JAVA操作資料庫一（Spring data jpa)
阿新 • • 發佈：2018-12-25
總的來說，JAVA操作資料庫還是相當方便的。
首先是核心配置檔案daoContext.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:jdbc="http://www.springframework.org/schema/jdbc" xmlns:c="http://www.springframework.org/schema/c" xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p" xmlns:jpa="http://www.springframework.org/schema/data/jpa" xsi:schemaLocation="http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-3.1.xsd http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd"> <jpa:repositories base-package="db,service" /> <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean" p:dataSource-ref="dataSource" p:persistenceUnitName="mypersistest" p:packagesToScan="entity" p:jpaVendorAdapter-ref="jpaVendorAdapter"/> <bean id="jpaVendorAdapter" class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"> <property name="database" value="ORACLE" /> <property name="showSql" value="true" /> <property name="generateDdl" value="true" /> </bean> <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager" /> <!-- PropertyPlaceholderConfigurer是一個容器後處理器，它會讀取 屬性檔案資訊，並將這些資訊設定成Spring配置檔案的資料。 --> <bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"> <property name="locations"> <list> <value>classpath:my.properties</value> <!-- 如果有多個屬性檔案,依次在下面列出來 --> <!--value>dbconn.properties</value--> </list> </property> </bean> <!-- Simple implementation of the standard JDBC DataSource interface, configuring the plain old JDBC DriverManager via bean properties --> <bean id="dataSource" class="oracle.jdbc.pool.OracleDataSource"> <property name="URL" value="${url}" /> <property name="user" value="${username}" /> <property name="password" value="${password}" /> <property name="implicitCachingEnabled" value="true"/> <property name="fastConnectionFailoverEnabled" value="true"/> </bean> </beans>
my.properties裡面的內容非常簡單
driverClassName=oracle.jdbc.driver.OracleDriver
url=jdbc:oracle:thin:@127.0.0.1:1521:orcl
username=myname
password=mypassword然後我們需要一個實體類，就是資料庫的表名，我叫做MyEntity，程式碼如下
有了表。我們還需要對錶的操作。import javax.persistence.*; import java.math.BigDecimal; @Entity public class MyEntity { @Id @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "prooduct_id_seq") @SequenceGenerator(name="prooduct_id_seq", sequenceName = "PRODUCT_ID_SEQ", allocationSize = 100) private Integer id; @Version private Integer version; private String testString; private BigDecimal testNumber; public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public Integer getVersion() { return version; } public void setVersion(Integer version) { this.version = version; } public String getTestString() { return testString; } public void setTestString(String testString) { this.testString = testString; } public BigDecimal getTestNumber() { return testNumber; } public void setTestNumber(BigDecimal testNumber) { this.testNumber = testNumber; } }
這就更加簡單了
public interface MyEntityRepository extends JpaRepository<MyEntity, Long> {//裡面可以寫各種複雜函式。暫時我們就先用一些基本的操作，所以無需寫任何程式碼
}最後在我們的服務類中進行測試
public class MyService { @Autowired MyEntityRepository myEntityRepository; public String processCommand(String anything) { String str = "hello"; List<MyEntity> myEntityList = myEntityRepository.findAll(); return str; } }
一切OK。成功拿到了表裡資料（表裡的資料可以用工具直接寫入資料庫）
真的是太輕鬆了。都沒幾行程式碼。如果有人設計好了資料庫，用Hibernate是可以直接生成MyEntity的類，也是說。對資料庫進行操作，基本不用寫啥程式碼，增刪改查都有了。
最後補下缺失的程式碼
import net.sf.json.JSONObject;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.context.ContextLoader;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import service.MyService;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
@RestController
@EnableWebMvc
@RequestMapping(value = "mytest")
public class MyController {
public MyController() {
wac = ContextLoader.getCurrentWebApplicationContext();
}
WebApplicationContext wac;
private static final Logger logger = LoggerFactory.getLogger(MyController.class);
@RequestMapping(value = "/{anything}", method = RequestMethod.POST, produces="application/json;charset=UTF-8")
public Object myServiceControl(HttpServletRequest request, HttpSession session, @PathVariable String anything)
{
String jsonRet = "hello";
logger.info(request.getMethod());
logger.info("anything is " + anything ) ;
try{
MyService myService = (MyService)wac.getBean("myService");
jsonRet = myService.processCommand(anything);
}catch(Exception e){
JSONObject jsonObject = new JSONObject();
e.printStackTrace();
jsonObject.put("result" , "-1");
jsonObject.put("desc" , e.toString());
return jsonObject.toString();
}
logger.info("end");
logger.info(jsonRet);
return jsonRet;
}
}pom.xml
<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/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>TestDataBaseGroup2</groupId>
<artifactId>TestDataBaseArt2</artifactId>
<packaging>war</packaging>
<version>1.0-SNAPSHOT</version>
<name>TestDataBaseArt Maven Webapp</name>
<url>http://maven.apache.org</url>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
<!-- oracle -->
<dependency>
<groupId>com.oracle</groupId>
<artifactId>ojdbc6</artifactId>
<version>11.2.0</version>
</dependency>
<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>6.0.5</version>
</dependency>
<!-- spring -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>4.3.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-orm</artifactId>
<version>4.3.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-aspects</artifactId>
<version>4.3.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>4.3.4.RELEASE</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>4.3.4.RELEASE</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.springframework.data/spring-data-jpa -->
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-jpa</artifactId>
<version>1.10.6.RELEASE</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.springframework.session/spring-session -->
<dependency>
<groupId>org.springframework.session</groupId>
<artifactId>spring-session</artifactId>
<version>1.2.2.RELEASE</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.springframework.data/spring-data-elasticsearch -->
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-elasticsearch</artifactId>
<version>2.0.5.RELEASE</version>
</dependency>
<!-- hibernate -->
<!-- https://mvnrepository.com/artifact/org.hibernate/hibernate-core -->
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>5.2.5.Final</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.hibernate/hibernate-c3p0 -->
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-c3p0</artifactId>
<version>5.2.5.Final</version>
</dependency>
<!-- https://mvnrepository.com/artifact/ch.qos.logback/logback-classic -->
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-classic</artifactId>
<version>1.1.8</version>
</dependency>
<!-- servlet -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>2.5</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<!-- https://mvnrepository.com/artifact/javax.inject/javax.inject -->
<dependency>
<groupId>javax.inject</groupId>
<artifactId>javax.inject</artifactId>
<version>1</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.h2database/h2 -->
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
<version>1.4.193</version>
</dependency>
<!-- json -->
<dependency>
<groupId>net.sf.json-lib</groupId>
<artifactId>json-lib</artifactId>
<version>2.3</version>
<classifier>jdk15</classifier>
</dependency>
</dependencies>
<build>
<finalName>OnlyMyTest</finalName>
</build>
</project>
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_3_1.xsd"
version="3.1">
<display-name>Archetype Created Web Application</display-name>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:applicationContext.xml,classpath:daoContext.xml</param-value>
</context-param>
<servlet>
<servlet-name>mvc-dispatcher</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:mvc-dispatcher-servlet.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>mvc-dispatcher</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app><?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://www.springframework.org/schema/beans"
xmlns:p="http://www.springframework.org/schema/p"
xmlns:c="http://www.springframework.org/schema/c"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:task="http://www.springframework.org/schema/task"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
http://www.springframework.org/schema/task
http://www.springframework.org/schema/task/spring-task-3.1.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd">
<!-- 定義Service元件，並將DAO元件注入Service元件 -->
<bean id="myService" class="service.MyService"
/>
<context:annotation-config />
</beans>