spring boot + spring data jpa

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发布时间：2019-06-29

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Spring Data Repository的核心接口是Repository(好像也没什么好惊讶的)。这个接口需要领域类(Domain Class)跟领域类的ID类型作为参数。这个接口主要是让你能知道继承这个类的接口的类型。CrudRepository 供了对被管理的实体类的一些常用CRUD方法。

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2. springboot 整合spring data jpa

默认你已经构建好了spring boot 项目，关于spring boot项目的新建，请参考：

2.1. 首先导入jar 包

springboot 整合spring data jpa 首先要导入依赖的jar包。pom.xml 文件中新增如下依赖：


            
                
     
      org.springframework.data
      
     
      spring-data-jpa
      
     
     
     
      org.hibernate
      
     
      hibernate-entitymanager
      
     
     
     
      org.aspectj
      
     
      aspectjweaver

<groupId>mysql</groupId>

<artifactId>mysql-connector-java</artifactId>

</dependency>


     
     
     
      com.mchange
      
     
      c3p0
      
     
      0.9.5.2
      
      
       
       
        commons-logging
        
       
        commons-logging

2.2 配置datasource

新建DBConfig. 文件配置数据源。

package com.example.config;import java.beans.PropertyVetoException; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.core.env.Environment; import com.mchange.v2.c3p0.ComboPooledDataSource; @Configuration public class DBConfig { @Autowired private Environment env; @Bean(name="dataSource") public ComboPooledDataSource dataSource() throws PropertyVetoException { ComboPooledDataSource dataSource = new ComboPooledDataSource(); dataSource.setDriverClass(env.getProperty("ms.db.driverClassName")); dataSource.setJdbcUrl(env.getProperty("ms.db.url")); dataSource.setUser(env.getProperty("ms.db.username")); dataSource.setPassword(env.getProperty("ms.db.password")); dataSource.setMaxPoolSize(20); dataSource.setMinPoolSize(5); dataSource.setInitialPoolSize(10); dataSource.setMaxIdleTime(300); dataSource.setAcquireIncrement(5); dataSource.setIdleConnectionTestPeriod(60); return dataSource; } }

2.3. 添加数据库连接信息

在配置文件application.properties中添加连接信息如下：

ms.db.driverClassName=com.mysql.jdbc.Driver ms.db.url=jdbc:mysql://localhost:3306/msm?prepStmtCacheSize=517&cachePrepStmts=true&autoReconnect=true&characterEncoding=utf-8&allowMultiQueries=true ms.db.username=root ms.db.password=admin ms.db.maxActive=500

2.4 配置JpaConfig

新建JpaConfig.java 文件内容如下：

package com.example.config;import java.util.HashMap; import java.util.Map; import javax.persistence.EntityManagerFactory; import javax.sql.DataSource; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.data.jpa.repository.config.EnableJpaRepositories; import org.springframework.orm.jpa.JpaTransactionManager; import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean; import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter; import org.springframework.transaction.PlatformTransactionManager; import org.springframework.transaction.annotation.EnableTransactionManagement; @Configuration //此处是你dao文件所在的包名 @EnableJpaRepositories("com.example.*.dao") @EnableTransactionManagement public class JpaConfig { @Autowired private DataSource dataSource; @Bean public EntityManagerFactory entityManagerFactory() { HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter(); LocalContainerEntityManagerFactoryBean factory = new LocalContainerEntityManagerFactoryBean(); factory.setJpaVendorAdapter(vendorAdapter); //此处com.example.*.model是你的java bean所在的包名 factory.setPackagesToScan("com.example.*.model"); factory.setDataSource(dataSource); Map
    
      jpaProperties = new HashMap
     
      (); jpaProperties.put("hibernate.ejb.naming_strategy","org.hibernate.cfg.ImprovedNamingStrategy"); jpaProperties.put("hibernate.jdbc.batch_size",50); factory.setJpaPropertyMap(jpaProperties); factory.afterPropertiesSet(); return factory.getObject(); } @Bean public PlatformTransactionManager transactionManager() { JpaTransactionManager txManager = new JpaTransactionManager(); txManager.setEntityManagerFactory(entityManagerFactory()); return txManager; } }

2.5 新建对应数据库表的实体类。（也就是java bean ）

注意 @Entity@Table(name = "sec_user")标签的使用，@Entity表示这个是一个实体类，@Table(name = "sec_user") 中sec_user 是数据库中对应的表名@Id@GeneratedValue 对应ID @Column(name = "name") 对应数据库中该列对应的列名，也就是属性名

package com.example.base.model;import java.util.Date;import javax.persistence.Column;import javax.persistence.Entity;import javax.persistence.GeneratedValue; import javax.persistence.Id; import javax.persistence.Table; import com.fasterxml.jackson.annotation.JsonIgnore; @Entity @Table(name = "sec_user") public class User { @Id @GeneratedValue(strategy=GenerationType.IDENTITY) private Integer id; @Column(name = "name") private String name; @Column(name = "password") private String password; @Column(name = "username") private String username; @Column(name = "division_id") private Integer divisionId; @Column(name = "email") private String email; @Column(name = "gender") private String gender; @Column(name = "mobilephone") private String mobilephone; @Column(name = "telephone") private String telephone; @Column(name = "user_type") private Integer userType; @Column(name = "create_by") private String createBy; @Column(name = "create_time") private Date createTime; @Column(name = "update_by") private String updateBy; @Column(name = "update_time") private Date updateTime; @Column(name = "disabled") private Integer disabled; @Column(name = "theme") private String theme; @Column(name = "is_ldap") private Integer isLdap; public String getName() { return name; } public void setName(String name) { this.name = name; } @JsonIgnore public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public Integer getDivisionId() { return divisionId; } public void setDivisionId(Integer divisionId) { this.divisionId = divisionId; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } public String getGender() { return gender; } public void setGender(String gender) { this.gender = gender; } public String getMobilephone() { return mobilephone; } public void setMobilephone(String mobilephone) { this.mobilephone = mobilephone; } public String getTelephone() { return telephone; } public void setTelephone(String telephone) { this.telephone = telephone; } public Integer getUserType() { return userType; } public void setUserType(Integer userType) { this.userType = userType; } public String getCreateBy() { return createBy; } public void setCreateBy(String createBy) { this.createBy = createBy; } public Date getCreateTime() { return createTime; } public void setCreateTime(Date createTime) { this.createTime = createTime; } public String getUpdateBy() { return updateBy; } public void setUpdateBy(String updateBy) { this.updateBy = updateBy; } public Date getUpdateTime() { return updateTime; } public void setUpdateTime(Date updateTime) { this.updateTime = updateTime; } public Integer getDisabled() { return disabled; } public void setDisabled(Integer disabled) { this.disabled = disabled; } public String getTheme() { return theme; } public void setTheme(String theme) { this.theme = theme; } public Integer getIsLdap() { return isLdap; } public void setIsLdap(Integer isLdap) { this.isLdap = isLdap; } public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } }

2.5 编写spring data jpa 的dao层（重头戏哦）

首先我们先了解一下 spring data jpa 的命名规范，然后再开始编写一个简单的例子。

例子：

新建UserJpaDao类继承 JpaRepository

package com.example.base.dao;import org.springframework.data.jpa.repository.JpaRepository;import org.springframework.data.jpa.repository.Query;import org.springframework.data.repository.query.Param;import com.example.base.model.User; /** * The Interface UserJpaDao. * @author abel */ public interface UserJpaDao extends JpaRepository
    
      { /** * Find by name. * * @param name the name * @return the user */ User findByName(String name); /** * Find by name and user name. * 如果参数名为多个字母组成，请首字母大写。勿使用驼峰命名，jpa不识别驼峰 * @param name the name * @param age the age * @return the user */ User findByNameAndAge(String name, Integer age); /** * Find user. * User为@Entity 的名字 * @param name the name * @return the user */ @Query("from User u where u.name=:name") User findUser(@Param("name") String name); }

2.6 service 层的编写（这一步和Spring mvc 已经没有什么差别的了。）

service 代码如下。（此处我就仅仅写了dao的一个方法）

package com.example.base.service;import com.example.base.model.User;/** * The Interface UserService. */public interface UserService { /** * Gets the user by name. * * @param username the user name * @return the user by name */ public User getUserByName(String username); }

实现如下：

package com.example.base.service.Impl;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;import com.example.base.dao.UserJpaDao;import com.example.base.model.User; import com.example.base.service.UserService; /** * * @ClassName UserServiceImpl * @author abel * @date 2016年11月10日 */ @Service public class UserServiceImpl implements UserService { @Autowired private UserJpaDao userJpaDao; /** * * @param UserName * @return */ @Override public User getUserByName(String username) { return userJpaDao.findByName(username); } }

2.7 controller 编写

package com.example.base.controller; import javax.servlet.http.HttpServletRequest; import java.util.Map; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.http.HttpStatus; import org.springframework.http.ResponseEntity; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestMethod; import org.springframework.web.bind.annotation.ResponseBody; import com.example.base.service.UserService; import com.example.base.util.CommonUtil; /** * * @ClassName UserController * @author abel * @date 2016年11月10日 */ @Controller @RequestMapping(value = "/users") public class UserController { @Autowired private UserService userService; /** * 通过spring data jpa 调用方法 api :localhost:8099/users/byname?username=xxx * * @param request * @return */ @RequestMapping(value = "/byname", method = RequestMethod.GET) @ResponseBody public ResponseEntity

转载于:https://www.cnblogs.com/wangjing666/p/7098142.html

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