http断点续传简单实现（java)

/* j#"?Oe{_1  
**SiteFileFetch.java &7!&]kA+  
*/ AKC';J  
package NetFox; O7I:Y85i#O  
import java.io.*; 0PI
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import java.net.*; E9;cd$}K  
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public class SiteFileFetch extends Thread {
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SiteInfoBean siteInfoBean = null; //文件信息Bean 6&S;Nrg9  
long[] nStartPos; //开始位置 E'?yI'~=  
long[] nEndPos; //结束位置 t?L;k+sMM  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 9w^1/t&=04  
long nFileLength; //文件长度 U,yU-8z/  
boolean bFirst = true; //是否第一次取文件 $(H%|Oyn  
boolean bStop = false; //停止标志 -~~"}u  
File tmpFile; //文件下载的临时信息 ='q:Io?T  
DataOutputStream output; //输出到文件的输出流 2i;G3"\  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） jw
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public SiteFileFetch(SiteInfoBean bean) throws IOException 7c1xB.g   
{ Gy hoo'<  
siteInfoBean = bean; ,`v)nwP  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); fHCLsI  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 5e~\o}
]  
if(tmpFile.exists ()) 'due'|#^  
{ UM(tM9  
bFirst = false; \?{nP6=  
read_nPos(); %|}obiV)  
} )Ge.1B$8h  
else TYGUB%A  
{ 8bLA6qmM\  
nStartPos = new long[bean.getNSplitter()]; cu5Yvp  
nEndPos = new long[bean.getNSplitter()]; m{  .'55  
} (ec?_N0=  
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} uIvy1h9m  
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public void run() 6e3s |  
{ JziuwL5,  
//获得文件长度 wN\%b}pp  
//分割文件 o@mZ6!ax3  
//实例FileSplitterFetch n#[-1(P  
//启动FileSplitterFetch线程 k3h
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//等待子线程返回 2F[smUL
 
try{ 1Y
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if(bFirst) wWv")dk3i  
{ I&?(=i)N  
nFileLength = getFileSize(); "Kx2k>ym  
if(nFileLength == -1) U~n>k<`sr  
{ jFY6}WY)}7  
System.err.println("File Length is not known!"); D::$YR ~R  
} !'o5X]s  
else if(nFileLength == -2) XW w=3$  
{ Y u\
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System.err.println("File is not access!"); la:i!qAH  
} D7H,49#1Q  
else &4Q(>"iL4  
{ 6!bp;iLKy  
for(int i=0;i<nStartPos.length;i++) j/`-x  
{ :Fz;nG-G  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ?piv]Z  
} Ca?5bCI,  
for(int i=0;i<nEndPos.length-1;i++) M9'Qs m  
{ SIv8EMGo  
nEndPos = nStartPos[i+1]; "jqC3$DKI  
} ^-?5=\`5  
nEndPos[nEndPos.length-1] = nFileLength; S=H<5*]g  
} g+;)?N*j  
} /` 891(f,  
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//启动子线程 \g<9_  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 1ThONrxu  
for(int i=0;i<nStartPos.length;i++) Vw.c0
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{ X~|P  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )nmLgsg  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ):OGhW
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nStartPos,nEndPos,i); NSH20$A<  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~CiVLSH=  
fileSplitterFetch.start(); }`#OA]NZ  
} _i{$5JJ+K2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), y`O !,kW  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); m99j]wr~c  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", P=PcO>  
nEndPos = " + nFileLength); Rj 2N+59rg  
// fileSplitterFetch[nPos.length-1].start(); 4lhoA  
[lZo'o  
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//等待子线程结束 ^Yz.,!B[  
//int count = 0; Q;{[U!\:  
//是否结束while循环 gZ%wmY  
boolean breakWhile = false; GWo^hIfJ  
i
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while(!bStop) R|aA6} /I  
{ y57]q#k  
write_nPos(); CBw/a0Uck  
Utility.sleep(500); EV{kd.=f  
breakWhile = true; c&r8q]u  
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for(int i=0;i<nStartPos.length;i++) w:xLg.Eq6  
{ H%
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if(!fileSplitterFetch.bDownOver) par|j]  
{ Ncr38~;w  
breakWhile = false; ^% y<7>%  
break; *fyC@fI>  
} ^DVj_&~  
} +p6cG\Gp  
if(breakWhile) \pI)tnu6'U  
break; NX7(;02  
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//count++; %\6ns  
//if(count>4) @i'24Q[6  
// siteStop(); #;FHyKx  
} 62lG,y_L  
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System.err.println("文件下载结束！"); Z* eb  
} 5sJi- ^  
catch(Exception e){e.printStackTrace ();} U:6 J~  
} [U+6Tj,  
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//获得文件长度 l%"[857  
public long getFileSize() k^3 ?Z2a  
{ |O0=Q,<m  
int nFileLength = -1; *?jU$&Qpj*  
try{ s/[15  
URL url = new URL(siteInfoBean.getSSiteURL()); 0tbximmDb  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); i*34/  
httpConnection.setRequestProperty("User-Agent","NetFox"); #hL<9j  
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int responseCode=httpConnection.getResponseCode(); N)'oX3?x  
if(responseCode>=400) 86Q\G.h7  
{ |jB]5ciT  
processErrorCode(responseCode); 5Pmmt&#/Z  
return -2; //-2 represent access is error 0v6(A4Y  
} !wH7;tU  
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String sHeader; xb#M{EE-.  
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for(int i=1;;i++) Ju5<wjQR\  
{ tln*Baq  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); vd7%#sHH&  
//Utility.log(in.readLine()); OiPE,sv  
sHeader=httpConnection.getHeaderFieldKey(i); RqTW$94RD  
if(sHeader!=null) Q*wub9  
{ Dw}8c
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if(sHeader.equals("Content-Length")) ,arFR'u>  
{ gM=oH   
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); d{_tOj$  
break; [@D+kL*>  
} d"zbY\`  
} z9mmZqhK\  
else (lv|-Phc.  
break; GCx1lm  
} Jp)>Wd  
} G<.p".o4  
catch(IOException e){e.printStackTrace ();} GRpS^%8i@  
catch(Exception e){e.printStackTrace ();} hpJ[VKe  
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Utility.log(nFileLength); Bkg/A;H  
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return nFileLength; p)}iUU2N  
} `q Sfo`  
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//保存下载信息（文件指针位置） PAF2=  
private void write_nPos() 1_vaSEov  
{ n"B"Aysz  
try{ jJ% *hDZ6t  
output = new DataOutputStream(new FileOutputStream(tmpFile)); f(q
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output.writeInt(nStartPos.length); S-[]z*  
for(int i=0;i<nStartPos.length;i++) w <zO  
{ q4_&C&7  
// output.writeLong(nPos); ,ry2J,IT7  
output.writeLong(fileSplitterFetch.nStartPos); zo66=vE!  
output.writeLong(fileSplitterFetch.nEndPos); [uO
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} yC.ve;lG  
output.close(); 4xLU15C  
} 3\eb:-B:@  
catch(IOException e){e.printStackTrace ();} $I(2}u?1+d  
catch(Exception e){e.printStackTrace ();} #W<D~C[I _  
} ]>h2h?2te  
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//读取保存的下载信息（文件指针位置） uiq)?XUKv  
private void read_nPos() ,6rg00wGE  
{ kM>0>fkjE  
try{ =8OPjcX.V  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 7NG^X"N{Ul  
int nCount = input.readInt(); H?8uy_Sc  
nStartPos = new long[nCount]; "Yw-1h`fR  
nEndPos = new long[nCount]; 2d+IROA  
for(int i=0;i<nStartPos.length;i++) (n7v $A  
{ ai"Kd=R  
nStartPos = input.readLong(); -05zcIVo  
nEndPos = input.readLong(); GRz`fO  
} eN]0]9JO  
input.close(); s]Z/0:`  
} *,1^{mb  
catch(IOException e){e.printStackTrace ();} #p~tkQ:'1  
catch(Exception e){e.printStackTrace ();} k!E`Xeob  
} SPA_a\6_  
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private void processErrorCode(int nErrorCode)
%)_R>.>  
{ KfJF9!U*?  
System.err.println("Error Code : " + nErrorCode); mMO:m8W  
} Cec!{]DL&  
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//停止文件下载 -[OGZP`8  
public void siteStop() Gad!}dz  
{ +GMM&6<  
bStop = true; pLMki=.Ld  
for(int i=0;i<nStartPos.length;i++) '/ 3..3k  
fileSplitterFetch.splitterStop(); Uxx=$&#  
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} oPRvd_~  
} reLYtv  
//负责部分文件的抓取 m<005_Z0Q  
**FileSplitterFetch.java [>#?C*s  
*/ ~]?Q'ER  
package NetFox; &s_O6cqgh  
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import java.io.*; VR5$[-E3  
import java.net.*; $Hqm 09w  
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public class FileSplitterFetch extends Thread { VkFTIyt  
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String sURL; //File URL 7(na?Z$  
long nStartPos; //File Snippet Start Position Q(gu";&  
long nEndPos; //File Snippet End Position ->&AJI0  
int nThreadID; //Thread's ID 2Jrr;"r  
boolean bDownOver = false; //Downing is over -?<wvUbR{  
boolean bStop = false; //Stop identical q{Hk27kt  
FileAccessI fileAccessI = null; //File Access interface uc~PKU?tO  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException oH!sJ&"#_  
{ 4W}8?&T  
this.sURL = sURL; tUv@4<~,/  
this.nStartPos = nStart; t`03$&Cx7  
this.nEndPos = nEnd; rs2~spN;h  
nThreadID = id; %stZ'
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 a?E]-Zf  
} VztalwI  
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public void run() *\m 53mb  
{ AS`0.RC-  
while(nStartPos < nEndPos && !bStop) Hk8:7"4Q  
{ F6Zl#eL  
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try{ x_{ua0BLDf  
URL url = new URL(sURL); F>2t=r*9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); LlL\7?_;  
httpConnection.setRequestProperty("User-Agent","NetFox"); cqr!*  
String sProperty = "bytes="+nStartPos+"-"; eSoOJ[&$  
httpConnection.setRequestProperty("RANGE",sProperty); Wcn3\v6_  
Utility.log(sProperty); Y&`Vs(  
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InputStream input = httpConnection.getInputStream(); ~}w(YQy=y  
//logResponseHead(httpConnection); &$jg *Kr  
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byte[] b = new byte[1024]; 3Gf^IV-  
int nRead; A_T-]YQ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) zMt"ST.  
{ U*,8,C  
nStartPos += fileAccessI.write(b,0,nRead); J]nb;4w  
//if(nThreadID == 1) EnA) Rz  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); C*ZgjFvB  
}  IPa08/  
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Utility.log("Thread " + nThreadID + " is over!"); L7_Mg{  
bDownOver = true; U2/H,D  
//nPos = fileAccessI.write (b,0,nRead); 
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} @no]*?Gpa  
catch(Exception e){e.printStackTrace ();} %m!o#y(hD`  
} h1G]w/.ws  
} Y}'C'PR  
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9c8zH{T_{  
//打印回应的头信息 *fW&-ic  
public void logResponseHead(HttpURLConnection con) IyIh0B~i  
{ "2+>!G RQ  
for(int i=1;;i++) PHi'&)|  
{ UtG@0(6C  
String header=con.getHeaderFieldKey(i); wKe^5|Rr  
if(header!=null) j[m\;3Sp  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); !tv3.:eT  
Utility.log(header+" : "+con.getHeaderField(header)); <<LmO-92  
else n_AW0i.  
break; Y1+4ppZ  
} ygS*))7 r  
} $$<9tqA  
SG |!wH^  
t*zve,?}  
public void splitterStop() BqP:]  
{ Hx2UDHF  
bStop = true; y.JAtsxD  
} t= "EbPE  
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} 5H:NY|  
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/* j\q1b:pE  
**FileAccess.java wd~e3%JM  
*//文件访问(定位，写) ,!F'h:   
package NetFox; ?+D_*'65D  
import java.io.*; Run)E*sf  
9 }|Bs=q  
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public class FileAccessI implements Serializable{ F0o7X
Ut  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 z 4Qz9#*"^  
RandomAccessFile oSavedFile; B{H;
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long nPos; JVwYV5-O<0  
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public FileAccessI() throws IOException  S&]+r<  
{ x^8xz5:O  
this("",0); i|Lir{vW  
} i' %V}2  
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public FileAccessI(String sName,long nPos) throws IOException dE_BV=H{  
{ ~e{Ag
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oSavedFile = new RandomAccessFile(sName,"rw"); .Di+G-#aEs  
this.nPos = nPos; 5oGnPF  
oSavedFile.seek(nPos); knh^q;q*  
} mV@.JFXKP  
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public synchronized int write(byte[] b,int nStart,int nLen) 8^\DQ&D  
{ ?'P8H^K6u  
int n = -1; xE;4#+_I  
try{ D@^ r  
oSavedFile.write(b,nStart,nLen); {Mp>+e@xx  
n = nLen; yC =5/wy`  
} ]?#f=/  
catch(IOException e) YUfuS3sX}  
{ ,(N&%  
e.printStackTrace (); (03m%\  
} "^;'.~@e8  
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return n; [ 8N1tZ{`  
} "}*P9-%  
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} .(VxeF(v_k  
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/* l@q.4hT  
**SiteInfoBean.java <'v?WV_  
*/ Cj"k Fq4  
package NetFox; #AyM!  
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public class SiteInfoBean { !vr">@}K  
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private String sSiteURL; //Site's URL {{ R/:-6?@  
private String sFilePath; //Saved File's Path *oY59Yf  
private String sFileName; //Saved File's Name QJTGeJ Y  
private int nSplitter; //Count of Splited Downloading File NAZxM9  
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public SiteInfoBean() 6JmS9ho  
{//nSplitter的缺省值为5 ORs<<H.d  
//default value of nSplitter is 5 P}~6yX  
this("","","",5); qdCa]n!d  
} Rde#=>@V  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {K*l,U  
{ ZajQ B  
sSiteURL= sURL; AQ32rJT8c`  
sFilePath = sPath; 1jh^-d5  
sFileName = sName; NVS U)#  
this.nSplitter = nSpiltter; 9^4^EY#  
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} .Ig`v  
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public String getSSiteURL() R7KHfXy'm  
{ tU!"CX  
return sSiteURL; Dgc[WsCEW  
} ym2\o_^(  
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public void setSSiteURL(String value) W
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{ |m"2B]"@  
sSiteURL = value; -F4CHpua  
} O#H`/z  
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public String getSFilePath()
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{ b?CmKiM%  
return sFilePath; W+H27qsv  
} yT-m9$^v  
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public void setSFilePath(String value) TqKL(Qw E  
{ |w>"oaLN|Q  
sFilePath = value; W`eYd|+C  
} 5ii`!y  
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public String getSFileName() er+m:XuV  
{ 3`n5[RV  
return sFileName; HMgZ&
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} Q6MDhv,  
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public void setSFileName(String value) .o:Pe2C  
{ QP7EPaW  
sFileName = value; s8WA@)L  
} z/F(z*'v  
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public int getNSplitter() 2(5wFc  
{ `2J6Dz"W  
return nSplitter; `;hsOfo  
} oE"!  
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public void setNSplitter(int nCount) Nq9Qsia&  
{ |I^\|5  
nSplitter = nCount; I =qd\  
} W5 fO1F  
} R|$=Pfg~4  

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/* }-V .upl  
**Utility.java ?j?{}Z  
*/ %a8'6^k  
package NetFox; C(}9  
6
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@2CYv>  
public class Utility { l"IBt:  
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public Utility() '
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{ &I:X[=;g  
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} > :!faWX  
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//线程睡眠 +@Fy) {C7  
public static void sleep(int nSecond) OJ@';ZyT=  
{ }s}b]v  
try{ Lt@4F   
Thread.sleep(nSecond); M[Y|$I}  
} KKGAk\X  
catch(Exception e) YDi_Gl$  
{ oxPOfI1%]  
e.printStackTrace (); U[U$1LSS  
} +'uF3-+WY  
} 6M"J3\ x  
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//日志 u\^<V)  
public static void log(String sMsg) Iy8gQdI  
{ K?-K<3]9f  
System.err.println(sMsg); 45/f}kvy
 
} O5Yk=-_m  
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public static void log(int sMsg) C0i:*1  
{ ?Sn$AS I  
System.err.println(sMsg); ;L(W'+  
} ?7^('  
} .N_0rPO,Kw  
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/* ^w8H=UkP!+  
**TestMethod.java Mr2dhSQ!  
*/ Fdm7k){A  
package NetFox; XXuU@G6Z7$  
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public class TestMethod { >9+@oGe(E  
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public TestMethod() &oTSff>p}  
{ ///xx/weblogic60b2_win.exe [%P_ Y/  
try{ 4%\L8:  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); <~"qz*_  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Y)c9]1qly  
SiteFileFetch fileFetch = new SiteFileFetch(bean); X]C-y,r[M  
fileFetch.start(); kul&m|  
} ~;UK/OZ  
catch(Exception e){e.printStackTrace ();} Yx(?KN7V?  
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} Y<w2_+(  
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public static void main(String[] args) 6/nhz6=  
{ <G2;nvRr  
new TestMethod(); 3t68cdFlz  
} 2~R"3c+^  
} Z(/jQ=ozQ  
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