JavaProxy動態(tài)代理詳解傳說中的AOP的一個應(yīng)用,（我讀ibatis）

java.lang.reflect.Proxy對象是對class文件的調(diào)用起到一個代理作用個方法的調(diào)用首先都要經(jīng)過proxy的處理方法。然后在proxy的處理方法(invoke方法)里面才真正的目的class里面的方法。。對每于目的class中的開始調(diào)用例如：Testt=newTest()?t.print(null)在沒有使用代理的情況下，這里的print方法的調(diào)用應(yīng)該是直接到Test類里面調(diào)用InvocationHandler對象(類)的時候。也就是把這個Test類出賣給了方法就要通過Proxy的處理方法invoke（實(shí)現(xiàn)說“被雙規(guī)了”這個方法了。這里當(dāng)把Test類綁定到Proxy，這樣如果要是再想調(diào)用Test類里面的InvocationHandler接口的）了。有那里調(diào)用。簡單的下面我們就來通過這個特性來做一個數(shù)據(jù)庫操作的日志記錄過濾器。在我們程序運(yùn)行中，數(shù)據(jù)庫調(diào)用階段的日志對我們分析程序的錯誤很有參考價值。這里我們就做一個代理的過濾器，用于記錄對數(shù)據(jù)庫的讀取，更新等一數(shù)據(jù)庫執(zhí)行的SQL,SQL的參數(shù)等。可謂意義還是有點(diǎn)的啦，這里老孫經(jīng)過一鼓的程序供大家參考。本文為參看ibatis源代碼。網(wǎng)上有人說這玩意就是AOP，我才不管它是啥P呢，能滿足我的要求便可。系列操作的接口日志的詳細(xì)記錄的過濾程序。用于記錄調(diào)用天的調(diào)試整理，搗這里我們創(chuàng)建5個java文件BaseProxy.java代理實(shí)現(xiàn)基類ConnectionProxy.java用于記錄調(diào)用PreparedStatementProxy.java用于記錄PreparedStatement對象的ResultSetProxy.java用于記錄ResultSet對象時候的日志。時候的日志。connection對象的時候記錄日志。方法調(diào)用過程的日志記錄方法調(diào)用的StatementProxy.java用于記錄Statement對象方法調(diào)用這里開始鋪設(shè)源代碼BaseProxy.java這個文件是基礎(chǔ)類，用于存放一些公共的參數(shù)，方法名稱，還有調(diào)用SQL的時候我們最關(guān)注的綁定變量的參數(shù)。packagexy?importjava.util.ArrayList?importjava.util.HashMap?importjava.util.HashSet?importjava.util.List?importjava.util.Map?importjava.util.Set?publicclassBaseProxy{/***存放statement對象的set方法。*/protectedstaticfinalSetsetMethods=newHashSet()?/***存放statement對象的get方法。*/protectedstaticfinalSetgetMethods=newHashSet()?

/***存放statement對象的exec的幾個方法。*/protectedstaticfinalSetexecSqlMethods=newHashSet()?privateMapparamsMap=newHashMap()?privateListparamsNames=newArrayList()?privateListparamsValues=newArrayList()?/***初始id,用于確定Proxy的同一個對象*/privatestaticintnextId=100000?/***用于確定Proxy的同一個對象*/protectedintid?static{setMethods.add("setString")?setMethods.add("setInt")?setMethods.add("setByte")?setMethods.add("setShort")?setMethods.add("setLong")?setMethods.add("setDouble")?setMethods.add("setFloat")?setMethods.add("setTimestamp")?setMethods.add("setDate")?setMethods.add("setTime")?setMethods.add("setArray")?setMethods.add("setBigDecimal")?setMethods.add("setAsciiStream")?setMethods.add("setBinaryStream")?setMethods.add("setBlob")?setMethods.add("setBoolean")?setMethods.add("setBytes")?setMethods.add("setCharacterStream")?setMethods.add("setClob")?setMethods.add("setObject")?setMethods.add("setNull")?getMethods.add("getString")?getMethods.add("getInt")?getMethods.add("getByte")?getMethods.add("getShort")?getMethods.add("getLong")?getMethods.add("getDouble")?getMethods.add("getFloat")?

getMethods.add("getTimestamp")?getMethods.add("getDate")?getMethods.add("getTime")?getMethods.add("getArray")?getMethods.add("getBigDecimal")?getMethods.add("getAsciiStream")?getMethods.add("getBinaryStream")?getMethods.add("getBlob")?getMethods.add("getBoolean")?getMethods.add("getBytes")?getMethods.add("getCharacterStream")?getMethods.add("getClob")?getMethods.add("getObject")?getMethods.add("getNull")?execSqlMethods.add("execute")?execSqlMethods.add("executeUpdate")?execSqlMethods.add("executeQuery")?}publicBaseProxy(){id=getNextId()?}/***用于取得proxy調(diào)用對象的id，這里防止id重復(fù)，所以是同步的*@return*/protectedsynchronizedstaticintgetNextId(){returnnextId++?}protectedvoidsetColumn(Objectkey,Objectvalue){paramsMap.put(key,value)?paramsNames.add(key)?paramsValues.add(value)?}protectedObjectgetColumn(Objectkey){returnparamsMap.get(key)?}protectedStringgetValueString(){returnparamsValues.toString()?}protectedStringgetTypeString(){ListtypeList=newArrayList(paramsValues.size())?for(inti=0?i<paramsValues.size()?i++){Objectvalue=paramsValues.get(i)?if(value==null){

typeList.add("null")?}else{typeList.add(value.getClass().getName())?}}returntypeList.toString()?}protectedStringgetColumnString(){returnparamsNames.toString()?}protectedvoidclearColumnInfo(){paramsMap.clear()?paramsNames.clear()?paramsValues.clear()?}}ConnectionProxy.java這個類把調(diào)用conncetion的無論哪個方法在invoke方法這里connection方法裝到了proxy代理過濾文件列表里面。這里，其實(shí)都要先通過ConnectionProxy類的invoke方法，我們記錄下調(diào)用的日志情況：packagexy?importjava.lang.reflect.InvocationHandler?importjava.lang.reflect.Method?importjava.lang.reflect.Proxy?importjava.sql.Connection?importjava.sql.PreparedStatement?importjava.sql.Statement?importmons.logging.Log?importmons.logging.LogFactory?/***本類用于記錄Connection一層的日志*/publicclassConnectionProxyextendsBaseProxyimplementsInvocationHandler{privatestaticfinalLoglog=LogFactory.getLog(ConnectionProxy.class)?privateConnectionconnection?privateConnectionProxy(Connectionconn){super()?this.connection=conn?log.debug("ConnectionId="+id)?}/*傳說中的invoke，所有Connection.class類調(diào)用的方法都要經(jīng)過他分配，很流氓的東西這里的類必須要實(shí)現(xiàn)InvocationHandler接口，這樣才有invoke的由來*/publicObjectinvoke(Objectprox,Methodmethod,Object[]params)throwsThrowable{

try{if("prepareStatement".equals(method.getName())){log.debug("ConnectionId="+id+"PreparingStatement:"+params[0].toString())?PreparedStatementstmt=(PreparedStatement)method.invoke(connection,params)?//這里才是真正的調(diào)用到該調(diào)用的文件stmt=PreparedStatementProxy.newInstance(stmt,(String)params[0])?returnstmt?//這里是出賣PreparedStatement.class等文件給代理的。}elseif("prepareCall".equals(method.getName())){log.debug("ConnectionId="+id+"prepareCallStatement:"+params[0].toString())?PreparedStatementstmt=(PreparedStatement)method.invoke(connection,params)?stmt=PreparedStatementProxy.newInstance(stmt,(String)params[0])?returnstmt?}elseif("createStatement".equals(method.getName())){log.debug("ConnectionId="+id+"createStatement:"+params[0].toString())?Statementstmt=(Statement)method.invoke(connection,params)?stmt=StatementProxy.newInstance(stmt)?returnstmt?}else{returnmethod.invoke(connection,params)?}}catch(Throwablet){throwt?}}/***這里讓這丫的Connection也進(jìn)入proxy的過濾文件列表*/publicstaticConnectionnewInstance(Connectionconn){InvocationHandlerhandler=newConnectionProxy(conn)?ClassLoadercl=Connection.class.getClassLoader()?/*看這里Connection.class被出賣他的調(diào)用都要先被ConnectionProxyinvoke看看，在這里了，到了，一下類我就不標(biāo)注了*/return(Connection)Proxy.newProxyInstance(cl,newClass[]{Connection.class},handler)?}}PreparedStatementProxy.javapackagexy?importjava.lang.reflect.InvocationHandler?

importjava.lang.reflect.Method?importjava.lang.reflect.Proxy?importjava.sql.CallableStatement?importjava.sql.PreparedStatement?importjava.sql.ResultSet?importmons.logging.Log?importmons.logging.LogFactory?/***本類用于記錄PreparedStatement的日志*/publicclassPreparedStatementProxyextendsBaseProxyimplementsInvocationHandler{privatestaticfinalLoglog=LogFactory.getLog(PreparedStatement.class)?privatePreparedStatementstatement?privateStringsql?privatePreparedStatementProxy(PreparedStatementstmt,Stringsql){this.statement=stmt?this.sql=sql?}publicObjectinvoke(Objectproxy,Methodmethod,Object[]params)throwsThrowable{try{if(execSqlMethods.contains(method.getName())){log.debug("PreparedStatementId="+id+"ExecutingStatement:"+sql)?log.debug("PreparedStatementId="+id+"Parameters:"+getValueString())?log.debug("PreparedStatementId="+id+"Types:"+getTypeString())?if("executeQuery".equals(method.getName())){ResultSetrs=(ResultSet)method.invoke(statement,params)?if(rs!=null){returnResultSetProxy.newInstance(rs)?}else{returnnull?}}else{returnmethod.invoke(statement,params)?}}elseif(setMethods.contains(method.getName())){if("setNull".equals(method.getName())){setColumn(params[0],null)?}else{//這里記錄那些綁定變量的參數(shù)了setColumn(params[0],params[1])?}returnmethod.invoke(statement,params)?

}elseif("getResultSet".equals(method.getName())){ResultSetrs=(ResultSet)method.invoke(statement,params)?if(rs!=null){returnResultSetProxy.newInstance(rs)?}else{returnnull?}}elseif("equals".equals(method.getName())){Objectps=params[0]?if(psinstanceofProxy){returnnewBoolean(proxy==ps)?}returnnewBoolean(false)?}elseif("hashCode".equals(method.getName())){returnnewInteger(proxy.hashCode())?}else{returnmethod.invoke(statement,params)?}}catch(Throwablet){throwt?}}/***這個方法里面，PreparedStatement.class,CallableStatement.class有這兩個方法被出賣給了PreparedStatementProxy，這里調(diào)用這兩個類的方法，都要先被invoke方法看看了*/publicstaticPreparedStatementnewInstance(PreparedStatementstmt,Stringsql){InvocationHandlerhandler=newPreparedStatementProxy(stmt,sql)?ClassLoadercl=PreparedStatement.class.getClassLoader()?return(PreparedStatement)Proxy.newProxyInstance(cl,newClass[]{PreparedStatement.class,CallableStatement.class},handler)?}}ResultSetProxy.java這里記錄ResultSet里面的方法的調(diào)用。這個類的每個方法的調(diào)用都會被記錄packagexy?importjava.lang.reflect.InvocationHandler?importjava.lang.reflect.Method?importjava.lang.reflect.Proxy?importjava.sql.ResultSet?importmons.logging.Log?importmons.logging.LogFactory?/***@authorkeyboardsun*******************

*@site**/publicclassResultSetProxyextendsBaseProxyimplementsInvocationHandler{privatestaticfinalLoglog=LogFactory.getLog(ResultSet.class)?booleanfirst=true?privateResultSetrs?privateResultSetProxy(ResultSetrs){super()?this.rs=rs?log.debug("ResultSetId="+id+"ResultSet")?}publicObjectinvoke(Objectproxy,Methodmethod,Object[]params)throwsThrowable{try{Objecto=method.invoke(rs,params)?if(getMethods.contains(method.getName())){if(params[0]instanceofString){setColumn(params[0],o)?}}elseif("next".equals(method.getName())||"close".equals(method.getName())){Strings=getValueString()?if(!"[]".equals(s)){if(first){first=false?log.debug("ResultSetId="+id+"Header:"+getColumnString())?}log.debug("ResultSetId="+id+"Result:"+s)?}clearColumnInfo()?}returno?}catch(Throwablet){throwt?}}/***這里ResultSet.class被出賣*/publicstaticResultSetnewInstance(ResultSetrs){InvocationHandlerhandler=newResultSetProxy(rs)?ClassLoadercl=ResultSet.class.getClassLoader()?return(ResultSet)Proxy.newProxyInstance(cl,newClass[]{ResultSet.class},

handler)?}/***Getthewrappedresultset*@returntheresultSet*/publicResultSetgetRs(){returnrs?}}StatementProxy.java這里Statement類的所有方法的調(diào)用也要被記錄的。packagexy?importjava.lang.reflect.InvocationHandler?importjava.lang.reflect.Method?importjava.lang.reflect.Proxy?importjava.sql.ResultSet?importjava.sql.Statement?importmons.logging.Log?importmons.logging.LogFactory?/***@authorkeyboardsun********************@site**/publicclassStatementProxyextendsBaseProxyimplementsInvocationHandler{privatestaticfinalLoglog=LogFactory.getLog(Statement.class)?privateStatementstatement?privateStatementProxy(Statementstmt){super()?this.statement=stmt?}publicObjectinvoke(Objectproxy,Methodmethod,Object[]params)throwsThrowable{try{if(execSqlMethods.contains(method.getName())){log.debug("StatementId="+id+"Statement:"+params[0].toString())?if("executeQuery".equals(method.getName())){ResultSetrs=(ResultSet)method.invoke(statement,params)?if(rs!=null){returnResultSetProxy.newInstance(rs)?}else{returnnull?}}else{

returnmethod.invoke(statement,params)?}}elseif("getResultSet".equals(method.getName())){ResultSetrs=(ResultSet)method.invoke(statement,params)?if(rs!=null){returnResultSetProxy.newInstance(rs)?}else{returnnull?}}elseif("equals".equals(method.getName())){Objectps=params[0]?if(psinstanceofProxy){returnnewBoolean(proxy==ps)?}returnnewBoolean(false)?}elseif("hashCode".equals(method.getName())){returnnewInteger(proxy.hashCode())?}else{returnmethod.invoke(statement,params)?}}catch(Throwablet){throwt?}}/***Statement.class被出賣*/publicstaticStatementnewInstance(Statementstmt){InvocationHandlerhandler=newStatementProxy(stmt)?ClassLoadercl=Statement.class.getClassLoader()?return(Statement)Proxy.newProxyInstance(cl,newClass[]{Statement.class},handler)?}}這里我們把整個過濾的框架都寫好了，入口就是上面的ConnectonProxy.java的newInstancenewInstance方法就可以了少寫了很多debug的代碼噢。方法，在我們的程序應(yīng)用中，獲取連接的時候只要通過這個。下面開始測試demo啦。各位look，效果不錯噢，讓我們packagenet.chinacsharp.main;importjava.sql.Connection;importjava.sql.DriverManager;importjava.sql.PreparedStatement;importjava.sql.ResultSet;importjava.util.ArrayList;importxy.ConnectionProxy;

publicclassRunTest{privatestaticConnectiongetConnection()throwsThrowable{Class.forName("oracle.jdbc.driver.OracleDriver").newInstance();Connectionconn=DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:ORACLEDB","password");"uwfe",returnConnectionProxy.newInstance(conn);//這里，因?yàn)檫@段代碼，數(shù)據(jù)庫的操作類全部被出賣給了Proxy}publicstaticvoidmain(Stringargs[]){try{Connectionconnection=getConnection();PreparedStatementstatement=null;statement=connection.prepareStatement("select*fromwork_flow_taskwhereTASK_TYPE_CODE=?ANDTASK_TYPE_NAME=?");statement.setString(1,"task/綜合室/station/ZHSXZHFCL.zhsxzhfjd");statement.setString(2,"綜合室協(xié)作回復(fù)階段");ResultSetrs=statement.executeQuery();while(set.next()){System.out.println(set.getString("TASK_TYPE_CODE"));System.out.println(set.getString("TASK_TYPE_NAME"));}}catch(Throwablee){e.printStackTrace();}}}這里我們跑一下，看看日志：注：這里的藍(lán)色的說明是我加上去的。DEBUGxy.ConnectionProxy-ConnectionId=100000DEBUGxy.ConnectionProxy-ConnectionId=100000PreparingStatement:select*fromwork_flow_taskwhereTASK_TYPE_CODE=?ANDTASK_TYPE_NAME=?DEBUGjava.sql.PreparedStatement-PreparedStatementId=100001ExecutingStatement:select*fromwork_flow_taskwhereTASK_TYPE_CODE=?ANDTASK_TYPE_NAME=?DEBUGjava.sql.PreparedStatement-PreparedStatementId=100001Parameters:[task/綜合室/station/ZHSXZHFCL.zhsxzhfjd,綜合室協(xié)作回復(fù)階段]//這里是set變量的職DEBUGjava.sql.PreparedStatement-PreparedStatementId=100001Types:[java.lang.String,java.lang.String]//set變量