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http断点续传简单实现(java)

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/* Nfv.v1Tt+  
**SiteFileFetch.java zt&"K0X|  
*/ 'W'['TV  
package NetFox; 9)P-<  
import java.io.*; d$DNiJ ,  
import java.net.*; jQ>~  
`"@Pr,L   
l9Xz,H   
public class SiteFileFetch extends Thread { MTI[Mez  
'M20v-[  
{`RCh]W  
SiteInfoBean siteInfoBean = null; //文件信息Bean py \KY R  
long[] nStartPos; //开始位置 ]#$l"ss,  
long[] nEndPos; //结束位置 |E]`rfr  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 73C7g< Mx  
long nFileLength; //文件长度 Fsdp"X.  
boolean bFirst = true; //是否第一次取文件 iO$Z?Dyg9  
boolean bStop = false; //停止标志 9 5cIdF 6m  
File tmpFile; //文件下载的临时信息 c+dmA(JC  
DataOutputStream output; //输出到文件的输出流 Z+p'3  
{X r|L  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) "XKcbdr8-  
public SiteFileFetch(SiteInfoBean bean) throws IOException $TU:iv1Fm  
{ Dx1f< A1  
siteInfoBean = bean; PMOyZ3  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); YCBp ]xuE  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); LIah'6qR  
if(tmpFile.exists ()) +K2p2Dw(k  
{ }N^3P0XjYq  
bFirst = false; 76IjM4&a  
read_nPos(); Nqy)jfyex  
} le7!:4/8  
else !+R_Z#gB  
{ r<)>k.] !  
nStartPos = new long[bean.getNSplitter()]; ][D/=-  
nEndPos = new long[bean.getNSplitter()]; V^S` d8?  
} G q&[T:  
)t?_3'W  
w'i8yl bZ  
{OIktG2gZ  
} {tKi8O^Rb  
%[l#S*)~  
:,8eM{.Q  
public void run() E]MyP=g$  
{ xZ\`f-zL  
//获得文件长度 w?JRY  
//分割文件 xZE%Gf_U  
//实例FileSplitterFetch aG*Mj;J  
//启动FileSplitterFetch线程 +uqP:z  
//等待子线程返回 F/ si =%  
try{ m)\wbkC  
if(bFirst) A?zxF5rfp  
{ 1yK=Yf%B  
nFileLength = getFileSize(); |'+ [ '  
if(nFileLength == -1) 1b` `y  
{ 6+.8nx:9X  
System.err.println("File Length is not known!"); *B*dWMh  
} |V dr/'  
else if(nFileLength == -2)  26[.te9  
{ _N1UL?  
System.err.println("File is not access!"); e0e3b]  
} Yn>y1~  
else &al\8  
{ 8GKqPS+  
for(int i=0;i<nStartPos.length;i++) nW"ml$  
{ g[D `.  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); b!l/O2 G  
} ,b${3*PPQ  
for(int i=0;i<nEndPos.length-1;i++) yv+DM`0  
{ X"fSM #  
nEndPos = nStartPos[i+1]; ;p8,=w  
} wK*b2r}0/  
nEndPos[nEndPos.length-1] = nFileLength; " ra C?H  
} ^2<nn op  
} z@tIC^s  
oc0z1u  
=JDa[_lpN  
//启动子线程 hcrx(oJ5  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; !fT3mI6u\  
for(int i=0;i<nStartPos.length;i++) )K>2  
{ I]jK]]@  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), S!{Kn ;@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), tLc~]G*\`s  
nStartPos,nEndPos,i); jHx)q|2\  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?S0gazZm  
fileSplitterFetch.start(); y^tp^  
} \?K>~{)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mEVne.D  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); g| M@/D l  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ^hIKDc!.m  
nEndPos = " + nFileLength); 4SGF8y@WU  
// fileSplitterFetch[nPos.length-1].start(); t=6Wk4  
SHt#%3EU  
8pE0ANbq  
//等待子线程结束 <f/wWu}  
//int count = 0; RxrUnMF  
//是否结束while循环 YA'_Ba(v)  
boolean breakWhile = false; jb {5   
w@Gk#  
h_?#.z0ih;  
while(!bStop) KGq4tlM6  
{ P6([[mmG  
write_nPos(); 3^%sz!jK+  
Utility.sleep(500); FK!UUy;  
breakWhile = true; )WR*8659e  
{WYmO1  
*JmU",X  
for(int i=0;i<nStartPos.length;i++) <Q%:c4N  
{ ?[~)D}] j  
if(!fileSplitterFetch.bDownOver) v>]^wH>/"  
{ N \Wd 0b  
breakWhile = false; W*D].|  
break; m<wEw-1.  
} B9Z=`c.T  
} ckg8x&Z  
if(breakWhile) `ek On@T0  
break; R`F8J}X_  
.|Bmg6g*  
[ Cu3D  
//count++; /{7we$+,p  
//if(count>4) AYLCdCoK.  
// siteStop(); ].,T Snb  
} /*2sg>e'QF  
@[] A&)B  
{V*OYYI`R  
System.err.println("文件下载结束!"); k w]m7 T  
} eH y.<VX  
catch(Exception e){e.printStackTrace ();} i<]Y0_?s  
} AG==A&d>$  
W;9Jah.  
%G>|u/:U  
//获得文件长度 k3FpD=N  
public long getFileSize() 0-{l4;o  
{ G*$a81dAX  
int nFileLength = -1; VtJy0OGcRP  
try{ t1h2ibO  
URL url = new URL(siteInfoBean.getSSiteURL()); TPeBb8v 8D  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {cF >, T  
httpConnection.setRequestProperty("User-Agent","NetFox"); OJH:k~]0!  
6"UL+$k  
dS[="Set  
int responseCode=httpConnection.getResponseCode(); xFcRp2W9R  
if(responseCode>=400) eS{ xma  
{ GOeYw[Vh  
processErrorCode(responseCode); U~Ai'1?xz  
return -2; //-2 represent access is error $={WtR  
} [va7+=[1=  
t<Z)D0.  
\p&a c&]  
String sHeader; $3C$])k  
UIl^s8/  
F< #!83*%  
for(int i=1;;i++) mp x/~`c  
{ Q(e3-a  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 0Q_@2  
//Utility.log(in.readLine()); al3[Ph5G  
sHeader=httpConnection.getHeaderFieldKey(i); nPj/C7j  
if(sHeader!=null) LpJ_HU7@lk  
{ $*u{i4b  
if(sHeader.equals("Content-Length")) <Gr775"  
{ }nW)+  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ,UD,)ZPf[  
break; ecI[lB  
} E*t0ia8  
} &_!g|-  
else bC mhlSNi  
break; aF'9&A;q  
} t,8p}2,$  
} tR]1c  
catch(IOException e){e.printStackTrace ();} # Y*cLN`Y7  
catch(Exception e){e.printStackTrace ();} jSj (ZU6  
}Pj3O~z  
1jhGshhp  
Utility.log(nFileLength); 1K;i/  
$*Q_3]AY]  
$K,6!FyBa  
return nFileLength; |5}~n"R5  
} q&-A}]  
V %cU @  
]v^;]0vcr  
//保存下载信息(文件指针位置) U/JeEI%L  
private void write_nPos() @zJhJ'~ Sl  
{ AjQ^ {P  
try{ M zLx2?  
output = new DataOutputStream(new FileOutputStream(tmpFile)); I2!0,1Q  
output.writeInt(nStartPos.length); 8'2lc  
for(int i=0;i<nStartPos.length;i++) PG1#Z?_  
{ s)e; c<(/  
// output.writeLong(nPos); 3-Q*umh  
output.writeLong(fileSplitterFetch.nStartPos); `aS9 o]t  
output.writeLong(fileSplitterFetch.nEndPos); g]g2`ab |  
} (zFUC]  
output.close(); V+()`>44  
} oj7X9~ nd  
catch(IOException e){e.printStackTrace ();} _`JY A  
catch(Exception e){e.printStackTrace ();} <h/\)bPB  
} oK GFDl]3  
jaAv_=93f  
U/B1/96lJ  
//读取保存的下载信息(文件指针位置) $rySz7NI  
private void read_nPos() ^;2dZgJ4^  
{ <N%8"o  
try{ \Mv8pU  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ;n*N9-|.  
int nCount = input.readInt(); O/IW.t  
nStartPos = new long[nCount]; qO<'_7TN[  
nEndPos = new long[nCount]; xy% lp{  
for(int i=0;i<nStartPos.length;i++) ua['rOnU  
{ dQ8}mH!  
nStartPos = input.readLong(); {.N" 6P  
nEndPos = input.readLong(); #lax0IYY=  
} #zcp!WE.OI  
input.close(); <%JRZYZ  
} ]]s_ 8u 3  
catch(IOException e){e.printStackTrace ();} X,/@#pSOz  
catch(Exception e){e.printStackTrace ();} xw5E!]~D  
} F6T@YSP  
bp6 La`+  
$a6&OH/  
private void processErrorCode(int nErrorCode) [)`9euR%  
{ *|x2"?d-F:  
System.err.println("Error Code : " + nErrorCode); -#b-@sD  
} -;z&">  
Q^v8n1  
*n0k2 p  
//停止文件下载 WT!8.M;Kv  
public void siteStop() #[*e$C  
{ FeS6>/  
bStop = true; -/aDq?<<  
for(int i=0;i<nStartPos.length;i++) /h0<0b?i  
fileSplitterFetch.splitterStop(); kRgyvA,*;  
{sy#&m(el  
g S;p::  
} u pf7:gk +  
} {MKq Yl{  
//负责部分文件的抓取 *g5df[  
**FileSplitterFetch.java lC6#EU;  
*/ J-fU,*Bk  
package NetFox; c7IgndVAV  
sHe:h XG'  
'?Q [.{<  
import java.io.*; &_&])V)<\S  
import java.net.*; `X]-blHo  
F'Fc)9qFa<  
WjGv%^?  
public class FileSplitterFetch extends Thread { J%xp1/= 2  
.9 WUp>  
|rf\]3 F  
String sURL; //File URL gtz!T2%  
long nStartPos; //File Snippet Start Position hX=+%^c%_A  
long nEndPos; //File Snippet End Position qJW>Y}  
int nThreadID; //Thread's ID DRi!WWivn  
boolean bDownOver = false; //Downing is over muo7KUT  
boolean bStop = false; //Stop identical 1uv"5`%s  
FileAccessI fileAccessI = null; //File Access interface hE!3kaS  
doXd6q4H  
E8>npDFv.  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 3l>P>[<o  
{ IqEY.2KN  
this.sURL = sURL; Tm_vo-   
this.nStartPos = nStart; f9D7T|J?10  
this.nEndPos = nEnd; \ +v_6F  
nThreadID = id; b0E(tPw5c  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "twV3R  
} @?K(+BGi  
>}<:5gZtA  
7%8,*T  
public void run() -z0,IYG }  
{ [j}%&$  
while(nStartPos < nEndPos && !bStop) ~SZ0Yu:X  
{ n<lU;  
wH!]B-hn  
8ne'x!1 D  
try{ _Ux>BJmP  
URL url = new URL(sURL); W1y,.6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); kOR%<#:J  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8pDJz_F!{  
String sProperty = "bytes="+nStartPos+"-"; .Rc&EO  
httpConnection.setRequestProperty("RANGE",sProperty); [O [ N_z  
Utility.log(sProperty); 4ej$)AdW3  
Qoq@=|7kxa  
g@nk0lQewj  
InputStream input = httpConnection.getInputStream(); + 7E6U*  
//logResponseHead(httpConnection); /D8cJgH-  
+zs;>'Sf  
<g,k[  
byte[] b = new byte[1024]; O(/K@e  
int nRead; 1WcT>_$  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) J~<:yBup}  
{ 4pq>R  
nStartPos += fileAccessI.write(b,0,nRead); ?Dm!;Z+7  
//if(nThreadID == 1) H:9( XW  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); DfV_08  
} wGISb\rr  
ffm19B=  
AGCqJ8`|T  
Utility.log("Thread " + nThreadID + " is over!"); RPaB4>  
bDownOver = true; m^T$H_*;  
//nPos = fileAccessI.write (b,0,nRead); 6Om-[^  
} Ko''G5+  
catch(Exception e){e.printStackTrace ();} FPFt3XL  
} <2H 0m  
} %DPtK)X1  
$j{ynh)^  
R) @ k|  
//打印回应的头信息 d-N<VVcy\  
public void logResponseHead(HttpURLConnection con) ])~*)I~Y  
{ Q6%m}R  
for(int i=1;;i++) K]kL?-A#'  
{ W .Hv2r3  
String header=con.getHeaderFieldKey(i); l*'jqR')h^  
if(header!=null) `?=AgGg  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); qg.[M*  
Utility.log(header+" : "+con.getHeaderField(header)); .Ji r<"*<  
else P$]Vb'Fz  
break; g-}Vu1w0{6  
} ,fET.s^|U  
} ,Z>RvLl  
_7$j>xX  
0yAvAx  
public void splitterStop() Jz:d\M~j5  
{ s977k2pp-  
bStop = true; lrq !}\aX  
} 2[M:WZ.1  
&g) `  
m(g$T  
} :?RK>}4|F  
S~Q7>oNm  
Z/beROW)  
/* wM!QU{Lz  
**FileAccess.java A| Y\Y}  
*//文件访问(定位,写) y62;&{?m  
package NetFox; ItOVx!"@9  
import java.io.*; 5QS d$J  
k92X)/ll'  
%WCpn<)  
public class FileAccessI implements Serializable{ |UR.7rOV  
8zVXQ!'  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 &]vd7Q.t  
RandomAccessFile oSavedFile; u3k+Xg:  
long nPos; XkdNWR0  
$AsM 9D<BE  
3\D jV2t  
public FileAccessI() throws IOException 5>A3;P  
{ iNQk{n  
this("",0); $(zJ  
} ZibHT:n  
j*xens$)  
`fc*/D  
public FileAccessI(String sName,long nPos) throws IOException &Puu Xz<  
{ fG,qax`:c  
oSavedFile = new RandomAccessFile(sName,"rw"); Vs07d,@w>  
this.nPos = nPos; PCaa _ 2  
oSavedFile.seek(nPos); C|!E' 8Rw  
} >Q+EqT  
|qbJ]v!  
k+i}U9c"  
public synchronized int write(byte[] b,int nStart,int nLen) NqF-[G<  
{ mup3ua]!  
int n = -1; h{PLyWH  
try{ /pb7  
oSavedFile.write(b,nStart,nLen); #Wc)wL-Tg  
n = nLen; bJBx~  
} 3`e1:`Hu  
catch(IOException e) `kj7I{'l%9  
{ Yhlk#>I  
e.printStackTrace (); &kO4^ A  
} Xq)'p8C?  
>nr1|2  
{g )kT_  
return n; :'!?dszS  
} cL1cBWd  
7<1Y%|x`  
4]dPhsey  
} m CdkYN#  
E&K8hY%5  
fp>o ^+VB  
/* CWDo_g $  
**SiteInfoBean.java %5z88-\  
*/ >eRbasshEI  
package NetFox; %pg*oX1VK6  
)m)>k` 0  
~RMOEH.o  
public class SiteInfoBean { Gu_s:cgB9F  
Y":hb;&  
VUt 6[~?  
private String sSiteURL; //Site's URL Qu;AU/Q<([  
private String sFilePath; //Saved File's Path G&n_vwZ%  
private String sFileName; //Saved File's Name 2qn~A0r  
private int nSplitter; //Count of Splited Downloading File _` D_0v(X  
KM\`,1?x92  
f%|g7[  
public SiteInfoBean() GuS3O)6Sg  
{//nSplitter的缺省值为5 .OWIlT4K  
//default value of nSplitter is 5 Jp,ohVRNq  
this("","","",5); Nm^q.)dO  
} { _ 1q`5o  
W&p-Z"=)  
j?8E >tM  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) _@RW7iP>  
{ c dGl[dQ/  
sSiteURL= sURL; 0 /H1INve  
sFilePath = sPath; 1zp,Suv  
sFileName = sName; }h]:I'R!  
this.nSplitter = nSpiltter; f,uxoAS  
9g*~X;`2  
{9=U6m^R2  
} Tw`l4S&  
Hv IN'  
p,1RRbyc  
public String getSSiteURL() GdP9Uj)n-  
{ tr'95'5W.  
return sSiteURL; mC93 &0  
} Q;^([39DI  
y-Ol1R3:c#  
hZJ Nh,,w  
public void setSSiteURL(String value) /3c1{%B\  
{ ^#Z(&/5f0  
sSiteURL = value; Em?skUnG,  
} /JfXK$`  
k1cBMDSokO  
#/1Bam6  
public String getSFilePath() DV.MvFV  
{ :?^(&3;  
return sFilePath; ~\kRW6  
} AV&eg e  
=AAH}  
dZYS5_wr  
public void setSFilePath(String value) +,KuYa{lu  
{ +X- k)9  
sFilePath = value; ![V<vIy  
} +0a',`yc  
p1D-Q7F  
!C+25vup  
public String getSFileName() Wx-{F  
{ J7maG|S(DF  
return sFileName; h*KhH>\  
} Ln: y|t  
Gs9jX/ #  
u*U?VZ5  
public void setSFileName(String value) !eO?75/  
{  m$cM+  
sFileName = value; }@#e D  
} dy0!Zz  
0b|!S/*A3  
O4#zsr:"  
public int getNSplitter() 5 QT9  
{ 8q0 .yhb  
return nSplitter; k+i=0 P0mf  
} -`gC?yff:  
 K A<  
H _2hr[  
public void setNSplitter(int nCount) <zUmcZ  
{ +GGj*sD  
nSplitter = nCount; 5eU/ [F9  
} !Zwl9DX3  
} Ue\&  
2V0R|YUt  
`2Z=Lp  
/* /bb4nM_E/  
**Utility.java }1>a71  
*/ WU\):n  
package NetFox; \\T I4A^#  
p 2i5/Ly  
b9vKux  
public class Utility { K0v,d~+]  
A< Na,EC  
-OHG1"/  
public Utility() /U`"|3  
{ fvx0]of  
V&>7i9lEz  
b6i0_fOO  
} E=B9FIx~<  
COT;KC6 n  
//线程睡眠 *?8Q:@:  
public static void sleep(int nSecond) b 9?w _  
{ 4VooU [Ka(  
try{ qzLRA.#f^  
Thread.sleep(nSecond); X}Csl~W8in  
} (0][hdI~B  
catch(Exception e) r9%W?fEBp  
{ _Nj;Ni2rD  
e.printStackTrace (); "K@os<  
} v ;9s  
} W,<Vr2J[  
7}#vANm  
//日志 r`krv-,O$  
public static void log(String sMsg) {P]l{W@li  
{ I;`V*/s8"  
System.err.println(sMsg); ALG #)$|  
} }cP 3i  
+j<Nu)0iY  
7OZ s~6(  
public static void log(int sMsg) =:2V4H(F  
{ 3)xV-Y9  
System.err.println(sMsg); -{w&ya4X  
} k-89(  
} wS5hXTb"  
Soa.thP  
Wm A:"!~M  
/* *7R3EUUk  
**TestMethod.java 5p>a]gp  
*/ z(]*'0)P  
package NetFox; %1 v)rg y  
(;n|>l?*  
@M,_mX  
public class TestMethod { 87HVD Di  
15zL,yo  
!At_^hSqz  
public TestMethod() o#T,vu0s  
{ ///xx/weblogic60b2_win.exe |9%>R*  
try{ "[8](3\v  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); $nVTN.k  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); V^0*S=N  
SiteFileFetch fileFetch = new SiteFileFetch(bean); $'&5gFr9  
fileFetch.start(); vxwctJ&  
} }:BF3cH> 0  
catch(Exception e){e.printStackTrace ();} USbiI %   
06ueE\@Sg  
)~5`A*Ku  
} $DMeUA\av  
/M#A[tZ3  
'*T7tl  
public static void main(String[] args) z><JbSE?  
{ E u@TCw8@  
new TestMethod(); >GjaA1,  
} hVlL"w*1  
} _W!g'HP-D  
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