http断点续传简单实现（java)

/* nD=N MqQ &  
**SiteFileFetch.java $bZ5@)E  
*/ fvA167\  
package NetFox; w3ZOCWJS  
import java.io.*; 5<7sVd.  
import java.net.*; @ xTVX'$  
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public class SiteFileFetch extends Thread { h+9~^<oFl  
}rWg']  
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SiteInfoBean siteInfoBean = null; //文件信息Bean h6;zAM}  
long[] nStartPos; //开始位置 "`* >co6r  
long[] nEndPos; //结束位置 %e+*&Z',  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 F$O$Y[  
long nFileLength; //文件长度 &NI\<C7_Gw  
boolean bFirst = true; //是否第一次取文件 }CrWmJu0  
boolean bStop = false; //停止标志 i=V2 /W}  
File tmpFile; //文件下载的临时信息 jk%H+<FU`  
DataOutputStream output; //输出到文件的输出流 k<rJm P{  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） >.hDt9@4  
public SiteFileFetch(SiteInfoBean bean) throws IOException M{YN^ Kk  
{ (/!zHq  
siteInfoBean = bean; Q>

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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); @q{.shqo  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); nu[["f~  
if(tmpFile.exists ()) g5*?2D}dqX  
{ /?}2OCq  
bFirst = false; /9?yw!  
read_nPos(); i\o * =+{r  
} CH5>u  
else d?/>Qqw:#  
{ SPtx_+ Q)S  
nStartPos = new long[bean.getNSplitter()]; K4OiKYq  
nEndPos = new long[bean.getNSplitter()]; TW1#'G_#  
} X*hPE=2` p  
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} Z!l]v.S  
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public void run() :_o^oi7G  
{ oZ
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//获得文件长度 U/h@Q\~U  
//分割文件 STPRC&7;  
//实例FileSplitterFetch Lw<.QMN%f  
//启动FileSplitterFetch线程 Y6(=cm  
//等待子线程返回 NGW:hgf  
try{ bE3mOml  
if(bFirst) 9A9T'g)Du  
{ Qr?1\H:Lq  
nFileLength = getFileSize(); 8cuI-Swz  
if(nFileLength == -1) F|8;Swb5  
{ 8T"kQB.Zv  
System.err.println("File Length is not known!"); y-"QY[  
} :kd]n$]  
else if(nFileLength == -2) v8C4BuwA  
{ 7'|aEH  
System.err.println("File is not access!"); t8*NldC  
} }?sC1]-j&  
else EIPXq  
{ y43ha  
for(int i=0;i<nStartPos.length;i++) v <OZ # L$  
{ a`LkP%  
nStartPos = (long)(i*(nFileLength/nStartPos.length));
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}
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for(int i=0;i<nEndPos.length-1;i++) ieXi6^M$  
{ 8uA!Vrp3  
nEndPos = nStartPos[i+1]; Jw{duM;]  
} #RHt;SFx  
nEndPos[nEndPos.length-1] = nFileLength; 6r`Xi&  
} 4I*'(6 ,!  
} 1had8K-  
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NB-%
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//启动子线程 R{Cbp=3J  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; y>^0q/=]?O  
for(int i=0;i<nStartPos.length;i++) `Io#440;  
{ h,,B"vPS  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4b6)+*[O  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^@Z8_PZo  
nStartPos,nEndPos,i); ^|2m&2  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); FwD q@Oj  
fileSplitterFetch.start(); ^$[iLX  
} YWL7.Y>%5  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8i)9ho<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); z|\n^ZK=  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 1X9J[5|ll  
nEndPos = " + nFileLength); ^1
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// fileSplitterFetch[nPos.length-1].start(); [\&2&  
lR]FQnZ  
@|e we.r  
//等待子线程结束 kU.@HJ[@j  
//int count = 0; =T1Xfib  
//是否结束while循环 ,T;D33XV  
boolean breakWhile = false; zMd><UQP{  
%Hhk 6tR,  
Ty7)j]b"zl  
while(!bStop) ,qNbo 11  
{ </aQ  
write_nPos(); DhD##5a  
Utility.sleep(500); <5}j(jxz}  
breakWhile = true; : t
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for(int i=0;i<nStartPos.length;i++) @#;*e] 1a  
{ \C4wWh-A  
if(!fileSplitterFetch.bDownOver) <2~DI0pp(  
{ .i^@v<+  
breakWhile = false; >7~,w1t  
break; ngI+afo   
} "<^n@=g'q  
} X-J85b_e  
if(breakWhile) *kcc]*6@s  
break; 6~x
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//count++; @.`k2lxGd~  
//if(count>4) '(g;nU<  
// siteStop(); m_
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} Gl[1K/,*  
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System.err.println("文件下载结束！"); +wQ}ZP&  
} 2b-g`60<  
catch(Exception e){e.printStackTrace ();} u6| IKZ  
} 4;eD}g
  
,s2C)bb-  
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//获得文件长度 7PBE(d%m  
public long getFileSize() ~$hR:I1  
{ .?LRt  
int nFileLength = -1; k!'+7K.  
try{ MU\Pggs  
URL url = new URL(siteInfoBean.getSSiteURL()); #)]/wqPoW  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); mIqm/5  
httpConnection.setRequestProperty("User-Agent","NetFox"); '?g&);4)k-  
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int responseCode=httpConnection.getResponseCode(); 5)5yH bS  
if(responseCode>=400) 8si{|*;hL  
{ VT=gb/W6)a  
processErrorCode(responseCode); PsD)]V9%:  
return -2; //-2 represent access is error 0rm(i*Q  
} o[i*i<jv-  
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String sHeader; S.q0L  
 yK$aVK"  
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for(int i=1;;i++) pS}IU{#;  
{ ~tZB1+%)  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); dnQ6Ras  
//Utility.log(in.readLine()); sg49a9`8  
sHeader=httpConnection.getHeaderFieldKey(i); leI ]zDk=  
if(sHeader!=null) %~8f0B|im  
{ S?J(VJqE  
if(sHeader.equals("Content-Length")) `"<hO 'WU  
{ lP*=4Jh  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); `AvK=]  
break; G6G-qqXy6  
} ]qu6/Z  
} 65*Hf3~~  
else c\&;
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break; \sfc!5G  
} '>n&3`r5  
} hw*u.46  
catch(IOException e){e.printStackTrace ();} [Q J  
catch(Exception e){e.printStackTrace ();} zufsmY4P  
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Utility.log(nFileLength); *[*q#b$j  
}xi?vAaTl  
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return nFileLength; )Q>Ao.  
} iA[o;D#  
@+Sr~:K  
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//保存下载信息（文件指针位置） |5X59! JL  
private void write_nPos() xXa4t4gR  
{ T?6<1n
U)  
try{ $#2<f 6  
output = new DataOutputStream(new FileOutputStream(tmpFile)); FQ`1c[M@  
output.writeInt(nStartPos.length); !H{>c@i  
for(int i=0;i<nStartPos.length;i++) mH4u@aQ}  
{ HavlN}h
 
// output.writeLong(nPos); q-
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output.writeLong(fileSplitterFetch.nStartPos); PAtv#)h  
output.writeLong(fileSplitterFetch.nEndPos); 9F?-zn;2s  
} CQ^(/B^c  
output.close(); 'mTY56Yq  
} pV_zePyOn  
catch(IOException e){e.printStackTrace ();} ^;.u}W  
catch(Exception e){e.printStackTrace ();} :N"&o(^  
} qu dY9_  
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//读取保存的下载信息（文件指针位置） b-#lKWso  
private void read_nPos() D6+3f#k6  
{ "5O>egt  
try{ a?8)47)  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); v+`'%E  
int nCount = input.readInt(); R5((
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nStartPos = new long[nCount]; }4H}*P>+  
nEndPos = new long[nCount]; WBkx!{\z  
for(int i=0;i<nStartPos.length;i++) jm@M"b'{  
{ D!/ 4u0m  
nStartPos = input.readLong(); /h.{g0Xc  
nEndPos = input.readLong(); xpo^\E?2  
} #62ThH~  
input.close(); hsS&|7Pt  
}
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catch(IOException e){e.printStackTrace ();} tcsb]/my  
catch(Exception e){e.printStackTrace ();} gsM^Pu09ud  
} |G$-5 7fk  
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private void processErrorCode(int nErrorCode) rqdN%=C  
{ vNuws_  
System.err.println("Error Code : " + nErrorCode); ITTEUw~+o  
} EG$-D@o\I  
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//停止文件下载 Kg"eS`-  
public void siteStop() c$L1aZo  
{ gO"G/  
bStop = true; ^_DwuY  
for(int i=0;i<nStartPos.length;i++) Zv=pS (9  
fileSplitterFetch.splitterStop(); $x]/|u/9  
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} L?N-uocT  
} NCG;`B`i  
//负责部分文件的抓取 92A9gY
  
**FileSplitterFetch.java #OM)71kB8  
*/ <OKc?[  
package NetFox; ag47$9(  
alHA&YC{K  
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import java.io.*; svl!"tMXl  
import java.net.*; 6o\uv  
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public class FileSplitterFetch extends Thread { 3o?eUwI}  
'VCuMCV  
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String sURL; //File URL 1Q? RD%lkf  
long nStartPos; //File Snippet Start Position
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long nEndPos; //File Snippet End Position X#JUorGp  
int nThreadID; //Thread's ID oQu>Qr{Zp  
boolean bDownOver = false; //Downing is over |Rkw/5  
boolean bStop = false; //Stop identical K/f-9hE F  
FileAccessI fileAccessI = null; //File Access interface 5|K[WvG@Co  
YW/V}C'>  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Cb+$|Kg/"b  
{ .udLMS/_  
this.sURL = sURL; >
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this.nStartPos = nStart; UdM2!f  
this.nEndPos = nEnd; Bl8|`R^g  
nThreadID = id; Uuu2wz3O0  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 w)@Wug  
} JJ_Z{  
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public void run() j7gTVfO  
{ >A-{/
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while(nStartPos < nEndPos && !bStop) un-%p#  
{ H{=G\N{  
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try{ OQKg/1  
URL url = new URL(sURL); 5>0\=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); KRT&]2  
httpConnection.setRequestProperty("User-Agent","NetFox"); fd>{UyU  
String sProperty = "bytes="+nStartPos+"-"; -k8sR1(  
httpConnection.setRequestProperty("RANGE",sProperty); =d^hiR!GN  
Utility.log(sProperty); W&|?8%"l]  
4aBVO%t  
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InputStream input = httpConnection.getInputStream(); !8[A;+o3P  
//logResponseHead(httpConnection); ``VE<:2+  
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!<=zFy[J.9  
byte[] b = new byte[1024]; n(eo_.W2|  
int nRead; 5!qf{4j  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) *p\Zc*N;%  
{ Kd+E]$F_OH  
nStartPos += fileAccessI.write(b,0,nRead); m+s*Io{Ip  
//if(nThreadID == 1) 63Gq5dF  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +ynhN\S$/  
} wyB]!4yy,  
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Utility.log("Thread " + nThreadID + " is over!"); FP=- jf/  
bDownOver = true; Er j{_i?R?  
//nPos = fileAccessI.write (b,0,nRead); _&V,yp!|  
} FVrB#Hw~  
catch(Exception e){e.printStackTrace ();} nf"#F@dk  
} +<[q"3
  
} tR'RB@kJ  
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8Z9>h:c1  
//打印回应的头信息 'ZMh<M[  
public void logResponseHead(HttpURLConnection con) f7Nmvla[q  
{ Ul]7IUzsu  
for(int i=1;;i++) JXe~ 9/!  
{ ly*v|(S&  
String header=con.getHeaderFieldKey(i); H(
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if(header!=null) ]zJO)(d$>  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 7UW\|r  
Utility.log(header+" : "+con.getHeaderField(header)); U.t][#<3  
else ]3Ia>i  
break; !Ea!"}  
} -;_"Y]#  
} ,v8e7T  
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public void splitterStop() mL`8COA  
{ ,IboPh&Q78  
bStop = true; |LQ%sV  
} ]j/= x2p  
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} Bt@?l]Y  
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/* Ev
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**FileAccess.java [=jZP,b&),  
*//文件访问(定位，写) q%kCTw  
package NetFox; eu$VKLY*  
import java.io.*; 9 CZ@IFS  
_^GBfM.  
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public class FileAccessI implements Serializable{ k $^/$N  
~"
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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 hjg
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RandomAccessFile oSavedFile; .p e3L7g  
long nPos; Q34u>VkdQI  
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public FileAccessI() throws IOException ,ESli/6  
{ f]%SFQ+  
this("",0); h?n?3x!(  
} _%2ukuJ `  
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public FileAccessI(String sName,long nPos) throws IOException hfY/)-60o  
{ EEZ~Bs}d  
oSavedFile = new RandomAccessFile(sName,"rw"); lF/ Xs  
this.nPos = nPos; "]]LQb$  
oSavedFile.seek(nPos); )yig=nn  
} ?
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#!O)-dyF  
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public synchronized int write(byte[] b,int nStart,int nLen) !|4]V}JQ  
{ 06AgY0\  
int n = -1; 1DcBF@3sWG  
try{ Q}B]b-c+E  
oSavedFile.write(b,nStart,nLen); \a;xJzc9  
n = nLen; -avxH?;?
7  
} >e6OlIW  
catch(IOException e) hIqUidJod  
{ N80ogio_Tk  
e.printStackTrace (); AA,/AKikd  
} nD eVYK  
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nsi?.c&0!  
return n; OjlX<y.  
} E%v0@  
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} p#P<V%  
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/* FNLS=4  
**SiteInfoBean.java 3h.,7,T  
*/ eJ45:]_%I@  
package NetFox; N(4y}-w$  

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public class SiteInfoBean { 3;Yd"  
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private String sSiteURL; //Site's URL gkx
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private String sFilePath; //Saved File's Path *l =f=  
private String sFileName; //Saved File's Name \f4rA
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private int nSplitter; //Count of Splited Downloading File e'$[PF  
qQ)1+^  
-|}?+W  
public SiteInfoBean() 9rz$c, Y(  
{//nSplitter的缺省值为5 'q:7PkN!p  
//default value of nSplitter is 5 LRu*%3xx  
this("","","",5); yKj}l,i~8  
} +zche  
%eofG]VM<  
/Lr`Aka5  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) *)w+xWmM3w  
{ /Q7q2Ne^*  
sSiteURL= sURL; aG;F=e  
sFilePath = sPath; H:hM(m0?q  
sFileName = sName; Dmi.@.  
this.nSplitter = nSpiltter; 9b=0 4aWHm  
Z|*#)<|~  
l9|K,YVW  
} zT)cg$8%fY  
.>TG{>sH  
Ua|iAD1  
public String getSSiteURL() :X}SuM?c  
{ S{l)hwlE  
return sSiteURL; Q.Nw#r+m  
} Fl($0}ER  
o[KZm17  
:t`W&z41  
public void setSSiteURL(String value) oZ/"^5  
{ GO2q"a  
sSiteURL = value; Pi5MFw'v  
} !\{2s!l~  
r3' DXP  
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public String getSFilePath() Xux[  
{ |(Wwh$  
return sFilePath; *V:U\
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} ;0m J4G  
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6|q"lS*$S  
public void setSFilePath(String value) 6p)&}m9!  
{ J/Y9X,  
sFilePath = value; 5
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} PCaFG;}  
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public String getSFileName() 46)[F0,$r  
{ C TG^lms  
return sFileName; V2?{ebx`  
} yc]_?S>9  
"4WnDd5"  
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public void setSFileName(String value) Jxe5y3* (  
{ g,WTXRy  
sFileName = value; T2]8w1l&K  
} .?g=mh79(  
ku*k+4rz  
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public int getNSplitter() Y1r'\@L w  
{ vA:ZR=)F  
return nSplitter; p#4*:rpq4  
} Xlug{ Uh  
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public void setNSplitter(int nCount) PO'K?hVS^w  
{ lGp:rw`
 
nSplitter = nCount; {~51h}>b#  
} L''VBY"?  
} p@Os  
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/* ) C~#W  
**Utility.java \ CcVk"/  
*/ LEnv/t6U  
package NetFox; y'2w*?  
"'``O~08/  
1r.2bL*~jw  
public class Utility { @qcUxu4  
9(HGe+R4o  
@+M1M2@Xz  
public Utility() \NDW@!X  
{ AX{<d@z`j  
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} -6_<]  
n)a/pO_  
//线程睡眠 lgVT~v{U`n  
public static void sleep(int nSecond) }Tm+gJA  
{ +K'YVB U}  
try{ (L4C1h_]9  
Thread.sleep(nSecond); 34)l3UI~  
} })@xWU6!  
catch(Exception e) C<:wSS^@1  
{ 0# 1~'e  
e.printStackTrace (); P;y!Y/$C  
} ^=-25%&^  
} lws.;abm%n  
!}P^O(oY  
//日志 [m< jM[w{  
public static void log(String sMsg) :+9. v  
{ k "7,-0gz  
System.err.println(sMsg); d/oD]aAEr  
} h8.(Q`tli  
0nI*9  
`3[
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public static void log(int sMsg) tD}{/`{_t  
{ !Y UT*  
System.err.println(sMsg); QrSO%Rm1*  
} h Ks  
} Wn;%B].I  
fOSJdX0e|Q  
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/* h8M}}   
**TestMethod.java /;q3Q#  
*/ ;H%'K  
package NetFox; ,{iMF (Nj  
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FR50y+h^$  
public class TestMethod { 9P <1/W!  
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~9!@BL\  
public TestMethod() 9@M;\ @&g  
{ ///xx/weblogic60b2_win.exe eUa:@cA  
try{ ri3*~?k00  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); pkG8g5(w  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); VWXyN  
SiteFileFetch fileFetch = new SiteFileFetch(bean); gQhYM7NP{5  
fileFetch.start(); c2GTN"  
} k?3mFWc  
catch(Exception e){e.printStackTrace ();} qixnaiZ  
_ !"[Zr  
buKkm$@w  
} A;/,</  
3,#qt}8`  
S>HfyZ&Pc  
public static void main(String[] args) }{J>kgr6  
{ ed/ "OgA  
new TestMethod(); ?g
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} :[_k .1-+  
} f0g_Gn $  
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