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http断点续传简单实现(java)

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/* ]; CTr0  
**SiteFileFetch.java 6$.I>8n  
*/ v%|S)^c?:  
package NetFox; }hoyjzv]L  
import java.io.*; 3_5]0:?]-  
import java.net.*; !=/wpsH  
=PQMd  
)fGIe rS  
public class SiteFileFetch extends Thread { agI"Kh]j?  
!Au@\/}  
f$2DV:wuC  
SiteInfoBean siteInfoBean = null; //文件信息Bean \jHHj\LLr.  
long[] nStartPos; //开始位置 gL/D| =  
long[] nEndPos; //结束位置 O/{X:Ja{  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 vGST{Lz;  
long nFileLength; //文件长度 :U{$G( <  
boolean bFirst = true; //是否第一次取文件 ~R+,4  
boolean bStop = false; //停止标志 7]J7'!Iz  
File tmpFile; //文件下载的临时信息 AJJa<c+j  
DataOutputStream output; //输出到文件的输出流 Ow3t2G  
}M0GPpv  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 1 x'H #  
public SiteFileFetch(SiteInfoBean bean) throws IOException +m>)q4e  
{ Yvn*evO4  
siteInfoBean = bean; 4S 7#B  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); zKllwIf i  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); m|by^40A(  
if(tmpFile.exists ()) .{8?eze[m  
{ y$Rh$e K  
bFirst = false; ?cvV~&$gc  
read_nPos(); 0e,U&B<W  
} 3!*qB-d  
else x o{y9VS  
{ RF|r@/S  
nStartPos = new long[bean.getNSplitter()]; Hgk@I;  
nEndPos = new long[bean.getNSplitter()]; ;i>(r;ZM  
}  &e%eIz  
E=&":I6O  
=3H*%  
tZz *O%  
} V/@7XAt  
Co^^rd@  
:< *xG&  
public void run() IW$qP&a  
{ WMXxP gik  
//获得文件长度 $MYAYj9r)  
//分割文件 m2j]wUh"  
//实例FileSplitterFetch 6-t:eo9  
//启动FileSplitterFetch线程 87p tab@  
//等待子线程返回 DPM4v7 S  
try{ PZYVLUw `  
if(bFirst) ph~ d%/^jI  
{ HU47 S  
nFileLength = getFileSize(); LKsK!X  
if(nFileLength == -1) RemjiCE0'  
{ ]z#9)i_l3  
System.err.println("File Length is not known!"); R\Of ,  
} (/ e[n.T  
else if(nFileLength == -2) 0wpGIT!2  
{ *Kmo1>^  
System.err.println("File is not access!"); ,(v=ZeI  
} ~(P\'H&(h  
else D0*+7n3  
{ ZO*?02c  
for(int i=0;i<nStartPos.length;i++) .:9XpKbt  
{ iL8:I)z  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); m2>$)\-;  
} Mq Q'Kjo  
for(int i=0;i<nEndPos.length-1;i++) D&|HS!  
{ G @8wv J  
nEndPos = nStartPos[i+1]; J}Ji /  
} C)(/NGf  
nEndPos[nEndPos.length-1] = nFileLength; v&3 Oc  
} V[^ +lR  
} Y5R|)x  
K [R.B!;N  
[n2)6B\/  
//启动子线程 30<3DA_P  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; :)j& t>aP  
for(int i=0;i<nStartPos.length;i++) ;uyQR8  
{ Ji e=/:&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3!Cab/T  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), (P|k$S?m  
nStartPos,nEndPos,i); 6e4A| <  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5$%CRm  
fileSplitterFetch.start(); q?=_{oH9  
} 7i0;Ss*  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (Nn)_caVb  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 5z@QAQ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", IiZXIG4H  
nEndPos = " + nFileLength); M2piJ'T4u  
// fileSplitterFetch[nPos.length-1].start(); 1( vcM  
]~kgsI[E  
!HSX:qAP$  
//等待子线程结束 i/aj;t  
//int count = 0; )Kg _E6  
//是否结束while循环 ,'a[1RN  
boolean breakWhile = false; Z/+H  
;s!GpO7+  
^^kL.C Ym  
while(!bStop) n{E9p3i  
{ }ZkGH}K_}  
write_nPos(); Ie'iAY  
Utility.sleep(500); ~NZ}@J{00_  
breakWhile = true; _GsHT\  
dEK bB  
R/ 3#(5  
for(int i=0;i<nStartPos.length;i++) 1pZ[r M'}  
{ ~'t+X  
if(!fileSplitterFetch.bDownOver) T~)zgu%q_  
{ Azag*M?  
breakWhile = false; .( X!*J]G  
break; wOrpp3I  
} E#/vgm=W;  
} )mE67{YJh~  
if(breakWhile) 0uhIJc'2  
break; VCc57 Bo  
g7O , <  
v.{I^=  
//count++; h45RwQ5Z  
//if(count>4) 8rM1kOCf  
// siteStop(); LT6VZ,S  
} Xf*}V+&WN  
3y]rhB  
{^6<Ohe4j  
System.err.println("文件下载结束!"); 0w ;#4X:m  
} u!9bhL`  
catch(Exception e){e.printStackTrace ();} [J+]1hCZ|  
} qY|NA)E)Bp  
6d%)MEM  
oPC qv  
//获得文件长度 @+(a{%~7y  
public long getFileSize() 6M X4h  
{ * Fz#x{zt  
int nFileLength = -1; N3o kN8d  
try{ :B1a2Y^"  
URL url = new URL(siteInfoBean.getSSiteURL()); /*hS0xN*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -r@/8"  
httpConnection.setRequestProperty("User-Agent","NetFox"); _T(MMc  
.R{+Pz D  
THHA~;00YN  
int responseCode=httpConnection.getResponseCode(); TTm  
if(responseCode>=400) K])| V  
{ vH/ Y]Am  
processErrorCode(responseCode); .8/W_iC92  
return -2; //-2 represent access is error  :IX_}|  
} brClYpp,h  
nQM7@"R  
,7*-%05[\  
String sHeader; +<W8kb  
9}Qrb@DT  
@ )m9#F  
for(int i=1;;i++) ff<ad l-  
{ eVB.g@%T  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +d/^0^(D\5  
//Utility.log(in.readLine()); 4&'_~qU  
sHeader=httpConnection.getHeaderFieldKey(i); <]kifiN#  
if(sHeader!=null) Z=CY6Zu7  
{ 2mVLR;s{_  
if(sHeader.equals("Content-Length")) ts~$'^K[-  
{ ~n`G>Oe3  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 9Qhk~^ngg  
break; aIABx!83>  
} AlQ  
} 4 Q FX  
else 8I|2yvhP  
break; =OU]<%  
} NJTC+`Hm  
} PbN"+qM  
catch(IOException e){e.printStackTrace ();} 8GFA}_(^R  
catch(Exception e){e.printStackTrace ();} mB]Y;R<  
]6 vqgu  
'c|Y*2@  
Utility.log(nFileLength); O.~@V(7ah  
um$K^  
6 &)fZt  
return nFileLength; b1`(f"&l  
} sT"h)I)]*  
Il9pL~u  
_Q3Ad>,U  
//保存下载信息(文件指针位置) MX#MDA-4  
private void write_nPos() \qh -fW; #  
{  %Jc>joU  
try{ VIjsz42C  
output = new DataOutputStream(new FileOutputStream(tmpFile)); J((.zLvz  
output.writeInt(nStartPos.length); MOEB{~v`;  
for(int i=0;i<nStartPos.length;i++) UCP4w@C  
{ pr(16P  
// output.writeLong(nPos); Ug|o ($CY  
output.writeLong(fileSplitterFetch.nStartPos); @43o4,  
output.writeLong(fileSplitterFetch.nEndPos); d^<a)>5h  
} =w&<LJPJ  
output.close(); h7H#sL[^  
} >@o}l:*  
catch(IOException e){e.printStackTrace ();} k$7@@?<  
catch(Exception e){e.printStackTrace ();} 6hs2B5)+  
} #e:*]A'I  
 _,2P4  
n|oAfJUk,  
//读取保存的下载信息(文件指针位置) @#%rTKD9F  
private void read_nPos() kGZ_/"iuO  
{ ' 1aU0<  
try{ =Xc[EUi<;g  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ~4~-^ t  
int nCount = input.readInt(); Bjz\L0d  
nStartPos = new long[nCount]; D~xU r )E  
nEndPos = new long[nCount]; {&Fh$H!  
for(int i=0;i<nStartPos.length;i++) $MmCh&V  
{ t;@VsQ8  
nStartPos = input.readLong(); @:~O  
nEndPos = input.readLong(); M_2[Wypw  
} m$xyUv1  
input.close(); 2dr[0tE  
} ul e]eRAG  
catch(IOException e){e.printStackTrace ();} Hize m!  
catch(Exception e){e.printStackTrace ();} !j)H !|R  
} o4b!U%  
[Pdm1]":(  
)CzWq}:  
private void processErrorCode(int nErrorCode) KsGSs9  
{ |*N.SS  
System.err.println("Error Code : " + nErrorCode); 8E/]k\  
} byv(:xk|'e  
ZpHT2-baVe  
FG~p _[K  
//停止文件下载 Z3G>DF:$  
public void siteStop() QY2!.a^q  
{ @\_ tS H  
bStop = true; \>j._#t$h  
for(int i=0;i<nStartPos.length;i++) ~u&3Ki*x  
fileSplitterFetch.splitterStop(); ctOC.  
<GShm~XD2  
-uiZp !  
} ML0o :8Bd\  
} ]do0{I%\eq  
//负责部分文件的抓取 r+;C}[E  
**FileSplitterFetch.java M"K$81  
*/ 0gVylQ  
package NetFox; :x97^.eW~  
 `-4c}T  
0z."6 r  
import java.io.*; O@3EJkv  
import java.net.*; g!7/iKj:  
(^eSm]<  
PDX^MYoN  
public class FileSplitterFetch extends Thread { !a3cEzs3  
N40.GL0s  
K 3?7Hndf2  
String sURL; //File URL +J$[RxQ#  
long nStartPos; //File Snippet Start Position c\.4I4uy  
long nEndPos; //File Snippet End Position <!&nyuSz  
int nThreadID; //Thread's ID G3 #c  
boolean bDownOver = false; //Downing is over PP&AF?C  
boolean bStop = false; //Stop identical /wI$}X5o~  
FileAccessI fileAccessI = null; //File Access interface 5_M9T 3  
uKh),@JV  
j0o_``  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException .0#?u1gXsX  
{ 9wC q  
this.sURL = sURL; hti)<#f  
this.nStartPos = nStart; iO3@2J  
this.nEndPos = nEnd; sxl29y^*  
nThreadID = id; F)lDK.  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 d/- f]   
} pF#nj`L  
,;H)CUe1"  
WU{G_Fqaz  
public void run() ar=uDb;  
{ xc8MOm  
while(nStartPos < nEndPos && !bStop) I 8`@Srw8  
{ e0+N1kY  
2>.B*P  
.'p_j(uv  
try{ Jp xJZJ  
URL url = new URL(sURL); LnxJFc:1K  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); sk$MJSE ~  
httpConnection.setRequestProperty("User-Agent","NetFox"); br>"96A1l  
String sProperty = "bytes="+nStartPos+"-";  _*9eAeJ  
httpConnection.setRequestProperty("RANGE",sProperty); &I:5<zK{  
Utility.log(sProperty); {*`qL0u]^  
C* b!E:  
#)hM]=,e  
InputStream input = httpConnection.getInputStream(); eL#pS=  
//logResponseHead(httpConnection); ;a XcGa  
%rzC+=*;  
tV9nC   
byte[] b = new byte[1024]; *rK}Ai  
int nRead; :o&qJ%  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) N{tNe-5  
{  4EJ  
nStartPos += fileAccessI.write(b,0,nRead); siZw-.  
//if(nThreadID == 1) F# y5T3(P  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); lSUEE0V%Q  
} 4W*52*'F,  
vkOCyi?c  
OSK 3X Qc  
Utility.log("Thread " + nThreadID + " is over!"); H.hF`n  
bDownOver = true; ,Za!  
//nPos = fileAccessI.write (b,0,nRead); |#LU"D  
} D4ESo)15'  
catch(Exception e){e.printStackTrace ();} /=*h\8c~  
} xJa  
} 1CU-^ j  
Jv %, v?  
UIi;&[  
//打印回应的头信息 B?`Gs^Y {z  
public void logResponseHead(HttpURLConnection con) xqs{d&W  
{ HJo&snT3  
for(int i=1;;i++) WolkW:(Cg  
{ NGOc:>}k>  
String header=con.getHeaderFieldKey(i); <La$'lG4J  
if(header!=null) J70#pF  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); {~_X-g5|]  
Utility.log(header+" : "+con.getHeaderField(header)); zt/b S/  
else WUm8 3"  
break; yl/-!  
} @e8b'w3  
} (/UW}$] h  
c>#T\AEkF  
!K-lO{Z^  
public void splitterStop() 7g8}]\i+  
{ 2a|9D \  
bStop = true; h+<vWo}H  
} ?{[ ISk)  
IL;JdIa  
l2vIKc  
}  +:k Iq  
D[32 t0  
?f f!(U  
/* KX D&FDkF  
**FileAccess.java W/DSj :  
*//文件访问(定位,写) "HX,RJ @^K  
package NetFox; ]CHO5'%,$  
import java.io.*; ^YG'p?r.s  
tj$&89  
@{N2I$%6  
public class FileAccessI implements Serializable{ d5Hp&tm  
_/(DEF+G  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 1W3+ng  
RandomAccessFile oSavedFile; 4efIw<1_  
long nPos; ko<u0SjF)u  
%3b;`Oa  
UdO(9Jc5^  
public FileAccessI() throws IOException g~E N3~  
{ k{\wjaf)  
this("",0); RP[^1  
} WV5z~[  
)S?.YCv?  
}_Y&kaM  
public FileAccessI(String sName,long nPos) throws IOException o]T-7Gs4p  
{ VWhq +8z  
oSavedFile = new RandomAccessFile(sName,"rw"); Ac^hZ.qPz  
this.nPos = nPos; T:FaD V{  
oSavedFile.seek(nPos); ,~8&0p  
} B|9[DNd  
m\*;Fx  
@M( hyS&on  
public synchronized int write(byte[] b,int nStart,int nLen) T{ WJf-pI  
{ eBT+|  
int n = -1; !m]_tB  
try{ iA.:{^_)09  
oSavedFile.write(b,nStart,nLen); C2e.RTxc  
n = nLen; z`]sWi F0  
} T-MC|>pv  
catch(IOException e) X|&v]mJ  
{ UP<B>Y1a  
e.printStackTrace (); B1^9mV'O  
} ,zF^^,lO7  
(#e,tu  
C"SG':  
return n; itYTV?bd  
} (V(8E%<c  
x)+ q$FB  
op8[8pt%  
} !)r1zSY"g  
"udA-;!@&  
5,_DM  
/* z:1"d R   
**SiteInfoBean.java 1S{AGgls5  
*/ z(!K8 T  
package NetFox; ,gO(zI-1  
,7:? Du}  
Sdzl[K/}  
public class SiteInfoBean { 2 xE+"?0  
Cfr2 ~w  
99GK6}~TGm  
private String sSiteURL; //Site's URL ptQCqQ1_d  
private String sFilePath; //Saved File's Path fK/|0@B8  
private String sFileName; //Saved File's Name *-eDU T|O  
private int nSplitter; //Count of Splited Downloading File A)9F_;BY  
.;J6)h  
r=gF&Og,?  
public SiteInfoBean() vJ?j#Ch  
{//nSplitter的缺省值为5 JZup} {a  
//default value of nSplitter is 5 g0-~ %A,  
this("","","",5); B<{Yj}..  
} 'z9}I #  
o}b_`O  
"}Oj N\  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) U[O7}Nsb"  
{ T9NTL\;  
sSiteURL= sURL; 'H8b+  
sFilePath = sPath; h+DK .$  
sFileName = sName; ,p' ;Xg6ez  
this.nSplitter = nSpiltter; ,a34=,  
bLsN?_jy  
.+A2\F.^  
} i%GNm D  
rM0Idc.$&&  
N{&Hq4^c  
public String getSSiteURL() R ~?9+  
{ o`M.v[O  
return sSiteURL; ^wlo;.8Y  
} Z,I0<ecaD  
HSj=g}r  
Yn5a4  
public void setSSiteURL(String value) ja&S^B^@  
{ ` InBhU>  
sSiteURL = value; r7+Ytr  
} 24I\smO  
=rN_8&  
tjJi|  
public String getSFilePath() z7!@^!r  
{ 2*@@Bw.XA  
return sFilePath; u= Vt3%q  
} 7v V~O@JP  
wBz5_ OFVw  
#k t+ )>  
public void setSFilePath(String value) "R0(!3  
{ ,CIsZ1[VS  
sFilePath = value; bL2b^UB~%  
} mvu$  
`s8!zy+  
hQ}y(2A.XI  
public String getSFileName() {JtfEna  
{ 9'0v]ar  
return sFileName; ~=t K17i  
} 8Z>=sUMQ  
aa&\HDh*  
&%;K_asV;  
public void setSFileName(String value) ^Is#_Z|  
{ o)+Uyl   
sFileName = value; :+Tvq,/"  
} W[qQDn!r  
T:g=P@  
lNx:_g:SrZ  
public int getNSplitter() -] `OaL!  
{ H'?dsc  
return nSplitter; uF\ ;m.  
} -DWnDku8=  
;uaZp.<um&  
F/:Jp3@  
public void setNSplitter(int nCount) K?6#jT6#  
{ g_e_L39  
nSplitter = nCount; HME`7dw?  
} ^v&)z ,  
} >#|%y>g .o  
6tN!]  
'a=' (,%  
/* =6xxZy[  
**Utility.java @QAI 0ZY  
*/ =-;J2Qlg6  
package NetFox; Lz=GA?lk[\  
c}mWAZ=wF  
hIFfvUl  
public class Utility { x%%OgO +>  
h`pXUnEZ  
}o7"2h ht  
public Utility() ,rWej;CzN  
{ Yl"l|2 :  
M"E7= J  
#_'| TT>p#  
} G'(8/os{  
c63yJqiW  
//线程睡眠 %Iv*u sXP  
public static void sleep(int nSecond) xnPi'?A]  
{ C]NL9Gq`  
try{ >tTu1#t  
Thread.sleep(nSecond); L]{1@~E:q  
} u9D#5NvGs  
catch(Exception e) QN^AihsPi  
{ qORRpWyx&  
e.printStackTrace (); D}]u9jS1  
} v_I)eac z  
} %OAvhutS  
`l + pk%  
//日志 TyN]Pa  
public static void log(String sMsg) p #Y2v  
{ E @7);i5K  
System.err.println(sMsg); =k:yBswi  
} PEPf=sm  
G }U'?p  
o>Q=V 0?  
public static void log(int sMsg) UpS7>c7s  
{ rvp#[RAaS}  
System.err.println(sMsg); Wph@LRB]  
}  I6rB_~]h  
} 'yNS(Bg=  
lC'U3Q&  
Ih^ziDcW  
/* U$7]*#@&  
**TestMethod.java 89\DS!\x9  
*/ Xsd+5="{N  
package NetFox; MP$9W)  
PAS0 D #  
ayr CLv  
public class TestMethod { dT'd C  
-d_7 q  
 |: ,i  
public TestMethod()  giORc  
{ ///xx/weblogic60b2_win.exe x`JhNAO>  
try{ XB;C~:  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); >8.o  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); AI#.G7'O  
SiteFileFetch fileFetch = new SiteFileFetch(bean); D]+]Br8  
fileFetch.start(); q}cm"lO$  
} 2k M;7:  
catch(Exception e){e.printStackTrace ();} %![3?|8~  
D|D) 782  
RiiwsnjC  
} ZK5 wZU  
R3hyz~\x&  
Dy|)u1?  
public static void main(String[] args) >G}g=zy@  
{ "ifv1KZ#  
new TestMethod(); Y(B3M=j  
} ndHUQ$/(  
} W9:(P  
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