com.ext_ext.mybatisext.plugin.paging.PagingPlugin Maven / Gradle / Ivy
package com.ext_ext.mybatisext.plugin.paging;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Properties;
import org.apache.ibatis.builder.StaticSqlSource;
import org.apache.ibatis.executor.Executor;
import org.apache.ibatis.executor.parameter.ParameterHandler;
import org.apache.ibatis.logging.Log;
import org.apache.ibatis.mapping.BoundSql;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.mapping.SqlCommandType;
import org.apache.ibatis.mapping.SqlSource;
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.scripting.xmltags.DynamicSqlSource;
import org.apache.ibatis.session.Configuration;
import org.apache.ibatis.session.ResultHandler;
import org.apache.ibatis.session.RowBounds;
import org.apache.ibatis.transaction.Transaction;
import com.ext_ext.mybatisext.MapperProxyExt;
import com.ext_ext.mybatisext.activerecord.MybatisExt;
import com.ext_ext.mybatisext.activerecord.dialect.DialectSQL;
import com.ext_ext.mybatisext.helper.Page;
import com.ext_ext.mybatisext.interceptor.MyBatisInvocation;
/**
*
*
* 分页查询时把List放入参数page中并返回
*
*
* @author dixingxing
* @date 2012-7-12
*/
@Intercepts({ @Signature(type = Executor.class, method = "query", args = { MappedStatement.class, Object.class,
RowBounds.class, ResultHandler.class }) })
public class PagingPlugin implements Interceptor {
//存储所有语句名称
HashMap map_statement = new HashMap();
//用户提供分页计算条数后缀
static final String COUNT_ID = "_count";
private static ThreadLocal> localPage = new ThreadLocal>();
private DialectSQL dialect;
public static void setPage( Page page ) {
localPage.set(page);
}
public static void removePage() {
localPage.remove();
}
public DialectSQL getDialect() {
if ( dialect == null ) {
return MybatisExt.dialectSQL;
}
return dialect;
}
public void setDialect( DialectSQL dialect ) {
this.dialect = dialect;
}
/**
* 获取所有statement语句的名称
*
*
* @param configuration
*/
protected synchronized void initStatementMap( Configuration configuration ) {
if ( !map_statement.isEmpty() ) {
return;
}
Collection statements = configuration.getMappedStatementNames();
for ( String element : statements ) {
map_statement.put(element, element);
}
}
/**
* 获取数据库连接
*
*
* @param transaction
* @param statementLog
* @return
* @throws SQLException
*/
protected Connection getConnection( Transaction transaction, Log statementLog ) throws SQLException {
Connection connection = transaction.getConnection();
return connection;
}
@Override
public Object intercept( Invocation invocation ) throws Throwable {
Object parameter = invocation.getArgs()[1];
Page page = seekPage();
if ( page == null ) {
return invocation.proceed();
} else {
return handlePaging(invocation, parameter, page);
}
}
/**
* 处理分页的情况
*
* @param invocation
* @param parameter
* @param page
* @throws SQLException
*/
@SuppressWarnings({ "rawtypes", "unchecked" })
protected Object handlePaging( Invocation invocation, Object parameter, Page page ) throws Exception {
MappedStatement mappedStatement = (MappedStatement) invocation.getArgs()[0];
Configuration configuration = mappedStatement.getConfiguration();
if ( map_statement.isEmpty() ) {
initStatementMap(configuration);
}
BoundSql boundSql = mappedStatement.getBoundSql(parameter);
SqlSource sourse = mappedStatement.getSqlSource();
SqlSource sqlsource = null;
if ( sourse instanceof DynamicSqlSource ) {
BoundSqlProxy ext = new BoundSqlProxy(configuration, page, boundSql, getDialect());
sqlsource = new SqlSourceProxyBoundSql(ext);
} else {
sqlsource = new StaticSqlSource(configuration, getLimitString(boundSql.getSql(), page),
boundSql.getParameterMappings());
}
String id = mappedStatement.getId();
// 查询结果集
MappedStatement.Builder builder = new MappedStatement.Builder(configuration, id, sqlsource,
SqlCommandType.SELECT);
builder.resultMaps(mappedStatement.getResultMaps()).resultSetType(mappedStatement.getResultSetType())
.statementType(mappedStatement.getStatementType());
MappedStatement query_statement = builder.build();
List data = (List) exeQuery(invocation, query_statement);
//设置到page对象
page.setRecords(data);
page.setCount(getTotalSize(invocation, configuration, mappedStatement, boundSql, parameter));
MyBatisInvocation myBatisInvocation = MapperProxyExt.getMyBatisInvocation();
if ( myBatisInvocation != null ) {
Class returnType = myBatisInvocation.getMethod().getReturnType();
if ( Page.class.equals(returnType) ) {
List pageList = new ArrayList(1);
pageList.add(page);
return pageList;
}
}
return data;
}
/**
* 根据提供的语句执行查询操作
*
*
* @param invocation
* @param query_statement
* @return
* @throws Exception
*/
protected Object exeQuery( Invocation invocation, MappedStatement query_statement ) throws Exception {
Object[] args = invocation.getArgs();
return invocation.getMethod().invoke(invocation.getTarget(),
new Object[ ] { query_statement, args[1], args[2], args[3] });
}
/**
* 获取总记录数量
*
*
* @param configuration
* @param mappedStatement
* @param sql
* @param parameter
* @return
* @throws SQLException
*/
@SuppressWarnings("rawtypes")
protected int getTotalSize( Invocation invocation, Configuration configuration, MappedStatement mappedStatement,
BoundSql boundSql, Object parameter ) throws Exception {
String count_id = mappedStatement.getId() + COUNT_ID;
int totalSize = 0;
if ( map_statement.containsKey(count_id) ) {
// 优先查找能统计条数的sql
List data = (List) exeQuery(invocation, mappedStatement.getConfiguration().getMappedStatement(count_id));
if ( data.size() > 0 ) {
totalSize = Integer.parseInt(data.get(0).toString());
}
} else {
Executor exe = (Executor) invocation.getTarget();
Connection connection = getConnection(exe.getTransaction(), mappedStatement.getStatementLog());
String countSql = getCountSql(boundSql.getSql());
totalSize = getTotalSize(configuration, mappedStatement, boundSql, countSql, connection, parameter);
}
return totalSize;
}
/**
* 拼接查询sql,加入limit
*
*
* @param sql
* @param page
*/
protected String getLimitString( String sql, Page page ) {
int start = (page.getPageNo() - 1) * page.getPageSize();
if ( start < 0 ) {
throw new RuntimeException("页码必须从1开始");
}
if ( getDialect() != null ) {
return getDialect().getPagingSQL(start, page.getPageSize(), sql);
}
StringBuffer sb = new StringBuffer(sql.length() + 100);
sb.append(sql);
sb.append(" LIMIT ").append(start).append(",").append(page.getPageSize());
return sb.toString();
}
/**
* 拼接获取条数的sql语句
*
*
* @param sqlPrimary
*/
protected String getCountSql( String sqlPrimary ) {
if ( getDialect() != null ) {
return getDialect().getPagingCountSQL(sqlPrimary);
}
String sqlUse = sqlPrimary.replaceAll("[\\s]+", " ");
String upperString = sqlUse.toUpperCase();
int order_by = upperString.lastIndexOf(" ORDER BY ");
if ( order_by > -1 ) {
sqlUse = sqlUse.substring(0, order_by);
}
String[] paramsAndMethod = sqlUse.split("\\s");
int count = 0;
int index = 0;
for ( int i = 0 ; i < paramsAndMethod.length ; i++ ) {
String upper = paramsAndMethod[i].toUpperCase();
if ( upper.length() == 0 ) {
continue;
}
if ( upper.equals("SELECT") ) {
count++;
} else if ( upper.equals("FROM") ) {
count--;
}
if ( count == 0 ) {
index = i;
break;
}
}
StringBuilder return_sql = new StringBuilder("SELECT COUNT(1) AS cnt ");
StringBuilder common_count = new StringBuilder();
for ( int j = index ; j < paramsAndMethod.length ; j++ ) {
common_count.append(" ");
common_count.append(paramsAndMethod[j]);
}
if ( upperString.contains(" GROUP BY ") ) {
throw new RuntimeException("不支持group by 分页,请自行提供sql语句以 查询语句+_count结尾.");
}
return return_sql.append(common_count).toString();
}
/**
* 计算总条数
*
*
* @param parameterObj
* @param countSql
* @param connection
* @return
*/
protected int getTotalSize( Configuration configuration, MappedStatement mappedStatement, BoundSql boundSql,
String countSql, Connection connection, Object parameter ) throws SQLException {
PreparedStatement stmt = null;
ResultSet rs = null;
int totalSize = 0;
try {
ParameterHandler handler = configuration.newParameterHandler(mappedStatement, parameter, boundSql);
stmt = connection.prepareStatement(countSql);
handler.setParameters(stmt);
rs = stmt.executeQuery();
if ( rs.next() ) {
totalSize = rs.getInt(1);
}
} catch ( SQLException e ) {
throw new RuntimeException("获取总条数错误，请自行提供计算总页数的语句，以{id}_count结尾");
} finally {
if ( rs != null ) {
rs.close();
rs = null;
}
if ( stmt != null ) {
stmt.close();
stmt = null;
}
}
return totalSize;
}
/**
* 寻找page对象
*
*
* @param parameter
*/
protected Page seekPage() {
Page page = localPage.get();
if ( page != null ) {
return page;
}
MyBatisInvocation inv = MapperProxyExt.getMyBatisInvocation();
Object[] args = inv.getArgs();
if ( args == null ) {
return null;
}
for ( Object arg : args ) {
if ( arg instanceof Page ) {
page = (Page) arg;
return page;
}
}
return page;
}
@Override
public Object plugin( Object target ) {
return Plugin.wrap(target, this);
}
@Override
public void setProperties( Properties properties ) {
}
}