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http断点续传简单实现(java)

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/* '*?WU_L(g  
**SiteFileFetch.java DBCK2PlJ  
*/ S p^9& ^  
package NetFox; "V$Bnz\n  
import java.io.*; `g6h9GC6  
import java.net.*; uvV;Mlo]  
v0YG,)_  
opJMS6%r  
public class SiteFileFetch extends Thread { bIEhgiH  
QCX8IIHG  
cdG |m[  
SiteInfoBean siteInfoBean = null; //文件信息Bean sRrzp=D  
long[] nStartPos; //开始位置 QNxl/y\l0  
long[] nEndPos; //结束位置 _<NMyRJo  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 a)#1{JaoY  
long nFileLength; //文件长度 *H.oP  
boolean bFirst = true; //是否第一次取文件 R hvfC5Hq  
boolean bStop = false; //停止标志 "B8"_D&  
File tmpFile; //文件下载的临时信息 Ns[ym>x#2  
DataOutputStream output; //输出到文件的输出流 2w-51tqm  
Hx\H $Y  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) h<SQL97N  
public SiteFileFetch(SiteInfoBean bean) throws IOException Ko/ I#)  
{ y;AL'vm9  
siteInfoBean = bean; K%X^n>O7C  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); &ZX{R#[L  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 8kIR y   
if(tmpFile.exists ()) =n' 4?W@  
{ ^-[?#]  
bFirst = false; gW1b~( fD  
read_nPos(); %0mMz.f  
} [_.5RPJP8  
else mUz\ra;z  
{ 6^c>,.R  
nStartPos = new long[bean.getNSplitter()]; ^+m+zd_  
nEndPos = new long[bean.getNSplitter()]; i6 (a@KRY  
} ZU9c 5/J  
OKvPL=~  
S:x?6IDPC^  
f}@jFhr'<  
} (<Th=Fns?  
=pk)3<GwF  
<@Fy5k-%.  
public void run() N]<!j$pOz  
{ L   
//获得文件长度 ~2zM kVH  
//分割文件 0sh/|`\  
//实例FileSplitterFetch zWb4([P;  
//启动FileSplitterFetch线程 Xj5~%DZp  
//等待子线程返回 XFh>U7z.  
try{ DmBS0NyR7Y  
if(bFirst) B-T/V-c7  
{ _"#!e{N|  
nFileLength = getFileSize(); n]u<!.X  
if(nFileLength == -1) yH<$k^0r*  
{ EgDQ+( -  
System.err.println("File Length is not known!"); H=\!2XS  
} )5.C]4jol  
else if(nFileLength == -2) ZZ.m(A TR  
{ D^-7JbE]  
System.err.println("File is not access!"); Kmdlf,[3d  
} RJON90,J  
else cn- nj]  
{ ( &frUQm  
for(int i=0;i<nStartPos.length;i++)  =Mb1o[  
{ (}5S  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); h#hxOVl%x  
} 5 XA=G  
for(int i=0;i<nEndPos.length-1;i++) I6s3+x;O  
{ | /|  
nEndPos = nStartPos[i+1]; `WOYoec   
} yj$TPe_BW  
nEndPos[nEndPos.length-1] = nFileLength; ZDC9oX @  
} bI y sl  
} >R2SQA o  
d|*"IFe  
wV)}a5+  
//启动子线程 \xUe/=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; !!:LJ  
for(int i=0;i<nStartPos.length;i++) d.2mT?`#  
{ vi)%$~  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), PccB]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), .?>5-od2  
nStartPos,nEndPos,i); snt(IJQ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7 uarh!  
fileSplitterFetch.start(); n 8pt\i0  
} _6Eu2|vM&  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7'-j%!#w  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); " sgjWo6  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", P/ oXDI8  
nEndPos = " + nFileLength); tWdhDt8$&  
// fileSplitterFetch[nPos.length-1].start(); Fbp{,V@F2  
07/L}b`P  
Y=T'WNaL)0  
//等待子线程结束 ZK'-U,Y.H7  
//int count = 0; 0iZGPe~  
//是否结束while循环 ~kCwJ<E  
boolean breakWhile = false; & ``d  
l6u&5[C  
_NcY I  
while(!bStop) oiH|uIsqR  
{ #DjCzz\  
write_nPos(); /S\cU`ZVe  
Utility.sleep(500); f N "tA  
breakWhile = true; =U. b% uC  
(LtkA|:  
X{g%kf,D=  
for(int i=0;i<nStartPos.length;i++) gLSA!#[ h  
{ ((rv]f{  
if(!fileSplitterFetch.bDownOver) =]>NDWqpHN  
{ f2,1<^{  
breakWhile = false; P=5NKg  
break; <q,+ON\'  
} Cj*-[ EL<  
} dtAbc7  
if(breakWhile)  pAu72O?  
break; M- 0i7%  
v[lnw} =m9  
&-1./?  
//count++; K{l5m{:%  
//if(count>4) S }>n1F_  
// siteStop(); cMzkL%  
} M/*NM= -a  
`E\imL  
|7^^*UzSK:  
System.err.println("文件下载结束!"); UHGcnz<  
} .!}hhiF,Z  
catch(Exception e){e.printStackTrace ();} /i)Hb`(S  
} IOK}+C0e  
Uw<&Wm`'  
x>~p;z#VX  
//获得文件长度 SLhEc  
public long getFileSize() !D o,>gO  
{ B/"2.,  
int nFileLength = -1; MbXq`%  
try{ lr2 rQo >  
URL url = new URL(siteInfoBean.getSSiteURL()); fRm}S>Nibb  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); p[WX'M0f  
httpConnection.setRequestProperty("User-Agent","NetFox"); y>\S@I  
zEw >SP1,  
2>\\@ 1  
int responseCode=httpConnection.getResponseCode(); {5%/T,  
if(responseCode>=400) +^6}   
{ n$2RCQ  
processErrorCode(responseCode); CT d|`  
return -2; //-2 represent access is error jLcHY-P0V  
} %TrF0{NR90  
G*\h\ @  
P=H+ #  
String sHeader; =ex'22  
5A&y]5-Q`  
V8O.3fo`[`  
for(int i=1;;i++) &!35/:~uD  
{ Ih1|LR/c  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); *T4<&  
//Utility.log(in.readLine()); XtBMp=7Oa  
sHeader=httpConnection.getHeaderFieldKey(i); y7<&vIEC  
if(sHeader!=null) Napf"Av  
{ \%,&~4 !  
if(sHeader.equals("Content-Length")) Y~n` ~(  
{ fn9#>~vrD  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); s%;<O:x8o  
break; "D* Wi7  
} &B!%fd.'  
} F3ZxhkF  
else J -Qh/d%]  
break; i9UI,b%X  
} uv4 _:   
} Wn!G.(Jq  
catch(IOException e){e.printStackTrace ();} 3z{S}~  
catch(Exception e){e.printStackTrace ();} 4x'AC%&Qi  
(OQ?<'Qa  
sXl ??UGe  
Utility.log(nFileLength); jiIST^Zq#t  
l9{#sas  
SvK1.NUa  
return nFileLength; ke/_k/  
} W'_/6_c$!  
GoE#Mxhxo  
Su8'$CFz$.  
//保存下载信息(文件指针位置) f|xLKcOP  
private void write_nPos() C]`eH *z~8  
{ /hdf{4  
try{ v5T9Y-{`  
output = new DataOutputStream(new FileOutputStream(tmpFile)); J-J3=JG  
output.writeInt(nStartPos.length); b2h":G|s  
for(int i=0;i<nStartPos.length;i++) WfGH|u  
{ lv:U%+A  
// output.writeLong(nPos); Fc0jQ@4=  
output.writeLong(fileSplitterFetch.nStartPos); pH9HK  
output.writeLong(fileSplitterFetch.nEndPos); h'^FrWaU/  
} ZHy><=2  
output.close(); ?gV'(3 !  
} /aUFc'5  
catch(IOException e){e.printStackTrace ();} Z|^MGyn  
catch(Exception e){e.printStackTrace ();} CKTrZxR"  
} %OI4a5V*l  
BV9*s  
Xa`(;CLW?  
//读取保存的下载信息(文件指针位置) xaXV ^ZM3  
private void read_nPos() = cfm=+  
{ 0->/`/xm  
try{ $ u2Cd4  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _1JmjIH)M  
int nCount = input.readInt(); PI7IBI  
nStartPos = new long[nCount]; ) YSh D  
nEndPos = new long[nCount]; 5_G'68;OV  
for(int i=0;i<nStartPos.length;i++) L? ;/cO^  
{ ,0T)Oc|HL/  
nStartPos = input.readLong(); - 8syjKTg  
nEndPos = input.readLong(); xQz#i-v  
} "2h5m4  
input.close(); A9BxwQU#  
} b*9e1/]  
catch(IOException e){e.printStackTrace ();} QAvWJydb  
catch(Exception e){e.printStackTrace ();} ;]h.m)~|  
} ,L-C(j  
4]UT+'RubX  
*5wv%-  
private void processErrorCode(int nErrorCode) v7@H\x*  
{ Qp&?L"U)2  
System.err.println("Error Code : " + nErrorCode);  nhfwOS  
} F7 uhuqA]N  
8Nvr93T,  
N^@ \tg=  
//停止文件下载 Lr M}?9'  
public void siteStop() Y}/jR6hK  
{ q[boWW  
bStop = true; ZA.fa0n  
for(int i=0;i<nStartPos.length;i++) ",ad7Y7i  
fileSplitterFetch.splitterStop(); yQS04Bl]  
}'jV/  
Kcn\g.  
} Ck(.N  
} v,\93mNp[  
//负责部分文件的抓取 I2*oTUSik  
**FileSplitterFetch.java |p'i,.(c_W  
*/ (^S5Sc=  
package NetFox; `9EVB;  
L; C|ow^c  
_z:Qhe  
import java.io.*; zMU68vwM  
import java.net.*; pSrsp r  
h]C2 8=N  
A}eOR=E  
public class FileSplitterFetch extends Thread { ocP*\NR  
YnxU(v'\  
NhtEW0xCr  
String sURL; //File URL Y?.gfEXSQo  
long nStartPos; //File Snippet Start Position >'0lw+a  
long nEndPos; //File Snippet End Position g!`BXmW  
int nThreadID; //Thread's ID ,$i<@2/=m  
boolean bDownOver = false; //Downing is over Qrz*Lvle h  
boolean bStop = false; //Stop identical X0x_+b? _  
FileAccessI fileAccessI = null; //File Access interface ]1Qi=2'  
;5RIwD  
y(a}IM3~  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 9R:(^8P8  
{ 'WnpwY  
this.sURL = sURL; O<iI  
this.nStartPos = nStart; Ey = 4 b  
this.nEndPos = nEnd; 8a!2zwUBV  
nThreadID = id; ULbP_y>(Y  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 #x|VfN5f  
} 7n>|D^  
Gavkil  
<|dj^.^  
public void run() C!kbZTO[p"  
{ #J3zTG(:@  
while(nStartPos < nEndPos && !bStop) Ris-tdg  
{ c.6QhE  
,|QU] E @  
`L">"V`$Bj  
try{ /]l f>\x1  
URL url = new URL(sURL); s|p(KWo2U  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +TWJNI  
httpConnection.setRequestProperty("User-Agent","NetFox"); +ks$UvtY  
String sProperty = "bytes="+nStartPos+"-"; xx}'l:}2 ]  
httpConnection.setRequestProperty("RANGE",sProperty); L.Vq1RU\"  
Utility.log(sProperty); 6fQ*X~| p  
PJ6$);9}6  
OMxxI6h  
InputStream input = httpConnection.getInputStream(); rX)o3>q^?  
//logResponseHead(httpConnection); %SFw~%@3&~  
y (ldO;.  
Y/!0Q6<[2Y  
byte[] b = new byte[1024]; tdb4?^.s  
int nRead; fIlIH  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) u4xA'X'~R  
{ Z_!9iA:X  
nStartPos += fileAccessI.write(b,0,nRead); ^zkd{ov  
//if(nThreadID == 1) `O jvt-5}E  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); J b|mXNcL  
} X[Y #+z4  
`ITDTZ J  
}K+\8em  
Utility.log("Thread " + nThreadID + " is over!"); ~JT lPU'  
bDownOver = true; > d)|r  
//nPos = fileAccessI.write (b,0,nRead); _qk9o  
} rcpvH}N:  
catch(Exception e){e.printStackTrace ();} hXBqz9  
} Zm5nLxM  
} ]#+5)[N$>  
<6gU2@1  
M`q#,Y?3^I  
//打印回应的头信息 J~:kuf21  
public void logResponseHead(HttpURLConnection con) 2%*|fF}I  
{ Dj/Q1KY$m  
for(int i=1;;i++) -1#e^9Ve\  
{ Vc{/o=1u  
String header=con.getHeaderFieldKey(i); Wa@6VY  
if(header!=null) $t%"Tr  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); *E$H;wKs8  
Utility.log(header+" : "+con.getHeaderField(header)); @$_rEdwi  
else l'P[5'.  
break; Y~<rQ  
} b<48#Qy~l  
} ,\Z8*Jr3Q  
Lp~c  
baA HP "  
public void splitterStop() mn,=V[f  
{ #`2GAM];7  
bStop = true; 7Ljs4>%l9j  
} chMt5L+5  
69[w/\  
`z5v}T  
} D_]i/ F%  
vs* _;vx  
%Tk}sfx  
/* I*%&)Hj~  
**FileAccess.java gDgP;i d  
*//文件访问(定位,写) t^dakL  
package NetFox; !<JG&9ODP  
import java.io.*; HP1X\h!Ke  
h%4 ~0  
<%T%NjNPQ  
public class FileAccessI implements Serializable{ tauP1&%oH{  
:6qUSE  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 {5?!`<fF  
RandomAccessFile oSavedFile; IiQWs1  
long nPos;  W\zL  
9p!dQx  
5LnB]dW  
public FileAccessI() throws IOException Qq6%53  
{ m  mw)C"  
this("",0); t(Cq(.u`:  
} \v B9fA:*  
\["1N-q b  
+/1P^U /  
public FileAccessI(String sName,long nPos) throws IOException 3RG/X  
{ jnx+wcd  
oSavedFile = new RandomAccessFile(sName,"rw"); ;L MEU_  
this.nPos = nPos; "dFdOb"O-  
oSavedFile.seek(nPos); .T[!!z#^  
} u&Ie%@:h9R  
Vz+=ZK r5  
Q|zE@nLS  
public synchronized int write(byte[] b,int nStart,int nLen) C]{V%jU  
{ E$oA+n~  
int n = -1; `3H?*\<(  
try{ *&~sr  
oSavedFile.write(b,nStart,nLen); Bil;@,Z#  
n = nLen; M]pel\{M  
} X,Q 6  
catch(IOException e) |i jW_r  
{ _r^G%Mvy|  
e.printStackTrace (); _j|n}7a  
} GNj/jU<o!  
'ocwXyP,  
,L8I7O}A;  
return n; cftn`:(&8  
} FeincZ!M  
>(YPkmH  
~Y}Z4" o  
} mw%[qeL V  
bE%mgaOh  
r[i~4N=  
/* V9);kD  
**SiteInfoBean.java "J0Oa?  
*/ B_6v'=7]  
package NetFox; 6='_+{   
tle K (^  
7m@^=w  
public class SiteInfoBean { Z"PDOwj5  
|M0,%~Kt  
h)aWerzL  
private String sSiteURL; //Site's URL D[FfJcV'$  
private String sFilePath; //Saved File's Path 9# .NPfMF  
private String sFileName; //Saved File's Name eo}S01bt  
private int nSplitter; //Count of Splited Downloading File ^me}k{x  
OM#OPB rB  
!ktA"Jx  
public SiteInfoBean() UO7a}Tz<  
{//nSplitter的缺省值为5 Iu)(Huv  
//default value of nSplitter is 5 =QO1FO  
this("","","",5); 2*UE&Gp  
} fQ?n(  
(J?}eb;>n  
OD2ai]!v+  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) :pV("tHE  
{ PK|`}z9  
sSiteURL= sURL; Z-;uzx  
sFilePath = sPath; n?ZH2dI \0  
sFileName = sName; :[ZC-hc\  
this.nSplitter = nSpiltter; bC,M&<N  
>?uH#%C5  
@a7(*<".  
} K:Xrfn{s  
x4 A TK  
yz&q2  
public String getSSiteURL() IQ27FV|3  
{ O (sFs1  
return sSiteURL; 1x<rh\oo  
} =.=. \K  
\]d*h]Hms  
b~jvmcr  
public void setSSiteURL(String value) <LA`PbQa  
{ h-v &I>  
sSiteURL = value; |jCE9Ve#  
} 2w.9Q (Sn  
PezWc18  
9@&Z`b_  
public String getSFilePath() 0m| Gp  
{ xuH<=-O>ki  
return sFilePath; gQcr'[[a  
} Qak@~b  
5['B- Iw  
O|g!Y(  
public void setSFilePath(String value) <)*g7  
{ Q`wA"mw6k  
sFilePath = value; C?c-V,  
} p?gLW/n  
g)G7 kB/<p  
SO jDtZ  
public String getSFileName() HjY-b*B  
{ 7g<`w LAH  
return sFileName; {XUfxNDf  
} xo"4mbTV  
0bQiUcg/  
06W=(fY  
public void setSFileName(String value) K]]r OF  
{ nO7o7bc  
sFileName = value; (P!reYyM  
} #$z-]i  
n|`):sP  
J5_ qqD)  
public int getNSplitter() &CP@] pi9L  
{ .g`*cDW^=  
return nSplitter; :phD?\!w8t  
} %a6]gsiv2<  
JFk|Uqs(  
_q 9lr8hx  
public void setNSplitter(int nCount) QNI|h;D  
{ hO@v\@;r  
nSplitter = nCount; wyhf:!-I  
} y Q @=\'  
} EqDYQ 7  
u9^;~i,  
qQR YHo>/e  
/* *UxB`iA  
**Utility.java bOGDz|H``  
*/ Ch!Q?4  
package NetFox; g~["O!K3  
ifCGNvDR  
_"Ke=v_5  
public class Utility { XI(@O)  
=gv/9ce)3  
cj_?*  
public Utility() *A9{H>Vq  
{ +Y^F>/4=Y  
^znv[  
[(UqPd$  
} k{w^MOHNg  
)Is*- W  
//线程睡眠 64j 4P 7  
public static void sleep(int nSecond) ovoI~k'  
{ eii7pbc  
try{ m%(JRh  
Thread.sleep(nSecond); PC7.+;1  
} )Ua2x@j'C@  
catch(Exception e) z4+6k-#):  
{ p00Bgo  
e.printStackTrace (); v@s`l#  
} ;{7lc9uRj  
} @"7dk.|  
hGHzO  
//日志 ~u& O  
public static void log(String sMsg) m95$V&  
{ Q&'Nr3H#tZ  
System.err.println(sMsg); qtwmTT)  
} _~q^YZ  
rBPxGBd4  
_qo1 GM&  
public static void log(int sMsg) nt`l6b  
{ RSeezP6#  
System.err.println(sMsg); H 6<@  
} uvM8 8#  
} `B 0*/ml  
DL!s)5!M  
&-Y:4.BXZ  
/* 07Cuoqt2  
**TestMethod.java zate%y  
*/ zO]dQ$r\Z  
package NetFox; Q&a<9e&  
d~$t{46  
F5q1VEe  
public class TestMethod { OHvzK8  
df rr.i  
*4VP5]!  
public TestMethod() sjkl? _  
{ ///xx/weblogic60b2_win.exe g*AqFY7|  
try{ :6iq{XV^  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); !K)|e4$  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); sb5kexGxkc  
SiteFileFetch fileFetch = new SiteFileFetch(bean); PS]X Lz  
fileFetch.start(); X0=- {<W  
} <Y6>L};  
catch(Exception e){e.printStackTrace ();} \Rt  
41D[[Gh  
nu -wQr  
} NVPYv#uK  
y>1 8)8  
;BvWU\!  
public static void main(String[] args) =S +:qk  
{ .}>[ Kr  
new TestMethod(); >Cc$ P  
} z<=t3dj  
} #Og_q$})f  
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