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http断点续传简单实现(java)

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/* _"B5S?  
**SiteFileFetch.java }?=$?3W  
*/ Em8C +EM  
package NetFox; ZVj/lOP X  
import java.io.*; 0XBv8fg  
import java.net.*; Jiljf2h  
+Q3i&"QB.  
W])<0R52  
public class SiteFileFetch extends Thread { L}1|R*b  
>>voLDDd  
/8i3I5*  
SiteInfoBean siteInfoBean = null; //文件信息Bean 7 Ld5  
long[] nStartPos; //开始位置 X rVF %  
long[] nEndPos; //结束位置 tTB,eR$  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Eh)PZvH  
long nFileLength; //文件长度 |P si?'4  
boolean bFirst = true; //是否第一次取文件 h7|#7 d  
boolean bStop = false; //停止标志 r9Wk7?w)  
File tmpFile; //文件下载的临时信息 O$ 7R<V  
DataOutputStream output; //输出到文件的输出流 [;/ydE=  
ShdE!q7  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ;{79d8/=  
public SiteFileFetch(SiteInfoBean bean) throws IOException tB_GEt2M  
{ f\}fUg 2  
siteInfoBean = bean; $]eITyC`P  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Gvk)H$ni  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); QQUYWC  
if(tmpFile.exists ()) /[iqga=  
{ Quy&CV{@  
bFirst = false; |Fk>NX  
read_nPos(); +wU9d8W  
} RHdcRojF  
else )B86  
{ -lL(:drn  
nStartPos = new long[bean.getNSplitter()]; 8[Ssrk  
nEndPos = new long[bean.getNSplitter()]; B\,pbOE?#  
} 9@LL_r`?<  
zU;%s<(p  
%- W3F5NK  
"/e:V-W   
} x t7ZrT  
/G`'9cD  
3,2|8Q,((!  
public void run() E({W`b~_f  
{ < `r+ZyM  
//获得文件长度 =ILE/ pC-|  
//分割文件 *"\QR>n   
//实例FileSplitterFetch f D<9k  
//启动FileSplitterFetch线程 Fy^=LrH=D  
//等待子线程返回 LE!xj 0  
try{ Tji G!W8  
if(bFirst) qU(,q/l  
{ 3xSt -MA  
nFileLength = getFileSize(); -\OvOkr  
if(nFileLength == -1) C:+-T+m[  
{ kQ5mIJ9(  
System.err.println("File Length is not known!"); eM";P/XaX  
} #)&kF+  
else if(nFileLength == -2) 6ge,2[PU  
{ DlHt#Ob7  
System.err.println("File is not access!"); `52+.*J+%  
} +yvtd]D$2W  
else !7C[\No(  
{ R_IUuz$e  
for(int i=0;i<nStartPos.length;i++) ,@mr})s  
{ ?RyeZKf  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); z>rl7&[@  
} v]UT1d=_T  
for(int i=0;i<nEndPos.length-1;i++) |sP;`h}I%  
{ \$.8iTr@  
nEndPos = nStartPos[i+1]; V2As 5  
} fhGI  
nEndPos[nEndPos.length-1] = nFileLength; TPjElBh  
} {z~n`ow  
} } + ]A?'&  
cR'l\iv+  
or~2r8  
//启动子线程 cEI "  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; *$K_Tii  
for(int i=0;i<nStartPos.length;i++) a_jw4"Sb  
{ |\/`YRg>  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), gEghDO_G  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 00jWs@K  
nStartPos,nEndPos,i); Q&j-a;L  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); z TYHwx  
fileSplitterFetch.start(); +ZFw3KEkz  
} #m x4pf{  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ='!E;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); S T#9auw  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", E@}N}SR  
nEndPos = " + nFileLength); Iw)}YZmn  
// fileSplitterFetch[nPos.length-1].start(); M]c"4 b;  
>6Y @8 )  
j)G<PW  
//等待子线程结束 lZ5LHUzP  
//int count = 0; k }amSsE  
//是否结束while循环 6pJFrWe{  
boolean breakWhile = false; ~Up5+7k@  
%y96]e1  
e}f#dR+(  
while(!bStop) 7+!FZo{?  
{ dC'8orFG+  
write_nPos(); `O+}$wP  
Utility.sleep(500); =Msr+P9Ai  
breakWhile = true; Q y4eDv5  
VQ}N& H)`  
KgD sqwy  
for(int i=0;i<nStartPos.length;i++) 5#275Hyv  
{ qLjLfJJ2  
if(!fileSplitterFetch.bDownOver) NUO#[7OK+x  
{ NL^;C3u  
breakWhile = false; |WkWZZ^  
break; 1tZ7%0R\g]  
} LZ=E  
} CMhl*dH  
if(breakWhile) 8}M-b6R V  
break; v[Mh[CyB  
3VZ}5  
14~#k%zO(  
//count++; $)YalZ  
//if(count>4) at|.Q*&a#  
// siteStop(); FOyANN'  
} ;W 3#q:  
UuKW`(?^  
iFOa9!_0n  
System.err.println("文件下载结束!"); *Uw"`l  
} uv|RpIve:  
catch(Exception e){e.printStackTrace ();} ul-O3]\'@  
} /Moyn"Kj{  
9GX'+$R]  
>6KwZr BB  
//获得文件长度 f8?hEa:js  
public long getFileSize() ?vBMx _0  
{ *b4W+E  
int nFileLength = -1; P<CPA7K  
try{ |jI|} ,I  
URL url = new URL(siteInfoBean.getSSiteURL()); swz)gh-*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :@b=;  
httpConnection.setRequestProperty("User-Agent","NetFox"); Dn l|B\  
}~v&  
a9uMgx}  
int responseCode=httpConnection.getResponseCode(); %$<v:eMAs  
if(responseCode>=400)  \4j(el  
{ < ZG!w^  
processErrorCode(responseCode); >:bXw#w]  
return -2; //-2 represent access is error ;uho.)%N`F  
} hRQw]  
en"\2+{Cg  
vkLKzsN' ]  
String sHeader; Q5&|1m Pb  
sis1Dh9:  
{(IHHA>  
for(int i=1;;i++) ^v&"{2  
{ 2c'<rkA  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); \Ez&?yb/  
//Utility.log(in.readLine()); SN 4JX  
sHeader=httpConnection.getHeaderFieldKey(i); 9T\\hM)k  
if(sHeader!=null) b5#Jo2C`AJ  
{ y5j ;Daq  
if(sHeader.equals("Content-Length")) <Zo{D |hW  
{ ?@^gpVK{  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Elt" tJ  
break; 3T /_#=9TV  
} RNopx3  
} _Qq lOc9  
else EeQ2\'t  
break; ck$>   
} ,ZZ5A;)  
} DFb hy  
catch(IOException e){e.printStackTrace ();} )m I i.  
catch(Exception e){e.printStackTrace ();} \D-X _.v  
g'9~T8i& ^  
`NQ;|!  
Utility.log(nFileLength); wkY$J\J  
w ^ X@PpP  
I  :8s3;  
return nFileLength; / <+F/R'=O  
} Q$5%9  
W!|l_/L'   
CropHB/t  
//保存下载信息(文件指针位置) BO+t o.  
private void write_nPos() ?weuq"*a  
{ k&:~l@?O  
try{ T[-Tqi NT  
output = new DataOutputStream(new FileOutputStream(tmpFile)); s~A:*2\  
output.writeInt(nStartPos.length); @cQ |`  
for(int i=0;i<nStartPos.length;i++) 6%V#_]  
{ @P">4xVX{  
// output.writeLong(nPos); )"g @"LJ=  
output.writeLong(fileSplitterFetch.nStartPos); #dFE}!"#`  
output.writeLong(fileSplitterFetch.nEndPos); aqgm  
} Hn]6re  
output.close(); H{uR+&<  
} "2:#bXM-  
catch(IOException e){e.printStackTrace ();} q8& ^E.K  
catch(Exception e){e.printStackTrace ();} E?jb?  
} M (:_(4~  
AgWG4C=  
t'DIKug&  
//读取保存的下载信息(文件指针位置) }:\e "Bfv  
private void read_nPos() F<O<=Ww  
{ =%{E^z>1  
try{ SJlL!<i$  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =kw6<!R  
int nCount = input.readInt(); C9j5Pd5q1L  
nStartPos = new long[nCount]; d 1 O+qS  
nEndPos = new long[nCount]; :eBp`dmn  
for(int i=0;i<nStartPos.length;i++) \wp8kSzC  
{ }7i}dyQv}  
nStartPos = input.readLong(); k~]\kv=  
nEndPos = input.readLong(); w69G6G(  
} sh%%U  
input.close(); 0C717  
} rUmnv%qTS  
catch(IOException e){e.printStackTrace ();} ^ lG^.  
catch(Exception e){e.printStackTrace ();} ze`qf%  
} scZ'/(b-E  
$oIGlKc:L  
iJk/fvi  
private void processErrorCode(int nErrorCode) ! 6_tdZ  
{ *jl_,0g]  
System.err.println("Error Code : " + nErrorCode); {/XU[rn  
} 7mYBxE/  
/?C6 oj1  
~{D:vj4>  
//停止文件下载 2vW@d[<J  
public void siteStop() h}%yG{'/M=  
{ {'G u@l  
bStop = true; EU()Nnm2  
for(int i=0;i<nStartPos.length;i++) y9Q"3LLic`  
fileSplitterFetch.splitterStop(); Of{'A  
WhL 1OG  
Q?Uk%t\hwc  
} [~ |e:  
} v?h8-yed  
//负责部分文件的抓取 <$`ud P@  
**FileSplitterFetch.java =_d-MJy~6  
*/ po+ 1  
package NetFox; JmVha!<qk  
1;9  %L@  
g$S<_$Iey  
import java.io.*; ,DbT4Ul c  
import java.net.*; l7GLN1#m  
}UHoa  
:aMp,DfM]P  
public class FileSplitterFetch extends Thread { _xXDvBU  
w5}2$r  
(?zZvW8  
String sURL; //File URL 2BIOA#@t  
long nStartPos; //File Snippet Start Position JY@x.?N5$  
long nEndPos; //File Snippet End Position `!g XA.9Uv  
int nThreadID; //Thread's ID %GDs/9  
boolean bDownOver = false; //Downing is over mH09* Z  
boolean bStop = false; //Stop identical $kk!NAW  
FileAccessI fileAccessI = null; //File Access interface W>]=0u4  
`'<&<P  
#oD * H:%*  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ^k}jPc6  
{ }[I|oV5*+&  
this.sURL = sURL; ^<O:`c6_  
this.nStartPos = nStart; cc$+"7/J^c  
this.nEndPos = nEnd; REwZ41   
nThreadID = id; )*3sE1  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 VR_bX|  
} jR&AQ-H&  
gL;tyf1P  
r`(U3EgP  
public void run() 18U CZ;)>  
{ O}_Z"y  
while(nStartPos < nEndPos && !bStop) FzGla})  
{ nLjo3yvV..  
h|Uy!?l  
K-*q3oh G  
try{ [-Dl,P=  
URL url = new URL(sURL); t Sf`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); hgi9%>o UB  
httpConnection.setRequestProperty("User-Agent","NetFox"); c/E6}OWA  
String sProperty = "bytes="+nStartPos+"-"; VR9C< tMSi  
httpConnection.setRequestProperty("RANGE",sProperty); ua vv  
Utility.log(sProperty); }nJG<rY  
h47l;`kD-#  
O~AOZ^a:2  
InputStream input = httpConnection.getInputStream(); hkL[hD  
//logResponseHead(httpConnection); 8TnByKZz  
~V4&l3o  
y(RK|r  
byte[] b = new byte[1024]; Ka\%kB>*`  
int nRead; SggS8$a`  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) fX2PteA0qX  
{ S?_ ;$Cn  
nStartPos += fileAccessI.write(b,0,nRead); K) "cwk-  
//if(nThreadID == 1) YEx7 6  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =1"8ua  
} O{9h'JU  
T9+ ?A l  
+}@HtjM  
Utility.log("Thread " + nThreadID + " is over!"); VJeN m3WNb  
bDownOver = true; xFY;aK  
//nPos = fileAccessI.write (b,0,nRead); v+|N7  
} nUvxO `2  
catch(Exception e){e.printStackTrace ();} bu#}`/\_  
} ( U |[C*  
} UC34AKm  
}9xEA[@;  
J$?*qZ(oO  
//打印回应的头信息 8vcV-+x  
public void logResponseHead(HttpURLConnection con) XK>/i}y  
{ YFCP'J"Z  
for(int i=1;;i++) +)fl9>Mb  
{ !:mo2zA  
String header=con.getHeaderFieldKey(i); 0VB~4NNR  
if(header!=null) +`x8[A)-  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); dSb|hA}@  
Utility.log(header+" : "+con.getHeaderField(header)); [$Ld>`3  
else }I'g@Pw9[  
break; (SLAq$gvd  
} ~o+HAc`=v  
} y$At$i>u  
XY8s\DK  
5u\si4BL{  
public void splitterStop() Wb"*9q06  
{ !#nlWX :~  
bStop = true; p_jDnb#  
} !ldb_*)h  
& ;+u.X  
5B? >.4R  
} wvm`JOP:A  
|Y!#`  
Y$ ;C@I  
/* ]cnLJ^2  
**FileAccess.java EIwTx:{F  
*//文件访问(定位,写) V>j6Juh  
package NetFox; lV-7bZ  
import java.io.*; )dJaF#6j  
RvYH(!pQ  
rs3Uk.Z^ '  
public class FileAccessI implements Serializable{ lu(<(t,Lbs  
V,($I'&/  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 92GO.xAD?  
RandomAccessFile oSavedFile; jl=<Q.Mm7  
long nPos; 5o5y3ibQ  
/GNRu  
a'ViyTBo  
public FileAccessI() throws IOException F t%f"Z  
{ K^k1]!W=  
this("",0); h@T}WZv  
} 7{ :| )  
RR><so%  
J56+eC(  
public FileAccessI(String sName,long nPos) throws IOException B3'qmi<  
{ Z^>[{|lIA  
oSavedFile = new RandomAccessFile(sName,"rw"); m u(HNj  
this.nPos = nPos; %lchz /  
oSavedFile.seek(nPos); W 0Q-&4  
} o*\kg+8  
hq/\'Z&!+P  
jpqq>Hbg_  
public synchronized int write(byte[] b,int nStart,int nLen) 50(/LV1  
{ [SgP1>M  
int n = -1; pc5-'; n  
try{ S'HM|&  
oSavedFile.write(b,nStart,nLen); 0yXUVKq3  
n = nLen; -@G |i$!  
} Gu<3*@Ng  
catch(IOException e) <oPo?r|oM|  
{ /g712\?M4  
e.printStackTrace (); Pv`yOx&nE  
} &~U8S^os  
l2=.;7 IV  
tOwwgf  
return n; )__vPPko i  
} F$ x@ ]  
&Hc8u,|  
GdR>S('  
} 9'Y~! vY  
FqQm *k_  
SZ~Ti|^  
/* U n2xZ[4  
**SiteInfoBean.java JTpKF_Za<  
*/ B @UaaWh  
package NetFox; 'rRo2oTN  
rOB-2@-  
xzy7I6X  
public class SiteInfoBean { ,Vt7Kiu  
'  G-]>  
c}Y(Myd  
private String sSiteURL; //Site's URL UMo=bs  
private String sFilePath; //Saved File's Path &6PZX0M  
private String sFileName; //Saved File's Name N6$pOQ  
private int nSplitter; //Count of Splited Downloading File IO`.]iG  
>f19P+  
;Mc\>i/  
public SiteInfoBean() 75@){ :  
{//nSplitter的缺省值为5 !~m)_Q5?~  
//default value of nSplitter is 5 tk<dp7y7  
this("","","",5); ]OM|Oo  
} 06pLa3oi  
s9~W( Wi  
J+[&:]=P  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) b'O>&V`  
{ Gk8"fs  
sSiteURL= sURL; z*l3O~mZ  
sFilePath = sPath; /lm;.7_J+  
sFileName = sName; 4/S 4bk*8  
this.nSplitter = nSpiltter; 7h<Q{X<A  
6~0S%Hz   
Y1H8+a5@  
} : +/V  
- P1OD)B  
II)\rVP5  
public String getSSiteURL() PLKp<kg  
{ N/TU cG|m\  
return sSiteURL; }q G{1Er  
} &'N{v@Oi)  
d%81}4f:  
^u:7U4  
public void setSSiteURL(String value) A0cC)bd&  
{ X + *@  
sSiteURL = value; m-dne/%_  
} @ _U]U  
MJV)| 2C  
IaH8#3+a  
public String getSFilePath() 8uM>UpX  
{ :f ybH)*  
return sFilePath; ,<zGvksk  
} )~T)$TS  
_jR%o1Y}  
dfiA- h  
public void setSFilePath(String value) &kHp}\  
{ Ji :2P*  
sFilePath = value;  VD;Ot<%  
} V2,54YE  
U voX\  
GX&BUP\  
public String getSFileName() =_\5h=`Yx  
{ n %"q>  
return sFileName; >:Na^+c  
} Y]P'; C_eP  
wP/&k`HQ#i  
'LpJ:Th  
public void setSFileName(String value) tlV>  
{ KF|+# qCN  
sFileName = value; n&D<l '4  
} Z%y>q|:  
2^bq4c4J  
|[CsLn;  
public int getNSplitter() xpx Un8.  
{ iN"kv   
return nSplitter; |o6 h:g  
} BDNn~aU#m  
P_B#  
GRB/N1=  
public void setNSplitter(int nCount) `$ZX]6G  
{ Y|_ #yb  
nSplitter = nCount; MGfDxHg]  
} @HxEp;*NH"  
} 6b~Zv$5^Y-  
]{{A/ j\  
N#Y%+1  
/* h=.|!u  
**Utility.java FAfk;<#'n+  
*/ x9Y1v1!5Pu  
package NetFox; $HF. 02{|  
+wXrQV  
{(w/_C9  
public class Utility { =${]j  
h$)(-_c3  
ah1d0e P  
public Utility() `utv@9 _z  
{ k<Z^93 S  
q&Y'zyHLP  
AqB5B5}  
} PUV)w\!&is  
"^F#oo%L  
//线程睡眠 mcy\nAf5%  
public static void sleep(int nSecond) Y (x_bJ  
{ 9 [v=`  
try{ =dx!R ,Bw  
Thread.sleep(nSecond); gELku .  
} N:GSfM@g  
catch(Exception e) BAG) -  
{ XE* @*  
e.printStackTrace (); 1 0lvhzU  
} k"&l o h  
} /:3:Ky3  
ye:pGa w  
//日志 /x,gdZPX  
public static void log(String sMsg) e:fp8 k<  
{ 91qk0z`N  
System.err.println(sMsg); Ef{rY|E  
} @wy|l)%  
P?p>'avP  
'bJ!~ML&  
public static void log(int sMsg) /ts=DxCC;  
{ 11[[Hk X@  
System.err.println(sMsg); reR><p  
} C,~wmS )@  
} 1j0OV9-|  
\ZX5dFu0  
T]-yTsto  
/* eQu%TZ(x-$  
**TestMethod.java <f.*=/]W2  
*/ gF-<%<RV  
package NetFox; o(w!x!["  
k4fc 5P  
.) uUpY%K^  
public class TestMethod { B4yU}v  
*GleeJWz  
74Xk^  8  
public TestMethod() wI><kdz  
{ ///xx/weblogic60b2_win.exe  UhN16|x  
try{ ,@kD9n5#  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 1^XuH('  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); mR@|]T  
SiteFileFetch fileFetch = new SiteFileFetch(bean); vw5f.8T;w  
fileFetch.start(); Z:DEET!c'k  
} RO[Ko-m|/N  
catch(Exception e){e.printStackTrace ();} J ^gtSn^  
HM57b>6  
1+6:K._C(m  
} '{dduHo  
%E#OUo[y/  
#<0Yx9Jh.  
public static void main(String[] args) ,Tc3koi  
{ 5OeTOI()&5  
new TestMethod(); )]WWx-Uf'  
} s3qWTdM  
} nfpkWyIu{  
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