http断点续传简单实现（java)

/* mc?5,oz;pz  
**SiteFileFetch.java q!7z4Cn  
*/ BEg%u)"([  
package NetFox; `8xmMA_l  
import java.io.*; 3xsC"c>  
import java.net.*; '-D-H}%;}M  
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public class SiteFileFetch extends Thread { WUQ2[)<  
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SiteInfoBean siteInfoBean = null; //文件信息Bean AVOqW0Z+y  
long[] nStartPos; //开始位置 8 fVI33  
long[] nEndPos; //结束位置 @+syD  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 j()_ VoB1  
long nFileLength; //文件长度 M< *5Y43  
boolean bFirst = true; //是否第一次取文件 >9esZ
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boolean bStop = false; //停止标志 ',z'.t  
File tmpFile; //文件下载的临时信息 &~6Z)}  
DataOutputStream output; //输出到文件的输出流 }bIEWho  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） |5V#&e\ES  
public SiteFileFetch(SiteInfoBean bean) throws IOException 2xni! *T+  
{ -[~{c]/c  
siteInfoBean = bean; $ZK4Ps -$  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); D(~6h,=m  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 8/-GrdyE  
if(tmpFile.exists ()) %HL@O]ftS  
{ #fG!dD42  
bFirst = false; .m7iXd{  
read_nPos(); NrgN{6u;  
} ORv[Gkq_N)  
else jzI\Q{[m'  
{ A0oC*/  
nStartPos = new long[bean.getNSplitter()]; _&XT =SW}  
nEndPos = new long[bean.getNSplitter()]; .o:Pe2C  
} ~Msee+ZZ :  
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} oE"!  
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public void run() lh7{2WQ  
{ , y{o!w  
//获得文件长度 Mq[;:  
//分割文件 (
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//实例FileSplitterFetch b\UQ6V  
//启动FileSplitterFetch线程 V F6OC4 K  
//等待子线程返回 WT'P[RU2  
try{ '
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if(bFirst) #ZCgpg$wM  
{ K\IS"b3X  
nFileLength = getFileSize(); H#m)`=nZSZ  
if(nFileLength == -1) {8@?9Z9R{  
{ 6xk"bIp  
System.err.println("File Length is not known!"); >]T(}S~  
}  O7s0M?4  
else if(nFileLength == -2) [5)1 4% x  
{ '3[Ecy#  
System.err.println("File is not access!"); dI>)4()  
} SN?jxQ  
else Tl8S|Rg  
{ e1~C>  
for(int i=0;i<nStartPos.length;i++) wy&VClT  
{ : 60PO  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); xb8fV*RO8A  
} }YU#}Ip@  
for(int i=0;i<nEndPos.length-1;i++) X2dTV}~i  
{ baR{  
nEndPos = nStartPos[i+1]; %+gze|J  
} {'"A hiR/  
nEndPos[nEndPos.length-1] = nFileLength; KOhy)h+ h  
} fa\<![8LAU  
} 6\4oHRJC  
>^|\wy  
/y@$|DI1  
//启动子线程 +_:Ih,-   
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 0m7J'gm{  
for(int i=0;i<nStartPos.length;i++) %[lX  H  
{ r5lp<md  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), DXSZ#^,S[W  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ;NLL?6~  
nStartPos,nEndPos,i); L9fhe,en  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); H!Uy4L~>  
fileSplitterFetch.start(); r.-NfK4  
} =c-j4xna>  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), JP!$uK{u  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 7<IrN\@U  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", bxkp9o  
nEndPos = " + nFileLength); FxM`$n~K  
// fileSplitterFetch[nPos.length-1].start(); HY5g>wv@  

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\
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//等待子线程结束 @,M!&l  
//int count = 0; Yx(?KN7V?  
//是否结束while循环 mEz&:A  
boolean breakWhile = false; \ts:'  
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cFGP3Q4{  
while(!bStop) Fd5{pM3  
{ K`(STvtM  
write_nPos(); {n$9o
  
Utility.sleep(500); e{To&gy~  
breakWhile = true; jl3RE|M\<  
{-Yp~HQF  
)w;XicT  
for(int i=0;i<nStartPos.length;i++) 'V 1QuSd  
{ hJhdHy=U  
if(!fileSplitterFetch.bDownOver) ?*[t'D9f-  
{ 3|9)A+,#  
breakWhile = false; Uk|Xs~@#E  
break; OR1XQij  
} _)2NFq  
} sw{EV0&>m  
if(breakWhile) <gf:QX!  
break; +r4US or  
2x$\vL0  
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//count++; 1i bQ'bZ  
//if(count>4) KkJcHU  
// siteStop(); d cPh@3  
} *=@Z\]"?  
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System.err.println("文件下载结束！"); (;~[}"  
} MZv&$KG4m@  
catch(Exception e){e.printStackTrace ();} 2$qeNy  
} RTLu]Bry  
?kE2S6j5  
'qQDM_+  
//获得文件长度 Fypqf|  
public long getFileSize() ]$0{PBndW  
{ ^row=5]E  
int nFileLength = -1; 6st(s@>  
try{ hLx*$Z>  
URL url = new URL(siteInfoBean.getSSiteURL()); 2[j|:Ng7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2/B(T5PY@  
httpConnection.setRequestProperty("User-Agent","NetFox"); Ls*.=ARq  
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aH'^`]'_=  
int responseCode=httpConnection.getResponseCode(); /\ ~{  
if(responseCode>=400) Lm,io\z  
{ F3';oyy  
processErrorCode(responseCode); rAP+nh ans  
return -2; //-2 represent access is error N|1J@"H  
}  78qf  
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?  
String sHeader; 3,N7Nfe  
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for(int i=1;;i++) sE>'~+1_O  
{ d@8_?G}  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 05|t  
//Utility.log(in.readLine()); pA+Qb.z5z  
sHeader=httpConnection.getHeaderFieldKey(i); -lb}}z+/  
if(sHeader!=null) X903;&Cim  
{ oDKgW?x  
if(sHeader.equals("Content-Length")) #z~D1Zl  
{ .(1=iL_3e  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); <C${1FO7If  
break; ?G!
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} nez5z:7F  
} dn%/SJC  
else Y$oBsg\v  
break; O}#*U+j  
} F^`sIrZvs  
} e|+uLbN&;c  
catch(IOException e){e.printStackTrace ();} ~@itZ,d\  
catch(Exception e){e.printStackTrace ();} f4@Dn >BJ  
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Utility.log(nFileLength); M&Ycw XV:Z  
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return nFileLength; Ix1ec^?f  
} _ogT(uYyr  
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//保存下载信息（文件指针位置） Eq'{uV:  
private void write_nPos() 6@Eip[e  
{ ~jF5%Gu  
try{ |6_<4lmTxF  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Oe2Tmvl  
output.writeInt(nStartPos.length); n6|}^O7  
for(int i=0;i<nStartPos.length;i++) (">!vz  
{ xA&G91|s  
// output.writeLong(nPos); 7p u*/W~  
output.writeLong(fileSplitterFetch.nStartPos); +twBFhS7k  
output.writeLong(fileSplitterFetch.nEndPos); K}
)j5CJ/  
} iW)FjDTP  
output.close(); &?zJ|7rh@|  
} J5|Dduv  
catch(IOException e){e.printStackTrace ();} I:mJWe  
catch(Exception e){e.printStackTrace ();} )O2^?Q quS  
} AQ+w%>G6  
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`$MO.K{  
//读取保存的下载信息（文件指针位置） o
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private void read_nPos() 8a-[Q  
{ !^`ZHJ-3>;  
try{ /*D]4AK  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); RQ/X{<lQ)  
int nCount = input.readInt(); <(
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nStartPos = new long[nCount]; u!{P{C  
nEndPos = new long[nCount]; nM}X1^PiK"  
for(int i=0;i<nStartPos.length;i++) #C!8a  
{ #kma)_X  
nStartPos = input.readLong(); m"+9[d_u  
nEndPos = input.readLong(); xx9qi^  
} 9"MC<  
input.close();
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} o{zo-:>Jp  
catch(IOException e){e.printStackTrace ();} p|AIz3  
catch(Exception e){e.printStackTrace ();} S'TF7u  
} A"S})  
7CwG(c/5  
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private void processErrorCode(int nErrorCode) eJJvEvZ,  
{ }tj@*n_  
System.err.println("Error Code : " + nErrorCode); a*%>H(x  
} Ce`{M&NSWX  
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*W#x#0j  
//停止文件下载 D%Pq*=W  
public void siteStop() PlBT H  
{ 'SOp!h$  
bStop = true; ULQ*cW&;?  
for(int i=0;i<nStartPos.length;i++) 2}509X(*  
fileSplitterFetch.splitterStop(); jF-z?  
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} i:{a-Bd  
} Y.Gr(]tk  
//负责部分文件的抓取 tr/S*0$  
**FileSplitterFetch.java KY4|C05,  
*/ -Ux/ Ug@  
package NetFox; f4X?\eGT  
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import java.io.*; ^*}L9Ot~  
import java.net.*; M^+~r,D1u  
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8 +uOYNXsA  
public class FileSplitterFetch extends Thread { H#wn3O  
=_Qt&B)  
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String sURL; //File URL bk#u0N  
long nStartPos; //File Snippet Start Position Pi)`[\{  
long nEndPos; //File Snippet End Position ot-!_w<  
int nThreadID; //Thread's ID $IB@|n  
boolean bDownOver = false; //Downing is over "R):B~8|H{  
boolean bStop = false; //Stop identical O!/J2SfuDH  
FileAccessI fileAccessI = null; //File Access interface bO^%#<7  
=_L"x~0I-  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Mgf80r=  
{ &)\0mpLK9  
this.sURL = sURL; JJ7-$h'0q  
this.nStartPos = nStart; QD /| zi  
this.nEndPos = nEnd; Y@#~8\_  
nThreadID = id; eMWY[f3  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 mn 8A%6W  
} T6AFwo,Q  
3(vI{[yhT  
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public void run() E})PNf;  
{ C{Aeud #5  
while(nStartPos < nEndPos && !bStop) y>Nlj%XH  
{ .;*0odxv  
i,* DWD+  
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try{ m,)Re8W-  
URL url = new URL(sURL); (Dc dR:/=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); N}.h_~6  
httpConnection.setRequestProperty("User-Agent","NetFox"); inR8m 4c]P  
String sProperty = "bytes="+nStartPos+"-"; a>""MC2  
httpConnection.setRequestProperty("RANGE",sProperty); Hhfqb"2on  
Utility.log(sProperty); 80:na7$)#  
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InputStream input = httpConnection.getInputStream(); c;(}Ih(#  
//logResponseHead(httpConnection); ;k!Ej-(  
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byte[] b = new byte[1024]; SM0
=  
int nRead; uQpV1o5iA  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) bjD0y cB[  
{ Xo]FOJ5  
nStartPos += fileAccessI.write(b,0,nRead); d{9jd{ _#G  
//if(nThreadID == 1) 6,cyi|s  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w3,QT}WvY  
} P
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Utility.log("Thread " + nThreadID + " is over!"); tJ'U<s  
bDownOver = true; .@1\26<  
//nPos = fileAccessI.write (b,0,nRead); )c+ZQq  
} nFxogCn
 
catch(Exception e){e.printStackTrace ();} t
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} %H%>6z x  
} ^H&6'A`  
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D>LdDhNn,`  
//打印回应的头信息 k('2K2P  
public void logResponseHead(HttpURLConnection con) &b{L|I'KYT  
{ 7!L"ef62o  
for(int i=1;;i++) NV*
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{ ,4EE9 ?J  
String header=con.getHeaderFieldKey(i); 7j._3'M=Kc  
if(header!=null) K$f~Fft  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ob-be2EysH  
Utility.log(header+" : "+con.getHeaderField(header)); `?`\!uP"  
else ?vM{9!M  
break; Hyc19|  
} W)j/[  
} ;QW)tv.y  
3%k@,Vvt  
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public void splitterStop() |A0kbC.  
{ 3osAWSCEL  
bStop = true; KA%tVBl  
} 5b|_?Em7  
//|9J(B]  
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} hM+nA::w  
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9SMM%(3, r  
/* u3ce\  
**FileAccess.java ><^A4s  
*//文件访问(定位，写) a-8~f8na{(  
package NetFox; ]Alu~Dw  
import java.io.*; #Wh"_zpM+  
gp(w6:w  
q$U;\Mg)  
public class FileAccessI implements Serializable{ K;S&91V)=  
Q:@Y/4=  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 va#~ \%`  
RandomAccessFile oSavedFile; %qN8uQx  
long nPos;
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1 5rE|m^  
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public FileAccessI() throws IOException ]3Mm"7`  
{ F~<$E*&h@  
this("",0); e|]g?!  
} _khQ  
7|"11^q  
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public FileAccessI(String sName,long nPos) throws IOException G}] ZZ  
{ 2t#9ih"9  
oSavedFile = new RandomAccessFile(sName,"rw"); kA\;h|Y3  
this.nPos = nPos; P'Rr5Xa  
oSavedFile.seek(nPos); 7r*>?]y+  
} AF **@iG  
];j
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A\k-OP]  
public synchronized int write(byte[] b,int nStart,int nLen) lzl4pnj  
{ ITq+Hk R  
int n = -1; Auv/w}zrr  
try{ ?Cmb3pX^\  
oSavedFile.write(b,nStart,nLen); .DCp)&m l;  
n = nLen;
}RW4  
} 'Y>!xm  
catch(IOException e) u4fTC})4{C  
{ e#&[4tQF  
e.printStackTrace (); :=*>:*.Kb  
} o3}12i S  
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*1%=?:$(r6  
return n; P),%S9jP;  
} NL2n\%n  
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} ]FQ4v.7  
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H$\?D+xlf  
/* hoSk  
**SiteInfoBean.java s7T=/SC54  
*/ 2yeq2v  
package NetFox; !YAkHrF`[0  
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public class SiteInfoBean { r|0C G^:C  
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\  
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private String sSiteURL; //Site's URL 6o6!Ol  
private String sFilePath; //Saved File's Path h-!(O^M  
private String sFileName; //Saved File's Name eYR/k
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private int nSplitter; //Count of Splited Downloading File C:gE   
1&wZJP=  
t41\nTZr  
public SiteInfoBean() j>0S3P,  
{//nSplitter的缺省值为5 /A##Yv!biR  
//default value of nSplitter is 5 8>O'_6Joj  
this("","","",5); TvM{ Q
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} VwtGHF'  
c.jnPVf:  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Fd|:7NRA<  
{ <*4=sX@  
sSiteURL= sURL; {jlm]<:&Z  
sFilePath = sPath; ?;uzx7@F  
sFileName = sName; 5)&e2V',y  
this.nSplitter = nSpiltter; vP&*(WfO)  
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} F"B!r-J  
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public String getSSiteURL() 0Dh a1[=  
{ ;zz"95X7  
return sSiteURL; LnR3C:NO k  
} +wT,dUin_<  
7 yF#G9,  
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public void setSSiteURL(String value) /R@(yT=t  
{ <|.S~HLTQ  
sSiteURL = value; li NPXS+  
} 2evM|Dj  
^{Syg;F=  
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{  
public String getSFilePath() 2LD4f[a;  
{ 7"8HlOHA  
return sFilePath; 4Ag+  
} U.>n]/&  
,9W0fm\t  
vi lNl|
 
public void setSFilePath(String value) ,wZ[Y 3  
{ xB9^DURr\  
sFilePath = value; 7g(rJGjtg  
} 5O)Z}  
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QC ]z--wu  
public String getSFileName() p'xj:bB  
{ VFG)|Z  
return sFileName; .@=d I  
} :i:Zc~%  
wl(}F^:/`  
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public void setSFileName(String value) ;&:UxmTf  
{ yfP&Q
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sFileName = value; QKHmOVh]  
} rZ
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public int getNSplitter() ]G|@F :  
{ >E)UmO{S  
return nSplitter; I<[(hPQ
Uf  
} '@pav>UPD  
p4aM`PW8>=  
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public void setNSplitter(int nCount) W>1\f0'  
{ rEddX  
nSplitter = nCount; S93NsrBbY  
} C"0gAN  
} bS0^AVA  
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#2u-L~n  
/* Zvr(c|Q  
**Utility.java `=CF |I  
*/ -U;s,>\)  
package NetFox; KZD&Ih(vC  
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'| Ag,x[  
public class Utility { sy>Pn  
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public Utility() xES+m/?KlZ  
{ 6EPC$*Xp!  
"I_T  
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} fnB-?8K<  
S6]D;c8GE  
//线程睡眠 's&Vg09D,  
public static void sleep(int nSecond) 3&2,[G04  
{ U][.ioc  
try{ bF B;N+>  
Thread.sleep(nSecond); xn6E f"  
} QjZ}*p  
catch(Exception e) #!,xjd  
{ ,pAMQ5  
e.printStackTrace (); [ >vS+G  
} y& Dd  
} 8mCr6$|
%  
%*jpQOw  
//日志 XWB>' UDQ#  
public static void log(String sMsg) ef53~x  
{ Odbjl[>k  
System.err.println(sMsg); C*c=@VAa  
} 8<_WtDg
 
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{]Lc]4J  
public static void log(int sMsg) &4{%3w_/  
{ d(]LRIn~1  
System.err.println(sMsg); =8tduB  
} W^yF5  
} L`"cu.l  
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czHO)uQ?d`  
/* G~m(
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**TestMethod.java V8,$<1Fi;-  
*/  *riGi  
package NetFox; RmzK?muk  
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9V"^F.>  
public class TestMethod { *b.>pY?2|  
ShSh/0   
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public TestMethod() 5[Q44$a{  
{ ///xx/weblogic60b2_win.exe kSI,Q!e\  
try{ jl7e6#zu  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Y-,#3%bT;;  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); @${!C\([1  
SiteFileFetch fileFetch = new SiteFileFetch(bean); @j^qT-0M  
fileFetch.start(); 1TbKnmTx  
} *$hO C%(  
catch(Exception e){e.printStackTrace ();} -iJ[9O  
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} 69IBG,N'  
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public static void main(String[] args) S++}kR);  
{ ZZeqOu7^  
new TestMethod(); u\Xi]pZ@X]  
} "M?(Ax  
} NtA}I)'SWU  
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