[Spring do Tutorial de Iniciação ao Tutorial de Combate Real] Capítulo 7 Spring Integrando Projetos da Web

Seven, projeto da Web integrado ao Spring

7.1 Ideias de integração

Até agora, toda vez que você pega um objeto, você deve primeiro criar um contêiner IOC, a operação é a seguinte:

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

Mas se esse tipo de operação for muito ineficiente em um projeto, o trabalho de inicialização do contêiner IOC deve ser preparado com antecedência e é uma operação única. No projeto da Web, o processo de carregamento do arquivo de configuração do Spring e criação do contêiner IOC é concluído quando o servidor é iniciado.

    A ideia de implementação é a seguinte:
        1. Ao iniciar o servidor, crie um objeto ServletContext para cada projeto;
        2. Use o listener para monitorar a criação do objeto ServletContext;
        3. Quando o listener detectar a criação do ServletContext, carregue o Arquivo de configuração do núcleo Spring;
        4. Armazene o contêiner IOC no objeto de domínio SetvletContext;
        5. Quando o objeto precisar ser obtido, retire o contêiner IOC do domínio ServletContext;

7.2. Etapas de implementação

7.2.1 Apresentando dependências 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 Implementação do Ouvinte

@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 Objeto Bean

@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 Servlet

@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 web.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 Implementação no Spring

    O ouvinte para inicializar o contêiner IOC foi implementado no Spring e o pacote jar do projeto da Web integrado do Spring precisa ser importado.

web.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>

O contêiner usado pelo Spring em projetos da Web é: 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 Implementação completa do projeto Web

7.4.1 applicationContext.xml

db.propriedades:

# 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>

web.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 Classes de entidade

@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 Dao

instrução 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;

interface:

public interface StudentDao {
    void insertStudent(Student student);

    void updateStudent(Student student);

    void deleteStudent(Integer id);

    Student selectStudentById(Integer id);

    List<Student> selectStudent();
}

Classe de implementação:

@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 Serviço

interface:

public interface StudentService {
    void addStudent(Student student);

    void editStudent(Student student);

    void removeStudent(Integer id);

    Student findStudentById(Integer id);

    List<Student> findStudent();
}

Classe de implementação:

@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 Servlet

@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 Páginas

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>

aluno.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>

estudante_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>