10—mybatis 通用mapper插件 pagehelper 分页
spring boot真的太好用了，大家以后多多使用，今天来说说pagehelper 来做mybatis分页，我用的是spring boot 做的开发，后面会把源码发出来。
pagehelper（https://github.com/pagehelper/Mybatis-PageHelper） 是什么我就不多说了，网上太多太多了。
还是上代码吧
Card表
CREATE TABLE `card` ( `id` int(11) NOT NULL DEFAULT '0', `cid` int(11) DEFAULT NULL, `title` varchar(60) DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; INSERT INTO `card` VALUES ('1', '2', 'aldsjkfla'); INSERT INTO `card` VALUES ('2', '3', '2222aldsjkfla'); INSERT INTO `card` VALUES ('3', '1', '2323'); INSERT INTO `card` VALUES ('4', '4', '4444444444'); INSERT INTO `card` VALUES ('5', '5', '55555555555555'); INSERT INTO `card` VALUES ('6', '6', '66666666666666'); INSERT INTO `card` VALUES ('7', '7', '77777777777777'); INSERT INTO `card` VALUES ('8', '8', '88888888888888888888'); INSERT INTO `card` VALUES ('9', '9', '999999999999999999'); INSERT INTO `card` VALUES ('10', '10', 'swswswsws'); INSERT INTO `card` VALUES ('11', '11', '112121222222'); INSERT INTO `card` VALUES ('12', '12', 'aaaaaa'); INSERT INTO `card` VALUES ('13', '13', 'asdfasdfadfadfadsf'); INSERT INTO `card` VALUES ('14', '14', 'aswsweerererer'); INSERT INTO `card` VALUES ('15', '15', 'dfdfdfdfdfa'); INSERT INTO `card` VALUES ('16', '16', 'dfdsfsadf'); INSERT INTO `card` VALUES ('17', '17', 'agtgtgtgtg'); INSERT INTO `card` VALUES ('18', '18', 'aaaggtgtg');
下面开始编码：
1.新建一个spring boot项目
2.导包
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 https://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.2.1.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <groupId>org.zn.test</groupId> <artifactId>testpage</artifactId> <version>0.0.1-SNAPSHOT</version> <name>testpage</name> <description>Demo project for Spring Boot</description> <properties> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> <exclusions> <exclusion> <groupId>org.junit.vintage</groupId> <artifactId>junit-vintage-engine</artifactId> </exclusion> </exclusions> </dependency> <!--自动构造java--> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <version>1.14.8</version> </dependency> <!--通用mapper启动器--> <dependency> <groupId>tk.mybatis</groupId> <artifactId>mapper-spring-boot-starter</artifactId> <version>2.0.4</version> </dependency> <!--分页助手启动器--> <dependency> <groupId>com.github.pagehelper</groupId> <artifactId>pagehelper-spring-boot-starter</artifactId> <version>1.2.5</version> </dependency> <!--mysql--> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.32</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
3. 配置文件，包括数据地址等信息
application.yml
server: port: 8099 spring: application: name: testpage datasource: url: jdbc:mysql://localhost:3306/card username: root password: 123456 driver-class-name: com.mysql.jdbc.Driver #显示sql语句 mybatis: configuration: log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
4.建立实体类 Card.java
package org.zn.test.testpage.entity; import lombok.Data; import lombok.ToString; import tk.mybatis.mapper.annotation.KeySql; import javax.persistence.Id; import javax.persistence.Table; @Table(name = "card") @Data @ToString public class Card { @Id @KeySql(useGeneratedKeys = true) private Integer id; private Integer cid; private String title; }
5.建立Mapper
CardMapper.java，这里注意用是通用mapper来实现的，所有继承tk.mybatis.mapper.common.Mapper的Mapper
package org.zn.test.testpage.mapper; import org.zn.test.testpage.entity.Card; import tk.mybatis.mapper.common.Mapper; public interface CardMapper extends Mapper<Card> { }
6.建立Servcie
CardService.java
package org.zn.test.testpage.service;
import com.github.pagehelper.PageHelper;
import com.github.pagehelper.PageInfo;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.zn.test.testpage.entity.Card;
import org.zn.test.testpage.mapper.CardMapper;
import tk.mybatis.mapper.entity.Example;
import java.util.List;
@Service
public class CardService {
@Autowired
private CardMapper cardMapper;
public List<Card> GetPageList(Integer page,Integer rows,String sortBy,Boolean desc,String key)
{
//分页
PageHelper.startPage(page,rows);
//过滤
Example example=new Example(Card.class);
if(key!=""&&!key.equals("")){
example.createCriteria().orLike("title","%"+key+"%");
}
//排序
if(sortBy!=""&&!key.equals("")){
String orderByClause=sortBy+(desc?" DESC":" ASC");
example.setOrderByClause(orderByClause);
}
//查询
List<Card> list=cardMapper.selectByExample(example);
PageInfo<Card> info=new PageInfo<Card>(list);
return info.getList();
}
}
7.建立Controller
HomeController.java
package org.zn.test.testpage.controller; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; import org.zn.test.testpage.entity.Card; import org.zn.test.testpage.service.CardService; import java.util.List; @RestController @RequestMapping("/home") public class HomeController { @Autowired private CardService cardService; @RequestMapping("/index") public String Index(int page,String key) { List<Card> list = cardService.GetPageList(page, 5, "id", true, key); StringBuilder sb = new StringBuilder(); for (Card item : list) { sb.append(item+"</br>"); } return sb.toString(); } }
8.配置启动类
TestpageApplication.java 就是spring boot启动类，要注意这里用@MapperScan("org.zn.test.testpage.mapper")，进入整包注入。
package org.zn.test.testpage; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import tk.mybatis.spring.annotation.MapperScan; @SpringBootApplication @MapperScan("org.zn.test.testpage.mapper") public class TestpageApplication { public static void main(String[] args) { SpringApplication.run(TestpageApplication.class, args); } }
9.启动，并访问
http://localhost:8099/home/index?page=1&key=a
看一下，是数据分页。
