@Intercepts({
        @Signature(type = Executor.class, method = "update", args = {MappedStatement.class, Object.class}),
        @Signature(type = Executor.class, method = "query", args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class})
})

@Intercepts({@Signature(type = Executor.class, method = "query",
        args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class})})
public class TestInterceptor implements Interceptor {
   public Object intercept(Invocation invocation) throws Throwable {
     Object target = invocation.getTarget(); //被代理對(duì)象
     Method method = invocation.getMethod(); //代理方法
     Object[] args = invocation.getArgs(); //方法參數(shù)
     // do something ...... 方法攔截前執(zhí)行代碼塊
     Object result = invocation.proceed();
     // do something .......方法攔截后執(zhí)行代碼塊
     return result;
   }
   public Object plugin(Object target) {
     return Plugin.wrap(target, this);
   }
}

<plugin interceptor="com.plugin.mybatis.MyInterceptor">
     <property name="username" value="xxx"/>
     <property name="password" value="xxx"/>
</plugin>

@Intercepts({
        @Signature(type = Executor.class, method = "update", args = {MappedStatement.class, Object.class}),
        @Signature(type = Executor.class, method = "query", args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class})
})
public class SQLInterceptor implements Interceptor { 
@Override
public Object intercept(Invocation invocation) throws Throwable {
.....
}
@Override
public Object plugin(Object target) {
    return Plugin.wrap(target, this);
}
@Override
public void setProperties(Properties properties) {
.....
}
}

/**
 * Mybatis - 通用分頁(yè)攔截器
 * <p>
 * GitHub: https://github.com/pagehelper/Mybatis-PageHelper
 * <p>
 * Gitee : https://gitee.com/free/Mybatis_PageHelper
 *
 * @author liuzh/abel533/isea533
 * @version 5.0.0
 */
@SuppressWarnings({"rawtypes", "unchecked"})
@Intercepts(
        {
                @Signature(type = Executor.class, method = "query", args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class}),
                @Signature(type = Executor.class, method = "query", args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class, CacheKey.class, BoundSql.class}),
        }
)
public class PageInterceptor implements Interceptor {
    private volatile Dialect dialect;
    private String countSuffix = "_COUNT";
    protected Cache<String, MappedStatement> msCountMap = null;
    private String default_dialect_class = "com.github.pagehelper.PageHelper";
    @Override
    public Object intercept(Invocation invocation) throws Throwable {
        try {
            Object[] args = invocation.getArgs();
            MappedStatement ms = (MappedStatement) args[0];
            Object parameter = args[1];
            RowBounds rowBounds = (RowBounds) args[2];
            ResultHandler resultHandler = (ResultHandler) args[3];
            Executor executor = (Executor) invocation.getTarget();
            CacheKey cacheKey;
            BoundSql boundSql;
            //由于邏輯關(guān)系，只會(huì)進(jìn)入一次
            if (args.length == 4) {
                //4 個(gè)參數(shù)時(shí)
                boundSql = ms.getBoundSql(parameter);
                cacheKey = executor.createCacheKey(ms, parameter, rowBounds, boundSql);
            } else {
                //6 個(gè)參數(shù)時(shí)
                cacheKey = (CacheKey) args[4];
                boundSql = (BoundSql) args[5];
            }
            checkDialectExists();
            List resultList;
            //調(diào)用方法判斷是否需要進(jìn)行分頁(yè)，如果不需要，直接返回結(jié)果
            if (!dialect.skip(ms, parameter, rowBounds)) {
                //判斷是否需要進(jìn)行 count 查詢(xún)
                if (dialect.beforeCount(ms, parameter, rowBounds)) {
                    //查詢(xún)總數(shù)
                    Long count = count(executor, ms, parameter, rowBounds, resultHandler, boundSql);
                    //處理查詢(xún)總數(shù)，返回 true 時(shí)繼續(xù)分頁(yè)查詢(xún)，false 時(shí)直接返回
                    if (!dialect.afterCount(count, parameter, rowBounds)) {
                        //當(dāng)查詢(xún)總數(shù)為 0 時(shí)，直接返回空的結(jié)果
                        return dialect.afterPage(new ArrayList(), parameter, rowBounds);
                    }
                }
                resultList = ExecutorUtil.pageQuery(dialect, executor,
                        ms, parameter, rowBounds, resultHandler, boundSql, cacheKey);
            } else {
                //rowBounds用參數(shù)值，不使用分頁(yè)插件處理時(shí)，仍然支持默認(rèn)的內(nèi)存分頁(yè)
                resultList = executor.query(ms, parameter, rowBounds, resultHandler, cacheKey, boundSql);
            }
            return dialect.afterPage(resultList, parameter, rowBounds);
        } finally {
            if(dialect != null){
                dialect.afterAll();
            }
        }
    }
    /**
     * Spring bean 方式配置時(shí)，如果沒(méi)有配置屬性就不會(huì)執(zhí)行下面的 setProperties 方法，就不會(huì)初始化
     * <p>
     * 因此這里會(huì)出現(xiàn) null 的情況 fixed #26
     */
    private void checkDialectExists() {
        if (dialect == null) {
            synchronized (default_dialect_class) {
                if (dialect == null) {
                    setProperties(new Properties());
                }
            }
        }
    }
    private Long count(Executor executor, MappedStatement ms, Object parameter,
                       RowBounds rowBounds, ResultHandler resultHandler,
                       BoundSql boundSql) throws SQLException {
        String countMsId = ms.getId() + countSuffix;
        Long count;
        //先判斷是否存在手寫(xiě)的 count 查詢(xún)
        MappedStatement countMs = ExecutorUtil.getExistedMappedStatement(ms.getConfiguration(), countMsId);
        if (countMs != null) {
            count = ExecutorUtil.executeManualCount(executor, countMs, parameter, boundSql, resultHandler);
        } else {
            countMs = msCountMap.get(countMsId);
            //自動(dòng)創(chuàng)建
            if (countMs == null) {
                //根據(jù)當(dāng)前的 ms 創(chuàng)建一個(gè)返回值為 Long 類(lèi)型的 ms
                countMs = MSUtils.newCountMappedStatement(ms, countMsId);
                msCountMap.put(countMsId, countMs);
            }
            count = ExecutorUtil.executeAutoCount(dialect, executor, countMs, parameter, boundSql, rowBounds, resultHandler);
        }
        return count;
    }
    @Override
    public Object plugin(Object target) {
        return Plugin.wrap(target, this);
    }
    @Override
    public void setProperties(Properties properties) {
        //緩存 count ms
        msCountMap = CacheFactory.createCache(properties.getProperty("msCountCache"), "ms", properties);
        String dialectClass = properties.getProperty("dialect");
        if (StringUtil.isEmpty(dialectClass)) {
            dialectClass = default_dialect_class;
        }
        try {
            Class<?> aClass = Class.forName(dialectClass);
            dialect = (Dialect) aClass.newInstance();
        } catch (Exception e) {
            throw new PageException(e);
        }
        dialect.setProperties(properties);
        String countSuffix = properties.getProperty("countSuffix");
        if (StringUtil.isNotEmpty(countSuffix)) {
            this.countSuffix = countSuffix;
        }
    }
}
}

<plugins>
    <!-- com.github.pagehelper為PageHelper類(lèi)所在包名 -->
    <plugin interceptor="com.github.pagehelper.PageInterceptor">
        <!-- 使用下面的方式配置參數(shù)，后面會(huì)有所有的參數(shù)介紹 -->
        <!-- reasonable：分頁(yè)合理化參數(shù)，默認(rèn)值為false。當(dāng)該參數(shù)設(shè)置為 true 時(shí)，pageNum<=0 時(shí)會(huì)查詢(xún)第一頁(yè)， pageNum>pages（超過(guò)總數(shù)時(shí)），會(huì)查詢(xún)最后一頁(yè)。默認(rèn)false 時(shí)，直接根據(jù)參數(shù)進(jìn)行查詢(xún)。-->
        <property name="reasonable" value="true"/>
        <!-- supportMethodsArguments：支持通過(guò) Mapper 接口參數(shù)來(lái)傳遞分頁(yè)參數(shù)，默認(rèn)值false，分頁(yè)插件會(huì)從查詢(xún)方法的參數(shù)值中，自動(dòng)根據(jù)上面 params 配置的字段中取值，查找到合適的值時(shí)就會(huì)自動(dòng)分頁(yè)。 使用方法可以參考測(cè)試代碼中的 com.github.pagehelper.test.basic 包下的 ArgumentsMapTest 和 ArgumentsObjTest。-->
        <property name="supportMethodsArguments" value="true"/>
        <!-- autoRuntimeDialect：默認(rèn)值為 false。設(shè)置為 true 時(shí)，允許在運(yùn)行時(shí)根據(jù)多數(shù)據(jù)源自動(dòng)識(shí)別對(duì)應(yīng)方言的分頁(yè) （不支持自動(dòng)選擇sqlserver2012，只能使用sqlserver），用法和注意事項(xiàng)參考下面的場(chǎng)景五-->
        <property name="autoRuntimeDialect" value="true"/>
        <!-- params：為了支持startPage(Object params)方法，增加了該參數(shù)來(lái)配置參數(shù)映射，用于從對(duì)象中根據(jù)屬性名取值， 可以配置 pageNum,pageSize,count,pageSizeZero,reasonable，不配置映射的用默認(rèn)值， 默認(rèn)值為pageNum=pageNum;pageSize=pageSize;count=countSql;reasonable=reasonable;pageSizeZero=pageSizeZero。-->
    </plugin>
    <plugin interceptor="com.a.b.common.sql.SQLInterceptor"/>
</plugins>

<dependency>-->
    <!--<groupId>com.github.pagehelper</groupId>-->
    <!--<artifactId>pagehelper-spring-boot-starter</artifactId>-->
    <!--<version>1.2.12</version>-->
</dependency>

<dependency>
    <groupId>com.github.pagehelper</groupId>
    <artifactId>pagehelper</artifactId>
    <version>5.1.10</version>
</dependency>

@Intercepts({
        @Signature(type = Executor.class, method = "update", args = {MappedStatement.class, Object.class}),
        @Signature(type = Executor.class, method = "query", args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class, CacheKey.class, BoundSql.class})
})

@Intercepts({
        @Signature(type = Executor.class, method = "update", args = {MappedStatement.class, Object.class}),
        @Signature(type = StatementHandler.class, method = "query", args = {MappedStatement.class, Object.class, RowBounds.class,ResultHandler.class})
})