從最基本的Java工程搭建SpringMVC+SpringDataJPA+Hibernate
本文會(huì)介紹從一個(gè)最基本的java工程,到Web工程,到集成Spring、SpringMVC、SpringDataJPA+Hibernate。
平時(shí)我們可能是通過(guò)一個(gè)模板搭建一個(gè)工程,或者是直接導(dǎo)入一個(gè)項(xiàng)目,而本文選擇從最基本的java工程開始,目的是為了展示更多原理。
當(dāng)然,我們還是從一個(gè)最基本的Maven工程開始,其實(shí)普通的非Maven工程,搭建過(guò)程幾乎是一模一樣的,只是Jar包需要我們手動(dòng)的添加到工程中,而Maven工程就只是修改配置文件即可。
下面就正式開始。
1、基于Maven(如果不使用Maven也可以用傳統(tǒng)的工程)創(chuàng)建最基本的Java工程
新建工程,選擇Maven Project,Next:
勾選為簡(jiǎn)單的工程(Create a simple project),Next:
Group id為你的域名反序,通常跟工程源碼的包名對(duì)應(yīng),Artifact id為這個(gè)Group id中工程的唯一名,根據(jù)你的愛(ài)好,怎么填都行,然后Finish:
這是得到的工程目錄結(jié)構(gòu)是這樣的:
pom.xml就是Maven的核心文件。
2、將工程設(shè)置為動(dòng)態(tài)網(wǎng)頁(yè)模式
接下來(lái)就將工程轉(zhuǎn)換為Web工程,右鍵打開工程屬性,如圖,點(diǎn)擊左邊菜單中的Project Facets,然后點(diǎn)擊Convert to faceted from...:
在右邊,我們勾選Dynamic Web Module(動(dòng)態(tài)網(wǎng)頁(yè)),然后點(diǎn)OK:
這時(shí)會(huì)多出一個(gè)WebContent目錄:
在WEB-INF目錄下,添加web.xml文件,內(nèi)如如下:
<?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" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0"> <display-name>SpringDataJPA</display-name> <welcome-file-list> <welcome-file>index.html</welcome-file> </welcome-file-list> </web-app>
然后添加一個(gè)歡迎頁(yè)index.html:
<html> <head> </head> <body> <h1>Hello Word!</h1> </body> </html>
這時(shí)目錄結(jié)構(gòu)如下:
這時(shí),就可以右鍵工程,Run On Server了,可以看下效果:
3、集成Spring+SpringMVC
新建包,并添加一些接口和類(具體代碼后面會(huì)列出來(lái)),包結(jié)構(gòu)如圖:
需要添加jar包,直接修改pom文件即可,如果為普通工程,按pom.xml中的jar包,添加到工程中即可。
首先添加使用的spring版本,方便統(tǒng)一管理,然后再添加所有需要的jar包,下面把此處需要的所有jar包添加進(jìn)來(lái),完成后的pom.xml如下:
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.anxpp</groupId> <artifactId>SpringDataJPA</artifactId> <version>0.0.1-SNAPSHOT</version> <properties> <!-- spring版本號(hào) --> <spring.version>4.2.5.RELEASE</spring.version> </properties> <dependencies> <!-- spring核心包 --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-core</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-web</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-orm</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-tx</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-jdbc</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-aop</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context-support</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-test</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-orm</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework.data</groupId> <artifactId>spring-data-jpa</artifactId> <version>1.10.1.RELEASE</version> </dependency> </dependencies> </project>
在WEB-INF目錄下添加Spring配置文件applicationContext.xml,并添加如下內(nèi)容:
<?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:aop="http://www.springframework.org/schema/aop" xmlns:p="http://www.springframework.org/schema/p" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:mvc="http://www.springframework.org/schema/mvc" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.2.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.2.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.2.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.2.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.2.xsd"> <!-- 開啟IOC注解掃描 --> <context:component-scan base-package="com.anxpp.demo" /> <!-- 開啟MVC注解掃描 --> <mvc:annotation-driven /> </beans>
修改web.xml,將spring添加進(jìn)去:
<?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" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0"> <display-name>SpringDataJPA</display-name> <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> <servlet-name>springmvc</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet </servlet-class> <init-param> <param-name>contextConfigLocation</param-name> <param-value>classpath*:springmvc-servlet.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>springmvc</servlet-name> <url-pattern>/*</url-pattern> </servlet-mapping> <welcome-file-list> <welcome-file>index.html</welcome-file> </welcome-file-list> </web-app>
下面開始編寫代碼,注意注解不要忘記寫,在本小節(jié)開始部分已經(jīng)給出了包的層次結(jié)構(gòu)。
實(shí)體User:
package com.anxpp.demo.core.entity; public class User { private Integer id; private String name; public User(Integer id, String name) { this.id = id; this.name = 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 "id:"+id+",name:"+name; } }
dao層接口UserDao:
package com.anxpp.demo.core.dao; import com.anxpp.demo.core.entity.User; public interface UserDao { User getUser(Integer id,String name); }
dao層實(shí)現(xiàn)UserDaoImpl:
package com.anxpp.demo.core.dao.impl; import org.springframework.stereotype.Repository; import com.anxpp.demo.core.dao.UserDao; import com.anxpp.demo.core.entity.User; @Repository public class UserDaoImpl implements UserDao{ @Override public User getUser(Integer id, String name) { return new User(id, name); } }
service層接口UserService:
package com.anxpp.demo.core.service; import com.anxpp.demo.core.entity.User; public interface UserService { User getUser(Integer id, String name); }
service層實(shí)現(xiàn):
package com.anxpp.demo.core.service.impl; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import com.anxpp.demo.core.dao.UserDao; import com.anxpp.demo.core.entity.User; import com.anxpp.demo.core.service.UserService; @Service public class UserServiceImpl implements UserService{ @Autowired UserDao userDao; @Override public User getUser(Integer id, String name) { return userDao.getUser(id, name); } }
controller層DemoController:
package com.anxpp.demo.controller; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.ResponseBody; import com.anxpp.demo.core.service.UserService; @Controller @RequestMapping("/") public class demoController { @Autowired UserService userService; @RequestMapping("/") @ResponseBody public String index(){ return "index"; } @RequestMapping("/getuser") @ResponseBody public String getUser(Integer id, String name){ return userService.getUser(id, name).toString(); } }
這是還不能直接Run On Server,因?yàn)閖ar包不會(huì)被一同發(fā)布,我們需要如下配置:
右鍵工程選擇屬性,按下圖配置:
這時(shí)候就可以運(yùn)行測(cè)試了,效果如下:
到這里,我們還沒(méi)有操作數(shù)據(jù)庫(kù)的。
4、添加返回Json格式數(shù)據(jù)支持
現(xiàn)在,我們常使用json作為數(shù)據(jù)傳輸?shù)母袷?,下面就為SpringMVC添加返回json的支持
首先添加jar包:
<dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-databind</artifactId> <version>2.5.0</version> </dependency> <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-core</artifactId> <version>2.5.0</version> </dependency> <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-annotations</artifactId> <version>2.5.0</version> </dependency>
然后改寫getUser()方法如下:
@RequestMapping("/getuser") @ResponseBody public Map<String, Object> getUser(Integer id, String name){ Map<String, Object> map = new HashMap<String, Object>(); map.put("state", "success"); map.put("data", userService.getUser(id, name)); return map; }
重新運(yùn)行后訪問(wèn)效果如下:
此時(shí),就可以返回json數(shù)據(jù)了。
5、配置靜態(tài)資源訪問(wèn)
通常情況下,WEB-INF目錄下的資源,我們是無(wú)法直接訪問(wèn)的,如果我們的網(wǎng)站是html+ajax構(gòu)成的,那么就可以在WEB-INF之外新建html的目錄,并為web.xml配置默認(rèn)的過(guò)濾器,不過(guò)注意要放到SpingMVC過(guò)濾器之前:
<servlet-mapping> <servlet-name>default</servlet-name> <url-pattern>*.html</url-pattern> </servlet-mapping>
如果一定要訪問(wèn)WEB-INF目錄內(nèi)的資源,通過(guò)查閱Spring官方文檔,發(fā)現(xiàn)有兩種方式
1、手寫一個(gè)資源映射器:
@Configuration @EnableWebMvc public class WebConfig extends WebMvcConfigurerAdapter { @Override public void addResourceHandlers(ResourceHandlerRegistry registry) { registry.addResourceHandler("/resources/**") .addResourceLocations("/public-resources/") .setCacheControl(CacheControl.maxAge(1, TimeUnit.HOURS).cachePublic()); } }
可以看到,還可以設(shè)置緩存時(shí)間的,而更簡(jiǎn)單的方式,就是xml配置:
<mvc:resources mapping="/resources/**" location="/public-resources/"> <mvc:cache-control max-age="3600" cache-public="true"/> </mvc:resources>
也可以加上下面的這個(gè):
<!-- 對(duì)靜態(tài)資源文件的訪問(wèn),將無(wú)法mapping到Controller的path交給default servlet handler處理--> <mvc:default-servlet-handler />
6、亂碼解決
我們通常使用ajax提交請(qǐng)求,但也常用地址欄直接測(cè)試。請(qǐng)求提交分get和post。
使用post提交請(qǐng)求是,一般是不會(huì)出現(xiàn)中文亂碼的,但是如果確實(shí)出現(xiàn)了亂碼,可以通過(guò)在web.xml添加一個(gè)編碼過(guò)濾器解決:
<filter> <filter-name>CharacterEncoding</filter-name> <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class> <init-param> <param-name>encoding</param-name> <param-value>UTF-8</param-value> </init-param> <init-param> <param-name>forceEncoding</param-name> <param-value>true</param-value> </init-param> </filter> <filter-mapping> <filter-name>CharacterEncoding</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>
上面只能解決post的中文亂碼,對(duì)于get(含瀏覽器地址欄直接提交方式),我們需要修改tomcat配置,在conf目錄下的server.xml中找到并如下修改:
<Connector connectionTimeout="20000" port="8080" protocol="HTTP/1.1" redirectPort="8443" URIEncoding="UTF-8"/>
如果我們只是測(cè)試,項(xiàng)目并沒(méi)有部署,可以直接在eclipse中的server下,找到server.xml,做出上面一樣的改動(dòng)即可:
7、整合SpringDataJPA+Hibernate
你可以通過(guò)這篇文字了解JPA:JPA規(guī)范介紹及實(shí)例(Java數(shù)據(jù)持久化解決方案)
SpringDataJPA也正是這樣一種輕量級(jí)的解決方案,而首選的Hibernate就實(shí)現(xiàn)了JPA。
首先還是jar包,SpringDataJPA的jar包,在之前整合Spring時(shí)已經(jīng)一并加入,下面是Hibernate(和mysql驅(qū)動(dòng))的jar包.
<!-- hibernate --> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-core</artifactId> <version>${hibernate.version}</version> </dependency> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-ehcache</artifactId> <version>${hibernate.version}</version> </dependency> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-entitymanager</artifactId> <version>${hibernate.version}</version> </dependency> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-c3p0</artifactId> <version>${hibernate.version}</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.9</version> </dependency>
統(tǒng)一管理的版本為:
<!-- hibernate 版本號(hào) --> <hibernate.version>5.1.0.Final</hibernate.version>
添加Jpa的配置文件persistence.xml到META-INF目錄下,本文介紹時(shí)數(shù)據(jù)庫(kù)使用MySQL。并添加如下內(nèi)容:
<?xml version="1.0" encoding="UTF-8"?> <persistence version="1.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"> <persistence-unit name="demo" transaction-type="RESOURCE_LOCAL"> <!-- provider>org.eclipse.persistence.jpa.PersistenceProvider</provider --> <provider>org.hibernate.ejb.HibernatePersistence</provider> <class>com.ninelephas.meerkat.pojo.User</class> <!-- MYSql 的連接 --> <properties> <property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver" /> <property name="hibernate.connection.url" value="jdbc:mysql://127.0.0.1:3306/demo?createDatabaseIfNotExist=true" /> <property name="hibernate.connection.username" value="root" /> <property name="hibernate.connection.password" value="root" /> <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect" /> </properties> </persistence-unit> </persistence>
Spring配置文件applicationContext.xml中增加JPA支持后的完整內(nèi)容:
<?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:aop="http://www.springframework.org/schema/aop" xmlns:p="http://www.springframework.org/schema/p" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:jpa="http://www.springframework.org/schema/data/jpa" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.2.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.2.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.2.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.2.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.2.xsd http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa.xsd"> <!-- 開啟IOC注解掃描 --> <context:component-scan base-package="com.anxpp.demo" /> <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"> <property name="jpaVendorAdapter"> <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"> <property name="generateDdl" value="true" /> <property name="database" value="MYSQL" /> </bean> </property> <property name="persistenceUnitName" value="demo" /> </bean> <!-- 開啟MVC注解掃描 --> <mvc:annotation-driven /> <bean class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver"> <property name="viewResolvers"> <list> <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="prefix" value="/WEB-INF/view/" /> <property name="suffix" value=".html" /> </bean> </list> </property> <!-- 用于將對(duì)象轉(zhuǎn)換為 JSON --> <property name="defaultViews"> <list> <bean class="org.springframework.web.servlet.view.json.MappingJackson2JsonView" /> </list> </property> </bean> <!-- 對(duì)靜態(tài)資源文件的訪問(wèn),將無(wú)法mapping到Controller的path交給default servlet handler處理 --> <mvc:default-servlet-handler /> <!-- 配置事務(wù)管理器 --> <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager"> <property name="entityManagerFactory" ref="entityManagerFactory" /> </bean> <!-- 啟用 annotation事務(wù) --> <tx:annotation-driven transaction-manager="transactionManager" /> <!-- 配置Spring Data JPA掃描目錄 --> <jpa:repositories base-package="com.anxpp.demo" /> </beans>
修改實(shí)體:
package com.anxpp.demo.core.entity; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.Table; @Entity @Table public class User { @Id @GeneratedValue(strategy = GenerationType.AUTO) private Integer id; private String name; public User() { } public User(String name) { this.name = 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 "id:"+id+",name:"+name; } }
可以刪掉dao層實(shí)現(xiàn)了,我們記住將dao層接口繼承自強(qiáng)大的JpaRepository:
public interface UserDao extends JpaRepository<User, Serializable>{ User findById(Integer id); }
是不是看上去特別簡(jiǎn)潔,而且都不需要寫實(shí)現(xiàn)的,SpringDataJPA會(huì)自動(dòng)幫我們完成。
修改service層接口:
package com.anxpp.demo.core.service; import java.util.List; import com.anxpp.demo.core.entity.User; public interface UserService { User findById(Integer id); User save(String name); List<User> findAll(); }
修改service層實(shí)現(xiàn):
package com.anxpp.demo.core.service.impl; import java.util.List; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import com.anxpp.demo.core.dao.UserDao; import com.anxpp.demo.core.entity.User; import com.anxpp.demo.core.service.UserService; @Service public class UserServiceImpl implements UserService{ @Autowired UserDao userDao; @Override public User findById(Integer id) { return userDao.findById(id); } @Override public User save(String name) { return userDao.save(new User(name)); } @Override public List<User> findAll() { return userDao.findAll(); } }
修改controller,提供多個(gè)測(cè)試接口:
package com.anxpp.demo.controller; import java.util.HashMap; import java.util.Map; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.ResponseBody; import com.anxpp.demo.core.service.UserService; @Controller @RequestMapping("/") public class demoController { @Autowired UserService userService; @RequestMapping("/") @ResponseBody public String index(){ return "index"; } @RequestMapping("/info") public String info(){ return "info"; } @RequestMapping("/findall") @ResponseBody public Map<String, Object> getUser(){ Map<String, Object> map = new HashMap<String, Object>(); map.put("state", "success"); map.put("data", userService.findAll()); return map; } @RequestMapping("/findbyid") @ResponseBody public Map<String, Object> findById(Integer id){ Map<String, Object> map = new HashMap<String, Object>(); map.put("state", "success"); map.put("data", userService.findById(id)); return map; } @RequestMapping("/add") @ResponseBody public Map<String, Object> save(String name){ Map<String, Object> map = new HashMap<String, Object>(); map.put("state", "success"); map.put("data", userService.save(name)); return map; } }
運(yùn)行效果:
那么,如果需要添加一個(gè)查找id大于指定值的指定姓氏的數(shù)據(jù)呢?
如果是SQL,我們會(huì)這樣寫(?表示參數(shù)):
SELECT * FROM user WHERE id>? AND name like '?%';
但是這里,我們連SQL(或者HQL)都可以不用寫,直接在dao層接口添加一個(gè)方法即可:
List<User> findByIdGreaterThanAndNameLike(Integer id,String name);
你不需要懷疑,上面的方法執(zhí)行偏偏就是能成功(注意:service實(shí)現(xiàn)的使用,調(diào)用該方法記得name+"%")!
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