category.class, 1);
System.out.println(c1.getId() +", " + c1.getName());
session.createQuery("from Category c").setCacheable(true).list();
}
二级缓存
List<Book> list = session.createQuery("from Book b left join fetch b.category").list();
for(Book elem : list) {
System.out.println(elem);
}
List<Category> list2 = session.createQuery("select distinct c from Category c left join fetch c.books").list();
for(Category elem : list2) {
System.out.println(elem);
}
总结：

1、一级缓存是session级别的，二级缓存和查询缓存都是sessionfactory级别的，查询缓存和二级缓存是一起来使用的

2、任何sql执行都会存入到同一个session的一级缓存中去

3、同时开启查询缓存和二级缓存，可以在不同session间共享缓存的结果

4、二级缓存缓存的是实体，不是属性

5、查询缓存的结果如果只是属性，那么查询缓存中存储的是id和属性的值，如果是实体的集合，那么查询缓存存储的只是实体的id，对应的实体会存储到二级缓存中去。

6、不同session间返回数据的顺序是，二级缓存先将数据返回，然后将数据存入本session的一级缓存中去，以便下次调用时的使用


2、Struts2:Struts2是一个基于MVC设计模式的Web应用框架，它本质上相当于一个servlet，在MVC设计模式中，Struts2作为控制器(Controller)来建立模型与视图的数据交互。Struts 2是Struts的下一代产品，是在 struts 1和WebWork的技术基础上进行了合并的全新的Struts 2框架。其全新的Struts 2的体系结构与Struts 1的体系结构差别巨大。Struts 2以WebWork为核心，采用拦截器的机制来处理用户的请求，这样的设计也使得业务逻辑控制器能够与ServletAPI完全脱离开，所以Struts 2可以理解为WebWork的更新产品。虽然从Struts 1到Struts 2有着太大的变化，但是相对于WebWork，Struts 2的变化很小。
1. web.xml
<filter>
<filter-name>struts2-filter</filter-name>
<filter-class>org.apache.struts2.dispatcher.filter.StrutsPrepareAndExecuteFilter</filter-class> 
</filter>
<filter-mapping>
<filter-name>struts2-filter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>

如果你的Action类没有继承ActionSupport，而你又没有在struts.xml中对应<action>标签中用method属性指定你自己的方法的话，
默认就要找execute方法，这时是必须要实现execute方法的，否则Struts2会找不到对应的方法而报错。
src下面struts.xml
<struts>

<!-- 配置的是全局的国际化资源包的基础包名 -->
<constant name="struts.custom.i18n.resources" value="myRes" />

<!-- 配置常量：struts.devMode是控制是否启用开发模式 -->
<constant name="struts.devMode" value="false" />

<constant name="struts.i18n.encoding" value="UTF-8" />

<constant name="struts.ognl.allowStaticMethodAccess" value="true"></constant>    

<include file="struts-user.xml" />

<package name="default" extends="struts-default">


<!-- 指定当前包中的默认处理器为notFound处理器：当请求到当前包中时，没有匹配到对应的action，则执行该默认action
<default-action-ref name="notFound" />
-->
<action name="notFound">
<result>/WEB-INF/jsp/not-found.jsp</result>
</action>

</package>

</struts>

struts-user.xml
<package name="zjp" extends="struts-default" namespace="/">

<!-- 全局（包范围）结果定义 -->
<global-results>
<result name="ex">/WEB-INF/jsp/errorHandle.jsp</result>
</global-results>

<!-- 全局（包范围）“异常映射”定义 -->
<global-exception-mappings>
<exception-mapping result="ex" exception="java.lang.Exception" />
</global-exception-mappings>

<action name="userLoginForm" class="sample.s2.web.action.UserAction"
method="loginForm">
<result name="success" type="dispatcher">
<param name="location">/WEB-INF/jsp/login.jsp</param>    
</result>
</action>

<action name="userLogin" class="sample.s2.web.action.UserAction"
method="login">
<result name="success" type="redirectAction">userHome</result>
<result name="error" type="chain">userLoginForm</result>
</action>

<action name="userHome" class="sample.s2.web.action.UserAction"
method="home">
<result>/WEB-INF/jsp/home.jsp</result>
</action>

<action name="userRegistForm" class="sample.s2.web.action.UserAction"
method="registForm">    
<result>/WEB-INF/jsp/regist.jsp</result>    
</action>

<action name="userRegist" class="sample.s2.web.action.UserAction" method="regist">    
<result type="chain">userRegistForm</result>    
</action>

</package>

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

<global-results>
<result name="ex">/WEB-INF/jsp/errorHandle.jsp</result>
</global-results>

<global-exception-mappings>
<exception-mapping result="ex" exception="java.lang.Exception" />
</global-exception-mappings>

<action name="adminLoginForm">
<result>/WEB-INF/jsp/mgr/admin-login.jsp</result>
</action>
</package>


<s:debug></s:debug>标签
type------------chain 、dispatcher 、stream 、redirect 、redirectAction 
UserAction 继承ActionSupport
private User u;    有get set 下面有
private Integer id;
private String name;
private Integer age;
private Date birthdate;
private boolean married;
private List<Integer> luckyNumbers; 
private List<Parent> parents;
private List<Game> games;

国际化资源包myRes_zh_CN.properties 、myRes_en_US.properties
<a href="/SampleStruts2/userLoginForm?request_locale=zh_CN">中文</a> | <a href="/SampleStruts2/userLoginForm?request_locale=en_US">English</a>
user.home.header=Hello:{0},Welcome to the site!
<h3><s:text name="user.home.header"><s:param>${currLoginId }</s:param></s:text></h3>
前端：<p><s:text name="user.login.form.label.loginId" /><input type="text" name="u.loginId" value="${loginId }" /></p>
后端：ctx.put("loginErrorMsg", super.getText("user.login.faile"));
服务器异常查看
<%@ taglib prefix="s" uri="/struts-tags"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>服务器异常</title>
<script type="text/javascript">

function showDetails() {
document.getElementById('details').style.display = 'block';
}
</script>
</head>
<body>
<h3>Sorry，服务器出错了，请稍后再试！</h3>
<p><a href="javascript: showDetails();">技术人员，查看详情</a></p>

<div id='details' style="font-size:12px; color: red; display:none;">
<p style="font-size:14px; font-weight: bold;">${ exception }</p>

<s:iterator value="#request.exception.stackTrace">
<p><s:property /></p>
</s:iterator>
</div>
</body>
</html>

传入id转成类
<p>喜欢的游戏：
<s:iterator value="#allGames" var="g">
<input type="checkbox" name="u.games" value="${g.id }" />${g.name }&nbsp;
</s:iterator>
</p>
src下面xwork-conversion.properties
内容sample.s2.entity.Game=sample.s2.web.typeconverter.GameTypeConverter
GameTypeConverter extends StrutsTypeConverter 内容
@Override
public Object convertFromString(Map context, String[] params, Class kls) {
int id = Integer.parseInt(params[0]);
Game game = new Game();
game.setId(id);
return game;
}

@Override
public String convertToString(Map arg0, Object obj) {
Game game = (Game)obj;
return "游戏信息：id=" + game.getId() + ", name=" + game.getName();
}

struths验证 userAction
private User u;    
同包下面userAction_zh_CN.properties
invalid.fieldvalue.u.age=u7528u6237u5E74u9F84u503Cu683Cu5F0Fu9519u8BEFuFF0Cu5FC5u987Bu662Fu4E2Au6574u6570 //年龄格式错误，必须是个整数
invalid.fieldvalue.u.birthdate=u51FAu751Fu65E5u671Fu683Cu5F0Fu9519u8BEFuFF0Cu5E94u8BE5u4F8Bu5982uFF1A1995-01-01 //出生日期格式错误，应该例如：1995-01-01
如果没有就在xwork.default.invalid.fieldvalue=u6570u636Eu7684u683Cu5F0Fu9519u8BEFu201C{0}u201D //数据的格式错误
前端显示<s:property value="[0].fieldErrors" />
格式验证失败返回input

上传文件
<action name="userRegist" class="sample.s2.web.action.UserAction" method="regist">
<interceptor-ref name="fileUpload">
<param name="allowedTypes">image/jpeg, image/png, image/gif</param>
<param name="maximumSize">1024000</param>
</interceptor-ref>
<interceptor-ref name="myDefault"/>
<result name="input" type="chain">userRegistForm</result>    
</action>

userAction_zh_CH.properties
struts.messages.error.uploading=Error uploading: {0}
struts.messages.error.file.too.large=u6587u4EF6{1}u592Au5927u4E86uFF0Cu5FC5u987Bu5C0Fu4E8E {4} u5B57u8282uFF01
struts.messages.error.content.type.not.allowed=u5934u50CFu6587u4EF6u5FC5u987Bu662Fu56FEu7247
struts.messages.error.file.extension.not.allowed=File extension not allowed: {0} "{1}" "{2}" {3}


private File face;    
if(face != null) {
System.out.println("face: " + face);

System.out.println("faceContentType: " + faceContentType);
/* 获取相对网站根路径的相应的磁盘路径 */
String realPath = ServletActionContext.getServletContext().getRealPath("/upload/" + faceFileName);
try {
FileUtils.copyFile(face, new File(realPath));
} catch (IOException e) {
e.printStackTrace();
}
} else {
System.out.println("用户未上传头像");

强加验证
UserAction-userRegist-validation.xml
<field name="u.age">
<field-validator type="required">
<message>年龄必填</message>
</field-validator>
<field-validator type="int">
<param name="min">18</param>
<param name="max">40</param>
<message>年龄必须在18到40岁之间</message>
</field-validator>
</field>

<field name="u.birthdate">
<field-validator type="required">
<param name="trim">true</param>
<message>出生日期不能为空</message>
</field-validator>
</field>

</validators>
前端
<s:property value="[1].fieldErrors['u.birthdate'][0]" />
自定义验证类型
src validators.xml
<validators>
<validator name="zip" class="sample.s2.web.validator.ZipValidator" />
</validators>

class
public class ZipValidator extends FieldValidatorSupport {

@Override
public void validate(Object action) throws ValidationException {
String fieldName = super.getFieldName(); // "zip"
String fieldValue = (String) super.getFieldValue(fieldName, action); // "610000"
if(fieldValue != null && !fieldValue.equals("")) {
System.out.println("fieldName: " + fieldValue);
System.out.println("fieldValue: " + fieldValue);
if(!Pattern.matches("^\d{6}$", fieldValue)) {
super.addFieldError(fieldName, action);
}
}
}

}

UserAction-userRegist-validation.xml
<field name="zip">
<field-validator type="zip">    
<message>邮政编码格式错误！</message>
</field-validator>
</field>

拦截器
<!-- 声明拦截器 -->
<interceptors>
<interceptor name="sample" class="sample.s2.web.interceptor.SampleInterceptor" />
<interceptor name="log" class="sample.s2.web.interceptor.LogInterceptor">
<param name="datePattern">yyyy年MM月dd日 HH点mm分ss秒</param>
</interceptor>
<interceptor-stack name="myDefault">
<interceptor-ref name="log" />
<interceptor-ref name="defaultStack" />
</interceptor-stack>
</interceptors>

<!-- 配置默认拦截器引用： 该包下的所有未直接配置拦截器引用的action，都使用myDefault这个拦截器栈 -->
<default-interceptor-ref name="myDefault" />

文件下载
<action name="download" class="sample.s2.web.action.ResourceAction" method="download">
<result name="success" type="stream">
<param name="inputName">is</param>
<param name="contentType">${contentType}</param>
<param name="contentDisposition">attchement;filename=${fileName}</param>
<param name="bufferSize">4096</param>
</result>
</action>

private Integer rid;

private InputStream is;
private String fileName;
private String contentType; //get set
public String download() throws UnsupportedEncodingException {

System.out.println("download... rid: " + rid);
if(rid == 1001) {
// 想下载/WEB-INF/resources/bbs_gd.doc
this.is = ServletActionContext.getServletContext().getResourceAsStream("/WEB-INF/resources/bbs_gd.doc");
this.fileName = URLEncoder.encode("bbs设计文档.doc", "utf-8");
System.out.println("fileName encode: " + this.fileName);
System.out.println("fileName decode: " + URLDecoder.decode(this.fileName, "UTF-8"));
this.contentType="application/msword";
} else if(rid == 1002) {
// 想下载10.jpg
this.is = ServletActionContext.getServletContext().getResourceAsStream("/WEB-INF/resources/10.jpg");
this.fileName = "10.jpg";
this.contentType = "image/jpeg";
}
// ActionContext.getContext().put("downloadError", "下载失败：必须是登录用户才能下载，现在马上<a href='#'>去登录</a>。");
return SUCCESS;
}

private InputStream fengJingInputName;

@Override
public String execute() throws Exception {

this.fengJingInputName = ServletActionContext.getServletContext().getResourceAsStream("/WEB-INF/resources/Ajax：2.avi");
return SUCCESS;
}

<action name="downloadFengJing" class="sample.s2.web.action.DownloadFengJingAction">
<!-- 启用拦截器：为当前处理器 -->
<interceptor-ref name="sample" />    
<interceptor-ref name="myDefault" />
<result type="stream">
<param name="inputName">fengJingInputName</param>
<param name="contentDisposition">attchement;filename=Ajax：2.avi</param>
</result>
</action>

权限验证
<package name="management" extends="json-default" namespace="/mgr">
<interceptors>
<!-- 声明“权限验证”拦截器 -->
<interceptor name="authority" class="sample.s2.web.interceptor.mgr.AuthorityInterceptor">
<param name="excludeMethods">loginForm,loginCheck</param>
</interceptor>

<!-- 声明“后台管理默认拦截器栈” -->
<interceptor-stack name="mgrDefaultStack">
<interceptor-ref name="authority" />
<interceptor-ref name="defaultStack" />
</interceptor-stack>
</interceptors>

AuthorityInterceptor.java

@SuppressWarnings("serial")
public class AuthorityInterceptor extends MethodFilterInterceptor {

@Override
protected String doIntercept(ActionInvocation invocation) throws Exception {    
ActionContext ctx = invocation.getInvocationContext();
if(ctx.getSession().get("currAdmin") == null) {
ctx.put("tip", "请先登录，再进行其他操作！");
return "login";
} else {
return invocation.invoke();
}    
}

}
<action name="getRandom" class="sample.s2.web.action.mgr.DemoAjaxAction" method="getRandom">
<result type="stream">
<param name="inputName">bais</param>
<param name="contentType">text/html;charset=UTF-8</param>
</result>
</action>
action name="getAllAdmins" class="sample.s2.web.action.mgr.DemoAjaxAction" method="getAllAdmins">
<result type="json">
<param name="root">admins</param>
<param name="contentType">application/json;charset=UTF-8</param>
</result>
</action>

private String type;    
private InputStream bais; 
private List<Admin> admins;

public String getRandom() throws Exception {

int offset = type.equals("small") ? 0 : 5;

String r = (int)(Math.random() * 5) + offset + "";    // "9"



bais = new ByteArrayInputStream(r.getBytes("utf-8"));

return SUCCESS;
}

public String getAllAdmins() {
admins = adminService.getAdmins();
return SUCCESS;
}

$(function(){

$.get("/SampleStruts2/mgr/getRandom", {"type" : "small"}, function(data){    
$("#num").text(data);    
});

$.getJSON("/SampleStruts2/mgr/getAllAdmins", function(data){
alert(data.length);    
});

});


3、Spring是一个开源框架，Spring是于2003 年兴起的一个轻量级的Java 开发框架，由Rod Johnson创建。
简单来说，Spring是一个分层的JavaSE/EEfull-stack(一站式) 轻量级开源框架。
src下面 applicationContext.xml
<bean id="inkPrinter" class="demo.spring4.bean.InkPrinter" />

<bean id="lesserPrinter" class="demo.spring4.bean.LesserPrinter" />

<bean id="computer" class="demo.spring4.bean.Computer">
<property name="printer" ref="lesserPrinter" />
</bean>

<bean id="zwj" class="demo.spring4.bean.Student" scope="prototype">
<property name="name" value="张无忌" />
<property name="age" value="23" />
<property name="birthdate">
<bean class="java.util.Date" />
</property>
<property name="lover" ref="zm" />
<property name="loveBooks">
<list>
<value>西游记</value>
<value>水浒传</value>
<value>三国演义</value>
<value>红楼梦</value>
</list>
</property>
<property name="scores">
<map>
<entry key="HTML" value="95" />
<entry key="JSP" value="87" />
<entry key="JavaBasic" value="91" />
</map>
</property>
<property name="healthPoster">
<props>
<prop key="height">1.81</prop>
<prop key="weight">82</prop>
</props>
</property>
</bean>

<bean id="zm" class="demo.spring4.bean.Student">
<constructor-arg index="0" value="赵敏" />
<constructor-arg index="1" value="22" />    
<property name="birthdate" ref="now" /><!-- ref属性代表引用了容器中的其他Bean的ID -->
</bean>

<bean id="now" class="java.util.Date" />

src test.properties
# a common properties file
name=u5F20u4E09
age=23
sex=male
height=1.79

public void testProperties() {
/*
Properties props = System.getProperties();
for(Object key : props.keySet()) {
System.out.println(key + " = " + props.get(key));
}
*/

Properties props = new Properties();
try {
props.load(new InputStreamReader(Spring4Test.class.getResourceAsStream("/test.properties"), "UTF-8"));
System.out.println(props);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

ApplicationContext context = new ClassPathXmlApplicationContext("/applicationContext.xml");
System.out.println("-- ApplicationContext 已经创建完成 -----------------------------
");

context.getBean("zwj");
context.getBean("zwj");
ApplicationContext context = new ClassPathXmlApplicationContext("/applicationContext.xml");
System.out.println("-- ApplicationContext 已经创建完成 -----------------------------
");

context.getBean("zwj");
context.getBean("zwj");

4、Spring MVC属于SpringFrameWork的后续产品，已经融合在Spring Web Flow里面。Spring 框架提供了构建 Web 应用程序的全功能 MVC 模块。使用 Spring 可插入的 MVC 架构，
从而在使用Spring进行WEB开发时，可以选择使用Spring的SpringMVC框架或集成其他MVC开发框架，如Struts1，Struts2等。
WEB-INF下面
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">

<servlet>
<servlet-name>springmvc</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:/springmvc-servlet.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>

<servlet-mapping>
<servlet-name>springmvc</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>

</web-app>

src下面    springmvc-servlet.xml
<context:component-scan base-package="demo.springmvc.web.controller" />

<mvc:annotation-driven />

<!-- 防止无法正确访问静态资源 -->
<mvc:default-servlet-handler/>

<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/jsp/" />
<property name="suffix" value=".jsp" />
</bean>

controller页面
@Controller
@RequestMapping("/mvc")
public class mvcController { //类上面
　　@Controller 负责注册一个bean 到spring 上下文中

　　@RequestMapping 注解为控制器指定可以处理哪些 URL 请求
Date类型转
//the parameter was converted in initBinder
@RequestMapping("/date")
public String date(Date date){
System.out.println(date);
return "hello";
}

//At the time of initialization,convert the type "String" to type "date"
@InitBinder
public void initBinder(ServletRequestDataBinder binder){
binder.registerCustomEditor(Date.class, new CustomDateEditor(new SimpleDateFormat("yyyy-MM-dd"),
true));
}

//pass the parameters to front-end
@RequestMapping("/show")
public String showPerson(Map<String,Object> map){
Person p =new Person();
map.put("p", p);
p.setAge(20);
p.setName("jayjay");
return "show";
}
　　前台可在Request域中取到"p"

//pass the parameters to front-end using ajax
@RequestMapping("/getPerson")
public void getPerson(String name,PrintWriter pw){
pw.write("hello,"+name); 
}
@RequestMapping("/name")
public String sayHello(){
return "name";
}
　　前台用下面的Jquery代码调用


$(function(){
$("#btn").click(function(){
$.post("mvc/getPerson",{name:$("#name").val()},function(data){
alert(data);
});
});
});

//redirect 
@RequestMapping("/redirect")
public String redirect(){
return "redirect:hello";
}