[Spring от Getting Started to Actual Combat Tutorial] Глава 7 Spring Интеграция веб-проектов

Seven, интегрированный веб-проект Spring

7.1 Идеи интеграции

До сих пор каждый раз, когда вы получаете объект, вы должны сначала создать IOC-контейнер, операция выглядит следующим образом:

ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");

Но если такого рода операции слишком неэффективны в проекте, работа по инициализации IOC-контейнера должна быть подготовлена ​​заранее и является разовой операцией. В веб-проекте процесс загрузки файла конфигурации Spring и создания IOC-контейнера завершается при запуске сервера.

    Идея реализации следующая:
        1. При запуске сервера создать объект ServletContext для каждого проекта
        2. Использовать прослушиватель для отслеживания создания объекта ServletContext
        3. Когда прослушиватель обнаружит создание ServletContext, загрузить Файл конфигурации ядра Spring
        4. Сохраните контейнер IOC в объекте домена SetvletContext
        5. Когда объект необходимо получить, выньте контейнер IOC из домена ServletContext.

7.2. Этапы реализации

7.2.1 Знакомство с зависимостями maven

<dependencies>
    <!-- servlet-api -->
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>3.1.0</version>
        <scope>provided</scope>
    </dependency>
    <!-- jsp-api -->
    <dependency>
        <groupId>javax.servlet.jsp</groupId>
        <artifactId>jsp-api</artifactId>
        <version>2.1</version>
        <scope>provided</scope>
    </dependency>
    <!-- jstl -->
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>jstl</artifactId>
        <version>1.2</version>
    </dependency>

    <!-- spring核心包-->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-core</artifactId>
        <version>4.3.18.RELEASE</version>
    </dependency>
    <!-- springbean包 -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-beans</artifactId>
        <version>4.3.18.RELEASE</version>
    </dependency>
    <!-- springcontext包 -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>4.3.18.RELEASE</version>
    </dependency>
    <!-- spring表达式包 -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-expression</artifactId>
        <version>4.3.18.RELEASE</version>
    </dependency>
    <!-- springAOP包 -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-aop</artifactId>
        <version>4.3.18.RELEASE</version>
    </dependency>
    <!-- springAspects包 -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-aspects</artifactId>
        <version>4.3.18.RELEASE</version>
    </dependency>
    <!-- spring对web的支持包 -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-web</artifactId>
        <version>4.3.18.RELEASE</version>
    </dependency>
    <!-- springJDBC包 -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-jdbc</artifactId>
        <version>4.3.18.RELEASE</version>
    </dependency>
    <!-- spring事务包 -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-tx</artifactId>
        <version>4.3.18.RELEASE</version>
    </dependency>
    <!-- mysql驱动 -->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.49</version>
    </dependency>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
        <scope>test</scope>
    </dependency>
</dependencies>

7.2.2 Реализация прослушивателя

@WebListener
public class SpringContextListener implements ServletContextListener {
    @Override
    public void contextInitialized(ServletContextEvent servletContextEvent) {
        /**
         * 在web项目中的上下对象创建之后，将spring的IOC容器放置在上下文对象
         */
        //1.获取上下文对象
        ServletContext sc = servletContextEvent.getServletContext();
        //2.创建IOC容器
        ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
        //3.将容器对象放入到上下文域中
        sc.setAttribute("ac", ac);
    }

    @Override
    public void contextDestroyed(ServletContextEvent servletContextEvent) {

    }
}

7.2.3 Объект компонента

@Component
public class Person {
    @Value("101")
    private Integer id;
    @Value("小明")
    private String name;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public String toString() {
        return "Person{" +
                "id=" + id +
                ", name='" + name + '\'' +
                '}';
    }
}

7.2.4 applicationContext.xml

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

    <context:component-scan base-package="com.newcapec"/>
</beans>

7.2.5 Сервлет

@WebServlet("/getPerson")
public class PersonServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        //1.取出容器
        ApplicationContext ac = (ApplicationContext) this.getServletContext().getAttribute("ac");

        //2.容器中获取对象
        Person person = ac.getBean("person", Person.class);

        System.out.println(person.getId() + "---" + person.getName());
    }
}

7.2.6 веб.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    <welcome-file-list>
        <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>
</web-app>

7.3 Реализация весной

    Слушатель для инициализации контейнера IOC был реализован в Spring, и необходимо импортировать пакет jar интегрированного веб-проекта Spring.

веб.xml：

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    <!-- 初始化IOC容器的spring中的监听器 -->
    <!--
        此监听器在创建IOC容器时，默认读取spring配置文件的位置是：/WEB-INF/applicationContext.xml
    -->
    <!-- 通过上下文初始化参数修改spring默认配置文件的位置及名称 -->
    <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>
</web-app>

Контейнер, используемый Spring в веб-проектах: WebApplicationContext.

//从上下文对象中获取IOC容器对象
WebApplicationContext ac = WebApplicationContextUtils.getWebApplicationContext(this.getServletContext());

Person person = ac.getBean("person", Person.class);
System.out.println(person.getId() + "---" + person.getName());

7.4 Полная реализация веб-проекта

7.4.1 applicationContext.xml

db.properties：

# Oracle相关配置
jdbc.oracle.driver=oracle.jdbc.driver.OracleDriver
jdbc.oracle.url=jdbc:oracle:thin:@localhost:1521:orcl
jdbc.oracle.username=scott
jdbc.oracle.password=tiger

# Mysql相关配置
jdbc.mysql.driver=com.mysql.jdbc.Driver
jdbc.mysql.url=jdbc:mysql://localhost:3306/ssm?characterEncoding=utf8&useSSL=false
jdbc.mysql.username=root
jdbc.mysql.password=root

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

    <!--开启注解，扫描公共包com.newcapec-->
    <context:component-scan base-package="com.newcapec"/>

    <!--配置数据源-->
    <context:property-placeholder location="classpath:db.properties"/>

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

    <!--配置jdbcTemplate-->
    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <property name="dataSource" ref="dataSource"/>
    </bean>

</beans>

веб.xml：

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    <!-- 初始化IOC容器的spring中的监听器 -->
    <!--
        此监听器在创建IOC容器时，默认读取spring配置文件的位置是：/WEB-INF/applicationContext.xml
    -->
    <!-- 通过上下文初始化参数修改spring默认配置文件的位置及名称 -->
    <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>
</web-app>

7.4.2 Классы сущностей

@Component
public class Student {

    private Integer id;
    private String name;
    private Integer age;
    private String major;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public String getMajor() {
        return major;
    }

    public void setMajor(String major) {
        this.major = major;
    }

    @Override
    public String toString() {
        return "Student{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", age=" + age +
                ", major='" + major + '\'' +
                '}';
    }
}

7.4.3 Дао

оператор sql:

CREATE TABLE `t_student`  (
  `id` int(11) NOT NULL AUTO_INCREMENT COMMENT '学生id',
  `name` varchar(20) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '学生姓名',
  `age` int(2) NULL DEFAULT NULL COMMENT '学生性别',
  `major` varchar(20) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '学生专业',
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 5 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Compact;

-- ----------------------------
-- Records of t_student
-- ----------------------------
INSERT INTO `t_student` VALUES (2, '小红', 1, '网络工程');
INSERT INTO `t_student` VALUES (3, 'tom', 12, '计算机');
INSERT INTO `t_student` VALUES (4, '曹操', 12, '挖墓');

SET FOREIGN_KEY_CHECKS = 1;

интерфейс:

public interface StudentDao {
    void insertStudent(Student student);

    void updateStudent(Student student);

    void deleteStudent(Integer id);

    Student selectStudentById(Integer id);

    List<Student> selectStudent();
}

Класс реализации:

@Repository("studentDao")
public class StudentDaoImpl implements StudentDao {

    @Autowired
    private JdbcTemplate jdbcTemplate;

    @Override
    public void insertStudent(Student student) {
        //String sql = "insert into t_student(id,name,age,major) values(seq_demo.nextval,?,?,?)";
        String sql = "insert into t_student(name,age,major) values(?,?,?)";
        jdbcTemplate.update(sql, student.getName(), student.getAge(), student.getMajor());
    }

    @Override
    public void updateStudent(Student student) {
        String sql = "update t_student set name=?,age=?,major=? where id=?";
        jdbcTemplate.update(sql, student.getName(), student.getAge(), student.getMajor(), student.getId());
    }

    @Override
    public void deleteStudent(Integer id) {
        String sql = "delete from t_student where id=?";
        jdbcTemplate.update(sql, id);
    }

    @Override
    public Student selectStudentById(Integer id) {
        String sql = "select id,name,age,major from t_student where id=?";
        RowMapper<Student> rowMapper = new BeanPropertyRowMapper<>(Student.class);
        return jdbcTemplate.queryForObject(sql, rowMapper, id);
    }

    @Override
    public List<Student> selectStudent() {
        String sql = "select id,name,age,major from t_student order by id desc";
        RowMapper<Student> rowMapper = new BeanPropertyRowMapper<>(Student.class);
        return jdbcTemplate.query(sql, rowMapper);
    }
}

7.4.3 Сервис

интерфейс:

public interface StudentService {
    void addStudent(Student student);

    void editStudent(Student student);

    void removeStudent(Integer id);

    Student findStudentById(Integer id);

    List<Student> findStudent();
}

Класс реализации:

@Service("studentService")
public class StudentServiceImpl implements StudentService {

    @Autowired
    private StudentDao studentDao;

    @Override
    public void addStudent(Student student) {
        studentDao.insertStudent(student);
    }

    @Override
    public void editStudent(Student student) {
        studentDao.updateStudent(student);
    }

    @Override
    public void removeStudent(Integer id) {
        studentDao.deleteStudent(id);
    }

    @Override
    public Student findStudentById(Integer id) {
        return studentDao.selectStudentById(id);
    }

    @Override
    public List<Student> findStudent() {
        return studentDao.selectStudent();
    }
}

7.4.4 Сервлет

@WebServlet({"/findStudent", "/addStudent", "/editStudent", "/removeStudent", "/getStudent"})
public class StudentServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        WebApplicationContext ac = WebApplicationContextUtils.getWebApplicationContext(this.getServletContext());
        StudentService studentService = ac.getBean("studentService", StudentService.class);

        String path = req.getServletPath();
        if (path.contains("find")) {
            List<Student> list = studentService.findStudent();
            req.setAttribute("list", list);
            req.getRequestDispatcher("/student.jsp").forward(req, resp);
        } else if (path.contains("add")) {
            String name = req.getParameter("name");
            String age = req.getParameter("age");
            String major = req.getParameter("major");
            Student student = new Student();
            student.setName(name);
            student.setAge(Integer.parseInt(age));
            student.setMajor(major);
            studentService.addStudent(student);
            req.getRequestDispatcher("/findStudent").forward(req, resp);
        } else if (path.contains("edit")) {
            String id = req.getParameter("id");
            String name = req.getParameter("name");
            String age = req.getParameter("age");
            String major = req.getParameter("major");
            Student student = new Student();
            student.setId(Integer.parseInt(id));
            student.setName(name);
            student.setAge(Integer.parseInt(age));
            student.setMajor(major);
            studentService.editStudent(student);
            req.getRequestDispatcher("/findStudent").forward(req, resp);
        } else if (path.contains("remove")) {
            String id = req.getParameter("id");
            studentService.removeStudent(Integer.parseInt(id));
            req.getRequestDispatcher("/findStudent").forward(req, resp);
        } else if (path.contains("get")) {
            String id = req.getParameter("id");
            Student student = studentService.findStudentById(Integer.parseInt(id));
            req.setAttribute("student", student);
            req.getRequestDispatcher("/student_edit.jsp").forward(req, resp);
        }
    }
}

7.4.5 Страницы

index.jsp：

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <base href="${pageContext.request.contextPath}/">
    <title>Title</title>
</head>
<body>
    <div style="text-align: center">
        <h1>欢迎使用...</h1>
        <a href="findStudent">学生列表</a>
    </div>
</body>
</html>

студент.jsp：

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
    <base href="${pageContext.request.contextPath}/">
    <title>Title</title>
</head>
<body>
    <div style="text-align: center;">
        <h1>学生列表</h1>
         <a href="student_add.jsp">新增</a>
        <table border="1" width="600" align="center">
            <tr>
                <th>编号</th>
                <th>姓名</th>
                <th>年龄</th>
                <th>专业</th>
                <th>操作</th>
            </tr>
            <c:forEach items="${list}" var="s">
                <tr>
                    <td>${s.id}</td>
                    <td>${s.name}</td>
                    <td>${s.age}</td>
                    <td>${s.major}</td>
                    <td>
                        <a href="getStudent?id=${s.id}">编辑</a>&emsp;&emsp;
                        <a href="removeStudent?id=${s.id}" onclick="return confirm('确定要删除吗?')">删除</a>
                    </td>
                </tr>
            </c:forEach>
        </table>
    </div>
</body>
</html>

student_add.jsp：

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <base href="${pageContext.request.contextPath}/">
    <title>Title</title>
</head>
<body>
    <div style="text-align: center">
        <h1>学生新增</h1>
        <form action="addStudent" method="post">
            <p>
                <label>姓名</label>
                <input type="text" name="name"/>
            </p>
            <p>
                <label>年龄</label>
                <input type="text" name="age"/>
            </p>
            <p>
                <label>专业</label>
                <input type="text" name="major"/>
            </p>
            <p>
                <button type="submit">提交</button>
            </p>
        </form>
    </div>
</body>
</html>

student_edit.jsp：

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <base href="${pageContext.request.contextPath}/">
    <title>Title</title>
</head>
<body>
    <div style="text-align: center">
        <h1>学生编辑</h1>
        <form action="editStudent" method="post">
            <input type="hidden" name="id" value="${student.id}">
            <p>
                <label>姓名</label>
                <input type="text" name="name" value="${student.name}"/>
            </p>
            <p>
                <label>年龄</label>
                <input type="text" name="age" value="${student.age}"/>
            </p>
            <p>
                <label>专业</label>
                <input type="text" name="major" value="${student.major}"/>
            </p>
            <p>
                <button type="submit">提交</button>
            </p>
        </form>
    </div>
</body>
</html>