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http断点续传简单实现(java)

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/* pH*L8tT  
**SiteFileFetch.java  c\x?k<=  
*/ YJ"gm]Pm  
package NetFox; d)0%|yX6  
import java.io.*; \{&55>  
import java.net.*; i 9b^\&&  
]ny(l#Hu:  
 t]vz+VQ  
public class SiteFileFetch extends Thread { L8$7^muad  
uj]GBo=  
?Rwn1.Z  
SiteInfoBean siteInfoBean = null; //文件信息Bean :J<S-d=  
long[] nStartPos; //开始位置 \e=@h!p  
long[] nEndPos; //结束位置 P_?1Rwm-45  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 [lnN~#(Y  
long nFileLength; //文件长度 PCU6E9~t2  
boolean bFirst = true; //是否第一次取文件 *".7O*jjV  
boolean bStop = false; //停止标志 QHQj6]  
File tmpFile; //文件下载的临时信息 % ,X(GwX  
DataOutputStream output; //输出到文件的输出流 "TxXrt%>A  
d6L(Q(:s  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 62zlO{ >rJ  
public SiteFileFetch(SiteInfoBean bean) throws IOException kO5KZ;+N-  
{ lS,Hr3Lz  
siteInfoBean = bean; c '(]n]a%  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); J L Z  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); \Js9U|lY  
if(tmpFile.exists ()) =X1$K_cN  
{ t=pG6U  
bFirst = false; #uH1!UQb  
read_nPos(); i@p?.%K{  
} hyBSS,I  
else i'57|;?  
{ F^w0TD8  
nStartPos = new long[bean.getNSplitter()]; j`#|z9`(pB  
nEndPos = new long[bean.getNSplitter()]; MJD4#G  
} NH?s  
0\mM^+fO  
<iMkHch  
5I<?HsK@  
} F>}).qx  
O+e8}Tmm  
\ 0CGS  
public void run() +&t{IP(?  
{ ?ph"|LyL  
//获得文件长度 JhD8.@} b~  
//分割文件 x7/2e{p uu  
//实例FileSplitterFetch p\,lbrv  
//启动FileSplitterFetch线程 Bq _<v)M*  
//等待子线程返回 H`".L^  
try{ 2.x3^/  
if(bFirst) 1'd "O @  
{ )GR^V=o7,Y  
nFileLength = getFileSize(); i&l$G55F  
if(nFileLength == -1) ZNx{7]=a  
{ CHLMY}O0  
System.err.println("File Length is not known!"); Kc(_?`  
} c"QI`;D_c  
else if(nFileLength == -2) 16] O^R;r  
{ s$]I@;_  
System.err.println("File is not access!"); YnNei 7R  
} xqG` _S l  
else Oa7W&wi  
{ g%+nMjif  
for(int i=0;i<nStartPos.length;i++)  (0k0gq;  
{ 'LX=yL]I  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); P@Qo2zTh%  
} zL_X?UmV  
for(int i=0;i<nEndPos.length-1;i++) SGbo|Xe7:  
{ 6\]-J*e>  
nEndPos = nStartPos[i+1]; Pjx9@i  
} Gis'IX(  
nEndPos[nEndPos.length-1] = nFileLength; 4RzG3CJdS  
} sC}/?^q  
} -OziUM1qs  
).&$pXj  
*JDc1$H0  
//启动子线程 L72GF5+!!  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; kQ:2@SOm  
for(int i=0;i<nStartPos.length;i++) 5= F-^  
{ u}$U|Cw-;T  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), p;B +g X  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {b+IDq`)=  
nStartPos,nEndPos,i); g_}@/5?y  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); G3e%~  
fileSplitterFetch.start(); X!"y>J  
} :q= XE$%H  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), KYeA=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); A 7sej  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", E dU3k'z$  
nEndPos = " + nFileLength); 7/~"\nN:/  
// fileSplitterFetch[nPos.length-1].start(); N* z<VZ  
"=RB #  
- Zw"o>  
//等待子线程结束 N[mOJa:  
//int count = 0; F4PD3E_#  
//是否结束while循环 z=u4&x|xA  
boolean breakWhile = false; @hv9 =v+  
%Cr- cR0  
vi=yR  
while(!bStop) H37Z\xS  
{ ?Jma^ S  
write_nPos(); sS0psw1  
Utility.sleep(500); X`vDhfh>N  
breakWhile = true; c1z5t]d   
N1SRnJu<f  
/ )EB~|4']  
for(int i=0;i<nStartPos.length;i++) v<-D>iJ  
{ |UBJu `%  
if(!fileSplitterFetch.bDownOver) A+dY~@*a  
{ )dvOg'it  
breakWhile = false; x~mXtqg  
break; g-]td8}#  
} kiECJ@5p  
} v(0vP}[Q7E  
if(breakWhile) pLIBNo?  
break; eygyVhJ  
}cf-r>WaR  
>0m-S :lk  
//count++; :@p`E}1r{  
//if(count>4) nd?m+C&W  
// siteStop(); Sj*H4ZHD<&  
} <^&'r5H  
sO*6F`eiZ  
w(@`g/b  
System.err.println("文件下载结束!"); SHaZ-d  
} y}3V3uqK  
catch(Exception e){e.printStackTrace ();} QO%LSRw  
} 7X.1QSuE  
ar{e<&Bny  
*r_.o;6  
//获得文件长度 Comu c  
public long getFileSize() i<T`]g  
{ H1@"Yg8  
int nFileLength = -1; FJD*A`a  
try{ E8503  
URL url = new URL(siteInfoBean.getSSiteURL());  aCTVY1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $~2A o[  
httpConnection.setRequestProperty("User-Agent","NetFox"); E>[~"~x"pV  
~C[,P\,  
_,'UP>Si  
int responseCode=httpConnection.getResponseCode(); m1cyCD  
if(responseCode>=400) nQgn^z#  
{ 7z$+ *]9-  
processErrorCode(responseCode); v:+se6HY?p  
return -2; //-2 represent access is error 4SOj>(a#  
} ]F_u  
d p?uq'  
]f\rB8k|&  
String sHeader; o 1b#q/  
n2QD*3i  
>SzTZ3!E  
for(int i=1;;i++) ;P{ *'@  
{ 4bKZ@r%  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); c=K M[s.  
//Utility.log(in.readLine()); 4Pt0^;H&jn  
sHeader=httpConnection.getHeaderFieldKey(i); D`gY6wX  
if(sHeader!=null) ~:0h o  
{ .=NK^  
if(sHeader.equals("Content-Length")) dzcPSbbpt  
{ '3xSzsDn  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); kn<[v;+  
break; ~jPe9  
} =*'` \}];"  
} F8k1fmM]Y  
else isN"7y|r:X  
break; 8=?I/9Xh  
} #a0 (Wh7  
} |ST&,a$(  
catch(IOException e){e.printStackTrace ();} =]"PSY7p  
catch(Exception e){e.printStackTrace ();} .d*vfE$  
2{qoWys8[  
_7;#0B  
Utility.log(nFileLength); ru U|  
oi!E v_h  
1]qhQd-u  
return nFileLength; ;^xku%u  
} =EG[_i{r  
*s/F4?*  
d2(n3Xf  
//保存下载信息(文件指针位置) xo*a9H?@  
private void write_nPos() *L!R4;ubE  
{ n. T [a  
try{ L h0<A%  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5=$D~>-#  
output.writeInt(nStartPos.length);  /f2*J  
for(int i=0;i<nStartPos.length;i++) [`:\(( 8  
{ <vAg\Tv:S  
// output.writeLong(nPos); p'R}z|d)  
output.writeLong(fileSplitterFetch.nStartPos); Q[k}_1sWs$  
output.writeLong(fileSplitterFetch.nEndPos); r+U-l#Q  
} KUp lN1Sy  
output.close(); :xA'X+d/'  
} X-%*`XG'  
catch(IOException e){e.printStackTrace ();} PeG8_X}u9  
catch(Exception e){e.printStackTrace ();} >97V2W  
} {:"bX~<^  
Kg%_e9nj#  
tV T(!&(  
//读取保存的下载信息(文件指针位置) _ '}UNIL  
private void read_nPos() ~+1t 17  
{ J4JKAv~3  
try{ Ltu;sw  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); -PX {W)Aw  
int nCount = input.readInt(); EBn7waBS  
nStartPos = new long[nCount]; =A,i9Z&  
nEndPos = new long[nCount]; _E1:3 N|  
for(int i=0;i<nStartPos.length;i++) .|rpj&>g  
{ LsLsSV  
nStartPos = input.readLong(); jKtbGVZ 7r  
nEndPos = input.readLong(); VfQSfNsi  
} 5ecqJ  
input.close(); uh GL1{  
} Vdjca:`  
catch(IOException e){e.printStackTrace ();} f6z[k_lLN  
catch(Exception e){e.printStackTrace ();} O/FQ'o1F  
} sqkPC_;A  
K/08F|]a  
toP7b  
private void processErrorCode(int nErrorCode) zIlQqyOQ8  
{ m7d? SU  
System.err.println("Error Code : " + nErrorCode); (l$bA_F \  
} VbZZ=q=Kd  
:*\JJ w  
=XqmFr;h  
//停止文件下载 ('>!dXA$  
public void siteStop() 1c\$ziB  
{ DSQ2z3s2  
bStop = true; ,Z3.Le"  
for(int i=0;i<nStartPos.length;i++) Y(-+>>j_  
fileSplitterFetch.splitterStop(); >`t |a  
/Jo*O=Lpo  
f):|Ad|  
} ;ASlsUE\)  
} uRp-yu[nt%  
//负责部分文件的抓取 7H=/FT?e]  
**FileSplitterFetch.java z;Kyg}  
*/ uv Z!3UH.  
package NetFox; =WHdy;  
b&0q%tCK  
BCFvqhF7s  
import java.io.*; |J8c|h<  
import java.net.*; 5I@< 6S&X  
vQ 5 p  
0Pbv7)=XL  
public class FileSplitterFetch extends Thread { 2o6%P}C  
_57i[U r  
}2G'3msx  
String sURL; //File URL x|1OGbBK  
long nStartPos; //File Snippet Start Position &,bJ]J)8O  
long nEndPos; //File Snippet End Position !x&/M*nBE  
int nThreadID; //Thread's ID B1\}'g8%f  
boolean bDownOver = false; //Downing is over Yz[^?M%(D  
boolean bStop = false; //Stop identical IY+P Yad  
FileAccessI fileAccessI = null; //File Access interface +$ P0&YaQ  
hg |DpP  
2y,f  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException N U\B  
{ rZ *}jD[  
this.sURL = sURL; !hEt UF  
this.nStartPos = nStart; ^ @sg{_.~l  
this.nEndPos = nEnd; k WF, *@.B  
nThreadID = id; TVQ9"C  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 )88z=5.  
} 3g)pLW  
  Lxs  
6>zO"9  
public void run() Fq9AO~z  
{ PjDYdT[  
while(nStartPos < nEndPos && !bStop) h>q& X4-  
{ C#+Gkzq  
6"z:s-V  
}c^`!9  
try{ &pV'/  
URL url = new URL(sURL); RlC|xj"l%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +A O(e  
httpConnection.setRequestProperty("User-Agent","NetFox"); A-qdTJP  
String sProperty = "bytes="+nStartPos+"-"; 6gNsh  
httpConnection.setRequestProperty("RANGE",sProperty); 3N[t2Y1r  
Utility.log(sProperty); FG:(H0  
G-~+FnUC  
5v6*.e'p  
InputStream input = httpConnection.getInputStream(); 1d"g $i4e  
//logResponseHead(httpConnection); 7gNJ}pLDx  
Nxp 7/Nn3  
xZwG@+U=X  
byte[] b = new byte[1024]; 1 VcZg%I  
int nRead; 0p)#!$  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Etj@wy/E  
{ 2ntL7F<ow  
nStartPos += fileAccessI.write(b,0,nRead); +7.\>Ucq`  
//if(nThreadID == 1) 4v_<<l  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); FxW~Co  
} 3)3?/y)_  
~ep-XO  
uD}Q}]Z  
Utility.log("Thread " + nThreadID + " is over!"); !g'kWE[  
bDownOver = true; a~>+I~^K5q  
//nPos = fileAccessI.write (b,0,nRead); 9'Le}`Gf  
} N8#wQ*MM>  
catch(Exception e){e.printStackTrace ();} -c{O!z6sX  
} 'S;INs2|->  
}  At @H  
eVGO6 2|!  
jb|al[p\  
//打印回应的头信息 EyO=M~nsS  
public void logResponseHead(HttpURLConnection con) 5bKM}? =L  
{ .nl!KzO6g  
for(int i=1;;i++) [3"k :  
{ F0(P 2j  
String header=con.getHeaderFieldKey(i); db -h=L|  
if(header!=null) >g+yw1nC  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~4fUaMT  
Utility.log(header+" : "+con.getHeaderField(header)); 4YX/=  
else /H3z~PBa  
break; 1DLAfsLlj  
} 6V-u<FJ  
} *t=8^q(K[  
mE\sD<b  
D<U^FT  
public void splitterStop() C>wOoXjt  
{ 4z%::?  
bStop = true; iI.pxo s  
} |qm_ESzl  
=HapCmrx8  
ZRHK?wg'#  
} & 6 wD  
= p{55dR  
79`OB##  
/* 1 etl:gcEC  
**FileAccess.java +-2o b90_m  
*//文件访问(定位,写) : 8h\x  
package NetFox; B8.a#@R  
import java.io.*; &YpViC4K.  
&rs   
1*U)\vK~  
public class FileAccessI implements Serializable{ E.LD1Pm0  
aG_@--=  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 pW5ch"HE  
RandomAccessFile oSavedFile; #!?jxfsFa  
long nPos; H?oBax:  
B! +rO~  
h @AKfE!\~  
public FileAccessI() throws IOException )SU\s+"M  
{ hQ7-m.UZw  
this("",0); 4*Uzomb?q  
} 4|U$ON?x  
! [3  /!  
5-*hAOThg  
public FileAccessI(String sName,long nPos) throws IOException qtrN=c3x  
{ yM}~]aQ y  
oSavedFile = new RandomAccessFile(sName,"rw"); G.")Bg  
this.nPos = nPos; Z=ZTSl   
oSavedFile.seek(nPos); pmwVVUEQ  
} = -bGH   
)_C+\K*  
e'I/}J  
public synchronized int write(byte[] b,int nStart,int nLen) (/gv U80  
{ c V$an  
int n = -1; $Z|HFV{  
try{ b!p]\B!  
oSavedFile.write(b,nStart,nLen); qPQ6`rD\  
n = nLen; Nwwn #+  
} )fy-]Ky *  
catch(IOException e) r{>`"  
{ f`<elWgc"  
e.printStackTrace (); 2x5^kN7  
} (n{x"rLy/  
z`}z7e'>  
6.Jvqn  
return n; & zR\Rmpt  
} _sqj~|K  
&L[i"1a  
+$}3=n34)  
} Bo,>blspw  
cs lZ;  
y#T.w0*  
/* r1 axC%  
**SiteInfoBean.java tgyW:<iv  
*/ fZ aTckbE  
package NetFox; Ko|m<;LX  
Y1Q240  
k=W~ot &  
public class SiteInfoBean { )-\C{>  
]-j.\+(*  
,B~5;/ |  
private String sSiteURL; //Site's URL 57wHo[CJ  
private String sFilePath; //Saved File's Path 'aWqj+Wbh  
private String sFileName; //Saved File's Name **V8a-@  
private int nSplitter; //Count of Splited Downloading File n!dXjInV  
yJK:4af;.  
R 7h^ @  
public SiteInfoBean() a,|Hn  
{//nSplitter的缺省值为5 I q?n*P$  
//default value of nSplitter is 5 9])Id;+91  
this("","","",5); ,<=gPs;x  
} )2 lB  
r.q*S4IS.m  
Qz"+M+~%&  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ^sKdN-{  
{ (_%l[:o6  
sSiteURL= sURL; 1Q_Q-Z  
sFilePath = sPath; KpBOmXE  
sFileName = sName; !,+<?o y  
this.nSplitter = nSpiltter; `w&?SXFO8  
z:a7)z  
=2t=Zyp0Y  
} Kf-XL ),3l  
o|$r;<o3R  
RNF%i~nhO  
public String getSSiteURL() &S=Qu?H  
{ (%c&Km7K  
return sSiteURL; Gf +>Aj U'  
} 4bCA"QM[[  
4_D *xW  
w@"Zjbs`  
public void setSSiteURL(String value) 3$?nzKTW\  
{ 0bpGPG's&  
sSiteURL = value; #<~oR5ddlb  
} * >/w,E]  
Lv?jg ?$  
Hu9nJ  
public String getSFilePath() <0VC`+p<)  
{ xw}rFY $  
return sFilePath; blLl1Ak  
} H&8~"h6n  
`_f&T}]  
K ton$%Li  
public void setSFilePath(String value) Egz6rRCvg  
{ 1Ys)b[:  
sFilePath = value; q*Oj5;  
} ?S;z!) H)P  
<:!E'WT#f  
7'OR ;b$  
public String getSFileName() g:O/~L0Xb  
{ r$v \\^?2  
return sFileName; Wks zN h  
} ]x).C[^  
ce;$)Ff\  
=), O;M  
public void setSFileName(String value) %K+hG=3O  
{ CIui9XNU  
sFileName = value; \K9.]PfbI  
} fW Pa1E@  
*s#6e}  
mzCd@<T,  
public int getNSplitter() );T&pm:C>  
{ TMD\=8Na  
return nSplitter; <"K2t Tg.  
} n=)LB& m  
S|xwYaoy%  
M@l|n  
public void setNSplitter(int nCount) /Xj{]i3{  
{ k( Ik+=u  
nSplitter = nCount; h oO847  
} Ml9m#c  
} QW'*^^  
P l!E$   
ju5o).!bg  
/* ^62z\Y  
**Utility.java E7i/gY  
*/ l-cBN^^  
package NetFox; p Hx$  
[m4M#Lg\0  
Ie K+  
public class Utility { @{U UB=}9  
DE7y\oO]  
AOkG.u-k  
public Utility() TV0sxod6  
{ JhjH_)  
!Pz#czo  
FGPqF;  
} ps?su`  
$IS!GS&:  
//线程睡眠 C~ A`h=A<  
public static void sleep(int nSecond) ?hAO-*);  
{ YcV^Fqi!  
try{ w >%^pO~}`  
Thread.sleep(nSecond); BQ<\[H;  
} VxS3lR=  
catch(Exception e) l]~9BPsR  
{ n!AW9]  
e.printStackTrace (); q6*i/"mN*  
} $UdBZT-  
} Tt9cX}&&  
k q]E@tE*3  
//日志 {]U \HE1w  
public static void log(String sMsg) GqNOWK2O  
{ "+4Jmf9  
System.err.println(sMsg); 00'SceL=`  
} ~(^pGL3<  
p;'.7_1  
Kxa1F,dZ  
public static void log(int sMsg) $m~&| s  
{ qou\4YZ  
System.err.println(sMsg); ]'?Ue7  
} #AP;GoIf"j  
} Z m%,L$F*L  
$=,pQ q  
vE8BB$D  
/* 7QnWw0  
**TestMethod.java mA$86 X_  
*/ 1=5HQ~|[TO  
package NetFox; Z9NND  
\2=I//YF  
m&b1H9ymd  
public class TestMethod { &;pM<h  
?% 8%1d  
\.oJ/++  
public TestMethod() 5M~+F"Hl  
{ ///xx/weblogic60b2_win.exe ,?Ie!r$6  
try{ Z*f%R\u  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); wkPjMmW+!  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); CbW[_\  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [&4+ <Nl'  
fileFetch.start(); K!qOO  
} ]" e'z  
catch(Exception e){e.printStackTrace ();} KQb&7k .  
V_ , `?>O  
iPV-w_HQ  
} T iL.py,  
d (x'\4(K  
3uxf n=E  
public static void main(String[] args) %.u*nM7sos  
{ h~]e~u V  
new TestMethod(); -BI!ZsC'  
} $Zo|t a^  
} P7zUf  
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