因为项目中常常用到分页，我又嫌弃网上流行的分页插件，所以手写了一个。以后再完善说明
@JsonSerialize(using = TmsQueryJsonSerialize.class,typing = JsonSerialize.Typing.DYNAMIC) public interface Page<T> { int getPageNo(); int getPageSize(); int getTotalCount(); void setTotalCount(int totalCount); List<T> getData(); void setData(List<T> data); } package com.shangqiao56; import java.util.List; public interface PageList<T> extends Page<T> ,List<T> { } /** * 对我们自己的page包装，让page实现List接口，ResultSetHandler 返回的必需是List类型 * @param <T> */ public class TmsPageWraper<T> implements PageList<T> { private TmsPage<T> page; public static TmsPageWraper wrap(TmsPage<?> tmsPage){ TmsPageWraper wraper= new TmsPageWraper(); wraper.page = tmsPage; return wraper; } @Override public int getTotalCount() { return page.getTotalCount(); } @Override public void setTotalCount(int totalCount) { this.page.setTotalCount(totalCount); } @Override public int getPageSize() { return page.getPageSize(); } @Override public int getPageNo() { return page.getPageNo(); } @Override public List<T> getData() { return page.getData(); } @Override public void setData(List<T> data) { page.setData(data); } @Override public int size() { return getData().size(); } @Override public boolean isEmpty() { return getData().isEmpty(); } @Override public boolean contains(Object o) { return getData().contains(o); } @Override public Iterator<T> iterator() { return page.iterator(); } @Override public Object[] toArray() { return getData().toArray(); } @Override public <T1> T1[] toArray(T1[] a) { return getData().toArray(a); } @Override public boolean add(T t) { return getData().add(t); } @Override public boolean remove(Object o) { return getData().remove(o); } @Override public boolean containsAll(Collection<?> c) { return getData().containsAll(c); } @Override public boolean addAll(Collection<? extends T> c) { return getData().addAll(c); } @Override public boolean addAll(int index, Collection<? extends T> c) { return getData().addAll(index,c); } @Override public boolean removeAll(Collection<?> c) { return getData().removeAll(c); } @Override public boolean retainAll(Collection<?> c) { return getData().retainAll(c); } @Override public void clear() { getData().clear(); } @Override public T get(int index) { return getData().get(index); } @Override public T set(int index, T element) { return getData().set(index,element); } @Override public void add(int index, T element) { getData().add(index,element); } @Override public T remove(int index) { return getData().remove(index); } @Override public int indexOf(Object o) { return getData().indexOf(o); } @Override public int lastIndexOf(Object o) { return getData().lastIndexOf(o); } @Override public ListIterator<T> listIterator() { return getData().listIterator(); } @Override public ListIterator<T> listIterator(int index) { return getData().listIterator(); } @Override public List<T> subList(int fromIndex, int toIndex) { return getData().subList(fromIndex,toIndex); } } import com.shangqiao56.Page; import com.shangqiao56.tms.TmsPage; import org.apache.ibatis.executor.ErrorContext; import org.apache.ibatis.executor.resultset.ResultSetHandler; import org.apache.ibatis.executor.statement.StatementHandler; import org.apache.ibatis.plugin.*; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.sql.*; import java.util.List; import java.util.Map; import java.util.Properties; /** * 分页插件，自动补全分页语句 */ @Intercepts( { @Signature(method = "handleResultSets", type = ResultSetHandler.class, args = {Statement.class}), @Signature(method = "prepare", type = StatementHandler.class, args = {Connection.class,Integer.class})}) public class PageInterceptor implements Interceptor { private static final Logger log = LoggerFactory.getLogger(PageInterceptor.class); private static final ThreadLocal<Page> pageContext = new ThreadLocal<>(); @Override public Object intercept(Invocation invocation) throws Throwable { Object target = invocation.getTarget(); Object result = null; TmsPageWraper pageWraper; if(target instanceof StatementHandler){ StatementHandler statementHandler = (StatementHandler) target; Object queryParams = statementHandler.getParameterHandler().getParameterObject(); TmsPage page = parsePage(queryParams); if(page != null){ /*** * 真有必要将page拆分成两个接口 */ pageWraper = TmsPageWraper.wrap(page); pageContext.set(pageWraper); Connection connection = (Connection)invocation.getArgs()[0]; /*** * //0表示不限制，参考 * @see Statement.setQueryTimeout */ int timeout = (invocation.getArgs()[1]!=null) ? (Integer)invocation.getArgs()[1]:0; String sql = statementHandler.getBoundSql().getSql(); result = prepare(connection,sql,timeout,page); //填充totalCount的值 String countSql = buildQueryCount(statementHandler.getBoundSql().getSql()); log.debug("generate a query count sql : {}",countSql); PreparedStatement coutStat =connection.prepareStatement(countSql); statementHandler.parameterize(coutStat); coutStat.setQueryTimeout(timeout); ResultSet rs = coutStat.executeQuery(); if(rs.next()) { Integer totalCount = rs.getInt(1); page.setTotalCount(totalCount); } }else{ result = invocation.proceed(); } }else if(target instanceof ResultSetHandler){ pageWraper = (TmsPageWraper) pageContext.get(); result = invocation.proceed(); if(pageWraper != null){ pageWraper.setData((List)result); pageContext.remove(); result = pageWraper; } } return result; } private Statement prepare(Connection connection,String querySql, Integer timeout, TmsPage<?> page) throws SQLException { // BoundSql bound = statementHandler.getBoundSql(); String sql = buildPageSql(querySql,page); //todo 我这边少了很多检查，去看 PreparedStatementHandler ErrorContext.instance().sql(sql); Statement statement = connection.prepareStatement(sql); statement.setQueryTimeout(timeout); return statement; } private TmsPage parsePage(Object parameter){ TmsPage page = null; if(parameter instanceof Page){ page = (TmsPage<?>) parameter; } if(parameter instanceof Map){ log.debug("query params {}",parameter); Map<String,Object> paraMap = (Map)parameter; for (Map.Entry<String, Object> entry : paraMap.entrySet()) { if(entry.getValue() instanceof TmsPage) page = (TmsPage)entry.getValue(); } } return page; } private static final String PAGE_SQL = " SELECT * FROM (SELECT A.*, ROWNUM RN FROM (%s) A WHERE ROWNUM <= %d) WHERE RN > %d"; protected String buildPageSql(String sql,TmsPage<?> page){ return String.format(PAGE_SQL,sql,page.getEndRow(),page.getStartRow()); } private String buildQueryCount(String sql){ int fromIdx = getFromIdx(sql); return "SELECT COUNT(1) " +sql.substring(fromIdx); } @Override public Object plugin(Object target) { if (target instanceof StatementHandler || target instanceof ResultSetHandler) { return Plugin.wrap(target, this); } else { return target; } } @Override public void setProperties(Properties properties) { } /*** * 获取sql语句中的from中的位置 * @param sql * @return */ private static int getFromIdx(String sql) { char[] chars = sql.toCharArray(); char c; int bcount=0; final String newWordstars = " )\n\t"; //from开始前能出现的单词 for (int i = 0; i < chars.length; i++) { c = chars[i]; if(c == '(') bcount++; else if(c == ')') bcount --; if(bcount != 0) continue; if(newWordstars.indexOf(c)!=-1){ if((chars[i+1]=='f'||chars[i+1]=='F') &&(chars[i+2]=='r'||chars[i+2]=='R') &&(chars[i+3]=='o'||chars[i+3]=='O') &&(chars[i+4]=='m'||chars[i+4]=='M') &&(chars[i+5]==' ' || chars[i+5]=='(' || chars[i+5]=='\n') ){ return i; } } } return -1; } } @Configuration @ConditionalOnClass({SqlSessionFactory.class, SqlSessionFactoryBean.class}) @ConditionalOnSingleCandidate(DataSource.class) @EnableConfigurationProperties({MybatisProperties.class}) @AutoConfigureAfter({DataSourceAutoConfiguration.class}) public class TmsMybatisAutoConfiguration implements InitializingBean { private static final Logger logger = LoggerFactory.getLogger(TmsMybatisAutoConfiguration.class); private final MybatisProperties properties; private final Interceptor[] interceptors; private final ResourceLoader resourceLoader; private final DatabaseIdProvider databaseIdProvider; private final List<ConfigurationCustomizer> configurationCustomizers; public TmsMybatisAutoConfiguration(MybatisProperties properties, ObjectProvider<Interceptor[]> interceptorsProvider, ResourceLoader resourceLoader, ObjectProvider<DatabaseIdProvider> databaseIdProvider, ObjectProvider<List<ConfigurationCustomizer>> configurationCustomizersProvider) { this.properties = properties; this.interceptors = (Interceptor[])interceptorsProvider.getIfAvailable(); this.resourceLoader = resourceLoader; this.databaseIdProvider = (DatabaseIdProvider)databaseIdProvider.getIfAvailable(); this.configurationCustomizers = (List)configurationCustomizersProvider.getIfAvailable(); } public void afterPropertiesSet() { this.checkConfigFileExists(); } private void checkConfigFileExists() { if (this.properties.isCheckConfigLocation() && StringUtils.hasText(this.properties.getConfigLocation())) { Resource resource = this.resourceLoader.getResource(this.properties.getConfigLocation()); Assert.state(resource.exists(), "Cannot find config location: " + resource + " (please add config file or check your Mybatis configuration)"); } } @Bean @ConditionalOnMissingBean public SqlSessionFactory sqlSessionFactory(DataSource dataSource) throws Exception { SqlSessionFactoryBean factory = new SqlSessionFactoryBean(); factory.setDataSource(dataSource); factory.setVfs(SpringBootVFS.class); if (StringUtils.hasText(this.properties.getConfigLocation())) { factory.setConfigLocation(this.resourceLoader.getResource(this.properties.getConfigLocation())); } this.applyConfiguration(factory); if (this.properties.getConfigurationProperties() != null) { factory.setConfigurationProperties(this.properties.getConfigurationProperties()); } if (!ObjectUtils.isEmpty(this.interceptors)) { factory.setPlugins(this.interceptors); } if (this.databaseIdProvider != null) { factory.setDatabaseIdProvider(this.databaseIdProvider); } if (StringUtils.hasLength(this.properties.getTypeAliasesPackage())) { factory.setTypeAliasesPackage(this.properties.getTypeAliasesPackage()); } if (this.properties.getTypeAliasesSuperType() != null) { factory.setTypeAliasesSuperType(this.properties.getTypeAliasesSuperType()); } if (StringUtils.hasLength(this.properties.getTypeHandlersPackage())) { factory.setTypeHandlersPackage(this.properties.getTypeHandlersPackage()); } if (!ObjectUtils.isEmpty(this.properties.resolveMapperLocations())) { factory.setMapperLocations(this.properties.resolveMapperLocations()); } return factory.getObject(); } private void applyConfiguration(SqlSessionFactoryBean factory) { org.apache.ibatis.session.Configuration configuration = this.properties.getConfiguration(); if (configuration == null && !StringUtils.hasText(this.properties.getConfigLocation())) { configuration = new org.apache.ibatis.session.Configuration(); } if (configuration != null && !CollectionUtils.isEmpty(this.configurationCustomizers)) { Iterator var3 = this.configurationCustomizers.iterator(); while(var3.hasNext()) { ConfigurationCustomizer customizer = (ConfigurationCustomizer)var3.next(); customizer.customize(configuration); } } factory.setConfiguration(configuration); } @Bean @ConditionalOnMissingBean public SqlSessionTemplate sqlSessionTemplate(SqlSessionFactory sqlSessionFactory) { ExecutorType executorType = this.properties.getExecutorType(); return executorType != null ? new SqlSessionTemplate(sqlSessionFactory, executorType) : new SqlSessionTemplate(sqlSessionFactory); } @Configuration @Import({TmsMybatisAutoConfiguration.AutoConfiguredMapperScannerRegistrar.class}) @ConditionalOnMissingBean({MapperFactoryBean.class}) public static class MapperScannerRegistrarNotFoundConfiguration implements InitializingBean { public MapperScannerRegistrarNotFoundConfiguration() { } public void afterPropertiesSet() { TmsMybatisAutoConfiguration.logger.debug("No {} found.", MapperFactoryBean.class.getName()); } } public static class AutoConfiguredMapperScannerRegistrar implements BeanFactoryAware, ImportBeanDefinitionRegistrar, ResourceLoaderAware { private BeanFactory beanFactory; private ResourceLoader resourceLoader; public AutoConfiguredMapperScannerRegistrar() { } public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) { if (!AutoConfigurationPackages.has(this.beanFactory)) { TmsMybatisAutoConfiguration.logger.debug("Could not determine auto-configuration package, automatic mapper scanning disabled."); } else { TmsMybatisAutoConfiguration.logger.debug("Searching for mappers annotated with @Mapper"); List<String> packages = AutoConfigurationPackages.get(this.beanFactory); if (TmsMybatisAutoConfiguration.logger.isDebugEnabled()) { packages.forEach((pkg) -> { TmsMybatisAutoConfiguration.logger.debug("Using auto-configuration base package '{}'", pkg); }); } ClassPathMapperScanner scanner = new ClassPathMapperScanner(registry); if (this.resourceLoader != null) { scanner.setResourceLoader(this.resourceLoader); } scanner.setAnnotationClass(Mapper.class); scanner.registerFilters(); scanner.doScan(StringUtils.toStringArray(packages)); } } public void setBeanFactory(BeanFactory beanFactory) { this.beanFactory = beanFactory; } public void setResourceLoader(ResourceLoader resourceLoader) { this.resourceLoader = resourceLoader; } } }