学习笔记 --Spring 框架

//概述

轻量级，一站式，开发框架

IoC，Inversion of Control，控制反转

DI，Dependency Injection，依赖注入

AOP，Aspect-Oriented Programming，面向切面编程：业务逻辑与非业务逻辑分离，如日志、安全...

IoC 容器：

对象创建、装配

对象生命周期管理

上下文环境

//IoC 容器

IoC = ApplicationContext (org.springframework.context, spring-context)

初始化

ApplicationContext context = new ClassPathXmlApplicationContext("application-context.xml");

或

ApplicationContext context = new FileSystemXmlApplicationContext("/home/user/conf/application-context.xml");

或在 web.xml 中

<context-param>
	<param-name>contextConfigLocation</param-name>
	<param-value>classpath:application-context.xml</param-value>
</context-param>

<listener>
	<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>

Bean 定义

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
	xmlns:p="http://www.springframework.org/schema/p"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
	http://www.springframework.org/schema/beans/spring-beans.xsd
	http://www.springframework.org/schema/context
	http://www.springframework.org/schema/context/spring-context.xsd">

	<bean id="screwDriver" class="com.netease.course.ScrewDriver"></bean>

</beans>

Bean 使用

//初始化容器

ApplicationContext context = new ClassPathXmlApplicationContext("application-context.xml");

//获取对象

ScrewDriver screwDriver = context.getBean("screwDriver", ScrewDriver.class);

//使用对象

screwDriver.use();

Bean 作用域

singleton，单例

<bean id="screwDriver" class="com.netease.course.ScrewDriver" scope="singleton"></bean>

默认为单例
prototype，每次引用创建一个实例

<bean id="screwDriver" class="com.netease.course.ScrewDriver" scope="prototype"></bean>

request scope, requestBean
session scope, sessionBean
application scope, appBean
global scope

Bean 生命周期回调

创建，申请资源
可以通过实现接口

public interface InitializingBean {
	void afterPropertiesSet() throws Exception;
}

或者直接在 application-context.xml 中配置

<bean id="screwDriver" class="com.netease.course.ScrewDriver" init-method="init"></bean>

对应代码

public class ScrewDriver {
   public void init() {
		System.out.println("Init screwDriver");
   }
}

销毁
可以通过实现接口

public interface DisposableBean {
	void destroy() throws Exception;
}

或者直接在 application-context.xml 中配置

<bean id="screwDriver" class="com.netease.course.ScrewDriver" destroy-method="cleanup"></bean>

对应代码

public class ScrewDriver {
   public void cleanup() {
		System.out.println("Cleanup screwDriver");
   }
}

关闭 Bean

((ConfigurableApplicationContext) context).close();

依赖注入

构造函数，强依赖

Setter 函数，可选依赖

配置 bean 的类的构造函数的参数

 <bean id="straightHeader" class="com.netease.course.StraightHeader">
	  <constructor-arg value="red"></constructor-arg>
	  <constructor-arg value="15"></constructor-arg>
  </bean>

或

<bean id="straightHeader" class="com.netease.course.StraightHeader">
    <constructor-arg index="0" value="red"></constructor-arg>
    <constructor-arg index="1" value="15"></constructor-arg>
</bean>

或

<bean id="straightHeader" class="com.netease.course.StraightHeader">
    <constructor-arg type="java.lang.String" value="red"></constructor-arg>
    <constructor-arg type="int" value="15"></constructor-arg>
</bean>

或

<bean id="straightHeader" class="com.netease.course.StraightHeader">
    <constructor-arg name="color" value="red"></constructor-arg>
    <constructor-arg name="size" value="15"></constructor-arg>
</bean>

需要传递集合类型的构造函数参数（如 map）时

<bean id="straightHeader" class="com.netease.course.StraightHeader">
    <constructor-arg>
        <map>
            <entry key="color" value="red"></entry>
            <entry key="size" value="15"></entry>
        </map>
    </constructor-arg>
    <constructor-arg name="size" value="15"></constructor-arg>
</bean>

传入 list 时

<bean id="straightHeader" class="com.netease.course.StraightHeader">
    <constructor-arg>
        <list>
            <value>red</value>
            <value>15</value>
        </list>
    </constructor-arg>
    <constructor-arg name="size" value="15"></constructor-arg>
</bean>

传入 Properties 时

<bean id="straightHeader" class="com.netease.course.StraightHeader">
    <constructor-arg>
        <props>
            <prop key="color">red</prop>
            <prop key="size">15</prop>
        </props>
    </constructor-arg>
    <constructor-arg name="size" value="15"></constructor-arg>
</bean>

从外部倒入配置时

  <bean id="straightHeader" class="com.netease.course.StraightHeader">
	  <constructor-arg name="color" value="${color}"></constructor-arg>
	  <constructor-arg name="size" value="${size}"></constructor-arg>
  </bean>
  <bean id="headerProperties" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
	<property name="location" value="classpath:header.properties" />
</bean>

在一个 bean 中添加所依赖的 bean

<bean id="screwDriver" class="com.netease.course.ScrewDriver">
    <constructor-arg>
        <ref bean="straightHeader" />
    </constructor-arg>
</bean>

通过 Setter 方法注入依赖

<bean id="straightHeader" class="com.netease.course.StraightHeader">
    <property name="color" value="${color}"></property>
    <property name="size" value="${size}"></property>
</bean>

自动装配

constructor 是按 byType 方式注入

   <bean id="screwDriver" class="com.netease.course.ScrewDriver" autowire="constructor">
	</bean>

或

   <bean id="screwDriver" class="com.netease.course.ScrewDriver" autowire="byName">
	</bean>

或

 <bean id="screwDriver" class="com.netease.course.ScrewDriver" autowire="byType">
  </bean>

Annotation

@Component：定义 Bean，或 @Component("name")

@Value：properties 注入

@Autowired & @Resource：自动装配依赖

@PostConstruct & @PreDestroy：生命周期回调

在 xml 中加入

 <context:component-scan base-package="com.netease.course" />

//AOP 技术

AOP 术语

Aspect：日志、安全等功能

Join point：函数执行或者属性访问

Advice：在某个函数执行点上要执行的切面功能

Pointcut：匹配横切目标函数的表达式

Advice 类型

Before：函数执行之前

After returning：函数正常返回之后

After throwing：函数抛出异常之后

After finally：函数返回之后

Around：函数执行前后

Spring AOP

非完整 AOP 实现

整合 AOP 和与 IoC

XML schema-based AOP

@AspectJ annotation-based AOP

@AspecsJ annotation-based AOP

aspectjweaver.jar

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:aop="http://www.springframework.org/schema/aop"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
	http://www.springframework.org/schema/beans/spring-beans-2.0.xsd
	http://www.springframework.org/schema/aop
	http://www.springframework.org/schema/aop/spring-aop-2.0.xsd">

	<aop:aspectj-autoproxy />

</beans>

定义 Aspect

   <bean id="loggingAspect" class="com.netease.course.LoggingAspect">
		   <!-- configure properties of aspect here as normal -->
   </bean>

相应代码中类名前加入 @Aspect

定义 Pointcut

@Pointcut("execution(* com.netease.course.Calculator.*(..))")

private void arithmetic() {}

Pointcut 表达式

designator(modifiers? return-type declaring-type? name(param) throws?)

designator: execution, within

modifiers: public, private

return-type: 返回类型，*

declaring-type: 包名，类名

name: 函数名，*

param: 参数列表，()无参，(..)任意参数

throws: 异常类型

可以组合

定义 Advice

@Before("com.netease.course.LoggingAspect.arithmetic()")

public void doLog() {

  //

}

或

@Before("execution(* com.netease.course.Calculator.*(..))")

public void doLog() {

    //

}

或

@AfterReturning("com.netease.course.LoggingAspect.arithmetic()")

public void doLog() {

    //

}

或

@AfterThrowing("com.netease.course.LoggingAspect.arithmetic()")

public void doLog() {

    //

}

或

@After("com.netease.course.LoggingAspect.arithmetic()")

public void doLog() {

    //

}

Advice 参数

函数上下文信息

@Before("com.netease.course.LoggingAspect.arithmetic()")

public void doLog(JoinPoint jp) {

    System.out.println(jp.getSignature() + ", " + jp.getArgs());

}

或

@Around("com.netease.course.LoggingAspect.arithmetic()")

public void doLog(ProceedingJoinPoint pjp) {

    System.out.println("start method: " + pjp.toString());

    Object retVal = pjp.proceed();

    System.out.println("stop method: " + pjp.toString());

}

返回值

@AfterReturning(pointcut="com.netease.course.LoggingAspect.arithmetic()"),

                returning="retVal")

public void doLog(Object retVal) {

    //

}

异常

@AfterThrowing(pointcut="com.netease.course.LoggingAspect.arithmetic()"),

               throwing="ex")

public void doLog(IllegalArgumentException ex) {

    //

}

目标函数参数

@Before("com.netease.course.LoggingAspect.arithmetic() && args(a, ..)")

public void doLog(JoinPoint jp, int a) {

    //

}

XML schema-based AOP

定义 Aspect 和 PointCut

 <aop:config>
	 <aop:aspect id="loggingAspect" ref="loggingBean">
		 <aop:pointcut id="arithmetic" expression="execution(* com.netease.course.Calculator.*(..))" />
	 </aop:aspect>
 </aop:config>

定义 Advice

 <aop:config>
	 <aop:aspect id="loggingAspect" ref="loggingBean">
		 <aop:before pointcut-ref="arithmetic" method="doLog" />
	 </aop:aspect>
 </aop:config>

或

 <aop:config>
	 <aop:aspect id="loggingAspect" ref="loggingBean">
		 <aop:before pointcut="execution(* com.netease.course.Calculator.*(..))" method="doLog" />
	 </aop:aspect>
 </aop:config>

或

 <aop:config>
	 <aop:aspect id="loggingAspect" ref="loggingBean">
		 <aop:after-returning pointcut-ref="arithmetic" returning="retVal" method="doLog" />
	 </aop:aspect>
 </aop:config>

或

 <aop:config>
	 <aop:aspect id="loggingAspect" ref="loggingBean">
		 <aop:after-throwing pointcut-ref="arithmetic" throwing="ex" method="doLog" />
	 </aop:aspect>
 </aop:config>

或

   <aop:aspect id="loggingAspect" ref="loggingBean">
       <aop:around pointcut-ref="arithmetic" method="doLog" />
   </aop:aspect>

//数据访问

DAO，Data Access Object

数据访问相关接口

ORM，Object Relation Mapping

对象关系映射

DataSource (javax.sql)

DriverManagerDataSource (org.springframework.jdbc.datasource)

BasicDataSource (org.apache.commons.dbcp)

   <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
	   <property name="driverClassName" value="${jdbc.driverClassName}" />
	   <property name="url" value="${jdbc.url}" />
	   <property name="username" value="${jdbc.username}" />
	   <property name="password" value="${jdbc.password}" />
   </bean>

   <context:property-placeholder location="db.properties" />

JdbcTemplate (org.springframework.jdbc.core)
设置 JdbcTemplate 的数据库配置信息

private JdbcTemplate jdbcTemplate;

@Autowired
public void setDataSource(DataSource dataSource) {
    this.jdbcTemplate = new JdbcTemplate(dataSource);
}

查询操作

    int rowCount = this.jdbcTemplate.queryForObject("select count(*) from user", Integer.class);
    int countOfNamedJoe = this.jdbcTemplate.queryForObject("select count(*) from user where first_name = ?", Integer.class, "Joe");
    String lastName = this.jdbcTemplate.queryForObject("select last_name from user where id = ?", new Object[]{1212L}, String.class);

更改操作

this.jdbcTemplate.update("insert into user (first_name, last_name) values (?, ?)", "Meimei", "Han");
或
this.jdbcTemplate.execute("create table user (id integer, first_name varchar(100), last_name varchar(100))");

对象匹配

    User user = this.jdbcTemplate.queryForObject("select last_name from user where id = ?",
            new Object[]{1212L},
            new RowMapper<User>() {
        public User mapRow(ResultSet rs, int rowNum) throws SQLException {
            User user = new User();
            user.setFirstName(rs.getString("first_name"));
            user.setLastName(rs.getString("last_name"));
            return user;
        }
    });

或

    List<User> users = this.jdbcTemplate.query("select last_name from user where id = ?",
            new Object[]{1212L},
            new RowMapper<User>() {
        public User mapRow(ResultSet rs, int rowNum) throws SQLException {
            User user = new User();
            user.setFirstName(rs.getString("first_name"));
            user.setLastName(rs.getString("last_name"));
            return user;
        }
    });

定义 JdbcTemplate

public class JdbcExampleDao implements ExampleDao {
	private JdbcTemplate jdbcTemplate;
	public void setDataSource(DataSource dataSource) {
		this.jdbcTemplate = new JdbcTemplate(dataSource);
	}
	//...DAO接口实现
}

可以在 xml 中配置相应的 bean
也可以用 annotation 的方法，如下：

@Repository
public class JdbcExampleDao implements ExampleDao {
	private JdbcTemplate jdbcTemplate;
	@Autowired
	public void setDataSource(DataSource dataSource) {
		this.jdbcTemplate = new JdbcTemplate(dataSource);
	}
	//...DAO接口实现
}

NamedParameterJdbcTemplate (org.springframework.jdbc.core)

private NamedParameterJdbcTemplate namedParameterJdbcTemplate;

@Autowired
public void setDataSource(DataSource dataSource) {
    this.namedParameterJdbcTemplate= new NamedParameterJdbcTemplate (dataSource);
}

public int countOfUserByFirstName(String firstName) {
	String sql = "select count(*) from usertest where first_name = :first_name";
	Map<String, String> namedParameters = Collections.singletonMap("first_name", firstName);
	return this.namedParameterJdbcTemplate.queryForObject(sql, namedParameters, Integer.class);
}

其他 api 接口

queryForObject(String sql, Map<String, ?> paramMap, RowMapper<T> rowMapper)
queryForObject(String sql, SqlParameterSource paramSource, Class<T> requiredType)

SqlParameterSource: MapSqlParameterSource, BeanPropertySqlParameterSource (org.springframework.jdbc.core.namedparam)
如：
public int countOfUserByFirstName(User user) {
	String sql = "select count(*) from usertest where first_name = :first_name";
	SqlParameterSource namedParameters = new BeanPropertySqlParameterSource(user);
	return this.namedParameterJdbcTemplate.queryForObject(sql, namedParameters, Integer.class);
}

异常处理

DataAccessException, "unchecked", 是一个基类（org.springframework.dao）

//事务管理

spring 事务管理

统一的事务编程模型，编程式事务及声明式事务（AOP）

public interface PlatformTransactionManager {

	TransactionStatus getTransaction(TransactionDefinition definition) throws TransactionException;

	void commit(TransactionStatus status) throws TransactionException;

	void rollback(TransactionStatus status) throws TransactionException;

}

事务管理器

PlatformTransactionManager (org.springframework.transaction)：

DataSourceTransactionManager (org.springframework.jdbc.datasource), JDBC

HibernateTransactionManager (org.springframework.orm.hibernate), Hibernate

TransactionDefinition

getName：事务名称

getIsolationLevel：隔离级别

getPropagationBehavior：传播行为

getTimeout：超时时间

isReadOnly：是否只读

TransactionStatus

isNewTransaction：是否是新事务

hasSavePoint：是否有 savepoint（诊断，NESTED）

isCompleted：是否完成

isRollbackOnly：事务结果是否是 rollback-only
setRollbackOnly：设置事务为 rollback-only

隔离级别

ISOLATION_READ_UNCOMMITTED：读未提交

ISOLATION_READ_COMMITTED：读提交

ISOLATION_REPEATABLE_READ：重复读

ISOLATION_SERIALIZABLE：串行化

ISOLATION_DEFAULT：默认

传播行为

PROPAGATION_MANDATORY：必须在一个事务中运行，不存在则抛异常

PROPAGATION_NEVER：不应该在事务中运行，存在则抛异常

PROPAGATION_NOT_SUPPORTED：不应该在事务中运行，存在则挂起

PROPAGATION_SUPPORTS：不需要事务，有则在事务中执行

PROPAGATION_REQUIRED：必须在事务中执行，如果不存在，则启动新事务（内部事务会影响外部事务）

PROPAGATION_NESTED：必须在事务中执行，如果不存在，则启动新事务（事务之间互不影响）

PROPAGATION_REQUIRES_NEW：必须在新事务中执行，挂起当前事务（独立 physical 事务）

声明式事务

添加 schema

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"
	xmlns:tx="http://www.springframework.org/schema/tx"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
	http://www.springframework.org/schema/beans/spring-beans-2.0.xsd
	http://www.springframework.org/schema/tx
	http://www.springframework.org/schema/tx/spring-tx.xsd
	http://www.springframework.org/schema/aop
	http://www.springframework.org/schema/aop/spring-aop-2.0.xsd">

定义事务管理器

<bean id="txManager"
    class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
    <property name="dataSource" ref="dataSource" />
</bean>
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
    destroy-method="close">
    <property name="driverClassName" value="${jdbc.driverClassName}" />
    <property name="url" value="${jdbc.url}" />
    <property name="username" value="${jdbc.username}" />
    <property name="password" value="${jdbc.password}" />
</bean>
<context:property-placeholder location="db.properties" />

定义事务 Advice

<tx:advice id="txAdvice" transaction-manager="txManager">
    <tx:attributes>
        <tx:method name="get*" read-only="true" />
        <tx:method name="*" />
    </tx:attributes>
</tx:advice>

定义 Pointcut

<aop:config>
    <aop:pointcut id="daoOperation"
        expression="execution(* com.netease.course.AccountDao.*(..))" />
    <aop:advisor advice-ref="txAdvice" pointcut-ref="daoOperation" />
</aop:config>

配置 <tx:method />

name: 匹配的函数名称，支持*匹配
propagation：事务传播行为
isolation：事务隔离级别
timeout：超时
read-only：是否只读事务
rollback-for：触发回滚的异常，用逗号分隔
no-rollback-for：不触发回滚的异常

采用 annotation 方法
@Transactional
xml 中添加

<tx:annotation-driven transaction-manager="txManager" />

相应代码

@Transactional(propagation=Propagation.REQUIRED, rollbackFor=Exception.class)
public boolean deleteClusterByClusterId(Sring clusterId) {
	// do work
}

@transactional
value：使用的 TransactionManager
propagation：事务传播行为
isolation：事务隔离级别
timeout：超时
readOnly：是否只读
rollbackFor：触发回滚的异常类对象数组
rollbackForClassName：触发回滚的异常类名称数组
noRollbackFor：不触发回滚的异常类对象数组
noRollbackForClassName：不触发回滚的异常类名称数组

编程式事务

定义 TransactionTemplate

public class SimpleService implements Service {
	private final TransactionTemplate transactionTemplate;
	public SimpleService(PlatformTransactionManager transactionManager) {
		this.transactionTemplate = new TransactionTemplate(transactionManager);
		this.transactionTemplate.setIsolationLevel(TransactionDefinition.ISOLATION_READ_UNCOMMITTED);
		this.transactionTemplate.setTimeout(30);
	}
}

使用 TransactionTemplate

public Object someMethod() {
    return transactionTemplate.execute(new TransactionCallback() {
        public Object doInTransaction(TransactionStatus status) {
            updateOperation1();
            return resultOfUpdateOperation2();
        }
    });
}

或（不返回结果）

public Object someMethodWithoutResult() {
    return transactionTemplate.execute(new TransactionCallbackWithoutResult() {
        protected void doInTransactionWithoutResult(TransactionStatus status) {
            updateOperation1();
            updateOperation2();
        }
    });
}

或（设置为遇到异常时只能回滚）

public Object someMethodWithoutResult() {
    return transactionTemplate
            .execute(new TransactionCallbackWithoutResult() {
                protected void doInTransactionWithoutResult(
                        TransactionStatus status) {
                    try {
                        updateOperation1();
                        updateOperation2();
                    } catch (SomeBusinessException e) {
                        status.setRollbackOnly();
                    }
                }
            });
}

PlatformTransactionManager 的实现

DefaultTransactionDefinition def = new DefaultTransactionDefinition();
def.setName("TxName");
def.setPropagationBehavior(TransactionDefinition.PROPAGATION_REQUIRED);

TransactionStatus status = txManager.getTransaction(def);
try {
    //do something
} catch (MyException ex) {
    txManager.rollback(status);
    throw ex;
}
txManager.commit(status);

整合 MyBatis

SqlSessionFactory
添加 mybatis-spring 依赖

    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis-spring</artifactId>
        <version>1.2.3</version>
    </dependency>
    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis</artifactId>
        <version>3.3.0</version>
    </dependency>

定义 SqlSessionFactoryBean

<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
    <property name="dataSource" ref="dataSource" />
    <property name="configLocation" value="classpath:sqlMapConfig.xml" />
    <property name="mapperLocations" value="classpath*:sample/config/mappers/**/*.xml" />
</bean>

定义 Mapper

public interface UserMapper {

	@Select("SELECT * FROM users WHERE id = #{userId}")
	User getUser(@Param("userId") String userId);
}

配置结果映射

@Results({
    @Result(property="id", column="id"),
    @Result(property="firstName", column="first_name"),
    @Result(property="lastName", column="last_name")
})

或者采用 xml 的方法，见 Mybatis 部分

定义 Mapper Bean

<bean id="userMapper" class="org.mybatis.spring.mapper.MapperFactoryBean">
    <property name="mapperInterface" value="com.netease.course.UserMapper" />
    <property name="sqlSessionFactory" ref="sqlSessionFactory" />
</bean>

或采用自动发现的机制

<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:mybatis="http://mybatis.org/schema/mybatis-spring"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
	http://www.springframework.org/schema/beans/spring-beans.xsd
	http://mybatis.org/schema/mybatis-spring
	http://mybatis.org/schema/mybatis-spring.xsd">

	<mybatis:scan base-package="com.netease.course" />
</beans>

当需要指定 SqlSessionFactory 时

<mybatis:scan base-package="com.netease.course" factory-ref="sqlSessionFactory" />

或者

<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
    <property name="basePackage" value="com.netease.course" />
    <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory" />
</bean>

使用 Mapper

public class SomeService {
	@Autowired
	private UserMapper userMapper;
	public User getUser(String userId) {
		return userMapper.getUser(userId);
	}
}

定义 SqlSessionTemplate 使用

<bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">
    <constructor-arg index="0" ref="sqlSessionFactory" />
</bean>

SqlSessionTemplate 使用

public class UserDao {
	@Autowired
	private SqlSession sqlSession;
	public User getUser(String userId) {
		return (User) sqlSession.selectOne("com.netease.course.UserMapper.getUser", userId);
	}
}

//Web 框架

DispatcherServlet

[servlet-name]-servlet.xml
HandlerMapping
Controllers
View 解析相关

WebApplicationContext

ContextLoaderListener

<listener>
	<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<context-param>
	<param-name>contextConfigLocation</param-name>
	<param-value>/WEB-INF/applicationContext*.xml</param-value>
</context-param>

Servlet WebApplicationContext (containing controllers, view resolvers, and other web-related beans)
Root WebAppliacationContext (containing middler-tier services, datasources, etc.)

实现 Controller

  @Controller
  @RequestMapping(value = "/hello")
  public class HelloController {
	  @RequestMapping(value = "/spring")
	  public void spring(HttpServletResponse response) throws IOException {
		  response.getWriter().write("Hello, Spring Web!!");
	  }
  }

定义 Controller

自动发现

 <context:component-scan base-package="com.netease.course" />

@RequestMapping
name: 名称
value & path: 路径，如"/hello"
method: 请求方法，如"GET"
params: 请求参数
headers: 请求头
consumes: 请求的媒体类型，"Content-Type"
produces: 响应的媒体类型，"ACCEPT"

注入路径中的变量

@RequestMapping(value="/users/{userId}")
public String webMethod(@PathVariable String userId) {
    //do work
}

或

@RequestMapping(value="/users/{userId:[a-z]+}")
public String webMethod(@PathVariable String userId) {
    //do work
}

函数参数
HttpServletRequest / HttpServletResponse, HttpSession (Servlet API)
Reader / Writer
@PathVariable
@RequestParam
@RequestHeader
HttpEntity
@RequestBody
Map / Model / ModelMap

函数返回值
void
String: view 名称，@ResponseBody
HttpEntity
View
Map
Model
ModelAndView

函数实现

@RequestMapping(value="/spring/{user}")

public void helloSpring(

        @PathVariable("user") String user,

        @RequestParam("msg") String msg,

        @RequestHeader("host") String host,

        HttpServletRequest request,

        Writer writer) throws IOException {

    writer.write("URI: " + request.getRequestURI());

    writer.write("Hello, " + user + ": " + msg + ", host=" + host);

}

或

@RequestMapping(value="/spring/login")

public void login(@ModelAttribute User user, Writer writer) {

    //do work

}

或

@RequestMapping(value="/users/login")

public String login(@RequestParam("name") String name, @RequestParam("password") String password, ModelMap map) {

    map.addAttribute("name", name);

    map.addAttribute("password", "******");

    return "user";

}

ModelMap
ModelMap 的实例是由 bboss mvc 框架自动创建并作为控制器方法参数传入，用户无需自己创建。

public String xxxxmethod(String someparam,ModelMap model)   
{   
	 //省略方法处理逻辑若干   
	  //将数据放置到ModelMap对象model中,第二个参数可以是任何java类型   
	  model.addAttribute("key",someparam);   
	 ......   
	 //返回跳转地址   
	  return "path:handleok";   
}

ModelAndView
ModelAndView 的实例是由用户手动创建的，这也是和 ModelMap 的一个区别。

public ModelAndView xxxxmethod(String someparam)   
{   
	 //省略方法处理逻辑若干   
	  //构建ModelAndView实例，并设置跳转地址   
	  ModelAndView view = new ModelAndView("path:handleok");   
	  //将数据放置到ModelAndView对象view中,第二个参数可以是任何java类型   
	  view.addObject("key",someparam);   
	 ......   
	 //返回ModelAndView对象view   
	  return view;   
}

上传文件

定义 bean

<bean id="multipartResolver"
    class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
    <property name="maxUploadSize" value="100000" />
</bean>

相应代码

@RequestMapping(value="/form", method=RequestMethod.POST)
public String handleFormUpload(@RequestParam("file") MultipartFile file) {
    // save the file
}

相应依赖

<dependency>
  <groupId>commons-fileupload</groupId>
  <artifactId>commons-fileupload</artifactId>
  <version>1.3.1</version>
</dependency>

HttpEntity

@RequestMapping(value="/something")
public ResponseEntity<String> handle(HttpEntity<byte[]> requestEntity) {
    String requestHeader = requestEntity.getHeaders().getFirst("MyRequestHeader");
    byte[] requestBody = requestEntity.getBody();
    // do something with requestHeader and requestBody
    HttpHeaders responseHeaders = new HttpHeaders();
    responseHeaders.set("MyResponseHeader", "MyValue");
    return new ResponseEntity<String>("hello spring", responseHeaders, HttpStatus.CREATED);
}

@RequestBody & @ResponseBody

@RequestMapping(value="/spring")
@ResponseBody
public String spring(@RequestBody String body) throws IOException {
    return "hello" + body;
}

MessageConverter，返回 Java 对象的转化
RequestBody ---> Object: 参数
ResponseBody <--- Object: 返回值

xml 文件配置

<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
	xmlns:mvc=“http://www.springframework.org/schema/mvc”
	xsi:schemaLocation="http://www.springframework.org/schema/beans
	http://www.springframework.org/schema/beans/spring-beans.xsd
	http://www.springframework.org/schema/mvc
	http://www.springframework.org/schema/mvc/spring-mvc.xsd
	http://www.springframework.org/schema/context
	http://www.springframework.org/schema/context/spring-context.xsd">
	<context:component-scan base-package="com.netease.course" />
	<mvc:annotation-driven />
</beans>

添加相应依赖，如 JSON 相关依赖

    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-core</artifactId>
        <version>2.6.4</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
        <version>2.6.4</version>
    </dependency>

View 解析

String 名称

View

ModelAndView

Map

Model

ViewResolver (org.springframework.web.servlet)：

InternalResourceViewResolver (org.springframework.web.servlet.view)
FreeMarkerViewResolver (org.springframework.web.servlet.view.freemarker)
ContentNegotiatingViewResolver (org.springframework.web.servlet.view)

InternalResourceViewResovler
Servlet, JSP
bean 定义

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

resultView -------> /WEB-INF/jsp/resultView.jsp

FreeMarkerViewResolver
FreeMarker
bean 定义

<bean id="freemarkerConfig"
    class="org.springframework.web.servlet.view.freemarker.FreeMarkerConfigurer">
    <property name="templateLoaderPath" value="/WEB-INF/freemarker/" />
</bean>
<bean id="viewResolver"
    class="org.springframework.web.servlet.view.freemarker.FreeMarkerViewResolver">
    <property name="cache" value="true" />
    <property name="prefix" value="" />
    <property name="suffix" value=".ftl" />
    <property name="contentType" value="text/html; charset=utf-8" />
</bean>

ContentNegotiatingViewResolver
ViewResovler 的组合
扩展名：user.json, user.xml, user.pdf
Accept 头（media types)：application / json, application / xml
bean 定义

<bean
    class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver">
    <property name="viewResolvers">
        <list>
            <bean id="viewResolver"
                class="org.springframework.web.servlet.view.freemarker.FreeMarkerViewResolver">
                <property name="cache" value="true" />
                <property name="prefix" value="" />
                <property name="suffix" value=".ftl" />
            </bean>
        </list>
    </property>
    <property name="defaultViews">
        <list>
            <bean
                class="org.springframework.web.servlet.view.json.MappingJackson2JsonView" />
        </list>
    </property>
</bean>

DefaultRequestToViewNameTranslator
example/admin/index.html ---------> admin/index
example/display.html -------> display

ContentNegotiatingViewResolver 根据路径后缀，选择不同视图

方法一：使用扩展名

http://localhost:8080/learn/user.xml 获取 xml 类型数据

http://localhost:8080/learn/user.json 获取 json 类型数据

http://localhost:8080/learn/user 使用默认 view 呈现，如 jsp

方法二：使用 http 请求头的 Accept

GET /user HTTP/1.1

Accept:application/xml

GET /user HTTP/1.1

Accept:application/json

方法三：使用参数

http://localhost:8080/learn/user?format=xml

http://localhost:8080/learn/user?format=json

同一资源，多种表述

<bean id="contentNegotiationManager" class="org.springframework.web.accept.ContentNegotiationManagerFactoryBean">  
    <!-- 是否启用扩展名支持，默认为true -->  
    <property name="favorPathExtenion" value="true" />  
    <!-- 是否启用参数支持，默认为true -->  
    <property name="favorParameter" value="false" />  
    <!-- 是否忽略掉accept header,默认为false -->  
    <property name="ignoreAcceptHeader" value="true" />  
      
    <!-- 扩展名到mimeType的映射 -->  
    <property name="mediaTypes">  
        <map>  
            <!-- 例如：/user.json 中的 .json 会映射到 application/json -->  
            <entry key="json" value="application/json" />  
            <entry key="xml" value="application/xml" />          
        </map>  
    </property>  
      
    <!-- 如果所有mediaType都没匹配上，就使用defaultContentType -->  
    <property name="defaultContentType" value="text/html"/>  
</bean>  
  
<bean class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver">  
    <!-- 解析器的执行顺序 -->  
    <property name="order" value="1" />  
    <property name="contentNegotiationManager" ref="contentNegotiationManager" />  
      
    <property name="defaultViews">  
        <list>  
            <bean class="org.springframework.web.servlet.view.json.MappingJackson2JsonView"></bean>  
            <bean class="org.springframework.web.servlet.view.xml.MarshallingView">  
                <constructor-arg>  
                    <bean class="org.springframework.oxm.jaxb.Jaxb2Marshaller">  
                        <property name="classesToBeBound">  
                            <list>  
                                <value>com.learn.model.User</value>  
                            </list>  
                        </property>  
                    </bean>  
                </constructor-arg>  
            </bean>  
        </list>  
    </property>  
      
</bean>  
<!-- 上面没匹配到则会使用这个视图解析器 ,解析为jsp  -->  
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">  
    <property name="order" value="2" />  
    <property name="prefix" value="/" />   
    <property name="suffix" value=".jsp"/>  
</bean>

Controller 中可以用 RequestMapping 匹配多个路径后缀

@RequestMapping(value = {"/users", "/users.html", "/users.json"})

public String getUsersInfo(ModelMap map) {

    List users = userServiceImp.getUsers();

    map.addAttribute("users", users);

    return "users";

}

FreeMarker

模板引擎

数据模型

对象：hashes

基本类型：scalars

注释

<#-- 这是注释 -->

插值：表达式

${animal.name}

直接指定值：

字符串，如“Zoo”, 'Zoo'

数字，如123.45

布尔值，如true，false

序列，如["zoo", "bar", 123]

值域，如0..9，0..<10

哈希表，如{"name":"green mouse", "price":150}

检索变量：

顶层变量：user

哈希表数据：user.name, user["name"]

列表数据：products[5]

连接操作：

users + "guest"

passwords + "joe":"secret123"

算术操作

逻辑操作

比较操作

FTL 标签：指令

开始标签：<#directivename parameters>

结束标签：

if 指令

<#if user=="Big Joe">, our beloved leader

list 指令

<#list animals as animal>

  ${animal.name}${animal.price} Euros

include 指令

<#include "/copyright_footer.html">

使用

创建配置

Configuration cfg = new Configuration(Configuration.VERSION_2_3_0);

cfg.setDirectoryForTemplateLoading(new File("/where/you/store/templates"));

cfg.setDefaultEncoding("UTF-8");

cfg.setTemplateExceptionHandler(TemplateExceptionHandler.RETHROW_HANDLER);

定义模板

定义数据模型

如

Map root = new HashMap<>();

root.put("user", "Big Joe");

Map latestProduct = new HashMap<>();

root.put("latestProduct", latestProduct);

latestProduct.put("url", "products/greenmouse.html");

latestProduct.put("name", "greenmouse");

添加依赖

  <dependency>

      <groupId>org.freemarkergroupId>

      <artifactId>freemarkerartifactId>

      <version>2.3.23version>

  dependency>

输出结果

    Template ftl = cfg.getTemplate("user.ftl");

    Writer outWriter = new OutputStreamWriter(System.out);

    ftl.process(root, outWriter);

工程模板

一般 java 目录

com.netease.course.dao

com.netease.course.meta

com.netease.course.service

com.netease.course.service.impl

com.netease.course.utils

com.netease.course.web.controller

com.netease.course.web.filter

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