前几天在这里分享了手写 sql 分页查询实现分页,现在来看看使用 mybatis 分页插件 pagehepler 来实现分页
使用分页插件的原因,简化了sql代码的写法,实现较好的物理分页,比写一段完整的分页sql代码,也能减少了误差性。
Mybatis分页插件 demo 项目地址:https://gitee.com/free/Mybatis_PageHelper
我这里使用 maven 工程实现:
1 <dependency>
2 <groupId>com.github.pagehelper</groupId>
3 <artifactId>pagehelper</artifactId>
4 <version>5.0.0</version>
5 </dependency>
官方文档有两种配置分页拦截器插件
<!--
plugins在配置文件中的位置必须符合要求,否则会报错,顺序如下:
properties?, settings?,
typeAliases?, typeHandlers?,
objectFactory?,objectWrapperFactory?,
plugins?,
environments?, databaseIdProvider?, mappers?
-->
<plugins>
<!-- com.github.pagehelper为PageHelper类所在包名 -->
<plugin interceptor="com.github.pagehelper.PageInterceptor">
<!-- 使用下面的方式配置参数,后面会有所有的参数介绍 -->
<property name="param1" value="value1"/>
</plugin>
</plugins>
使用 spring 的属性配置方式,可以使用 plugins
属性像下面这样配置:
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<!-- 注意其他配置 -->
<property name="plugins">
<array>
<bean class="com.github.pagehelper.PageInterceptor">
<property name="properties">
<!--使用下面的方式配置参数,一行配置一个 -->
<value>
params=value1
</value>
</property>
</bean>
</array>
</property>
</bean>
这里我项目中使用的是第二种,里面的参数根据实际情况配置,也可以不配置
mapper 层 sql 语句按照一般查询写法,不用写分页:
1 <!-- 分页查询 -->
2 <select id="finds" resultType="country">
3 SELECT
4 id,
5 countryname,
6 countrycode
7 FROM
8 country
9 </select>
mapper 层接口:
1 /**
2 * 查询
3 * @param params
4 * @return
5 */
6 public List<Country> finds();
service 业务层接口:
1 /**
2 * 分页查询
3 * @param params 分页参数 pageNo(页码),pageSize(每页查询数目)
4 * @return
5 */
6 public PageInfo<Country> finds(Params params);
service 业务层实现类:PageHelper.startPage(1, 10);
第一个参数表示第几页,第二个参数表示每页显示的记录数
执行完 PageHelper.startPage(1, 10);语句后,紧跟着的第一个select方法会被分页:List<Country> blogs = countryMapper.finds();
然后再用 PageInfo 对查询结果进行包装,PageInfo<Country> pageInfo = new PageInfo<Country>(blogs);
并将 pageInfo 返回到控制层
1 /**
2 * 查询
3 */
4 public PageInfo<Country> finds(Params params) {
5
6 //查询
7 int pageNo = params.getPageNo();
8 int pageSize = params.getPageSize();
9
10 PageHelper.startPage(pageNo, pageSize);
11 List<Country> blogs = countryMapper.finds();
12 //用PageInfo对结果进行包装
13 PageInfo<Country> pageInfo = new PageInfo<Country>(blogs);
14
15 return pageInfo;
16
17 }
这里返回 pageInfo 后,在 controller 层传入 params 分页参数 和 解析 pageInfo:
List<Country> clist = pageInfo.getList(); 再将 clist 放进作用域,在前台页面利用<c:forEach></c:forEach>可循环获得分页数据
1 /**
2 * 首页,并且分页查询
3 * @return
4 */
5 @RequestMapping("/index")
6 public ModelAndView index(Params params){
7
8 ModelAndView modelAndView = new ModelAndView();
9 //一开始第一页,查询10条
10 params.setPageNo(1);
11 params.setPageSize(10);
12 PageInfo<Country> pageInfo = countryService.finds(params);
13
14 List<Country> clist = pageInfo.getList();
15
16 //查询数量
17 long couts = countryService.counts();
18
19 modelAndView.addObject("clist", clist);
20 modelAndView.addObject("couts", couts);
21 modelAndView.setViewName("index");
22
23 return modelAndView;
24 }
1 <project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://maven.apache.org/POM/4.0.0"
2 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
3 <modelVersion>4.0.0</modelVersion>
4 <groupId>com.krry</groupId>
5 <artifactId>maven_pagehepler_ora</artifactId>
6 <packaging>war</packaging>
7 <version>1.0-SNAPSHOT</version>
8 <name>maven_pagehepler_ora</name>
9 <url>http://maven.apache.org</url>
10
11 <properties>
12 <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
13 <!-- MyBatis Generator -->
14 <!-- Java接口和实体类 -->
15 <targetJavaProject>${basedir}/src/main/java</targetJavaProject>
16 <targetMapperPackage>com.isea533.mybatis.mapper</targetMapperPackage>
17 <targetModelPackage>com.isea533.mybatis.model</targetModelPackage>
18 <!-- XML生成路径 -->
19 <targetResourcesProject>${basedir}/src/main/resources</targetResourcesProject>
20 <targetXMLPackage>mapper</targetXMLPackage>
21 <!-- 编译jdk版本 -->
22 <jdk.version>1.6</jdk.version>
23 <!-- 依赖版本 -->
24 <mybatis.version>3.3.1</mybatis.version>
25 <mapper.version>3.3.6</mapper.version>
26 <pagehelper.version>5.0.0</pagehelper.version>
27 <mysql.version>5.1.29</mysql.version>
28 <spring.version>4.1.2.RELEASE</spring.version>
29 <mybatis.spring.version>1.2.4</mybatis.spring.version>
30 </properties>
31
32 <dependencies>
33 <dependency>
34 <groupId>junit</groupId>
35 <artifactId>junit</artifactId>
36 <version>4.11</version>
37 <scope>test</scope>
38 </dependency>
39 <dependency>
40 <groupId>log4j</groupId>
41 <artifactId>log4j</artifactId>
42 <version>1.2.17</version>
43 </dependency>
44
45 <!--web-->
46 <dependency>
47 <groupId>javax.servlet</groupId>
48 <artifactId>servlet-api</artifactId>
49 <version>2.5</version>
50 <scope>provided</scope>
51 </dependency>
52 <dependency>
53 <groupId>javax.servlet.jsp</groupId>
54 <artifactId>jsp-api</artifactId>
55 <version>2.1</version>
56 <scope>provided</scope>
57 </dependency>
58 <dependency>
59 <groupId>javax.servlet</groupId>
60 <artifactId>jstl</artifactId>
61 <version>1.2</version>
62 </dependency>
63 <dependency>
64 <groupId>javax.ws.rs</groupId>
65 <artifactId>javax.ws.rs-api</artifactId>
66 <version>2.0</version>
67 </dependency>
68 <dependency>
69 <groupId>javax.websocket</groupId>
70 <artifactId>javax.websocket-api</artifactId>
71 <version>1.0</version>
72 </dependency>
73 <dependency>
74 <groupId>javax.annotation</groupId>
75 <artifactId>javax.annotation-api</artifactId>
76 <version>1.2</version>
77 </dependency>
78 <dependency>
79 <groupId>javax.transaction</groupId>
80 <artifactId>javax.transaction-api</artifactId>
81 <version>1.2</version>
82 </dependency>
83
84 <!--Spring-->
85 <dependency>
86 <groupId>org.springframework</groupId>
87 <artifactId>spring-context</artifactId>
88 </dependency>
89 <dependency>
90 <groupId>org.springframework</groupId>
91 <artifactId>spring-orm</artifactId>
92 </dependency>
93 <dependency>
94 <groupId>org.springframework</groupId>
95 <artifactId>spring-oxm</artifactId>
96 </dependency>
97 <dependency>
98 <groupId>org.springframework</groupId>
99 <artifactId>spring-jdbc</artifactId>
100 </dependency>
101 <dependency>
102 <groupId>org.springframework</groupId>
103 <artifactId>spring-tx</artifactId>
104 </dependency>
105 <dependency>
106 <groupId>org.springframework</groupId>
107 <artifactId>spring-web</artifactId>
108 </dependency>
109 <dependency>
110 <groupId>org.springframework</groupId>
111 <artifactId>spring-webmvc</artifactId>
112 </dependency>
113 <dependency>
114 <groupId>org.springframework</groupId>
115 <artifactId>spring-aop</artifactId>
116 </dependency>
117 <dependency>
118 <groupId>org.springframework</groupId>
119 <artifactId>spring-test</artifactId>
120 </dependency>
121
122 <!--spring-oxm依赖-->
123 <dependency>
124 <groupId>org.codehaus.castor</groupId>
125 <artifactId>castor-xml</artifactId>
126 <version>1.3.3</version>
127 </dependency>
128 <!--spring-json依赖-->
129 <dependency>
130 <groupId>com.fasterxml.jackson.core</groupId>
131 <artifactId>jackson-databind</artifactId>
132 <version>2.4.2</version>
133 </dependency>
134 <dependency>
135 <groupId>com.fasterxml.jackson.dataformat</groupId>
136 <artifactId>jackson-dataformat-xml</artifactId>
137 <version>2.4.2</version>
138 </dependency>
139 <!--spring-aop依赖-->
140 <dependency>
141 <groupId>org.aspectj</groupId>
142 <artifactId>aspectjweaver</artifactId>
143 <version>1.8.2</version>
144 </dependency>
145
146 <!--上传文件-->
147 <dependency>
148 <groupId>commons-fileupload</groupId>
149 <artifactId>commons-fileupload</artifactId>
150 <version>1.3.1</version>
151 </dependency>
152
153 <!--mysql-->
154 <dependency>
155 <groupId>mysql</groupId>
156 <artifactId>mysql-connector-java</artifactId>
157 <version>${mysql.version}</version>
158 </dependency>
159
160 <!--druid-->
161 <dependency>
162 <groupId>com.alibaba</groupId>
163 <artifactId>druid</artifactId>
164 <version>1.0.11</version>
165 </dependency>
166
167 <!--Mybatis-->
168 <dependency>
169 <groupId>org.mybatis</groupId>
170 <artifactId>mybatis</artifactId>
171 <version>${mybatis.version}</version>
172 </dependency>
173 <dependency>
174 <groupId>org.mybatis</groupId>
175 <artifactId>mybatis-spring</artifactId>
176 <version>${mybatis.spring.version}</version>
177 </dependency>
178 <!-- Mybatis Generator -->
179 <dependency>
180 <groupId>org.mybatis.generator</groupId>
181 <artifactId>mybatis-generator-core</artifactId>
182 <version>1.3.2</version>
183 <scope>compile</scope>
184 <optional>true</optional>
185 </dependency>
186 <!--分页插件-->
187 <dependency>
188 <groupId>com.github.pagehelper</groupId>
189 <artifactId>pagehelper</artifactId>
190 <version>${pagehelper.version}</version>
191 </dependency>
192 <!--通用Mapper-->
193 <dependency>
194 <groupId>tk.mybatis</groupId>
195 <artifactId>mapper</artifactId>
196 <version>${mapper.version}</version>
197 </dependency>
198
199 <dependency>
200 <groupId>org.apache.commons</groupId>
201 <artifactId>commons-lang3</artifactId>
202 <version>3.3.2</version>
203 </dependency>
204
205
206 </dependencies>
207 <dependencyManagement>
208 <dependencies>
209 <dependency>
210 <groupId>org.springframework</groupId>
211 <artifactId>spring-framework-bom</artifactId>
212 <version>${spring.version}</version>
213 <type>pom</type>
214 <scope>import</scope>
215 </dependency>
216 </dependencies>
217 </dependencyManagement>
218 <repositories>
219 <repository>
220 <id>nexus</id>
221 <name>local private nexus</name>
222 <url>http://maven.oschina.net/content/groups/public/</url>
223 <releases>
224 <enabled>true</enabled>
225 </releases>
226 <snapshots>
227 <enabled>false</enabled>
228 </snapshots>
229 </repository>
230 <repository>
231 <id>sonatype-nexus-releases</id>
232 <name>Sonatype Nexus Releases</name>
233 <url>http://oss.sonatype.org/content/repositories/releases</url>
234 <releases>
235 <enabled>true</enabled>
236 </releases>
237 <snapshots>
238 <enabled>false</enabled>
239 </snapshots>
240 </repository>
241 <repository>
242 <id>sonatype-nexus-snapshots</id>
243 <name>Sonatype Nexus Snapshots</name>
244 <url>http://oss.sonatype.org/content/repositories/snapshots</url>
245 <releases>
246 <enabled>false</enabled>
247 </releases>
248 <snapshots>
249 <enabled>true</enabled>
250 </snapshots>
251 </repository>
252 </repositories>
253 <build>
254 <plugins>
255 <plugin>
256 <groupId>org.apache.maven.plugins</groupId>
257 <artifactId>maven-compiler-plugin</artifactId>
258 <version>3.2</version>
259 <configuration>
260 <source>1.7</source>
261 <target>1.7</target>
262 </configuration>
263 </plugin>
264 </plugins>
265 </build>
266 </project>
1 <?xml version="1.0" encoding="UTF-8"?>
2 <beans xmlns="http://www.springframework.org/schema/beans"
3 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"
4 xmlns:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx"
5 xmlns:util="http://www.springframework.org/schema/util" xmlns:p="http://www.springframework.org/schema/p"
6 xsi:schemaLocation="http://www.springframework.org/schema/beans
7 http://www.springframework.org/schema/beans/spring-beans.xsd
8 http://www.springframework.org/schema/aop
9 http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
10 http://www.springframework.org/schema/tx
11 http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
12 http://www.springframework.org/schema/context
13 http://www.springframework.org/schema/context/spring-context-3.0.xsd
14 http://www.springframework.org/schema/util
15 http://www.springframework.org/schema/util/spring-util-3.0.xsd
16 ">
17
18
19 <!-- 配置包扫描 -->
20 <context:component-scan base-package="com.krry"></context:component-scan>
21
22 <!-- 导入外部资源文件 -->
23 <context:property-placeholder location="classpath:jdbc.properties" />
24
25
26 <!-- 配置druid数据源 -->
27 <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource"
28 init-method="init" destroy-method="close">
29 <property name="driverClassName" value="${db.driver}" />
30 <property name="url" value="${db.url}" />
31 <property name="username" value="${db.username}" />
32 <property name="password" value="${db.password}" />
33 </bean>
34
35 <!-- 注册事务管理器 -->
36 <bean id="txMgr"
37 class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
38 <property name="dataSource" ref="dataSource"></property>
39 </bean>
40
41 <!-- 开启事务注解驱动 -->
42 <tx:annotation-driven transaction-manager="txMgr" />
43
44 <!-- 配置mybatis的sqlSessionFactory -->
45 <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
46 <property name="dataSource" ref="dataSource"/>
47 <property name="configLocation" value="classpath:mybatis-config.xml"></property>
48 <property name="typeAliasesPackage" value="com.krry.entity"/>
49 <property name="plugins">
50 <array>
51 <bean class="com.github.pagehelper.PageInterceptor">
52 <!-- 这里的几个配置主要演示如何使用,如果不理解,一定要去掉下面的配置 -->
53 <property name="properties">
54 <value>
55
56 </value>
57 </property>
58 </bean>
59 </array>
60 </property>
61 </bean>
62
63 <!-- 配置可以整体扫描Mapper的一个扫描器 -->
64 <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
65 <!--如果有多个报路径,用逗号分开即可 -->
66 <property name="basePackage" value="com.krry.mapper"></property>
67 <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"></property>
68 </bean>
69
70 </beans>
1 <?xml version="1.0" encoding="UTF-8"?>
2 <!DOCTYPE configuration
3 PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
4 "http://mybatis.org/dtd/mybatis-3-config.dtd">
5
6 <configuration>
7 <settings>
8 <!-- 全局映射器启用缓存 -->
9 <setting name="cacheEnabled" value="true" />
10 <!-- 查询时,关闭关联对象即时加载以提高性能 -->
11 <setting name="lazyLoadingEnabled" value="true" />
12 <!-- 设置关联对象加载的形态,此处为按需加载字段(加载字段由SQL指 定),不会加载关联表的所有字段,以提高性能 -->
13 <setting name="aggressiveLazyLoading" value="false" />
14 <!-- 对于未知的SQL查询,允许返回不同的结果集以达到通用的效果 -->
15 <setting name="multipleResultSetsEnabled" value="true" />
16 <!-- 允许使用列标签代替列名 -->
17 <setting name="useColumnLabel" value="true" />
18 <!-- 允许使用自定义的主键值(比如由程序生成的UUID 32位编码作为键值),数据表的PK生成策略将被覆盖 -->
19 <setting name="useGeneratedKeys" value="true" />
20 <!-- 给予被嵌套的resultMap以字段-属性的映射支持 -->
21 <setting name="autoMappingBehavior" value="FULL" />
22 <!-- 对于批量更新操作缓存SQL以提高性能 -->
23 <setting name="defaultExecutorType" value="BATCH" />
24 <!-- 数据库超过25000秒仍未响应则超时 -->
25 <setting name="defaultStatementTimeout" value="25" />
26 <setting name="lazyLoadTriggerMethods" value="equals,clone,hashCode,toString"/>
27 </settings>
28
29 <typeAliases>
30 <!--自定义user对象的别名 -->
31 <!-- <typeAlias type="com.krry.mybatis.sysmanage.entity.User" alias="user"/> -->
32 <!-- 批量定义别名 -->
33 <package name="com.krry.entity" />
34 </typeAliases>
35
36 </configuration>
1 <?xml version="1.0" encoding="UTF-8" ?>
2 <beans xmlns="http://www.springframework.org/schema/beans"
3 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
4 xmlns:p="http://www.springframework.org/schema/p"
5 xmlns:context="http://www.springframework.org/schema/context"
6 xmlns:util="http://www.springframework.org/schema/util"
7 xmlns:mvc="http://www.springframework.org/schema/mvc"
8 xsi:schemaLocation="http://www.springframework.org/schema/beans
9 http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
10 http://www.springframework.org/schema/context
11 http://www.springframework.org/schema/context/spring-context-3.0.xsd
12 http://www.springframework.org/schema/util
13 http://www.springframework.org/schema/util/spring-util-3.0.xsd
14 http://www.springframework.org/schema/mvc
15 http://www.springframework.org/schema/mvc/spring-mvc.xsd
16 ">
17
18 <!-- 开启注解模式驱动 -->
19 <bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" />
20 <!-- 开启mvc的注解模式 user 还会注册一个ConversionService 子类FormattingConversionServiceFactoryBean-->
21 <mvc:annotation-driven>
22 <mvc:message-converters register-defaults="true">
23 <bean class="com.krry.core.UTF8StringHttpMessageConverter">
24 <property name="supportedMediaTypes">
25 <list>
26 <value>text/plain;charset=UTF-8</value>
27 <value>text/html;charset=UTF-8</value>
28 </list>
29 </property>
30 </bean>
31 <bean class="org.springframework.http.converter.BufferedImageHttpMessageConverter"/>
32 <bean class="org.springframework.http.converter.ByteArrayHttpMessageConverter"/>
33 <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
34 <property name="prefixJson" value="false" />
35 <property name="objectMapper">
36 <bean class="com.fasterxml.jackson.databind.ObjectMapper">
37 <!-- 处理responseBody 里面日期类型 -->
38 <property name="dateFormat">
39 <bean class="java.text.SimpleDateFormat">
40 <constructor-arg type="java.lang.String" value="yyyy-MM-dd HH:mm:ss" />
41 </bean>
42 </property>
43 <!-- 为null字段时不显示 -->
44 <property name="serializationInclusion">
45 <value type="com.fasterxml.jackson.annotation.JsonInclude.Include">NON_NULL</value>
46 </property>
47 </bean>
48 </property>
49 <property name="supportedMediaTypes">
50 <list>
51 <value>application/json;charset=UTF-8</value>
52 <value>application/x-www-form-urlencoded;charset=UTF-8</value>
53 </list>
54 </property>
55 </bean>
56 </mvc:message-converters>
57 </mvc:annotation-driven>
58
59
60 <!-- 扫包 -->
61 <context:component-scan base-package="com.krry.controller"></context:component-scan>
62
63 <!--对静态资源文件的访问 必须要设置,因为在springmvc的配置中配置了/匹配所有请求,
64 此工程所有的请求(.do ,addUser,js/image/css)都会被springmvc解析,
65 必须对所有的静态资源文件进行过滤放行 -->
66 <!-- 静态资源过滤 下面二选一-->
67 <!--<mvc:default-servlet-handler/> -->
68 <mvc:resources mapping="/resource/**" location="/resource/" />
69
70
71
72 <!-- 视图渲染 jsp/freemaker/velocity-->
73 <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
74 <!-- 制定页面存放的路径 -->
75 <property name="prefix" value="/WEB-INF/pages/"></property>
76 <!-- 文件的后缀 -->
77 <property name="suffix" value=".jsp"></property>
78 </bean>
79
80 </beans>
jdbc.properties 和 log4j.properties 就不用展示了,都差不多的
1 <?xml version="1.0" encoding="UTF-8"?>
2 <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" version="2.5">
3 <display-name>maven_pagehepler</display-name>
4 <welcome-file-list>
5 <welcome-file>index/index</welcome-file>
6 </welcome-file-list>
7 <context-param>
8 <param-name>contextConfigLocation</param-name>
9 <param-value>classpath:applicationContext.xml</param-value>
10 </context-param>
11 <listener>
12 <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
13 </listener>
14 <listener>
15 <listener-class>org.springframework.web.util.IntrospectorCleanupListener</listener-class>
16 </listener>
17 <filter>
18 <filter-name>encoding</filter-name>
19 <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
20 <init-param>
21 <param-name>encoding</param-name>
22 <param-value>UTF-8</param-value>
23 </init-param>
24 </filter>
25 <filter-mapping>
26 <filter-name>encoding</filter-name>
27 <url-pattern>/*</url-pattern>
28 </filter-mapping>
29 <servlet>
30 <servlet-name>maven_pagehepler</servlet-name>
31 <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
32 <init-param>
33 <param-name>contextConfigLocation</param-name>
34 <param-value>classpath:springmvc.xml</param-value>
35 </init-param>
36 </servlet>
37 <servlet-mapping>
38 <servlet-name>maven_pagehepler</servlet-name>
39 <url-pattern>/index/index</url-pattern>
40 </servlet-mapping>
41 <servlet-mapping>
42 <servlet-name>maven_pagehepler</servlet-name>
43 <url-pattern>/</url-pattern>
44 </servlet-mapping>
45 </web-app>
1 package com.krry.entity;
2
3 public class Country {
4
5
6 /**
7 * 主键
8 */
9 private Integer id;
10
11 /**
12 * 名称
13 */
14 private String countryname;
15
16 /**
17 * 代码
18 */
19 private String countrycode;
20
21
22
23 public Country(Integer id, String countryname, String countrycode) {
24 this.id = id;
25 this.countryname = countryname;
26 this.countrycode = countrycode;
27 }
28
29 /**
30 * 获取主键
31 *
32 * @return Id - 主键
33 */
34 public Integer getId() {
35 return id;
36 }
37
38 /**
39 * 设置主键
40 *
41 * @param id 主键
42 */
43 public void setId(Integer id) {
44 this.id = id;
45 }
46
47 /**
48 * 获取名称
49 *
50 * @return countryname - 名称
51 */
52 public String getCountryname() {
53 return countryname;
54 }
55
56 /**
57 * 设置名称
58 *
59 * @param countryname 名称
60 */
61 public void setCountryname(String countryname) {
62 this.countryname = countryname;
63 }
64
65 /**
66 * 获取代码
67 *
68 * @return countrycode - 代码
69 */
70 public String getCountrycode() {
71 return countrycode;
72 }
73
74 /**
75 * 设置代码
76 *
77 * @param countrycode 代码
78 */
79 public void setCountrycode(String countrycode) {
80 this.countrycode = countrycode;
81 }
82 }
1 package com.krry.entity;
2
3 /**
4 *
5 * Params
6 * @author krry
7 * @version 1.0.0
8 *
9 */
10 public class Params {
11
12 private Integer pageSize = 10;
13 private Integer pageNo = 0;
14
15
16 public Integer getPageNo() {
17 return pageNo;
18 }
19
20 public void setPageNo(Integer pageNo) {
21 this.pageNo = pageNo;
22 }
23
24 public Integer getPageSize() {
25 return pageSize;
26 }
27
28 public void setPageSize(Integer pageSize) {
29 this.pageSize = pageSize;
30 }
31
32 }
1 package com.krry.mapper;
2
3 import java.util.List;
4
5 import com.krry.entity.Country;
6
7 /**
8 *
9 * Mapper:操作数据库
10 * @author krry
11 * @version 1.0.0
12 *
13 */
14 public interface CountryMapper {
15
16 /**
17 * 查询
18 * @param params
19 * @return
20 */
21 public List<Country> finds();
22
23 /**
24 * 计算
25 * com.krry.dao.admin
26 * 方法名:countBlogs
27 * @author krry
28 * @param params
29 * @return int
30 * @exception
31 * @since 1.0.0
32 */
33 public long counts();
34
35
36 }
1 <?xml version="1.0" encoding="UTF-8" ?>
2 <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
3 "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
4
5 <mapper namespace="com.krry.mapper.CountryMapper" >
6
7 <!-- 分页查询 -->
8 <select id="finds" resultType="country">
9 SELECT
10 id,
11 countryname,
12 countrycode
13 FROM
14 country
15 </select>
16
17 <!-- 查询博客数量 -->
18 <select id="counts" resultType="long">
19 SELECT
20 count(*)
21 FROM
22 country
23 </select>
24
25
26 </mapper>
1 package com.krry.service;
2
3 import java.util.HashMap;
4 import java.util.List;
5
6 import javax.servlet.http.HttpServletRequest;
7
8 import org.apache.ibatis.annotations.Param;
9
10 import com.github.pagehelper.PageInfo;
11 import com.krry.entity.Country;
12 import com.krry.entity.Params;
13
14 /**
15 * service层:处理业务逻辑(impl里面实现)
16 * @author asusaad
17 *
18 */
19 public interface ICountryService {
20
21 /**
22 * 分页查询所有博客
23 * @param params 分页参数 pageNo(页码),pageSize(每页查询数目)
24 * @return
25 */
26 public PageInfo<Country> finds(Params params);
27
28 /**
29 * 计算博客数量
30 * @param params
31 * @return
32 */
33 public long counts();
34
35 }
1 package com.krry.service.impl;
2
3 import java.util.HashMap;
4 import java.util.List;
5
6 import org.springframework.beans.factory.annotation.Autowired;
7 import org.springframework.stereotype.Service;
8 import org.springframework.web.servlet.ModelAndView;
9
10 import com.github.pagehelper.PageHelper;
11 import com.github.pagehelper.PageInfo;
12 import com.krry.entity.Country;
13 import com.krry.entity.Params;
14 import com.krry.mapper.CountryMapper;
15 import com.krry.service.ICountryService;
16
17 /**
18 * 实现service层接口
19 * @author asusaad
20 *
21 */
22 @Service
23 public class CountryService implements ICountryService{
24
25 @Autowired
26 private CountryMapper countryMapper;
27
28 /**
29 * 查询
30 */
31 public PageInfo<Country> finds(Params params) {
32
33 //查询
34 int pageNo = params.getPageNo();
35 int pageSize = params.getPageSize();
36
37 PageHelper.startPage(pageNo, pageSize);
38 List<Country> blogs = countryMapper.finds();
39 //用PageInfo对结果进行包装
40 PageInfo<Country> pageInfo = new PageInfo<Country>(blogs);
41
42 return pageInfo;
43
44 }
45
46 /**
47 * 计算
48 * @param params
49 * @return
50 */
51 public long counts(){
52
53 long couts = countryMapper.counts();
54
55 return couts;
56 }
57
58
59
60 }
1 package com.krry.controller;
2
3 import java.util.ArrayList;
4 import java.util.HashMap;
5 import java.util.List;
6
7 import org.junit.Test;
8 import org.springframework.beans.factory.annotation.Autowired;
9 import org.springframework.stereotype.Controller;
10 import org.springframework.web.bind.annotation.RequestMapping;
11 import org.springframework.web.bind.annotation.ResponseBody;
12 import org.springframework.web.servlet.ModelAndView;
13
14 import com.github.pagehelper.PageInfo;
15 import com.krry.entity.Country;
16 import com.krry.entity.Params;
17 import com.krry.service.ICountryService;
18
19 /**
20 * KrryController
21 * controller层,作为请求转发
22 * @author asusaad
23 *
24 */
25 @Controller //表示是多例模式,每个用户返回的web层是不一样的
26 @RequestMapping("/index")
27 public class KrryController {
28
29 @Autowired
30 private ICountryService countryService;
31
32 /**
33 * 首页,并且分页查询
34 * @return
35 */
36 @RequestMapping("/index")
37 public ModelAndView index(Params params){
38
39 ModelAndView modelAndView = new ModelAndView();
40 //一开始第一页,查询10条
41 params.setPageNo(1);
42 params.setPageSize(10);
43 PageInfo<Country> pageInfo = countryService.finds(params);
44
45 List<Country> clist = pageInfo.getList();
46
47 //查询数量
48 long couts = countryService.counts();
49
50 modelAndView.addObject("clist", clist);
51 modelAndView.addObject("couts", couts);
52 modelAndView.setViewName("index");
53
54 return modelAndView;
55 }
56
57 /**
58 * ajax请求 的 分页查询
59 * @param params
60 * @return
61 */
62 @ResponseBody
63 @RequestMapping("/loadData")
64 public HashMap<String, Object> loadData(Params params){
65
66
67 HashMap<String, Object> map = new HashMap<String, Object>();
68 PageInfo<Country> pageInfo = countryService.finds(params);
69 List<Country> clist = pageInfo.getList();
70 map.put("clist", clist);
71
72 return map;
73 }
74 //
75
76 }