Spring Boot Mysql 数据库操作示例

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本文默认你的开发环境.数据库已经安装好

想用使用数据库.我们需要现在pom文件中添加相应的依赖

pom.xml

<?xml version="1.0" encoding="UTF-8"?> 
<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.imgod</groupId> 
  <artifactId>testjpa</artifactId> 
  <version>0.0.1-SNAPSHOT</version> 
  <packaging>war</packaging> 
 
  <name>TestJpa</name> 
  <description>Demo project for Spring Boot</description> 
 
  <parent> 
    <groupId>org.springframework.boot</groupId> 
    <artifactId>spring-boot-starter-parent</artifactId> 
    <version>1.4.2.RELEASE</version> 
    <relativePath /> <!-- lookup parent from repository --> 
  </parent> 
 
  <properties> 
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> 
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> 
    <java.version>1.8</java.version> 
  </properties> 
 
  <dependencies> 
    <dependency> 
      <groupId>org.springframework.boot</groupId> 
      <artifactId>spring-boot-starter-data-jpa</artifactId> 
    </dependency> 
    <dependency> 
      <groupId>org.springframework.boot</groupId> 
      <artifactId>spring-boot-starter-web</artifactId> 
    </dependency> 
 
    <dependency> 
      <groupId>org.springframework.boot</groupId> 
      <artifactId>spring-boot-starter-tomcat</artifactId> 
      <scope>provided</scope> 
    </dependency> 
    <dependency> 
      <groupId>org.springframework.boot</groupId> 
      <artifactId>spring-boot-starter-test</artifactId> 
      <scope>test</scope> 
    </dependency> 
    <dependency> 
      <groupId>mysql</groupId> 
      <artifactId>mysql-connector-java</artifactId> 
    </dependency> 
    <dependency> 
      <groupId>org.springframework.boot</groupId> 
      <artifactId>spring-boot-starter-jdbc</artifactId> 
    </dependency> 
    <!-- 添加Hibernate依赖 --> 
    <dependency> 
      <groupId>org.hibernate</groupId> 
      <artifactId>hibernate-core</artifactId> 
    </dependency> 
  </dependencies> 
 
  <build> 
    <plugins> 
      <plugin> 
        <groupId>org.springframework.boot</groupId> 
        <artifactId>spring-boot-maven-plugin</artifactId> 
      </plugin> 
    </plugins> 
  </build> 
 
 
</project>

我们的配置文件进行数据库的配置

application.properties:

spring.datasource.url=jdbc:mysql://127.0.0.1:3306/test 
spring.datasource.username=root 
spring.datasource.password=imgod1 
spring.datasource.driver-class-name=com.mysql.jdbc.Driver 
spring.datasource.max-idle=10 
spring.datasource.max-wait=10000 
spring.datasource.min-idle=5 
spring.datasource.initial-size=5 
spring.jpa.properties.hibernate.hbm2ddl.auto=update

前面配置的是数据库信息,最后一行配置的是.如果我们定义的实体在数据库中没有对应的表的话.会帮我们自动创建

我们的实体类型

User.Java

package com.imgod.bean; 
 
import javax.persistence.Entity; 
import javax.persistence.GeneratedValue; 
import javax.persistence.GenerationType; 
import javax.persistence.Id; 
import javax.persistence.Table; 
import javax.validation.constraints.NotNull; 
 
@Entity 
@Table(name = "users") 
public class User { 
  @Id 
  @GeneratedValue(strategy = GenerationType.AUTO) 
  private int id; 
  @NotNull 
  private String email; 
  @NotNull 
  private String name; 
 
  public int getId() { 
    return id; 
  } 
 
  public void setId(int id) { 
    this.id = id; 
  } 
 
  public String getEmail() { 
    return email; 
  } 
 
  public void setEmail(String email) { 
    this.email = email; 
  } 
 
  public String getName() { 
    return name; 
  } 
 
  public void setName(String name) { 
    this.name = name; 
  } 
 
}

对应数据库中的user表,没有的话会自动创建

想对数据库进行操作,我们需要创建一个接口继承CrudRepository

UserDao.java

package com.imgod.dao; 
 
import org.springframework.data.domain.Pageable; 
import org.springframework.data.repository.CrudRepository; 
import org.springframework.stereotype.Repository; 
import org.springframework.transaction.annotation.Transactional; 
 
import com.imgod.bean.User; 
import java.lang.String; 
import java.util.List; 
 
@Transactional 
@Repository 
public interface UserDao extends CrudRepository<User, Integer> { 
  //jpa 方法名就是查询语句,只要规法写方法名一切就都可以完成(当然.有时候会造成方法名又臭又长) 
  User findByEmail(String email);//根据邮箱查询 
  List<User> findByName(String name);//根据用户名查询 
   
  //select * from test.users where email='imgod@qq.com' and name='imgod'; 
  List<User> findByNameAndEmail(String name,String email);//根据用户名和邮箱进行查询 
   
  //select * from test.users where email='imgod@qq.com' and name='imgod4444' order by id desc; 
  List<User> findByNameAndEmailOrderByIdDesc(String name,String email);//根据用户名和邮箱进行查询,排序 
   
  //select * from test.users where email='imgod@qq.com' and name='imgod4444' order by id desc limit 2; 
  List<User> findTop2ByNameAndEmailOrderByIdDesc(String name,String email);//根据用户名和邮箱进行查询,排序,前两个 
 
  //根据邮箱进行分页查询 
  List<User> findByEmail(String email,Pageable pageable);//根据用户名和邮箱进行查询 
}

实现CrudRepository我们就可以对数据库进行一些基础操作了

如果我们想要实现更多的操作.需要自己按照严格的命名规则为方法定义方法名

下面就是我们重要的控制器的实现了:

package com.imgod.controller; 
 
import java.util.List; 
 
import org.springframework.beans.factory.annotation.Autowired; 
import org.springframework.data.domain.PageRequest; 
import org.springframework.web.bind.annotation.RequestMapping; 
import org.springframework.web.bind.annotation.RestController; 
 
import com.imgod.bean.User; 
import com.imgod.dao.UserDao; 
 
@RestController 
public class UserController { 
  @Autowired 
  private UserDao userDao; 
 
  /** 
   * 根据邮件去查找 
   * 
   * @param email 
   * @return 
   */ 
  @RequestMapping(value = "/findUserByEmail") 
  public Object getUserByEmail(String email) { 
    System.out.println("email:" + email); 
    User user = userDao.findByEmail(email); 
    if (null == user) { 
      return "暂无数据"; 
    } else { 
      return user; 
    } 
 
  } 
 
  /** 
   * 获取所有的用户信息 
   * 
   * @return 
   */ 
  @RequestMapping(value = "/getall") 
  public Object getAllUser() { 
    List<User> list = (List<User>) userDao.findAll(); 
    if (null == list || list.size() == 0) { 
      return "暂无数据"; 
    } else { 
      return list; 
    } 
 
  } 
 
  /** 
   * 删除指定id用户 
   * 
   * @param id 
   * @return 
   */ 
  @RequestMapping(value = "/deleteUser") 
  public Object deleteuUser(int id) { 
    User user = userDao.findOne(id); 
    if (null == user) { 
      return "删除用户失败:" + id + "没找到该用户"; 
    } else { 
      userDao.delete(id); 
      return "删除用户成功:" + id; 
    } 
 
  } 
 
  /** 
   * 添加用户 
   * 
   * @param id 
   * @param email 
   * @param name 
   * @return 
   */ 
  @RequestMapping(value = "/adduser") 
  public Object addUser(String id, String email, String name) { 
    System.out.println("email:" + email); 
 
    int tempId = Integer.parseInt(id); 
    System.out.println("tempId:" + tempId + "email:" + email + "name:" + name); 
 
    User tempUser = userDao.findOne(tempId); 
    if (null == tempUser) { 
      tempUser = new User(); 
      tempUser.setId(tempId); 
    } 
    tempUser.setEmail(email); 
    tempUser.setName(name); 
    User resultUser = userDao.save(tempUser); 
    if (null == resultUser) { 
      return "新增用户失败"; 
    } else { 
      return "新增用户:" + resultUser.getName(); 
    } 
 
  } 
 
  // 条件查询 
 
  /** 
   * 获取姓名和邮箱是指定内容的用户 
   * 
   * @return 
   */ 
  @RequestMapping(value = "/getUser1") 
  public Object getUser(String email, String name) { 
    List<User> userList = userDao.findByNameAndEmail(name, email); 
    if (null != userList && userList.size() != 0) { 
      return userList; 
    } else { 
      return "没找到符合要求的用户"; 
    } 
 
  } 
 
  /** 
   * 获取姓名和邮箱是指定内容的用户并排序 
   * 
   * @return 
   */ 
  @RequestMapping(value = "/getUser2") 
  public Object getUser2(String email, String name) { 
    List<User> userList = userDao.findByNameAndEmailOrderByIdDesc(name, email); 
    if (null != userList && userList.size() != 0) { 
      return userList; 
    } else { 
      return "没找到符合要求的用户"; 
    } 
 
  } 
 
  /** 
   * 获取姓名和邮箱是指定内容的用户并排序,前两个 
   * 
   * @return 
   */ 
  @RequestMapping(value = "/getUser3") 
  public Object getUser3(String email, String name) { 
    List<User> userList = userDao.findTop2ByNameAndEmailOrderByIdDesc(name, email); 
    if (null != userList && userList.size() != 0) { 
      return userList; 
    } else { 
      return "没找到符合要求的用户"; 
    } 
 
  } 
 
  /** 
   * 分页获取邮箱为指定内容的数据 
   * 
   * @return 
   */ 
  @RequestMapping(value = "/getUser4") 
  public Object getUser4(String email, int page) { 
    // page 属于下标 从0开始 0代表是第一页 
    List<User> userList = userDao.findByEmail(email, new PageRequest(page, 2)); 
    if (null != userList && userList.size() != 0) { 
      return userList; 
    } else { 
      return "没找到符合要求的用户"; 
    } 
 
  } 
}

如此我们就完成了对数据库的操作: