在使用Spring Boot或者Spring Cloud开发业务时,经常会需要查数据库(本文以MySQL数据库为例),这时候通常会用到MyBatis,数据量比较多页面展示就会要求分页,接下来正式开始。
1. Spring工程创建和添加Maven依赖
<!-- MyBatis-Plus -->
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>3.0.1</version>
</dependency>
<!-- MySQL -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.38</version>
</dependency>
2. 添加application.properties配置
server.port=8080
spring.application.name=demo
spring.datasource.url=jdbc:mysql://192.168.1.11:3306/test?useUnicode=true&useSSL=false&characterEncoding=utf8&autoReconnect=true&failOverReadOnly=false&serverTimezone=Asia/Shanghai
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
3. 创建表user对应的对象User
import com.baomidou.mybatisplus.annotation.TableName;
import java.io.Serializable;
import java.time.LocalDateTime;
@TableName("user")
public class SignalFixed implements Serializable {
private static final long serialVersionUID = 1L;
private Integer age;
private String name;
public static long getSerialVersionUID() {
return serialVersionUID;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
4. 创建UserMapper
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.example.demo.model.User;
import org.apache.ibatis.annotations.Mapper;
@Mapper
public interface UserMapper extends BaseMapper<User> {
}
5. 配置分页插件(重点,没配分页不生效)
import com.baomidou.mybatisplus.extension.plugins.PaginationInterceptor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class MybatisPlusPageHelperConfig {
public MybatisPlusPageHelperConfig() {
}
@Bean
public PaginationInterceptor paginationInterceptor() {
return new PaginationInterceptor();
}
}
6. 编写controller进行测试
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.example.demo.mapper.UserMapper;
import com.example.demo.model.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;
@RestController
public class Test {
@Autowired
private UserMapper userMapper;
@GetMapping("/test")
public String test() {
QueryWrapper<User> queryWrapper = new QueryWrapper<>();
Page<User> page = new Page<>(0, 1);
List<User> users = userMapper.selectPage(page, queryWrapper).getRecords();
return user.get(0).getName();
}
}
7. 运行Spring Boot的Application, 在页面http://localhost:8080/test访问得到结果