Spring_MVC(1)构建简单web应用

/**
 * 2010-1-23
 */
 package org.zlex.spring.service;

 /**
 *
 * @author <a href="mailto:[email protected]">梁栋</a>
 * @version 1.0
 * @since 1.0
 */
 public interface AccountService {

     /**
     * 验证用户身份
     *
     * @param username
     * @param password
     * @return
     */
     boolean verify(String username, String password);

}

/**
 * 2010-1-23
 */
package org.zlex.spring.service;

/**
 * 
 * @author <a href="mailto:[email protected]">梁栋</a>
 * @version 1.0
 * @since 1.0
 */
public interface AccountService {

	/**
	 * 验证用户身份
	 * 
	 * @param username
	 * @param password
	 * @return
	 */
	boolean verify(String username, String password);

}

接口不需要任何Spring注解相关的东西，它就是一个简单的接口！
重要的部分在于实现层，如下所示：
AccountServiceImpl.java

/**
 * 2010-1-23
 */
 package org.zlex.spring.service.impl;

 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 import org.zlex.spring.dao.AccountDao;
 import org.zlex.spring.domain.Account;
 import org.zlex.spring.service.AccountService;

 /**
 *
 * @author <a href="mailto:[email protected]">梁栋</a>
 * @version 1.0
 * @since 1.0
 */
 @Service
 @Transactional
 public class AccountServiceImpl implements AccountService {

     @Autowired
     private AccountDao accountDao;

     /*
     * (non-Javadoc)
     *
     * @see org.zlex.spring.service.AccountService#verify(java.lang.String,
     * java.lang.String)
     */
     @Override
     public boolean verify(String username, String password) {

        Account account = accountDao.read(username);

         if (password.equals(account.getPassword())) {
             return true;
         } else {
             return false;
        }
    }

}

/**
 * 2010-1-23
 */
package org.zlex.spring.service.impl;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import org.zlex.spring.dao.AccountDao;
import org.zlex.spring.domain.Account;
import org.zlex.spring.service.AccountService;

/**
 * 
 * @author <a href="mailto:[email protected]">梁栋</a>
 * @version 1.0
 * @since 1.0
 */
@Service
@Transactional
public class AccountServiceImpl implements AccountService {

	@Autowired
	private AccountDao accountDao;

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.zlex.spring.service.AccountService#verify(java.lang.String,
	 * java.lang.String)
	 */
	@Override
	public boolean verify(String username, String password) {

		Account account = accountDao.read(username);

		if (password.equals(account.getPassword())) {
			return true;
		} else {
			return false;
		}
	}

}

注意以下内容：

@Service
 @Transactional

@Service
@Transactional

注解@Service用于标识这是一个Service层实现，@Transactional用于控制事务，将事务定位在业务层，这是非常务实的做法！
接下来，我们来看持久层：AccountDao和AccountDaoImpl类
AccountDao.java

/**
 * 2010-1-23
 */
 package org.zlex.spring.dao;

 import org.zlex.spring.domain.Account;

 /**
 *
 * @author <a href="mailto:[email protected]">梁栋</a>
 * @version 1.0
 * @since 1.0
 */
 public interface AccountDao {

     /**
     * 读取用户信息
     *
     * @param username
     * @return
     */
    Account read(String username);

}

/**
 * 2010-1-23
 */
package org.zlex.spring.dao;

import org.zlex.spring.domain.Account;

/**
 * 
 * @author <a href="mailto:[email protected]">梁栋</a>
 * @version 1.0
 * @since 1.0
 */
public interface AccountDao {

	/**
	 * 读取用户信息
	 * 
	 * @param username
	 * @return
	 */
	Account read(String username);

}

这个接口就是简单的数据提取，无需任何Spring注解有关的东西！
再看其实现类：
AccountDaoImpl.java

/**
 * 2010-1-23
 */
 package org.zlex.spring.dao.impl;

 import org.springframework.stereotype.Repository;
 import org.zlex.spring.dao.AccountDao;
 import org.zlex.spring.domain.Account;

 /**
 *
 * @author <a href="mailto:[email protected]">梁栋</a>
 * @version 1.0
 * @since 1.0
 */
 @Repository
 public class AccountDaoImpl implements AccountDao {

     /* (non-Javadoc)
     * @see org.zlex.spring.dao.AccountDao#read(java.lang.String)
     */
     @Override
     public Account read(String username) {

         return new Account(username,"wolf");
    }

}

/**
 * 2010-1-23
 */
package org.zlex.spring.dao.impl;

import org.springframework.stereotype.Repository;
import org.zlex.spring.dao.AccountDao;
import org.zlex.spring.domain.Account;

/**
 * 
 * @author <a href="mailto:[email protected]">梁栋</a>
 * @version 1.0
 * @since 1.0
 */
@Repository
public class AccountDaoImpl implements AccountDao {

	/* (non-Javadoc)
	 * @see org.zlex.spring.dao.AccountDao#read(java.lang.String)
	 */
	@Override
	public Account read(String username) {
	 
		return new Account(username,"wolf");
	}

}

这里只需要注意注解：

@Repository

@Repository

意为持久层，Dao实现这层我没有过于细致的介绍通过注解调用ORM或是JDBC来完成实现，这些内容后续细述！
这里我们没有提到注解@Component，共有4种“组件”式注解：

引用

 
@Component:可装载组件 
@Repository:持久层组件 
@Service:服务层组件 
@Controller:控制层组件

这样spring容器就完成了控制层、业务层和持久层的构建。
启动应用，访问http://localhost:8080/spring/account.do?username=snow&password=wolf
观察控制台，如果得到包含“true”的输出，本次构建就成功了！