Java简单实现SpringMVC+MyBatis分页插件

1.封装分页page类

package com.framework.common.page.impl;

import java.io.serializable;

import com.framework.common.page.ipage;
/**
 * 
 * 
 *
 */
public abstract class basepage implements ipage, serializable {

  /**
   * 
   */
  private static final long serialversionuid = -3623448612757790359l;
  
  public static int default_page_size = 20;
  private int pagesize = default_page_size;
  private int currentresult;
  private int totalpage;
  private int currentpage = 1;
  private int totalcount = -1;

  public basepage(int currentpage, int pagesize, int totalcount) {
    this.currentpage = currentpage;
    this.pagesize = pagesize;
    this.totalcount = totalcount;
  }

  public int gettotalcount() {
    return this.totalcount;
  }

  public void settotalcount(int totalcount) {
    if (totalcount < 0) {
      this.totalcount = 0;
      return;
    }
    this.totalcount = totalcount;
  }

  public basepage() {
  }

  public int getfirstresult() {
    return (this.currentpage - 1) * this.pagesize;
  }

  public void setpagesize(int pagesize) {
    if (pagesize < 0) {
      this.pagesize = default_page_size;
      return;
    }
    this.pagesize = pagesize;
  }

  public int gettotalpage() {
    if (this.totalpage <= 0) {
      this.totalpage = (this.totalcount / this.pagesize);
      if ((this.totalpage == 0) || (this.totalcount % this.pagesize != 0)) {
        this.totalpage += 1;
      }
    }
    return this.totalpage;
  }

  public int getpagesize() {
    return this.pagesize;
  }

  public void setpageno(int currentpage) {
    this.currentpage = currentpage;
  }

  public int getpageno() {
    return this.currentpage;
  }

  public boolean isfirstpage() {
    return this.currentpage <= 1;
  }

  public boolean islastpage() {
    return this.currentpage >= gettotalpage();
  }

  public int getnextpage() {
    if (islastpage()) {
      return this.currentpage;
    }
    return this.currentpage + 1;
  }

  public int getcurrentresult() {
    this.currentresult = ((getpageno() - 1) * getpagesize());
    if (this.currentresult < 0) {
      this.currentresult = 0;
    }
    return this.currentresult;
  }

  public int getprepage() {
    if (isfirstpage()) {
      return this.currentpage;
    }
    return this.currentpage - 1;
  }


}

package com.framework.common.page.impl;

import java.util.list;
/**
 * 
 * 
 *
 */
public class page extends basepage {

  /**
   * 
   */
  private static final long serialversionuid = -970177928709377315l;

  public static threadlocal<page> threadlocal = new threadlocal<page>();

  private list<?> data; 
  
  public page() {
  }

  public page(int currentpage, int pagesize, int totalcount) {
    super(currentpage, pagesize, totalcount);
  }

  public page(int currentpage, int pagesize, int totalcount, list<?> data) {
    super(currentpage, pagesize, totalcount);
    this.data = data;
  }

  public list<?> getdata() {
    return data;
  }

  public void setdata(list<?> data) {
    this.data = data;
  }
  

}

2.封装分页插件

package com.framework.common.page.plugin;

import java.sql.connection;
import java.sql.preparedstatement;
import java.sql.resultset;
import java.sql.sqlexception;
import java.util.list;
import java.util.properties;

import javax.xml.bind.propertyexception;

import org.apache.commons.lang3.stringutils;
import org.apache.ibatis.executor.errorcontext;
import org.apache.ibatis.executor.executorexception;
import org.apache.ibatis.executor.statement.basestatementhandler;
import org.apache.ibatis.executor.statement.routingstatementhandler;
import org.apache.ibatis.mapping.boundsql;
import org.apache.ibatis.mapping.mappedstatement;
import org.apache.ibatis.mapping.parametermapping;
import org.apache.ibatis.mapping.parametermode;
import org.apache.ibatis.plugin.interceptor;
import org.apache.ibatis.plugin.intercepts;
import org.apache.ibatis.plugin.invocation;
import org.apache.ibatis.plugin.plugin;
import org.apache.ibatis.reflection.metaobject;
import org.apache.ibatis.reflection.property.propertytokenizer;
import org.apache.ibatis.scripting.xmltags.foreachsqlnode;
import org.apache.ibatis.session.configuration;
import org.apache.ibatis.type.typehandler;
import org.apache.ibatis.type.typehandlerregistry;

import com.framework.common.page.impl.page;
import com.framework.common.utils.reflectutil;
/**
 * 
 * 
 *
 */
@intercepts({ @org.apache.ibatis.plugin.signature(type = org.apache.ibatis.executor.statement.statementhandler.class, method = "prepare", args = { connection.class }) })
public class pageplugin implements interceptor {

  private string dialect = "";
  private string pagesqlid = "";

  @override
  public object intercept(invocation invocation) throws throwable {
    if (invocation.gettarget() instanceof routingstatementhandler) {
      basestatementhandler delegate = (basestatementhandler) reflectutil
          .getvaluebyfieldname(
              (routingstatementhandler) invocation.gettarget(),
              "delegate");
      mappedstatement mappedstatement = (mappedstatement) reflectutil
          .getvaluebyfieldname(delegate,
              "mappedstatement");

      page page = page.threadlocal.get();
      if (page == null) {
        page = new page();
        page.threadlocal.set(page);
      }

      if (mappedstatement.getid().matches(".*(" + this.pagesqlid + ")$") && page.getpagesize() > 0) {
        boundsql boundsql = delegate.getboundsql();
        object parameterobject = boundsql.getparameterobject();

        string sql = boundsql.getsql();
        string countsqlid = mappedstatement.getid().replaceall(pagesqlid, "count");
        mappedstatement countmappedstatement = null;
        if (mappedstatement.getconfiguration().hasstatement(countsqlid)) {
          countmappedstatement = mappedstatement.getconfiguration().getmappedstatement(countsqlid);
        }
        string countsql = null;
        if (countmappedstatement != null) {
          countsql = countmappedstatement.getboundsql(parameterobject).getsql();
        } else {
          countsql = "select count(1) from (" + sql + ") t_count";
        }
        
        int totalcount = 0;
        preparedstatement countstmt = null;
        resultset resultset = null;
        try {
          connection connection = (connection) invocation.getargs()[0];
          countstmt = connection.preparestatement(countsql);
          boundsql countboundsql = new boundsql(mappedstatement.getconfiguration(), countsql, boundsql.getparametermappings(), parameterobject);
          
          setparameters(countstmt, mappedstatement, countboundsql, parameterobject);
          
          resultset = countstmt.executequery();
          if(resultset.next()) {
            totalcount = resultset.getint(1);
          }
        } catch (exception e) {
          throw e;
        } finally {
          try {
            if (resultset != null) {
              resultset.close();
            }
          } finally {
            if (countstmt != null) {
              countstmt.close();
            }
          }
        }
        
        page.settotalcount(totalcount);
        
        reflectutil.setvaluebyfieldname(boundsql, "sql", generatepagesql(sql,page));
      }
    }

    return invocation.proceed();
  }
  

  /** 
   * 对sql参数(?)设值,参考org.apache.ibatis.executor.parameter.defaultparameterhandler 
   * @param ps 
   * @param mappedstatement 
   * @param boundsql 
   * @param parameterobject 
   * @throws sqlexception 
   */ 
  private void setparameters(preparedstatement ps,mappedstatement mappedstatement,boundsql boundsql,object parameterobject) throws sqlexception { 
    errorcontext.instance().activity("setting parameters").object(mappedstatement.getparametermap().getid()); 
    list<parametermapping> parametermappings = boundsql.getparametermappings(); 
    if (parametermappings != null) { 
      configuration configuration = mappedstatement.getconfiguration(); 
      typehandlerregistry typehandlerregistry = configuration.gettypehandlerregistry(); 
      metaobject metaobject = parameterobject == null ? null: configuration.newmetaobject(parameterobject); 
      for (int i = 0; i < parametermappings.size(); i++) { 
        parametermapping parametermapping = parametermappings.get(i); 
        if (parametermapping.getmode() != parametermode.out) { 
          object value; 
          string propertyname = parametermapping.getproperty(); 
          propertytokenizer prop = new propertytokenizer(propertyname); 
          if (parameterobject == null) { 
            value = null; 
          } else if (typehandlerregistry.hastypehandler(parameterobject.getclass())) { 
            value = parameterobject; 
          } else if (boundsql.hasadditionalparameter(propertyname)) { 
            value = boundsql.getadditionalparameter(propertyname); 
          } else if (propertyname.startswith(foreachsqlnode.item_prefix)&& boundsql.hasadditionalparameter(prop.getname())) { 
            value = boundsql.getadditionalparameter(prop.getname()); 
            if (value != null) { 
              value = configuration.newmetaobject(value).getvalue(propertyname.substring(prop.getname().length())); 
            } 
          } else { 
            value = metaobject == null ? null : metaobject.getvalue(propertyname); 
          } 
          typehandler typehandler = parametermapping.gettypehandler(); 
          if (typehandler == null) { 
            throw new executorexception("there was no typehandler found for parameter "+ propertyname + " of statement "+ mappedstatement.getid()); 
          } 
          typehandler.setparameter(ps, i + 1, value, parametermapping.getjdbctype()); 
        } 
      } 
    } 
  } 
  
  /** 
   * 根据数据库方言，生成特定的分页sql 
   * @param sql 
   * @param page 
   * @return 
   */ 
  private string generatepagesql(string sql,page page){ 
    if(page!=null && stringutils.isnotblank(dialect)){ 
      stringbuffer pagesql = new stringbuffer(); 
      if("mysql".equals(dialect)){ 
        pagesql.append(sql); 
        pagesql.append(" limit "+page.getcurrentresult()+","+page.getpagesize()); 
      }else if("oracle".equals(dialect)){ 
        pagesql.append("select * from (select tmp_tb.*,rownum row_id from ("); 
        pagesql.append(sql); 
        pagesql.append(") as tmp_tb where rownum <= "); 
        pagesql.append(page.getcurrentresult()+page.getpagesize()); 
        pagesql.append(") where row_id > "); 
        pagesql.append(page.getcurrentresult()); 
      } 
      return pagesql.tostring(); 
    }else{ 
      return sql; 
    } 
  } 

  @override
  public object plugin(object target) {
    return plugin.wrap(target, this);
  }

  @override
  public void setproperties(properties properties) {
    try {
      if (stringutils.isempty(this.dialect = properties
          .getproperty("dialect"))) {
        throw new propertyexception("dialect property is not found!");
      }
      if (stringutils.isempty(this.pagesqlid = properties
          .getproperty("pagesqlid"))) {
        throw new propertyexception("pagesqlid property is not found!");
      }
    } catch (propertyexception e) {
      e.printstacktrace();
    }
  }

}

3.mybatis配置文件:mybatis-config.xml

<?xml version="1.0" encoding="utf-8"?>
<!doctype configuration public "-//mybatis.org//dtd sql map config 3.0//en" "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
  <plugins>
    <plugin interceptor="com.framework.common.page.plugin.pageplugin">
      <property name="dialect" value="mysql" />
      <property name="pagesqlid" value="bypage" />
    </plugin>
  </plugins>
</configuration>

4.分页拦截器

package com.framework.common.page.interceptor;

import javax.servlet.http.httpservletrequest;
import javax.servlet.http.httpservletresponse;

import org.apache.commons.lang3.math.numberutils;
import org.springframework.web.servlet.modelandview;
import org.springframework.web.servlet.handler.handlerinterceptoradapter;

import com.framework.common.page.impl.page;
/**
* 
* 14 *
*/
public class pageinterceptor extends handlerinterceptoradapter {

 @override
 public void posthandle(httpservletrequest request,
     httpservletresponse response, object handler,
     modelandview modelandview) throws exception {
   super.posthandle(request, response, handler, modelandview);
   page page = page.threadlocal.get();
   if (page != null) {
     request.setattribute("page", page);
   }
   page.threadlocal.remove();
 }

 @override
 public boolean prehandle(httpservletrequest request,
     httpservletresponse response, object handler) throws exception {
   string pagesize = request.getparameter("pagesize");
   string pageno = request.getparameter("pageno");
   page page = new page();
   if (numberutils.isnumber(pagesize)) {
     page.setpagesize(numberutils.toint(pagesize));
   }
   if (numberutils.isnumber(pageno)) {
     page.setpageno(numberutils.toint(pageno));
   }
   page.threadlocal.set(page);
   return true;
 }

}

5.spring配置

<!-- =================================================================== 
- load property file 
- =================================================================== -->
<context:property-placeholder location="classpath:application.properties" />

<bean id="sqlsessionfactory" class="org.mybatis.spring.sqlsessionfactorybean">
  <property name="datasource" ref="datasource" />
  <property name="configlocation" value="classpath:mybatis-config.xml" />
  <property name="mapperlocations">
    <list>
      <value>classpath:/com/framework/mapper/**/*mapper.xml</value>
    </list>
  </property>
</bean>

<!-- =================================================================== 
- 通过扫描的模式，扫描目录下所有的dao， 根据对应的mapper.xml为其生成代理类 
- =================================================================== -->
<bean id="mapperscannerconfigurer" class="org.mybatis.spring.mapper.mapperscannerconfigurer">
  <property name="basepackage" value="com.framework.dao" />
  <property name="processpropertyplaceholders" value="true" />
  <property name="sqlsessionfactorybeanname" value="sqlsessionfactory" />
</bean>

6.springmvc配置拦截器

<!-- 分页拦截器 -->
  <bean id="pageinterceptor" class="com.framework.common.page.interceptor.pageinterceptor"></bean>
  
  <!-- 配置拦截器 -->
  <bean class="org.springframework.web.servlet.mvc.method.annotation.requestmappinghandlermapping">
    <property name="interceptors">
      <list>
        <ref bean="pageinterceptor" />
      </list>
    </property>
  </bean>