spring MVC 注解详解，注解入门

本文主要介绍使用注解方式配置的spring mvc，包括数据访问层的实现

web.xml配置：

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
  <display-name>s3h3</display-name>
   <context-param>
     <param-name>contextConfigLocation</param-name>
     <param-value>classpath:applicationContext*.xml</param-value>
</context-param>
  <listener>
     <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>

<servlet>
     <servlet-name>spring</servlet-name>
     <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
     <load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
     <servlet-name>spring</servlet-name>  
     <url-pattern>*.do</url-pattern>
</servlet-mapping>
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
</web-app>

spring-servlet,主要配置controller的信息

<?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:p="http://www.springframework.org/schema/p"
        xmlns:context="http://www.springframework.org/schema/context"
   xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
       http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
       http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
       http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd">

  <context:annotation-config />
       
      <context:component-scan base-package="com.mvc.controller" />
  
      <bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" />

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

       <bean id="multipartResolver"
          class="org.springframework.web.multipart.commons.CommonsMultipartResolver"
          p:defaultEncoding="utf-8" />
</beans>

applicationContext.xml代码

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context"
xmlns:p="http://www.springframework.org/schema/p" xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="
         http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
   http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
   http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
   http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd">

<context:annotation-config />
<context:component-scan base-package="com.mvc" />  

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

<bean id="sessionFactory"
  class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
  <property name="dataSource" ref="dataSource" />
  <property name="hibernateProperties">
   <props>
    <prop key="hibernate.dialect">${dataSource.dialect}</prop>
    <prop key="hibernate.hbm2ddl.auto">${dataSource.hbm2ddl.auto}</prop>
    <prop key="hibernate.hbm2ddl.auto">update</prop>
   </props>
  </property>
  <property name="packagesToScan">
   <list>
    <value>com.mvc.entity</value>
   </list>
    </property>
</bean>

<bean id="transactionManager"
  class="org.springframework.orm.hibernate3.HibernateTransactionManager">
  <property name="sessionFactory" ref="sessionFactory" />
  <property name="dataSource" ref="dataSource" />
</bean>

<bean id="dataSource"
  class="org.springframework.jdbc.datasource.DriverManagerDataSource">
  <property name="driverClassName" value="${dataSource.driverClassName}" />
  <property name="url" value="${dataSource.url}" />
  <property name="username" value="${dataSource.username}" />
  <property name="password" value="${dataSource.password}" />
</bean>

<bean id="entityDao" class="com.mvc.dao.EntityDaoImpl">
  <property name="sessionFactory" ref="sessionFactory" />
</bean>
<tx:annotation-driven transaction-manager="transactionManager" />
<tx:annotation-driven mode="aspectj"/>

    <aop:aspectj-autoproxy/>
</beans>

hibernate.properties数据库连接配置

dataSource.password=123
dataSource.username=root
dataSource.databaseName=test
dataSource.driverClassName=com.mysql.jdbc.Driver
dataSource.dialect=org.hibernate.dialect.MySQL5Dialect
dataSource.serverName=localhost:3306
dataSource.url=jdbc:mysql://localhost:3306/test
dataSource.properties=user=${dataSource.username};databaseName=${dataSource.databaseName};serverName=${dataSource.serverName};password=${dataSource.password}
dataSource.hbm2ddl.auto=update

配置已经完成，下面开始例子
先在数据库建表，例子用的是mysql数据库

CREATE TABLE  `test`.`student` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(45) NOT NULL,
  `psw` varchar(45) NOT NULL,
  PRIMARY KEY (`id`)
)

建好表后，生成实体类

package com.mvc.entity;

import java.io.Serializable;

import javax.persistence.Basic;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name = "student")
public class Student implements Serializable {
    private static final long serialVersionUID = 1L;
    @Id
    @Basic(optional = false)
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id", nullable = false)
    private Integer id;
    @Column(name = "name")
    private String user;
    @Column(name = "psw")
    private String psw;
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }

    public String getUser() {
        return user;
    }
    public void setUser(String user) {
        this.user = user;
    }
    public String getPsw() {
        return psw;
    }
    public void setPsw(String psw) {
        this.psw = psw;
    }
}

Dao层实现

package com.mvc.dao;

import java.util.List;

public interface EntityDao {
    public List<Object> createQuery(final String queryString);
    public Object save(final Object model);
    public void update(final Object model);
    public void delete(final Object model);
}

package com.mvc.dao;

import java.util.List;

import org.hibernate.Query;
import org.springframework.orm.hibernate3.HibernateCallback;
import org.springframework.orm.hibernate3.support.HibernateDaoSupport;

public class EntityDaoImpl extends HibernateDaoSupport implements EntityDao{
    public List<Object> createQuery(final String queryString) {
        return (List<Object>) getHibernateTemplate().execute(
                new HibernateCallback<Object>() {
                    public Object doInHibernate(org.hibernate.Session session)
                            throws org.hibernate.HibernateException {
                        Query query = session.createQuery(queryString);
                        List<Object> rows = query.list();
                        return rows;
                    }
                });
    }
    public Object save(final Object model) {
        return  getHibernateTemplate().execute(
                new HibernateCallback<Object>() {
                    public Object doInHibernate(org.hibernate.Session session)
                            throws org.hibernate.HibernateException {
                        session.save(model);
                        return null;
                    }
                });
    }
    public void update(final Object model) {
        getHibernateTemplate().execute(new HibernateCallback<Object>() {
            public Object doInHibernate(org.hibernate.Session session)
                    throws org.hibernate.HibernateException {
                session.update(model);
                return null;
            }
        });
    }
    public void delete(final Object model) {
        getHibernateTemplate().execute(new HibernateCallback<Object>() {
            public Object doInHibernate(org.hibernate.Session session)
                    throws org.hibernate.HibernateException {
                session.delete(model);
                return null;
            }
        });
    }
}

Dao在applicationContext.xml注入

Dao只有一个类的实现，直接供其它service层调用，如果你想更换为其它的Dao实现，也只需修改这里的配置就行了。
开始写view页面，WEB-INF/view下新建页面student.jsp，WEB-INF/view这路径是在spring-servlet.xml文件配置的，你可以配置成其它，也可以多个路径。student.jsp代码

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ include file="/include/head.jsp"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>添加</title>
<script language="javascript" src="<%=request.getContextPath()%></script>
<style></style><style mce_bogus="1">table{  border-collapse:collapse;  }
td{  border:1px solid #f00;  }</style>
<script type="text/javascript"></script>
</head>
<body>

<input id="add" type="button" onclick="add()" value="添加"/>
<table >
    <tr>
        <td>序号</td>
        <td>姓名</td>
        <td>密码</td>
        <td>操作</td>
    </tr>
    <c:forEach items="${list}" var="student">
    <tr id="<c:out value="${student.id}"/>">
        <td><c:out value="${student.id}"/></td>
        <td><c:out value="${student.user}"/></td>
        <td><c:out value="${student.psw}"/></td>
        <td>
            <input type="button" value="编辑"/>
            <input type="button" onclick="del('<c:out value="${student.id}"/>')" value="删除"/>
        </td>
    </tr>
    </c:forEach>

</table>
</body>
</html>

student_add.jsp

controller类实现，只需把注解写上，spring就会自动帮你找到相应的bean，相应的注解标记意义，不明白的，可以自己查下@Service，@Controller，@Entity等等的内容。

package com.mvc.controller;

import java.util.List;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.servlet.ModelAndView;

import com.mvc.entity.Student;
import com.mvc.service.StudentService;

@Controller
@RequestMapping("/student.do")
public class StudentController {
    protected final transient Log log = LogFactory
    .getLog(StudentController.class);
    @Autowired
    private StudentService studentService;
    public StudentController(){

    }

    @RequestMapping
    public String load(ModelMap modelMap){
        List<Object> list = studentService.getStudentList();
        modelMap.put("list", list);
        return "student";
    }

    @RequestMapping(params = "method=add")
    public String add(HttpServletRequest request, ModelMap modelMap) throws Exception{
        return "student_add";
    }

    @RequestMapping(params = "method=save")
    public String save(HttpServletRequest request, ModelMap modelMap){
        String user = request.getParameter("user");
        String psw = request.getParameter("psw");
        Student st = new Student();
        st.setUser(user);
        st.setPsw(psw);
        try{
            studentService.save(st);
            modelMap.put("addstate", "添加成功");
        }
        catch(Exception e){
            log.error(e.getMessage());
            modelMap.put("addstate", "添加失败");
        }

        return "student_add";
    }

    @RequestMapping(params = "method=del")
    public void del(@RequestParam("id") String id, HttpServletResponse response){
        try{
            Student st = new Student();
            st.setId(Integer.valueOf(id));
            studentService.delete(st);
            response.getWriter().print("{\"del\":\"true\"}");
        }
        catch(Exception e){
            log.error(e.getMessage());
            e.printStackTrace();
        }
    }
}

service类实现

package com.mvc.service;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import com.mvc.dao.EntityDao;
import com.mvc.entity.Student;

@Service
public class StudentService {
@Autowired
private EntityDao entityDao;

@Transactional
public List<Object> getStudentList(){
  StringBuffer sff = new StringBuffer();
  sff.append("select a from ").append(Student.class.getSimpleName()).append(" a ");
  List<Object> list = entityDao.createQuery(sff.toString());
  return list;
}

public void save(Student st){
  entityDao.save(st);
}
public void delete(Object obj){
  entityDao.delete(obj);
}
}

OK，例子写完。有其它业务内容，只需直接新建view，并实现相应comtroller和service就行了，配置和dao层的内容基本不变，也就是每次只需写jsp（view），controller和service调用dao就行了。

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spring MVC 注解详解，注解入门

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