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http断点续传简单实现(java)

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/* k/#321Z  
**SiteFileFetch.java UYOR@x #  
*/ 7{DSLKtN  
package NetFox; -]vPF|  
import java.io.*; 1ml{oqNj  
import java.net.*; \bWo"Yo  
F$&{@hd  
L+$9 ,<'[  
public class SiteFileFetch extends Thread { f{u3RCfX~2  
UkXf)  
j.y8H  
SiteInfoBean siteInfoBean = null; //文件信息Bean Nm=\~LP90  
long[] nStartPos; //开始位置 5"&{Egc_  
long[] nEndPos; //结束位置 IgU65p  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Lr`G. e  
long nFileLength; //文件长度 .6nNqGua1  
boolean bFirst = true; //是否第一次取文件 ZU-vZD>  
boolean bStop = false; //停止标志 k'$UA$2d  
File tmpFile; //文件下载的临时信息 FYu=e?L  
DataOutputStream output; //输出到文件的输出流  MfNguh  
Z3]ut #`  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ~$3X>?Q  
public SiteFileFetch(SiteInfoBean bean) throws IOException _; ].  
{ aI0}E O  
siteInfoBean = bean; $s-HG[lX[  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); w st)O{4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); c'r7sI%Yi  
if(tmpFile.exists ()) hJ1:#%Qe.  
{ v"dj%75O?e  
bFirst = false; 4chSo.= 4V  
read_nPos(); 6~j.S "  
} =W~K_jE5lo  
else E _DSf  
{ *q.qO )X}3  
nStartPos = new long[bean.getNSplitter()]; +W P  
nEndPos = new long[bean.getNSplitter()]; %SJ9Jr,  
} : {Crc   
g[~"c}  
:7+E fu  
V=,VOw4  
} |P"p/iY  
ekj@;6 d]  
tzeS D C  
public void run() y-iuOzq4  
{ c_xo6+:l  
//获得文件长度 C4jq T  
//分割文件 Iq-+X3i  
//实例FileSplitterFetch ,\BGxGNAmV  
//启动FileSplitterFetch线程 aT %A<'O!  
//等待子线程返回 62X;gb  
try{ Ox` +Z0)a  
if(bFirst) )`ZTu -|  
{ 62 biOea  
nFileLength = getFileSize(); p/a)vN+*x'  
if(nFileLength == -1) XY;cz  
{ zl W 5$cC[  
System.err.println("File Length is not known!"); uZ-yu|1  
} y:N QLL>  
else if(nFileLength == -2) 9(>l trA  
{ 5Y\wXqlY  
System.err.println("File is not access!"); #*[G,s#t^  
} tp,e:4\ 8Q  
else q+/c+u?=^  
{ 8yH*  
for(int i=0;i<nStartPos.length;i++) 'ju{j`b  
{ 72gQ<Si  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ",\,lqV  
} *jps}uk<  
for(int i=0;i<nEndPos.length-1;i++) $~|#Rz%v  
{ 94umk*ib  
nEndPos = nStartPos[i+1]; pm-SDp>s  
} ptS1d$  
nEndPos[nEndPos.length-1] = nFileLength; )|88wa(M  
} 2[W1EQI  
} ubn`w=w$  
H}OOkzwrA  
i>n.r_!E  
//启动子线程 tH_e?6]  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; rRN7H L+b  
for(int i=0;i<nStartPos.length;i++) @iZ"I i&+  
{ 0ivlKe%  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), BTXS+mvl  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), (GVH#}uB  
nStartPos,nEndPos,i); kMGK 8y  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); OIK14D:  
fileSplitterFetch.start(); Zc"Vf]:  
} paUlp7x  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 'sCj\N  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); YlW~  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 5 } 9}4e  
nEndPos = " + nFileLength); D:9/;9V  
// fileSplitterFetch[nPos.length-1].start(); =(f+geA"hm  
47R4gs#W  
AnV\{A^  
//等待子线程结束 &C eG4_Mi  
//int count = 0; 4~Ptn/ g  
//是否结束while循环 a1;P2ikuK  
boolean breakWhile = false; x/NR_~Rnk  
(vCMff/ Y1  
gO*:< B g  
while(!bStop) CKShz]1  
{ xkIRI1*!  
write_nPos(); ~c>*3*  
Utility.sleep(500); FE+Y#  
breakWhile = true; 6&o9mc\I  
K-&&%Id6R  
M{U{iS  
for(int i=0;i<nStartPos.length;i++) d, fX3  
{ ,6,sz]3-  
if(!fileSplitterFetch.bDownOver) -c-#1_X5  
{ ;P9P2&c8c  
breakWhile = false; bkQEfx.  
break; s? /#8 `  
} NZ(c>r6  
} ecK{+Z'G  
if(breakWhile) adG=L9 "n  
break; E|ce[|2  
9$&+0  
N=J$+  
//count++; U$[C>~r  
//if(count>4) SST1vzm!  
// siteStop(); 2ZMYA=[!  
} d'~sy>  
GE`:bC3  
t?NB#/#%x  
System.err.println("文件下载结束!"); Mg H,"G  
} G1 ?."  
catch(Exception e){e.printStackTrace ();} AtRu)v6r  
} (fmcWHs  
d\aarhD8*  
P+iZ5S\kL=  
//获得文件长度 ?{s!.U[T@  
public long getFileSize() d52l)8  
{ PI>PEge!&  
int nFileLength = -1; R:zPU   
try{ *')g}2iB  
URL url = new URL(siteInfoBean.getSSiteURL()); sY4sq5'!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2 s,[DC  
httpConnection.setRequestProperty("User-Agent","NetFox"); vn"2"hPF|  
ZMmaM "9  
zzsQfI#  
int responseCode=httpConnection.getResponseCode(); (Dr g  
if(responseCode>=400) LG6VeYe|\X  
{ xaO9?{O  
processErrorCode(responseCode); -%]O-'  
return -2; //-2 represent access is error 8'Dp3x^W>  
} M17oAVN7D  
 laX(?{_  
BZy&;P  
String sHeader; yjZ]_.  
5~T`R~Uqb  
J&4QI( b.  
for(int i=1;;i++) 70,V>=aJ  
{ 7;dTQ.%n  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); y,&UST  
//Utility.log(in.readLine()); J(*q OGBD  
sHeader=httpConnection.getHeaderFieldKey(i); NvH9?Ek"  
if(sHeader!=null) Xz)UH<  
{ @xKLRw  
if(sHeader.equals("Content-Length")) ji(W+tQ2Y'  
{ Q3MG+@)S  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 5b X*8H D  
break; ?! >B}e&,  
} T"1H%65`V  
} [Nb0&:$ay  
else 12 HBq8o  
break; lqFDX d  
} =;DmD?nZ  
} ;-p1z% u  
catch(IOException e){e.printStackTrace ();} 9"Vch;U$  
catch(Exception e){e.printStackTrace ();} nU]n]gd  
WAPN,WuW  
`>CHE'_  
Utility.log(nFileLength); [+0rlmB  
dz fR ^Gv  
}gL:"C"~  
return nFileLength; n< UuVu  
}  L><# I  
>|%dN jf@Q  
4Q2=\-KFj  
//保存下载信息(文件指针位置) pG?AwB~@n  
private void write_nPos() q) %F#g  
{ &phers  
try{ SN!TE,=I  
output = new DataOutputStream(new FileOutputStream(tmpFile)); i^j1 i  
output.writeInt(nStartPos.length); z-<091,  
for(int i=0;i<nStartPos.length;i++) E (DNK  
{ *Ag</g@ h  
// output.writeLong(nPos);  pME17 af  
output.writeLong(fileSplitterFetch.nStartPos); O@;;GJ  
output.writeLong(fileSplitterFetch.nEndPos); e?W-vi%  
} shjc`Tqm  
output.close(); ~`'!nzP5H  
} :s8^nEK  
catch(IOException e){e.printStackTrace ();} 8S2sNpLi-g  
catch(Exception e){e.printStackTrace ();} FEqs4<}E  
} VOc_7q_=  
]IbX<  
MD(?Wh  
//读取保存的下载信息(文件指针位置) [RtTi<F^  
private void read_nPos() F?!P7 zW  
{ %LBa;M  
try{ 3IXai)6U  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); H;('h#=cD  
int nCount = input.readInt(); }Rujh4*  
nStartPos = new long[nCount]; HUF],[N  
nEndPos = new long[nCount]; H4%2"w6|!  
for(int i=0;i<nStartPos.length;i++) y/}[S@4uB  
{ Hc?8Q\O:  
nStartPos = input.readLong(); Dep.Qfv{-  
nEndPos = input.readLong(); <9zzjgzG{c  
} ,(d\!T/]'  
input.close(); &)UZ9r`z  
} ${(v Er#}k  
catch(IOException e){e.printStackTrace ();} !|!k9~v!  
catch(Exception e){e.printStackTrace ();} USF9sF0l  
} Z(Styn/x  
~s.~X5  
0ws1S(pq  
private void processErrorCode(int nErrorCode) UQq ,Xq  
{ 1'.SHY|  
System.err.println("Error Code : " + nErrorCode); +tsF.Is!t  
} k'O^HMAn!  
0,1x- yD  
"Zk# bQ2j  
//停止文件下载 ,4kly_$BH  
public void siteStop() MA}~bfB  
{ L{;Sc_  
bStop = true; G]Rb{v,r  
for(int i=0;i<nStartPos.length;i++) Po(Y',xI[  
fileSplitterFetch.splitterStop(); i.QS(gM  
kV >[$6  
GnAG'.t-Z  
} @bPR"j5D  
} Eb 8vnB#  
//负责部分文件的抓取 K1`Z}k_p.  
**FileSplitterFetch.java 0tA~Y26  
*/ X#;n Gq)5  
package NetFox; d|I_SI1  
UA>3,|gV1  
GvAP  
import java.io.*; b/#SkxW#S  
import java.net.*; &xhwx>C`K  
'3%JhG)#  
y!z2+q2  
public class FileSplitterFetch extends Thread { @= E~`  
F~bDA~  
[z:.52@!  
String sURL; //File URL #%Hk-a=>)#  
long nStartPos; //File Snippet Start Position _v/w ,z  
long nEndPos; //File Snippet End Position C ~e&J&zh  
int nThreadID; //Thread's ID ^$FNu~|K  
boolean bDownOver = false; //Downing is over fAEgrw%Ti  
boolean bStop = false; //Stop identical $7bLw)7  
FileAccessI fileAccessI = null; //File Access interface Cs:?9G  
<K g=?wb  
P}`|8b1W  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException >m$jJlAv8  
{ _h6j, )  
this.sURL = sURL; !+UU[uM  
this.nStartPos = nStart; K20,aWBq;3  
this.nEndPos = nEnd; R"wBDWs  
nThreadID = id; UC e{V]T  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 LoUHStt  
} }4uHT.)  
a/\SPXQ/9  
%fT%,( w}t  
public void run() 2Kkm-#p7  
{ -/V,<@@T  
while(nStartPos < nEndPos && !bStop) F_U9;*f]  
{ '2S/FOb  
| 2Vhj<6  
Y9 /`w@"v  
try{ m&P B5s\=  
URL url = new URL(sURL); qnu<"$   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); o5@d1A  
httpConnection.setRequestProperty("User-Agent","NetFox"); elqm/u  
String sProperty = "bytes="+nStartPos+"-"; =:M/hM)#  
httpConnection.setRequestProperty("RANGE",sProperty); vh$If0  
Utility.log(sProperty); \?D~&d,a=  
m >Rdsn~l  
=.`:jZG  
InputStream input = httpConnection.getInputStream(); "u.'JE;j  
//logResponseHead(httpConnection); ~GLWhe-  
A'tv[T d8,  
+F?}<P_v  
byte[] b = new byte[1024]; _v#Vf*#  
int nRead; dc dVB>D  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) l\/uXP?  
{ S.zY0  
nStartPos += fileAccessI.write(b,0,nRead); 1!%T<!A.  
//if(nThreadID == 1) qyKI.X3n*  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 'uW&AD p  
} | |u  
[t6Y,yo&h4  
2@6Qifxd@  
Utility.log("Thread " + nThreadID + " is over!"); Al3*? H&  
bDownOver = true; ,bxGd!&{Q  
//nPos = fileAccessI.write (b,0,nRead); ;=UkTn}N?l  
} wX4gyr  
catch(Exception e){e.printStackTrace ();} zcy`8&{A<?  
}  nb\pBl  
} o?g9Grk  
}*P?KV (  
K0{ ,*>C  
//打印回应的头信息 2M>`W5  
public void logResponseHead(HttpURLConnection con) #Q1 |]  
{ eJ0Xfw%y%T  
for(int i=1;;i++) qoP /` Y6  
{ g5;Ig  
String header=con.getHeaderFieldKey(i); m@y<wk(  
if(header!=null) >|pN4FS  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); KJ7-Vl>  
Utility.log(header+" : "+con.getHeaderField(header)); <c&Nm_)  
else hK UK#xx  
break; #0f6X,3  
} (@Kc(>(: Y  
} :CsrcT=  
,YBe|3  
4iv&!hAc;  
public void splitterStop() Mt*V-`+\  
{ d f j;e%H  
bStop = true; F@b=S0}K  
} Ae;mU[MK/  
I uC7Hx`z  
e0M'\'J  
} A[`2Mnj  
P}"T 3u\N  
**.g^Pyc  
/* AqT}^fS  
**FileAccess.java T7^?j :kJ/  
*//文件访问(定位,写) 6!C>J#T  
package NetFox; 3 TRG] 5  
import java.io.*; \ cdns;  
_`. Q7  
!ou;yE&<,  
public class FileAccessI implements Serializable{ s &f\gp1  
oS~;>]W  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 s`|KT&r  
RandomAccessFile oSavedFile; <rFh93  
long nPos; mRy0zN>?  
M6j~`KSE  
Y(Y#H$w  
public FileAccessI() throws IOException vwzElZ{C:v  
{ +(Jh$b_  
this("",0); kz G W/  
} buDz]ec b  
iZ4"@G:,  
wlEK"kKU  
public FileAccessI(String sName,long nPos) throws IOException }lP`3e  
{ !gcea?I  
oSavedFile = new RandomAccessFile(sName,"rw"); - LB}=  
this.nPos = nPos; Fd<eh(g9P  
oSavedFile.seek(nPos); (|pM^+  
} dl(!{tZ#  
Ed+jSO0  
7~SnY\B|  
public synchronized int write(byte[] b,int nStart,int nLen) gfKv$~  
{ $}fY B/  
int n = -1; hrGX65>  
try{ i v.G  
oSavedFile.write(b,nStart,nLen); viJP6fh  
n = nLen; q0b*#j  
} 0lOR.}]q  
catch(IOException e) 211V'|a_ >  
{ )iJv?Y\]  
e.printStackTrace (); _M^^0kf  
} d5`D[,]d  
`lrNH]B  
LQR^lD+_=  
return n; ]0g p.R  
} Cu_-QE  
s~ou$!|  
;/H/Gn+  
} Gzs$0Ki=  
<+<Nsza  
j<R&?*  
/* *U$%mZS]1  
**SiteInfoBean.java de;CEm<n  
*/ 5hh6;)  
package NetFox; li{!Jp5]1b  
y;(G%s1  
?<S fhjU  
public class SiteInfoBean { IVVX3RI  
qlnA7cK!  
:, 3S5!(y  
private String sSiteURL; //Site's URL saDu'SmYV  
private String sFilePath; //Saved File's Path KT17I&:  
private String sFileName; //Saved File's Name nPDoK!r'  
private int nSplitter; //Count of Splited Downloading File p 16+(m  
R&$fWV;'  
0g~Cdp  
public SiteInfoBean() qJ .XI   
{//nSplitter的缺省值为5 rU(-R@["  
//default value of nSplitter is 5 qe22 kE#  
this("","","",5); EB@rIvUi,  
} L$rr:^J  
bnPhhsR  
|>1#)cONW  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ,6o tm  
{ i g .  
sSiteURL= sURL; gdg``U;)p  
sFilePath = sPath; 8'NT_NPNb  
sFileName = sName; i29a1nD4Hm  
this.nSplitter = nSpiltter; Z[0/x.pp$  
P]OUzI,  
fn.;C  
} M?o_J4  
TuaP  
V F b  
public String getSSiteURL() r'lANl-v  
{ EWY'E;0@5  
return sSiteURL; ~|N,{GaL  
} X?;iSekI4  
$RunGaX!=N  
iXWB  
public void setSSiteURL(String value) G]{^.5  
{ >_G'o  
sSiteURL = value; lR9uD9Dr  
} |.$7.8g  
 cV_-Bcb  
Oi]B%Uxy=  
public String getSFilePath() t;-F]  
{ *B84Y.df  
return sFilePath; )heHERbJ  
} 4%|r$E/TQ  
!H<%X~|,  
I6gduvkXi4  
public void setSFilePath(String value) cSNeWJKA6  
{ wh2E$b(-  
sFilePath = value; Aa]3jev  
} cMoJHC,!  
z.?slYe[  
M4CC&?6\  
public String getSFileName() >oaL-01i  
{ Azp!;+  
return sFileName; "WO0 rh`  
} Fs(S!;  
qZ +K4H  
@`8a 3sL)  
public void setSFileName(String value) B#35)QI  
{ jA[")RVG  
sFileName = value; 8OO[Le]1  
} NV@$\ <  
O6ugN-d>  
q)KOI` A  
public int getNSplitter() H* +7{;$  
{ eH[i<Z  
return nSplitter; K{V.N</  
} |JP'j1 Ka  
Df:/r%  
bR~5 :A^  
public void setNSplitter(int nCount) R,=8)OI2  
{ (0.JoeA`y  
nSplitter = nCount; i\gt @  
} T:9M|mD  
} |F<%gJ  
F- u"zox  
o)x&|0_  
/* 7Cbr'!E\_V  
**Utility.java W:6#0b"_#  
*/ Dhfor+Epy  
package NetFox; q(L.i)w$  
7~'%ThUb$-  
fX6pW%Q'6  
public class Utility { "a33m:]J  
?4Fev_5m  
rc~)%M<[2  
public Utility() 1$6 u  
{ mH5>50H;  
{?EmO+![}  
bn5O2  
} +7n vy^m  
SW+;%+`  
//线程睡眠 8Q{9AoQ3'  
public static void sleep(int nSecond) ^Jdg%U?  
{ B,%KvL&xMX  
try{ OYn5k6  
Thread.sleep(nSecond); pv&iJ7RN  
} F M YcZ+4  
catch(Exception e) PxvxZJf$@  
{ GK6CnSV8d  
e.printStackTrace (); BM)a,fIgo  
} }1+2&Ps50  
} f~TkU\Rh  
D!Nc&|X^  
//日志 zxx9)I@?A  
public static void log(String sMsg) WX_g  
{ X.,R%>O}`P  
System.err.println(sMsg); ~| ZAS]  
} $AMcU5^b7  
K V?+9qa,  
^T1caVb|>  
public static void log(int sMsg) nU\.`.39 +  
{ >uQjygjj  
System.err.println(sMsg); ]VtP7 Y  
} *8yC6|wL?  
} b].U/=Hs  
wgvCgr<  
v4uQ0~k~X  
/* e7&RZ+s#wZ  
**TestMethod.java f4NN?"W)  
*/ @KLX,1K  
package NetFox; Az#kE.8b*A  
,pf\g[tz  
t U~q4$qqE  
public class TestMethod { ]*U; }  
9(vp`Z8B4  
~HT:BO$  
public TestMethod() (I>SqM Y  
{ ///xx/weblogic60b2_win.exe -y?ve od#  
try{  w+5OI9  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); oblw!)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); mRGr+m  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Y(EF )::  
fileFetch.start(); VAyAXN~  
} Lk^bzW>f  
catch(Exception e){e.printStackTrace ();} c5O8,sT  
X9^q-3&60  
fLSDt(c',  
} (r}StR+  
pjSM7PhQ  
qxZf!NX5  
public static void main(String[] args) ^r7KEeVD  
{ $`0,N_C<}  
new TestMethod(); F4Cq85#  
} 2@HmZ!|Q  
} 9fM=5  
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