package com.example.segmentfaulttest0.utils;
import lombok.Data;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;
/**
 * @description:分頁工具類
 * @author: 袁凱
 * @time: 2023/12/14 19:36
 */
@Data
public class PageUtils<E extends Serializable> implements Serializable {
    private static final long serialVersionUID = 1L;
    /**
     * 總記錄數(shù)
     */
    private int totalCount;
    /**
     * 每頁記錄數(shù)
     */
    private int pageSize;
    /**
     * 總頁數(shù)
     */
    private int totalPage;
    /**
     * 當(dāng)前頁數(shù)
     */
    private int currPage;
    /**
     * 列表數(shù)據(jù)
     */
    private List<E> list;
    /**
     *
     * @param pageSize  每頁記錄數(shù)
     * @param currPage  當(dāng)前頁數(shù)
     * @param totalList 總記錄列表
     */
    public PageUtils(int pageSize, int currPage, List<E> totalList) {
        this.totalCount = totalList.size();
        this.pageSize = pageSize;
        this.totalPage = (int) Math.ceil((double) totalCount / pageSize);
        this.currPage = currPage;
        this.list = this.currPage >= 1 ? totalList.stream().skip((long) (currPage - 1) * pageSize).limit(pageSize).collect(Collectors.toList()) : new ArrayList<>();
    }
}

@GetMapping("/select")
    public TableDataInfo selectSelectiveLike() {
        startPage();
        List<Vrt> vrtList = vrtService.selectSelectiveLike(new Vrt());
        PageInfo<Vrt> pageInfo = new PageInfo<>(vrtList);
        List<VrtVo> vrtVos = new ArrayList<>();
        for (Vrt vrt : vrtList) {
            VrtVo vrtVo = new VrtVo();
            BeanUtils.copyProperties(vrt, vrtVo);
            List<VrtPhone> vrtPhoneList = vrt.getVrtPhoneList();
            if (vrtPhoneList != null && !vrtPhoneList.isEmpty()) {
                vrtVo.setNum(vrtPhoneList.size());
            } else {
                vrtVo.setNum(0);
            }
            vrtVos.add(vrtVo);
        }
        // 1.由于PageInfo中參數(shù)很多，有時候并不需要，因此自定義了一個TableDataInfo對象用于封裝參數(shù)
        // 2.我們在這里手動將PageInfo的值傳遞給VO的分頁對象即可
        TableDataInfo tableDataInfo = new TableDataInfo();
        tableDataInfo.setCode(HttpStatus.SUCCESS);
        tableDataInfo.setRows(vrtVos);
        tableDataInfo.setMsg("查詢成功");
        tableDataInfo.setTotal(pageInfo.getTotal());
        return tableDataInfo;
    }

package com.example.segmentfaulttest0.Interceptor;
import org.apache.ibatis.executor.Executor;
import org.apache.ibatis.executor.resultset.ResultSetHandler;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.plugin.*;
import org.apache.ibatis.session.ResultHandler;
import org.apache.ibatis.session.RowBounds;
import java.sql.Statement;
import java.util.Properties;
/**
 * @description:自定義插件，用于攔截mybatis的query方法
 * @author: 袁凱
 * @time: 2023/12/18 16:53
 */
//mybatis的攔截器注解以及簽名注解，用于需要攔截的類名，方法名，參數(shù)類型
@Intercepts({//注意看這個大花括號，也就這說這里可以定義多個@Signature對多個地方攔截，都用這個攔截器
    @Signature(type = Executor.class,
        method = "query",
        args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class})
})
//@Intercepts({
//    @Signature(
//        type = Executor.class,
//        method = "update",
//        args = {MappedStatement.class, Object.class}),
//})
public class MyPlugin implements Interceptor {
    public MyPlugin() {
        System.out.println("myplugin");
    }
    @Override
    public Object intercept(Invocation invocation) throws Throwable {
        //攔截成功，do something
        System.out.println("do something");
        return invocation.proceed();
    }
    @Override
    public Object plugin(Object target) {
        return Plugin.wrap(target, this);    //將被攔截對象生成代理對象
    }
    /**
     * 用于獲取pom.xml中property標(biāo)簽中寫入的屬性
     * @param properties
     */
    @Override
    public void setProperties(Properties properties) {
        Interceptor.super.setProperties(properties);
    }
}

package com.example.segmentfaulttest0.config;
import com.example.segmentfaulttest0.Interceptor.MyPlugin;
import org.apache.ibatis.session.SqlSessionFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import java.util.List;
/**
 * @description:Mybatis相關(guān)配置
 * @author: 袁凱
 * @time: 2023/12/18 17:39
 */
@Configuration
public class MybatisConfig {
    @Autowired
    private List<SqlSessionFactory> sqlSessionFactoryList;
    @Bean
    public void myPlugin() {
        for (SqlSessionFactory sqlSessionFactory : sqlSessionFactoryList) {
            org.apache.ibatis.session.Configuration configuration = sqlSessionFactory.getConfiguration();
            // 最后添加的會更早執(zhí)行
            configuration.addInterceptor(new MyPlugin());
        }
    }
}

@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 {

public Object intercept(Invocation invocation) throws Throwable {
        try {
            // 1.根據(jù)重載的攔截query方法不同，獲取不同的對象以及緩存key
            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;
            if (args.length == 4) {
                boundSql = ms.getBoundSql(parameter);
                cacheKey = executor.createCacheKey(ms, parameter, rowBounds, boundSql);
            } else {
                cacheKey = (CacheKey)args[4];
                boundSql = (BoundSql)args[5];
            }
            // 2.mybatis對不同的數(shù)據(jù)庫進行方言相關(guān)的檢查
            this.checkDialectExists();
            if (this.dialect instanceof BoundSqlInterceptor.Chain) {
                boundSql = ((BoundSqlInterceptor.Chain)this.dialect).doBoundSql(Type.ORIGINAL, boundSql, cacheKey);
            }
            List resultList;
            if (!this.dialect.skip(ms, parameter, rowBounds)) {
                this.debugStackTraceLog();
                if (this.dialect.beforeCount(ms, parameter, rowBounds)) {
                    // 3.執(zhí)行一條sql，select count(*) from xxx獲取總條數(shù)（根據(jù)原語句決定）
                    Long count = this.count(executor, ms, parameter, rowBounds, (ResultHandler)null, boundSql);
                    if (!this.dialect.afterCount(count, parameter, rowBounds)) {
                        Object var12 = this.dialect.afterPage(new ArrayList(), parameter, rowBounds);
                        return var12;
                    }
                }
                // 4.根據(jù)分頁參數(shù)執(zhí)行語句，在原語句的基礎(chǔ)上添加了limit ？,？
                resultList = ExecutorUtil.pageQuery(this.dialect, executor, ms, parameter, rowBounds, resultHandler, boundSql, cacheKey);
            } else {
                resultList = executor.query(ms, parameter, rowBounds, resultHandler, cacheKey, boundSql);
            }
            Object var16 = this.dialect.afterPage(resultList, parameter, rowBounds);
            return var16;
        } finally {
            if (this.dialect != null) {
                this.dialect.afterAll();
            }
        }
    }

public static <E> Page<E> startPage(int pageNum, int pageSize, boolean count, Boolean reasonable, Boolean pageSizeZero) {
        Page<E> page = new Page(pageNum, pageSize, count);
        page.setReasonable(reasonable);
        page.setPageSizeZero(pageSizeZero);
        // 1.使用threadlocal進行線程存儲，為每個線程保存每個          分頁參數(shù)（當(dāng)前頁、頁數(shù)）
        Page<E> oldPage = getLocalPage();
        if (oldPage != null && oldPage.isOrderByOnly()) {
            page.setOrderBy(oldPage.getOrderBy());
        }
        setLocalPage(page);
        return page;
    }

public static <E> List<E> pageQuery(Dialect dialect, Executor executor, MappedStatement ms, Object parameter, RowBounds rowBounds, ResultHandler resultHandler, BoundSql boundSql, CacheKey cacheKey) throws SQLException {
        if (!dialect.beforePage(ms, parameter, rowBounds)) {
            return executor.query(ms, parameter, RowBounds.DEFAULT, resultHandler, cacheKey, boundSql);
        } else {
            parameter = dialect.processParameterObject(ms, parameter, boundSql, cacheKey);
            String pageSql = dialect.getPageSql(ms, boundSql, parameter, rowBounds, cacheKey);
            BoundSql pageBoundSql = new BoundSql(ms.getConfiguration(), pageSql, boundSql.getParameterMappings(), parameter);
            Map<String, Object> additionalParameters = getAdditionalParameter(boundSql);
            Iterator var12 = additionalParameters.keySet().iterator();
            while(var12.hasNext()) {
                String key = (String)var12.next();
                pageBoundSql.setAdditionalParameter(key, additionalParameters.get(key));
            }
            if (dialect instanceof BoundSqlInterceptor.Chain) {
                // 1.他會再次調(diào)用PageHelper類里面的threadlocal，并獲取里面的分頁參數(shù)
                pageBoundSql = ((BoundSqlInterceptor.Chain)dialect).doBoundSql(Type.PAGE_SQL, pageBoundSql, cacheKey);
            }
            return executor.query(ms, parameter, RowBounds.DEFAULT, resultHandler, cacheKey, pageBoundSql);
        }
    }

// 回到pageHelper類中，他會將分頁參數(shù)封裝成Page對象，再放入threadlocal中
   public BoundSql doBoundSql(BoundSqlInterceptor.Type type, BoundSql boundSql, CacheKey cacheKey) {
        Page<Object> localPage = getLocalPage();
        BoundSqlInterceptor.Chain chain = localPage != null ? localPage.getChain() : null;
        if (chain == null) {
            BoundSqlInterceptor boundSqlInterceptor = localPage != null ? localPage.getBoundSqlInterceptor() : null;
            BoundSqlInterceptor.Chain defaultChain = this.pageBoundSqlInterceptors != null ? this.pageBoundSqlInterceptors.getChain() : null;
            if (boundSqlInterceptor != null) {
                chain = new BoundSqlInterceptorChain(defaultChain, Arrays.asList(boundSqlInterceptor));
            } else if (defaultChain != null) {
                chain = defaultChain;
            }

            if (chain == null) {
                chain = DO_NOTHING;
            }

            if (localPage != null) {
                localPage.setChain((BoundSqlInterceptor.Chain)chain);
            }
        }

        return ((BoundSqlInterceptor.Chain)chain).doBoundSql(type, boundSql, cacheKey);
    }

//1.集成了ArrayList類，用于封裝分頁信息以及封裝查詢出來的結(jié)果
public class Page<E> extends ArrayList<E>

//1.根據(jù)傳入的Page對象，獲取其中的參數(shù)，如total
public class PageInfo<T> extends PageSerializable<T> {