Spring Boot Mysql 数据库操作示例

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:

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