mybatis在mysql中的分页扩展

applicationContext.xml

	<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="configLocation" value="classpath:/mybatis-config.xml" />
</bean>

mybatis-config.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<settings>
<!-- 设置成 true就可以启动缓存,一般的修改要1分钟才能生效(因为设置的flushInterval="60000" )
如果是在一个xxxxMapper.xml里面修改的数据库的数据,就直接清空本mapper的缓存 -->
<setting name="cacheEnabled" value="false"/>
<setting name="useGeneratedKeys" value="false"/>
</settings>
<plugins>
<plugin interceptor="com.system.util.DiclectStatementHandlerInterceptor" />
<plugin interceptor="com.system.util.DiclectResultSetHandlerInterceptor" />
</plugins>
</configuration>

DiclectResultSetHandlerInterceptor.java

package com.system.util;

import java.sql.Statement;
import java.util.Properties; import org.apache.ibatis.executor.resultset.FastResultSetHandler;
import org.apache.ibatis.executor.resultset.NestedResultSetHandler;
import org.apache.ibatis.executor.resultset.ResultSetHandler;
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.plugin.Signature;
import org.apache.ibatis.session.RowBounds; @Intercepts({ @Signature(type = ResultSetHandler.class, method = "handleResultSets", args = { Statement.class }) })
public class DiclectResultSetHandlerInterceptor implements Interceptor { public Object intercept(Invocation invocation) throws Throwable {
FastResultSetHandler resultSet = (FastResultSetHandler) invocation.getTarget();
if(!(resultSet instanceof NestedResultSetHandler)) {
RowBounds rowBounds = (RowBounds) ReflectUtil.getClassField(resultSet, "rowBounds");
if (rowBounds.getLimit() > 0 && rowBounds.getLimit() < RowBounds.NO_ROW_LIMIT) {
ReflectUtil.setClassField(resultSet, "rowBounds", new RowBounds());
}
}
return invocation.proceed();
} public Object plugin(Object target) {
return Plugin.wrap(target, this);
} public void setProperties(Properties properties) {}
}

 

DiclectStatementHandlerInterceptor.java

package com.system.util;

import java.sql.Connection;
import java.util.Properties; import org.apache.ibatis.executor.statement.PreparedStatementHandler;
import org.apache.ibatis.executor.statement.RoutingStatementHandler;
import org.apache.ibatis.executor.statement.StatementHandler;
import org.apache.ibatis.mapping.BoundSql;
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.plugin.Signature;
import org.apache.ibatis.session.RowBounds; @Intercepts( { @Signature(type = StatementHandler.class, method = "prepare", args = { Connection.class }) })
public class DiclectStatementHandlerInterceptor implements Interceptor { public Object intercept(Invocation invocation) throws Throwable {
RoutingStatementHandler statement = (RoutingStatementHandler) invocation.getTarget();
StatementHandler handler = (StatementHandler) ReflectUtil.getClassField(statement, "delegate");
if (handler instanceof PreparedStatementHandler){
RowBounds rowBounds = (RowBounds) ReflectUtil.getSuperClassField(handler, "rowBounds");
if (rowBounds.getLimit() > 0 && rowBounds.getLimit() < RowBounds.NO_ROW_LIMIT) {
BoundSql boundSql = statement.getBoundSql();
String sql = boundSql.getSql();
sql = getLimitString(sql, rowBounds.getOffset(), rowBounds.getLimit());
ReflectUtil.setClassField(boundSql, "sql", sql);
}
}
return invocation.proceed();
} public Object plugin(Object target) {
return Plugin.wrap(target, this);
} public void setProperties(Properties properties) {
} public String getLimitString(String sql, int offset, int limit) {
limit = offset+limit;
sql = sql.trim();
boolean isForUpdate = false;
if ( sql.toLowerCase().endsWith(" for update") ) {
sql = sql.substring( 0, sql.length()-11 );
isForUpdate = true;
}
StringBuffer pagingSelect = new StringBuffer( sql.length()+100 );
pagingSelect.append(sql); pagingSelect.append(" limit "+offset+","+limit);
if ( isForUpdate ) {
pagingSelect.append( " for update" );
} return pagingSelect.toString();
}
}

  

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