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http断点续传简单实现(java)

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/* 4i.&geX A.  
**SiteFileFetch.java n_4.`vs  
*/ za}Kd^KeB  
package NetFox; V )Oot|  
import java.io.*; Y- Q)sv  
import java.net.*; 2+I5VPf  
[u;(4sa}  
hSxK*.W*3  
public class SiteFileFetch extends Thread { Iila|,cM  
GApvRR+Z  
2q]ZI  
SiteInfoBean siteInfoBean = null; //文件信息Bean Zyr| J!VF  
long[] nStartPos; //开始位置 ovOV&Zt  
long[] nEndPos; //结束位置 QVRQUd  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 `q\F C[W  
long nFileLength; //文件长度 /k ?l%AH  
boolean bFirst = true; //是否第一次取文件  H{yBD xw  
boolean bStop = false; //停止标志 kP}l"CN4  
File tmpFile; //文件下载的临时信息 VRgckh m  
DataOutputStream output; //输出到文件的输出流 0 LXu!iix  
(SQGl!Lai0  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ~CHcbEWk)W  
public SiteFileFetch(SiteInfoBean bean) throws IOException |EdEV*.ej  
{ n:B){'S  
siteInfoBean = bean; %z.V$2  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); <m^a ?q^  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); J/D~]U  
if(tmpFile.exists ()) v(R^LqE  
{ f+ZOE?"  
bFirst = false; U\, N  
read_nPos(); :R +BC2x  
} F WU >WHX  
else </ "Wh4>C  
{ N%'(8%;  
nStartPos = new long[bean.getNSplitter()]; [kpQ:'P3  
nEndPos = new long[bean.getNSplitter()]; $L( ,lB  
} mE1Vr  
=SuJ*  
@YRy)+  
3QKBuo  
} 5 (!FQ  
?u&|'ASo  
k%u fgHl!  
public void run() =w;-4  
{ -xLK/QAL  
//获得文件长度 ;nL7Hizo,  
//分割文件 a#+$.e5  
//实例FileSplitterFetch |A,.mOT  
//启动FileSplitterFetch线程 y{<js!au  
//等待子线程返回 8@+<W%+th  
try{ N-b'O`C  
if(bFirst) -hfkF+=U'  
{ R\X;`ptT  
nFileLength = getFileSize(); o<p4r}*AVJ  
if(nFileLength == -1) %-fS:~$  
{ p %.Adxx  
System.err.println("File Length is not known!"); -6WSYpHV  
} AxH`4=3<  
else if(nFileLength == -2) BMQ4i&kF|  
{ ~|, "w90  
System.err.println("File is not access!"); 6AdUlPM  
} Drf Au  
else #@w/S:KbJt  
{ 82+2 PE{  
for(int i=0;i<nStartPos.length;i++) 'LuxF1>  
{ }+MA*v[06  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ^fsC]9NS  
} _g9j_ x:=  
for(int i=0;i<nEndPos.length-1;i++) -DJ ,<f*$  
{ t~dK\>L  
nEndPos = nStartPos[i+1]; x!W5'DO  
} wj0_X;L  
nEndPos[nEndPos.length-1] = nFileLength; \p}GW  
} k >.U!  
} k,'MmAz  
0~_I9|FN  
N"RPCd_  
//启动子线程 XYD-5pG  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; b;*'j9ly  
for(int i=0;i<nStartPos.length;i++) zsd<0^ p\{  
{ 7&HcrkP]  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \(=xc2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), v9,cL.0&  
nStartPos,nEndPos,i); |;(P+Q4lB  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); IO7gq+  
fileSplitterFetch.start(); A /c  
} k^ fW /  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *' es(]W  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); q9VBK(,X  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", DzA'MX  
nEndPos = " + nFileLength); htrtiJ1  
// fileSplitterFetch[nPos.length-1].start(); eJn_gKWb  
A7XA?>~+|  
(RrC<5"  
//等待子线程结束 D+ .vg?8  
//int count = 0; Z  eY *5m  
//是否结束while循环 Ktt(l-e+  
boolean breakWhile = false; )+Z.J]$O-  
J4 j:nd  
z19%!k  
while(!bStop)  )h>dD  
{ ]oz>/\!  
write_nPos(); `-cw[@uD  
Utility.sleep(500); x[)]u8^A  
breakWhile = true; 9An \uH)mL  
"X!1^)W -8  
UUbO\_&y  
for(int i=0;i<nStartPos.length;i++) D%?9[Qb  
{ ~#VDJ[Z  
if(!fileSplitterFetch.bDownOver) P*}aeu&lnD  
{ khT[  
breakWhile = false; 2*cc26o  
break; #u+qV!4  
} Y=_*Ai  
} @q># ]8  
if(breakWhile) xQzW6H|  
break; lgK5E *^  
FL^t} vA  
&;r'JIp  
//count++; 3m4 sh~  
//if(count>4) n"}*C|(k  
// siteStop(); bUM4^m  
} ZdY$NpR,  
Btr>ek  
Hd7Vp:KM  
System.err.println("文件下载结束!"); _akjgwu  
} v+trHdSBYE  
catch(Exception e){e.printStackTrace ();} t;PG  
} 8'qlg|{!~  
j"pyK@v2B  
5! +{JTXa  
//获得文件长度 .V}bfd[k$  
public long getFileSize() =;Co0Q`  
{ XhWo~zh"  
int nFileLength = -1; =oiz@Q@H  
try{ o$U{.#  
URL url = new URL(siteInfoBean.getSSiteURL()); qe e_wx  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3m-g-  
httpConnection.setRequestProperty("User-Agent","NetFox"); p/7'r  
UH+#Nel+!  
zLg$|@E&  
int responseCode=httpConnection.getResponseCode(); o /1+ }f  
if(responseCode>=400) aMkuyqPf{  
{ L\bc R  
processErrorCode(responseCode); T$<'ZC  
return -2; //-2 represent access is error h#)\K| qs  
} i-p,x0th  
hgDFhbHtd6  
9jx>&MnWs  
String sHeader; M$>Nd6,@N  
z?kE((Ey  
]:T:cO0_n  
for(int i=1;;i++) y@2"[fo3~  
{ U,fPG/9  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +7 j/.R  
//Utility.log(in.readLine()); Lc]hwMGR*  
sHeader=httpConnection.getHeaderFieldKey(i); dN:^RCFzS  
if(sHeader!=null) %gSmOW2.c^  
{ QGGBI Ku   
if(sHeader.equals("Content-Length")) Vu4LC&q  
{ ePaC8sd0  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); U#PgkP[4  
break; k,<7)-  
} ]-a/)8  
} [TqX"@4NS  
else cG@W o8+  
break; Qz2jV  
} jeA2y jAC  
} YD9vWk \/  
catch(IOException e){e.printStackTrace ();} 0Ny +NE:6M  
catch(Exception e){e.printStackTrace ();} )#hR}|  
@;{ZnRv14  
{9j0k`A  
Utility.log(nFileLength); x5;D'Y t"|  
Zn Rj}y  
KiE'O{Y  
return nFileLength; >Lo'H}[pF  
} .A6pPRy e  
9asA-'fZ  
H0t#J  
//保存下载信息(文件指针位置) 42,dHYdt  
private void write_nPos() u%1JdEWZd  
{ `jhbKgR[  
try{ 4R8Qn^  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Ic&YiATj  
output.writeInt(nStartPos.length); --c)!Vxzx  
for(int i=0;i<nStartPos.length;i++) LL+_zBP.   
{ LtKR15h,  
// output.writeLong(nPos); a%6=sqxE  
output.writeLong(fileSplitterFetch.nStartPos); X2,v'`U5&  
output.writeLong(fileSplitterFetch.nEndPos); )?l7I*  
} ,qV7$u  
output.close(); loBW#>  
} )u]=^  
catch(IOException e){e.printStackTrace ();} ZdPqU \G^q  
catch(Exception e){e.printStackTrace ();} IC$"\7 @  
} +~,q"6  
gOE ?  
KZ65# UVX  
//读取保存的下载信息(文件指针位置) gF2 93Ez  
private void read_nPos() q%]5/.J  
{ +R{~%ZTK  
try{ w6lx&K-  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); VtU2&  
int nCount = input.readInt(); M-+!z5 q~d  
nStartPos = new long[nCount]; P-yVc2YH  
nEndPos = new long[nCount]; C+t|fSJ  
for(int i=0;i<nStartPos.length;i++) d}Y#l}!E6  
{ !Bg^-F:N  
nStartPos = input.readLong(); ":=h1AJY  
nEndPos = input.readLong(); b%C7 kL-  
} GGZ9DC\{  
input.close(); .]<gm9l  
} ]1h9:PF  
catch(IOException e){e.printStackTrace ();} I?\P^f  
catch(Exception e){e.printStackTrace ();} v9f%IE4fX  
} z`u$C+Ov  
h+YPyeAs  
!g|[A7<|  
private void processErrorCode(int nErrorCode) '*&V7:  
{ h{jm  
System.err.println("Error Code : " + nErrorCode); W>b\O">  
} fti0Tz'  
}y(cv}8Y  
KxFA@3  
//停止文件下载 c2s73i z  
public void siteStop() ]a*26AbU+  
{ 20Jlf?  
bStop = true; rCA0c8  
for(int i=0;i<nStartPos.length;i++) ICG:4n(,  
fileSplitterFetch.splitterStop(); pk;S"cnk  
$t5>1G1j7  
c7tO'`q$e  
} Y10  
} +I:/8,&-x  
//负责部分文件的抓取 #a]\3X  
**FileSplitterFetch.java ;uZeYY?   
*/ ye}86{l  
package NetFox; J~ *>pp#U  
G#E8xA"{/  
c% ?@3d  
import java.io.*; 2J3y 1  
import java.net.*; 3YUF\L]yyw  
DwTVoCC  
4JH^R^O<n  
public class FileSplitterFetch extends Thread { Z`%^?My  
VPVg \K{  
+lf`Dd3  
String sURL; //File URL wjOJn]  
long nStartPos; //File Snippet Start Position c2Y\bKeN  
long nEndPos; //File Snippet End Position e%7#e%1s  
int nThreadID; //Thread's ID HA&hu /mw_  
boolean bDownOver = false; //Downing is over ]\ZmK0q<:  
boolean bStop = false; //Stop identical ,,S 2>X*L  
FileAccessI fileAccessI = null; //File Access interface AJ#YjkO>]  
H>-{.E1bG  
(8NE'd8  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException d@Wze[M?0  
{ }p8iq  
this.sURL = sURL; "412w^5[T  
this.nStartPos = nStart; ,kFp%qNj  
this.nEndPos = nEnd;  Tx'anP  
nThreadID = id; x69RQ+Vw  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &$~irI  
} yi-0CHo  
:/>Zky8,k  
_vAc/_ N  
public void run() ClPE_Cfw~  
{ 52'6wwv6?  
while(nStartPos < nEndPos && !bStop) }Cb-7/  
{ T*(mi{[T  
G) 37?A)  
rfh`;G5s  
try{ _ZK*p+u%  
URL url = new URL(sURL); .rlLt5b%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "5\6`\/  
httpConnection.setRequestProperty("User-Agent","NetFox"); }/L#<n`Z  
String sProperty = "bytes="+nStartPos+"-"; nH+wU;M  
httpConnection.setRequestProperty("RANGE",sProperty); 8>I4e5Ym  
Utility.log(sProperty); od&wfwk(  
%9L+ Q1o  
_.m|Ml,`{  
InputStream input = httpConnection.getInputStream(); 6_;n bqY&  
//logResponseHead(httpConnection); [mG!-.ll  
'PTQ S,E  
5n e&6  
byte[] b = new byte[1024]; dTwYDV}:  
int nRead; fK^;?4  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) A":cS }Ui  
{ v*OT[l7  
nStartPos += fileAccessI.write(b,0,nRead); 2LCOB&-Ww  
//if(nThreadID == 1) `j 4>  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 'W&ewZH_h  
} CX]L'  
]#'& x%m  
ahN8IV=+Gm  
Utility.log("Thread " + nThreadID + " is over!"); ; 2aPhA  
bDownOver = true; .k,,PuP  
//nPos = fileAccessI.write (b,0,nRead); "z*?#&?,  
} GgtYO4,  
catch(Exception e){e.printStackTrace ();} Vf$$e)  
} E>u U6#v  
} VMu?mqEa  
"9NWsy}<c  
K}Q:L(SSr\  
//打印回应的头信息 Fj`K$K?  
public void logResponseHead(HttpURLConnection con) {_Fh3gjb/  
{ Ia[<;":U  
for(int i=1;;i++) mPo.Z"uy7  
{ gzDfx&.0  
String header=con.getHeaderFieldKey(i); |[)pQGw  
if(header!=null) ?YF2Uc8z%2  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Z~;rp`P  
Utility.log(header+" : "+con.getHeaderField(header)); K[Vj+qdyl  
else {}H/N   
break; ^SIA%S3  
} vm =d?*cR  
} \9R=fA18  
=tGRy@QV'\  
FA%V>&;`  
public void splitterStop() UC.kI&A  
{ 4)p ID`  
bStop = true; -'^:+FU  
} KppYe9?  
2g5jGe*0  
n.G.f bO  
} A~< cp)E  
z0|-OCmL  
]VS:5kOj`  
/* {f;DhB-jj  
**FileAccess.java {"|la;*I  
*//文件访问(定位,写) _]L]_Bh  
package NetFox; Zlrbd  
import java.io.*; D"IxQ2}k  
)OK"H^}f  
7zowvE?#  
public class FileAccessI implements Serializable{ bR?xz-g%<3  
f @Vd'k<  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 2dDhO  
RandomAccessFile oSavedFile;  *qFl&*h}  
long nPos; #S[Y}-]T  
UQbk%K2  
x4v&%d=M  
public FileAccessI() throws IOException lWUQkS  
{ |*l^<==  
this("",0); ~m[Gp;pL  
} 1yFIIj:^|  
G7r.Jm^q  
b)r;a5"<5  
public FileAccessI(String sName,long nPos) throws IOException l9 &L$,=  
{ LyG`q3@  
oSavedFile = new RandomAccessFile(sName,"rw"); lcVG<*gf-  
this.nPos = nPos; $v5 >6+-n  
oSavedFile.seek(nPos); ~JP3C5q  
} *] !r T&E  
|+qsO ;  
!=u=P9I  
public synchronized int write(byte[] b,int nStart,int nLen) gJ>#HEkMB  
{ u~~ ~@p  
int n = -1; Emw]`  
try{ d<w]>T5VW  
oSavedFile.write(b,nStart,nLen); gu&W:FY  
n = nLen; |\94a  
} n3$u9!|P  
catch(IOException e) 3#eAXIW[  
{ -vc ,O77z"  
e.printStackTrace (); +x<OyjY5?]  
} L^K,YlNBR  
bgkBgugZhX  
:m>Vp  
return n; PzustC|  
} 5f2=`C0_  
 \+:`nz3m  
\ rKUPI\  
} cg9*+]rc  
=)a %,H  
^)h&s*  
/* +{#Z^y6&  
**SiteInfoBean.java 9_ ~9?5PU  
*/ ;j+*}|!  
package NetFox; !/X>k{  
\S{ihS@J  
{Z178sik  
public class SiteInfoBean { d<E2=WVB6  
a %?v/Ku  
q d:"LS  
private String sSiteURL; //Site's URL b;NVvc(  
private String sFilePath; //Saved File's Path fUPYCw6F  
private String sFileName; //Saved File's Name c{qTVi5e  
private int nSplitter; //Count of Splited Downloading File 8<@X=Z  
qxYCT$1  
s4Vju/  
public SiteInfoBean() }vg|05L  
{//nSplitter的缺省值为5 uO1^nK  
//default value of nSplitter is 5 7p>T6jK)  
this("","","",5); r> .l^U9hJ  
} Qh* }v!3Jo  
x'SIHV4M@Q  
c5pK%I}O  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 5'%O]~  
{ J/PK #<  
sSiteURL= sURL; &%eM  
sFilePath = sPath; 8?|W-rN  
sFileName = sName; 9E|QPT  
this.nSplitter = nSpiltter; ~RZN+N  
6z'0fi|EN  
77j"zr7v  
} ?v'CuWS  
735l&(3A\  
%4BQY>O)@  
public String getSSiteURL() ce719n$   
{ "W_E!FP]r  
return sSiteURL; xn)F(P 0kv  
} j)Z0K$z=  
\gv-2.,  
)Lk2tvr  
public void setSSiteURL(String value) k?/!`   
{ dKL9}:oUa  
sSiteURL = value; z80*Ylx  
} /q/^B> ]  
Kek %io  
tCGA3t  
public String getSFilePath() P2U4,?_e  
{ ?}EWfsA  
return sFilePath; S&;)F|-q  
} m}2hIhD9  
X7gB.=\X  
>y!O_@>z  
public void setSFilePath(String value) Z&h:3;  
{ 6F%6]n  
sFilePath = value; $"#M:V @  
} +aqQa~}r  
B%o%%A8*g  
=PnNett}a  
public String getSFileName() !~ j9Oc^  
{ {96NtR0Z  
return sFileName; Zjs,R{  
} ]{I>HA5[  
y{XNB}E  
*$/Go8t4u  
public void setSFileName(String value) $jBi~QqOf  
{ {xP-p"?p  
sFileName = value; *Tmqs@L  
} gLx?0eBBA  
.mOm@<Xdg  
Oo ^ AE  
public int getNSplitter() !A14\  
{ - 8jlh  
return nSplitter; VRHS 4  
} B =DV!oUg  
.dvs&+I  
R/6 v#9m7  
public void setNSplitter(int nCount) >z,Y%A  
{ R1.Yx?  
nSplitter = nCount; 8-smL^~%#  
} y;O 6q206  
} n"R$b:  
Lf{pTxKr  
h,]lN'JG{  
/* .R S  
**Utility.java UY:Be8C A  
*/ DYe w6B-  
package NetFox; dLf ;g}W  
TBHd)BhI.  
0 eOdE+  
public class Utility { 'SIc2H  
U)3?&9H  
K5(T7S  
public Utility() NCm=l  
{ Yt r*"-  
H 'nLC,  
9mpQusM  
} [yRqSB  
[y<s]C6E  
//线程睡眠 <FN +  
public static void sleep(int nSecond) ](IOn:MuDE  
{ #!rH}A>n+  
try{ |6`7kb;p  
Thread.sleep(nSecond); h5^We"}+  
} Q"qJ0f)  
catch(Exception e) f_:>36{1^!  
{ >(sS4_O7N  
e.printStackTrace (); N0ZD+  
} :rvBx"  
} /&!o]fU1C  
TNcMrbWA  
//日志 A\ tBmL_s  
public static void log(String sMsg) I."s&]FZ  
{ y cWY.HD  
System.err.println(sMsg); u#->?  
} qz!^< M  
2J` LZS  
2[KHmdgtB  
public static void log(int sMsg) \ow(4O#  
{ 4XeO^#  
System.err.println(sMsg); ikPr>  
} J/[PA[Rf  
} % <h2^H\O  
V. o*`V  
J!'IkC$>  
/* w *o _s  
**TestMethod.java **ls 4CE<  
*/ zXd#kw;  
package NetFox; YIYuqtnSJ  
e"2x!(&n(  
u5,vchZ  
public class TestMethod { d-]!aFj|U  
=e6!U5 f  
A}1:fw\Fn3  
public TestMethod() #|Je%t}~  
{ ///xx/weblogic60b2_win.exe [bN_0T.YI  
try{ <H1e+l{8$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); V("T9g  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); =1mIk0H`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ]oC7{OoX  
fileFetch.start(); 'qidorT>N  
} f{'N O`G  
catch(Exception e){e.printStackTrace ();} b/=>'2f  
?;go5f+X  
h0VeXUM;.  
} sWgzHj(c  
/(i~Hpp  
S's I[?\x  
public static void main(String[] args) ZXWm?9uw  
{ o1Wf#Zq   
new TestMethod(); G:MQ_tfr&  
} |:d_IB@  
} e#?rK=C?9  
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