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http断点续传简单实现(java)

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/* E2yz=7sv5  
**SiteFileFetch.java CSL4P)  
*/ x9*ys;~w  
package NetFox;  g@(30{  
import java.io.*; CB@B.)E  
import java.net.*; |,fh)vO  
By/bVZks  
Pt3[|4L  
public class SiteFileFetch extends Thread { `Wwh`]#"~d  
3GWrn ,f  
\2eFpy(  
SiteInfoBean siteInfoBean = null; //文件信息Bean  'O1.6*K  
long[] nStartPos; //开始位置 aT/KT,!  
long[] nEndPos; //结束位置 'o8\`\'H!  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Gt.*_E  
long nFileLength; //文件长度 |7S:l9;  
boolean bFirst = true; //是否第一次取文件 F9D"kG;Dk  
boolean bStop = false; //停止标志 xhD$e= g  
File tmpFile; //文件下载的临时信息 ?HxS)Pqq  
DataOutputStream output; //输出到文件的输出流 [xS5z1;  
5k`e^ARf  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) s#Q _Gu  
public SiteFileFetch(SiteInfoBean bean) throws IOException LsotgQ8   
{ >\-3P $  
siteInfoBean = bean; Hrv),Ce  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); d:$G|<uA  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); hd=j56P5P  
if(tmpFile.exists ()) I! ITM<Z$l  
{ &.*T\3UO  
bFirst = false; <\xQ7|e  
read_nPos(); @{de$ ODu  
} lvig>0:M  
else G\IocZ3Gz  
{ |x[$3R1@  
nStartPos = new long[bean.getNSplitter()]; r2)pAiTM*  
nEndPos = new long[bean.getNSplitter()];  bn|DRy  
} A@ { !:_55  
][ N) 2_^M  
<wqRk<  
9e76 pP(  
} $@4e(Zrmo  
l2M/ ,@G  
!Ba3` B5l  
public void run() ].c@Gm_(  
{ ~)!VV)  
//获得文件长度 o9^$hDs,si  
//分割文件 I]UA0[8X  
//实例FileSplitterFetch mc56L[  
//启动FileSplitterFetch线程 Suj}MEiv  
//等待子线程返回 u;{T2T  
try{ F_~6n]Sr  
if(bFirst) 5lG|A6+w{  
{ A&?WP\_z  
nFileLength = getFileSize(); O^Dc&w  
if(nFileLength == -1) -q|*M:R  
{ | )S{(#k  
System.err.println("File Length is not known!"); i&B?4J)  
} T7X!#j" \  
else if(nFileLength == -2) EXH!glR[$  
{ 'NRN_c9  
System.err.println("File is not access!"); o|BFvhg  
} ="=#5C  
else k@lXXII ?  
{ ]qF<Zw7  
for(int i=0;i<nStartPos.length;i++) %G^(T%q| m  
{ 4I+.^7d  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); sF, uIr/  
} Xd5! Ti}  
for(int i=0;i<nEndPos.length-1;i++) &?fvt  
{ !c v6 #:  
nEndPos = nStartPos[i+1]; =NI.d>kvC  
} E{?L= ^cU  
nEndPos[nEndPos.length-1] = nFileLength; gx&\Kw6HM  
} N_*u5mfQX  
} TosPk(o(  
]r]+yM|  
-y9Pn>~V  
//启动子线程 Ed8U;U b  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; fa/P%9db  
for(int i=0;i<nStartPos.length;i++) >J?jr&i  
{ eF*TLI<[^I  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), fjF!>Dy  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), G<Th<JF)Q  
nStartPos,nEndPos,i); 'XG:1Bpm  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); h7)VJY  
fileSplitterFetch.start(); 6Eij>{v  
} FDZeIj9uF  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -+`az)lrp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 9 #.<E5:  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", |A2W8b {]  
nEndPos = " + nFileLength); &P{o{  
// fileSplitterFetch[nPos.length-1].start(); 2"B}}  
LJ:mJ#  
7v.#o4nPK  
//等待子线程结束 D6"~fjHh  
//int count = 0; [+Yl;3 &]  
//是否结束while循环 (bM)Nd  
boolean breakWhile = false; IH*U!_ `  
`,hW;p>-  
5>0\e_V  
while(!bStop) 0]/,m4a#n  
{ 5? S{W  
write_nPos(); :4Id7Ce  
Utility.sleep(500); _wIBm2UO  
breakWhile = true; 8b8e^\l(  
z|taa;iM  
JuKk"tr~RB  
for(int i=0;i<nStartPos.length;i++) #3AYz82w  
{ w+URCj  
if(!fileSplitterFetch.bDownOver) )UxQf37  
{ "Yc^Nc  
breakWhile = false; L5i#Kh_  
break; !- Cs?  
} 8T!fGzHx  
} $4#=#aKW.  
if(breakWhile) p3>Q<  
break; mdmZ1:PBM  
YMd&To0s  
a 5~G  
//count++; /gMa"5?,  
//if(count>4) OtrXYiKB   
// siteStop(); #VP-T; Ahe  
} 8ItCfbqa6  
?[a7l:3-[  
|>jqH @\P  
System.err.println("文件下载结束!"); RPofa+  
} 4O5n6~24  
catch(Exception e){e.printStackTrace ();} \#IJ=+z   
} c %6 @ z  
Y`E {E|J  
Xs.$2  
//获得文件长度 &mO/u= u  
public long getFileSize() 6&/ Ew4 e  
{ P@o,4\;K  
int nFileLength = -1; y^0HCp{  
try{ (mOqv9pn  
URL url = new URL(siteInfoBean.getSSiteURL()); e|OG-t[$*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); fwar8 i1  
httpConnection.setRequestProperty("User-Agent","NetFox"); C.Wms}XA  
DKaG?Y,*p  
mfp`Iy"}+  
int responseCode=httpConnection.getResponseCode(); ~(*co[_  
if(responseCode>=400) 6qmo ZAg  
{ E#&c]9QM75  
processErrorCode(responseCode); 4F1.D9u  
return -2; //-2 represent access is error 3thG*^C5  
} gz)wUQ|W  
6@,'m  
E@'CU9Fo  
String sHeader; wXIe5  
y5Z<uwXc  
3f7t%  
for(int i=1;;i++) o0-fUCmC  
{ KNUMz4  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ;_Of`C+  
//Utility.log(in.readLine()); s$+: F$Y0  
sHeader=httpConnection.getHeaderFieldKey(i); -?2&5YB  
if(sHeader!=null) US*<I2ZLh  
{ jmA{rD W  
if(sHeader.equals("Content-Length")) \V!X& a  
{ G74a9li@  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); B[U.CAUn  
break; ,sRrV $,"  
} O. .@<.  
} ~[ ks|  
else Cs~\FI1wR  
break; L2V $%*6  
} aLyhxmn ^)  
} d q+7K  
catch(IOException e){e.printStackTrace ();}  4.Jaw+  
catch(Exception e){e.printStackTrace ();} HnKF#<  
>R'VY "\  
y>pq*i  
Utility.log(nFileLength); FclSuQWti  
yg]nS<K~4  
[gg 7Z|Hu  
return nFileLength; 51FK~ 5  
} -+S~1`0  
j8ohzX[Y  
/9vMGef@  
//保存下载信息(文件指针位置) 59%f|.Z)  
private void write_nPos() s+\qie  
{ XQg%*Rw+t  
try{ cO"Xg<#y  
output = new DataOutputStream(new FileOutputStream(tmpFile)); >-./kI "  
output.writeInt(nStartPos.length); -T>wi J  
for(int i=0;i<nStartPos.length;i++) `QyALcO   
{ J1v0 \  
// output.writeLong(nPos); 0z<]\a4  
output.writeLong(fileSplitterFetch.nStartPos); 5M.n'*   
output.writeLong(fileSplitterFetch.nEndPos); 4|o{_g[  
} aR(Z~z;C  
output.close(); q0KXuMK  
} J9KLO=  
catch(IOException e){e.printStackTrace ();} bZ@53  
catch(Exception e){e.printStackTrace ();} Xy(SzJ %  
} X7B)jH%N  
 pmpn^ZR  
s R0e&Y  
//读取保存的下载信息(文件指针位置) qKb- aP-  
private void read_nPos() !kk %;XSZ  
{ gm%bxr@X~  
try{ Y_ ;i  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); x#}eC'Q  
int nCount = input.readInt(); 1 0Tg > H  
nStartPos = new long[nCount]; Gv2./<{#  
nEndPos = new long[nCount]; PTc\I  
for(int i=0;i<nStartPos.length;i++) G<WDyoN=O  
{ @W5hrei  
nStartPos = input.readLong(); JV6U0$g_S  
nEndPos = input.readLong(); :tS>D5dz(  
} zZjLt1  
input.close(); d}B_ll#j-  
} :$Di.|l@7  
catch(IOException e){e.printStackTrace ();} ,I:m*.q  
catch(Exception e){e.printStackTrace ();} +>9^])K|  
} OD!CnK  
ug3lMN4UX  
yp/V 8C  
private void processErrorCode(int nErrorCode) JU,RO oz(  
{ Hn]n]wsLy  
System.err.println("Error Code : " + nErrorCode); &DhA$o"'  
} z o))x(  
QRG)~  
GWE0 UO}  
//停止文件下载 R (Pa Q  
public void siteStop() ^HN  
{ JX,#W!d  
bStop = true; ~^ 5n$jq  
for(int i=0;i<nStartPos.length;i++) 9QQ@Y}  
fileSplitterFetch.splitterStop(); t>|N4o  
)/i|"`)>_  
1^"aR#  
} WuQ<AS=   
} #1hz=~YO  
//负责部分文件的抓取 H?bs K~  
**FileSplitterFetch.java v+_Y72h*a  
*/ )B5gs%u]  
package NetFox; <XcMc<h~  
yt#;3  
xgw)`>p,W  
import java.io.*; Bst>9V&R  
import java.net.*; 7a_n\]t465  
d"`>&8*  
+6Fdi*:  
public class FileSplitterFetch extends Thread { &)}:Y!qiu  
>xMhA`l  
eeTaF!W  
String sURL; //File URL ~I^[rP~  
long nStartPos; //File Snippet Start Position (GOrfr  
long nEndPos; //File Snippet End Position "?(Fb_}i  
int nThreadID; //Thread's ID \kGtYkctZ  
boolean bDownOver = false; //Downing is over 7tO$'q*h  
boolean bStop = false; //Stop identical nVA'O  
FileAccessI fileAccessI = null; //File Access interface 2o}G<7r  
NcMq>n  
, p=8tf#  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException IMw)X0z  
{ %1+~(1P  
this.sURL = sURL; N}<U[nh'  
this.nStartPos = nStart; tZ24}~da  
this.nEndPos = nEnd; KK3xz*W0  
nThreadID = id; Wk#-LkI  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 tSLl'XeN  
} ~vZzKRVS  
u,9U0ua@;  
&fhurzzAm  
public void run() ]8nm9qmF<  
{ e>9{36~jh  
while(nStartPos < nEndPos && !bStop) !td.ks0  
{ _ll aH  
/ H/Ne )r  
=QO[zke:  
try{ fv'P!+)t  
URL url = new URL(sURL); b'"%   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;pK"N:|  
httpConnection.setRequestProperty("User-Agent","NetFox"); c)YGwkY,,  
String sProperty = "bytes="+nStartPos+"-"; #;\;F PuZ  
httpConnection.setRequestProperty("RANGE",sProperty); `%I{l  
Utility.log(sProperty); ##ea-"m8  
#/=yz<B  
3t6'5{  
InputStream input = httpConnection.getInputStream(); yk6UuI^/  
//logResponseHead(httpConnection); #{cpG2Rs  
=zGz|YI*?  
Rk0 rHC6[  
byte[] b = new byte[1024]; Y[]t_o)  
int nRead; {NqGWkGt*b  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) w:@M|O4`  
{ <:t\P.  
nStartPos += fileAccessI.write(b,0,nRead); +ANIm^@  
//if(nThreadID == 1) S.>9tV2Ca  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +-137!x\q  
} #$)rwm.jW?  
H pfI  
=W^L8!BE'  
Utility.log("Thread " + nThreadID + " is over!"); Z6ex<[`I  
bDownOver = true; ?kefRev<#h  
//nPos = fileAccessI.write (b,0,nRead); R6.#gb8^oS  
} +34jot.!  
catch(Exception e){e.printStackTrace ();} )BrqE uX@"  
} Gnq~1p5^  
} 2b` M(QL  
  `.-C6!  
5-po>1g'  
//打印回应的头信息 y_r6T XnGL  
public void logResponseHead(HttpURLConnection con) X*) :N]  
{ }#^F'%zf  
for(int i=1;;i++) {XW>:EU'N  
{ ->{WO+6(  
String header=con.getHeaderFieldKey(i); /T'nY{  
if(header!=null) bG?[":k  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); t!C-G+It  
Utility.log(header+" : "+con.getHeaderField(header)); F+r6/e6a  
else 2p[3Ap  
break; {<8#T`I  
} ] 6B!eB !  
} xq*yZ5:5Jo  
B 1.@K}  
Ww4G  
public void splitterStop() }'- )  
{ -*r';Mz;  
bStop = true; E/ )+hK&  
} 5E|2 S_)G  
Z:Am\7 I  
KgS xF#  
} !!>G{  
bm?TMhC  
!d_A?q'hN  
/* P dnK@a  
**FileAccess.java 8~>3&jX  
*//文件访问(定位,写) e /Y+S;a  
package NetFox; x{5*%}lX8  
import java.io.*; yp/*@8%_E  
Rw% KEUDm  
|XZf:}q5:  
public class FileAccessI implements Serializable{ u9(AT>HxT  
C(hg"_W ou  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 + k:?;ZG  
RandomAccessFile oSavedFile; ?Fv(4g  
long nPos; Lo4t:H&  
h^,a 1'  
1jVcL)szU  
public FileAccessI() throws IOException %9M49 s  
{ x$I>e  
this("",0); MG>;|*$%  
} ,//=yW  
=G6@:h=  
#n r1- sf|  
public FileAccessI(String sName,long nPos) throws IOException M$9h)3(B  
{ y0]O 6.{  
oSavedFile = new RandomAccessFile(sName,"rw"); sqRuqUj+  
this.nPos = nPos; G= e[TR)i  
oSavedFile.seek(nPos); :8 :>CHa  
} RPwSo.c4  
Cv33?l-8%_  
*^()el,d  
public synchronized int write(byte[] b,int nStart,int nLen) 4+"SG@i`W  
{ $la,_Sr  
int n = -1; Y.J$f<[R  
try{ ~~mQ  
oSavedFile.write(b,nStart,nLen); C? S%fF  
n = nLen; *1Q?~  
} GYO"1PM  
catch(IOException e) 9:s!#FYFM  
{ ?=&*6H_v  
e.printStackTrace (); =j-{Mxb3  
} IZLX[y  
O8%/Id  
KW\`&ki  
return n; \)*qW[C$a  
} pz+#1=b]  
?*=Jq  
tTal<4  
} (B5G?cB9  
L\I/2aiE  
~MF. M8  
/* 1)y}.y5S  
**SiteInfoBean.java (X/JXu{  
*/ "^`AS"z'  
package NetFox; m{|n.b  
A\>qoR!Y  
&/p 9+gd  
public class SiteInfoBean { PR0]:t)E  
; V8 =B8w  
t)h3GM  
private String sSiteURL; //Site's URL X@rAe37h+  
private String sFilePath; //Saved File's Path RWYA`  
private String sFileName; //Saved File's Name ="4)!  
private int nSplitter; //Count of Splited Downloading File KMa?2cJH#  
%o>1$f]  
q_bB/   
public SiteInfoBean() E),T,   
{//nSplitter的缺省值为5 `fXcW)  
//default value of nSplitter is 5 A7se#"w  
this("","","",5); O#g31?TO  
} lf 3W:0 K  
 OxRzKT  
*&s_u)b  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) FsjblB3?E  
{ &>SE9w/ ?o  
sSiteURL= sURL; r.[kD"l  
sFilePath = sPath; .vg;K@{  
sFileName = sName; oVdmgmT.Y  
this.nSplitter = nSpiltter; 3f0RMk$pH  
TD'1L:mv  
WD<M U ]  
} ET4YoH>  
3~ylBJJ  
occ}|u  
public String getSSiteURL() Pg7/g=Va  
{ i{.!1i:  
return sSiteURL; [||$1u\%  
} raCxHY  
B^Vb=* QRo  
%5b2vrg~*  
public void setSSiteURL(String value) 5K0Isuu>>  
{ 74_ji!  
sSiteURL = value; e([}dz  
} Ad[-YT  
6v-h!1p{u  
YvonZ  
public String getSFilePath() p 4=^ UP  
{ z@2NAC  
return sFilePath; nL9m{$Zv  
} k 2~j:&p  
OvkYzI`  
yfj<P/aA+  
public void setSFilePath(String value) u7K0m! jW  
{ 1:?Wv DN=  
sFilePath = value; \7RP6o  
} qbjRw!2?w  
: 7'anj  
\O[Cae:^?  
public String getSFileName() xGjEEBL  
{ [dL#0~CL$  
return sFileName; rLVS#M#&e>  
} q*>`HTPcU  
O3S_P]{*ny  
mU;TB%#)  
public void setSFileName(String value) 8d-_'MXk3  
{ d bw`E"g  
sFileName = value; Y%2<}3P  
} J}BS/Tr}=  
"~tEmMz  
% %*t{0!H+  
public int getNSplitter() l&zd7BM9(  
{ a4?:suX$  
return nSplitter; P:=3;d{v  
} J^U#dYd  
*g7dB2{  
> >p3#~/  
public void setNSplitter(int nCount) tcfUhSz,I  
{ Y>r9"X| &H  
nSplitter = nCount; Pt E>08  
} R ~#\gMs  
} f5AK@]4G  
AkGCIn3  
5E$)Ip  
/* L0}"H .  
**Utility.java #,Rmu  
*/ w _n)*he)z  
package NetFox; z"|^Y|`m  
^b'[ 81%  
A>Js`s  
public class Utility { C]82Mt  
Jjv, )@yo  
9M<{@<]dm  
public Utility() d+$a5 [^9  
{ bX8Bn0#a+  
+`zM^'^$  
-3A#a_fu  
} xI$B",?(  
U)2\=%8  
//线程睡眠 M '[.ay  
public static void sleep(int nSecond) ,u/GA<'#M  
{ CtS*"c,j  
try{ nI&Tr_"tm  
Thread.sleep(nSecond); 72.Z E%Ue  
} WI ' ;e4  
catch(Exception e) w[t!?(![>  
{ ):1NeJOFF  
e.printStackTrace (); p3&w/K{L6w  
} G}d@^9FkE  
} r\Zz=~![<  
s#>Bwn&b)  
//日志 j*xxOwf  
public static void log(String sMsg) xDm^f^}>  
{ =JY9K0S~  
System.err.println(sMsg); ex1bjM7  
} 4$C:r&K  
__OD^?qa  
d H]'&&M  
public static void log(int sMsg) 'Tj9btM*cL  
{ &^9 2z:?  
System.err.println(sMsg); ZBi|B D  
} q<dZy? f  
} x xWnB  
a2/!~X9F  
g^/  
/* 3+rud9T  
**TestMethod.java adRvAq]mA  
*/ %Sf%XNtu  
package NetFox; lOYzo  
1*,f  
'(4$h3-gv7  
public class TestMethod { jNBvy1  
\hoYQK j  
lku}I4  
public TestMethod()  `C9/=  
{ ///xx/weblogic60b2_win.exe eJlTCXeZ|  
try{ 3!ZndW SHV  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); bd_&=VLTC  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); x8+W9i0[1  
SiteFileFetch fileFetch = new SiteFileFetch(bean); .IXkdy  
fileFetch.start(); |]y]K%  
} v!JQ;OX  
catch(Exception e){e.printStackTrace ();} BxVo>r  
0rP`BK|  
bS[;d5  
} p'tB4V qT  
5 ELKL#(  
>,wm-4&E  
public static void main(String[] args) nO.RB#I$F  
{ d2Pqi* K  
new TestMethod(); ( E;!.=%  
} ~H`~&?  
} 3Uw}!>`%  
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