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http断点续传简单实现(java)

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/* 7ukDS]  
**SiteFileFetch.java \>[gl!B_Rr  
*/ )/TVJAJ  
package NetFox; AI fk"2  
import java.io.*; w:R]!e_6\9  
import java.net.*; V'yxqI?  
oZvG3_H4.  
B}5XRgq  
public class SiteFileFetch extends Thread { ,CW%JIM  
L&HzN{K  
j&}B<f _6J  
SiteInfoBean siteInfoBean = null; //文件信息Bean ^V,@=QL3U  
long[] nStartPos; //开始位置 q_5 8Lw  
long[] nEndPos; //结束位置 3mA/Nu_  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Ib(,P3  
long nFileLength; //文件长度 !L$oAqW  
boolean bFirst = true; //是否第一次取文件 =0Y'f](2eW  
boolean bStop = false; //停止标志 <w11nB)  
File tmpFile; //文件下载的临时信息 ~$ WQ"~z  
DataOutputStream output; //输出到文件的输出流 | VRq$^g  
1 ' %-y  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) _ ^3@PM>  
public SiteFileFetch(SiteInfoBean bean) throws IOException KqY>4tb  
{ faJ8zX  
siteInfoBean = bean; Z{16S=0  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); bl9E&B/  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); G[B*TM6$  
if(tmpFile.exists ()) sp,(&Y]US  
{ A3!2"}L  
bFirst = false; 7x:F!0:  
read_nPos(); w`38DF@K  
} a!{hC)d*  
else .=aMjrME  
{ 3?6Ber y=  
nStartPos = new long[bean.getNSplitter()]; X)FQ%(H<  
nEndPos = new long[bean.getNSplitter()]; g&8.A(  
} W.sD2f  
,DQ >&_DK  
],#ZPUn  
Z~B+*HF  
} 1r&AB!Z #  
IT7:QEfKU  
l>33z_H^  
public void run() ";58B} ki  
{ $o: :PDQ?  
//获得文件长度 w7[0  
//分割文件 zkvH=wL  
//实例FileSplitterFetch :4b- sg#  
//启动FileSplitterFetch线程 m R"9&wq  
//等待子线程返回  2fbvU  
try{ LDSbd,GF  
if(bFirst) /XC;.dLA#  
{ aGe\.A=  
nFileLength = getFileSize(); Pyit87h{  
if(nFileLength == -1) 2}1!WIin  
{ |oB]6VS`  
System.err.println("File Length is not known!"); [kQ"6wh8  
} SwQOFE/Dv~  
else if(nFileLength == -2) @V*au:  
{ U@MOvW)  
System.err.println("File is not access!"); $Jt8d|UP  
} | eK,Td%  
else ~MD><w>  
{ lp 3(&p<:  
for(int i=0;i<nStartPos.length;i++) @)8NI[=6O  
{ ZlUFJ*pk  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); I\)N\mov e  
} +# A|Zp<  
for(int i=0;i<nEndPos.length-1;i++) jh-kCF  
{ <:H  
nEndPos = nStartPos[i+1]; X@G[=Rs  
} ZO]E@?Oav  
nEndPos[nEndPos.length-1] = nFileLength; | H5Ync[s  
} _p?I{1O  
} 3<yCe%I:  
ggzAU6J  
P'KY.TjWb  
//启动子线程 XWJ0=t&}  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; _y.mpX&  
for(int i=0;i<nStartPos.length;i++) Ni/|C19Z  
{ jAsh   
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), vQE` c@^{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), .kz(V5  
nStartPos,nEndPos,i); (p}9^Y  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :a#|  
fileSplitterFetch.start(); #zh6=.,7  
} DWHOS XA4  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), S;G"L$&\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 75' Ua$  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ;g!xQvcR  
nEndPos = " + nFileLength); 8Fyc#Xo8  
// fileSplitterFetch[nPos.length-1].start(); B>c[Zg1  
](idf(j  
99=[>Ck)G  
//等待子线程结束 GA}hp%  
//int count = 0; kjQIagw  
//是否结束while循环 })Ix .!p  
boolean breakWhile = false; eU<]h>2  
w/)e2CH  
;w>Q{z  
while(!bStop) !^rITiy  
{ gt(X!iN]  
write_nPos(); Ss*Lg K_  
Utility.sleep(500); m(Pz7U.Q  
breakWhile = true; 3g4vpKg6c  
*=r@vQ  
O p!  
for(int i=0;i<nStartPos.length;i++) <<~lV5  
{ ^*j[&:d  
if(!fileSplitterFetch.bDownOver) j58Dki->.  
{ PkZf(=-X  
breakWhile = false; 6T5A31 Q  
break; {3_Ffsg`  
} fwz5{>ON]  
} CYY X\^hA  
if(breakWhile) 7cJO)cm0'  
break; !c3Qcva  
vgd}09y  
woC FN1W  
//count++; mRix0XBI~  
//if(count>4) e\+~  
// siteStop(); wt3Z?Pb  
} T/X?ZK(T  
3(XHF3q  
[v>Z(  
System.err.println("文件下载结束!"); S:"z<O  
} Vb"T],N1m  
catch(Exception e){e.printStackTrace ();} N P0Hgd  
} k1@  A'n  
wjw<@A9  
l=<F1Lz  
//获得文件长度 R  oF  
public long getFileSize() , .NG.Q4f  
{ N23+1h  
int nFileLength = -1; B[2h   
try{ _ cHV3cz  
URL url = new URL(siteInfoBean.getSSiteURL()); Dg];(c+/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 96([V|5K  
httpConnection.setRequestProperty("User-Agent","NetFox"); h<!khWFS  
e2_r0I^C  
%$!R]B)  
int responseCode=httpConnection.getResponseCode(); 9Le/'ovq  
if(responseCode>=400) n8y,{|  
{ R-0_226  
processErrorCode(responseCode); 071E%u,  
return -2; //-2 represent access is error xhp-4  
} 6O[wVaC1u  
C$]%1<-Iv]  
,sQ0atk7ma  
String sHeader; Ra15d^  
o 0cc+  
H8Z Z@@ qm  
for(int i=1;;i++) d~xU?)n)  
{ LbmB([p  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); wb}N-8x  
//Utility.log(in.readLine()); cxF?&0[mY  
sHeader=httpConnection.getHeaderFieldKey(i); UVQa af  
if(sHeader!=null) %RK\Hz2q3  
{ k(vEp ]  
if(sHeader.equals("Content-Length")) o )}<   
{ ytcG6WN3  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader));  el*pYI  
break; W> -E.#!_  
}  6@Z'fT4  
} s5Bmv\e.i5  
else j@_) F^12  
break; W;)FNP|MT  
} @{$Cv"6769  
} \Z7([Gh  
catch(IOException e){e.printStackTrace ();} o\:f9JL  
catch(Exception e){e.printStackTrace ();} =-s20mdj  
(fI&(";t  
U!-+v:SF  
Utility.log(nFileLength); "3>*i!i  
3I{ta/(  
)su <Ji*  
return nFileLength; /B#lju!  
} *~lgU4  
K {1ZaEH  
>[P7Zlwv4  
//保存下载信息(文件指针位置) ws=9u-  
private void write_nPos() p9] 7g%  
{ 2ZzD^:V[}  
try{ t5B|c<Hb\  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 7)6Yfa]I%  
output.writeInt(nStartPos.length); [E :`jY  
for(int i=0;i<nStartPos.length;i++) h9OL%n 7m'  
{ Gk]qE]hi  
// output.writeLong(nPos); E( 4lu%  
output.writeLong(fileSplitterFetch.nStartPos); qzbkxQu]g  
output.writeLong(fileSplitterFetch.nEndPos); ?GD? J(S  
} gp&& c,  
output.close(); Hk~ gcG  
} :`"T Eif  
catch(IOException e){e.printStackTrace ();} +` Y ?-  
catch(Exception e){e.printStackTrace ();} Ev|{~U  
} EwBN+v;)  
=rO>b{,hs  
P@S;>t{TD  
//读取保存的下载信息(文件指针位置) 8KELN(o$ 7  
private void read_nPos() r/$)c_x`  
{ 22|M{  
try{ LXfeXWw?,  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ';CuJ XAj  
int nCount = input.readInt(); i7!mMO8]  
nStartPos = new long[nCount]; Y" +1,?yH  
nEndPos = new long[nCount]; g!) LhE  
for(int i=0;i<nStartPos.length;i++) 08n%% F  
{ P)j9\ muc  
nStartPos = input.readLong(); zhm!sMlO  
nEndPos = input.readLong(); MfpWow-#{  
} V1b_z  
input.close(); O> ^~SO  
} D>#v 6XI  
catch(IOException e){e.printStackTrace ();} VOK$;s'9}  
catch(Exception e){e.printStackTrace ();} f;XsShxr  
} \t(r@q q  
f]6` GsE  
[W|7r n,q  
private void processErrorCode(int nErrorCode) bz@=zLBt  
{ 7'/2:"  
System.err.println("Error Code : " + nErrorCode); WUK.>eM0  
} A%8`zR  
l|tp0[  
&*:)5F5  
//停止文件下载 7LZb*+>  
public void siteStop() y<x_v )k-  
{ JO6vzoS3  
bStop = true; C`T5d  
for(int i=0;i<nStartPos.length;i++) h/bYtE  
fileSplitterFetch.splitterStop(); ?UhAjtYIS  
|iJZC  
}/}`onRZ  
} eHyuO)(xH1  
} h+u|MdOY\  
//负责部分文件的抓取 ez:o9)N4  
**FileSplitterFetch.java y^|3]G3  
*/ j%y+W{Q[  
package NetFox; hA1hE?c`  
vc{]c }  
f I-"8f0_  
import java.io.*; l'lDzB+.*  
import java.net.*; #_L&  
#cF8)GC  
.lj!~_  
public class FileSplitterFetch extends Thread { G]DN!7]@g  
 eV=sDx  
./*,Thc  
String sURL; //File URL >Pd23TsN  
long nStartPos; //File Snippet Start Position T:~W.3  
long nEndPos; //File Snippet End Position  (mD:[|.  
int nThreadID; //Thread's ID tsC|R~wW  
boolean bDownOver = false; //Downing is over eKti+n.  
boolean bStop = false; //Stop identical 2DqHqq9m  
FileAccessI fileAccessI = null; //File Access interface 5$Q`P',*Ua  
%c2i.E/G  
" /-v 9  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException x[@3;_'K  
{ QAnfxt6  
this.sURL = sURL; R/xCS.yl}  
this.nStartPos = nStart; {Qmb!`F  
this.nEndPos = nEnd; uqeWdj*Y  
nThreadID = id; [Et\~'2w8=  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 k)' z<EL6c  
} CIvT5^}  
7Bd_/A($  
'R5l =Wf  
public void run() nln[V$   
{ HZ4 ^T7G  
while(nStartPos < nEndPos && !bStop) _7H J'  
{ OiEaVPSI;  
`rJ ~*7-  
ly5L-=Xb  
try{ M@[gT?m v1  
URL url = new URL(sURL); $ rnr;V  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); q8v!{Os+#  
httpConnection.setRequestProperty("User-Agent","NetFox"); Guc^gq}  
String sProperty = "bytes="+nStartPos+"-"; /j\TmcnU^  
httpConnection.setRequestProperty("RANGE",sProperty); {#Cm> @')  
Utility.log(sProperty); /[dAgxL  
E004"E<E  
8_$2aqr  
InputStream input = httpConnection.getInputStream(); k8>^dZub  
//logResponseHead(httpConnection); J0bs$  
\)kAhKtG  
~'\u:Imuo  
byte[] b = new byte[1024]; gy`qEY~B&  
int nRead; HW,55#yG  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) JY8pV+q @=  
{ ]h$TgX  
nStartPos += fileAccessI.write(b,0,nRead); p5t#d)  
//if(nThreadID == 1) w.- i !Ls  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); h!%`odl%  
} v!C+W$,T  
Gw,kC{:C  
o[6"XJ  
Utility.log("Thread " + nThreadID + " is over!"); XYTcG;_z  
bDownOver = true; HhH'\-[t  
//nPos = fileAccessI.write (b,0,nRead); D+PUi!  
}  Jl,x~d  
catch(Exception e){e.printStackTrace ();} XKIJ6M~5k  
} DdBr Jx  
} >G7U7R}R  
S6Pb V}  
..mz!:Zs0  
//打印回应的头信息 _J;a[Ky+[  
public void logResponseHead(HttpURLConnection con) Hf|:A(vCx  
{ w2AWdO6  
for(int i=1;;i++) R;2 -/MT-  
{ 7Wn]l!  
String header=con.getHeaderFieldKey(i); r5wXuA,Um  
if(header!=null) %z(=GcWm  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); X/749"23  
Utility.log(header+" : "+con.getHeaderField(header)); 7s3<}  
else Nuq/_x  
break; W)O'( D  
} 6E4L4Vb  
} JwVv+9hh  
th|Q NG  
aX:$Q }S  
public void splitterStop() 6* w;xf  
{ w Vmy`OV/  
bStop = true; nzDY!Y  
} mn` Ae=  
HEN9D/O=  
U %l{>*q  
} . C?gnOq  
,r4af<  
a@1gMZc*  
/* `r Ql{$9IC  
**FileAccess.java ? GW3E  
*//文件访问(定位,写) m!(K  
package NetFox; +R$KEGu~0Y  
import java.io.*; Ne_>%P|I_  
')<$AMy1  
xy>mM"DOH  
public class FileAccessI implements Serializable{ FFGTIT# {"  
(^\i(cfu6Q  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 '5\1uB PKW  
RandomAccessFile oSavedFile; +[+ Jd)Z  
long nPos; _Z&R'`kg  
;_*F [ }w  
K)OlCpHc  
public FileAccessI() throws IOException %Kp}Wo6  
{ (FHh,y~v  
this("",0); )cXc"aj@s  
} z>~3*a9&  
krU2S-  
|{Q,,<C  
public FileAccessI(String sName,long nPos) throws IOException Gx)D~7lz  
{ P]GGnT(!  
oSavedFile = new RandomAccessFile(sName,"rw"); ]f?LQCTq<b  
this.nPos = nPos; 0g\&3EvD  
oSavedFile.seek(nPos); .EQFHStr  
} ln7.>.F  
Fjb[Ev  
d-aF-  
public synchronized int write(byte[] b,int nStart,int nLen) mH"`46  
{ Q<qIlNE  
int n = -1; @hPbD?)M  
try{ Ja1*a,],L  
oSavedFile.write(b,nStart,nLen); mHy]$Z  
n = nLen; 2BY:qz%:  
} lhU#/}Z  
catch(IOException e) &D#v0!e~x  
{ X(9Ff=0.~  
e.printStackTrace (); KNhH4K2iP8  
} DGnswN%n1  
lLv0lf  
xB#E&}Ho  
return n; cAS5&T<  
} HS7!O  
EC0auB7G  
r{_'2Z_i  
} <[bDNe["?  
I\_R& v  
;z#9>99rH  
/* YX(%jcj*  
**SiteInfoBean.java ~S9nLb:O{  
*/ C Qebb:y  
package NetFox; |%}?*|-  
4=Zlsp  
(Lp-3Xx  
public class SiteInfoBean { JQqDUd  
%oo&M;  
{T9g\F*  
private String sSiteURL; //Site's URL kMA>)\  
private String sFilePath; //Saved File's Path U Lq%,ca  
private String sFileName; //Saved File's Name RfD$@q9  
private int nSplitter; //Count of Splited Downloading File Y~6pJNR  
gE&f}M-  
E:ytdaiT  
public SiteInfoBean() `}bUf epMJ  
{//nSplitter的缺省值为5 ?l/rg6mbI'  
//default value of nSplitter is 5 x?kZD~|{)  
this("","","",5); uH#NJoR O  
} ZI1RB fR  
h;6@-\6  
ntT| G0E  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Q.Acmht#  
{  T-\,r  
sSiteURL= sURL; gM8eO-d  
sFilePath = sPath; c8u0\X,  
sFileName = sName; >,v~,<3 i  
this.nSplitter = nSpiltter; 1NTe@r!y  
U7W ct %  
6!$S1z#wM  
} C{D2mSS  
4}CRM# W2  
.&Z Vy{uP  
public String getSSiteURL() {:Q2Itsy  
{ |Yx8Ez  
return sSiteURL; :1iw_GhJf  
} @P-7a`3*  
A28w/ =e7  
3O.-'U1K  
public void setSSiteURL(String value) khR3[ju{^  
{ I'gnw~  
sSiteURL = value; "~ /3  
} \yqiv"'  
;Cwn1N9S  
gOkO8P6P8  
public String getSFilePath() WXM_H0K  
{ #df43_u  
return sFilePath; \=@}(<4  
} QqDF_  
Wi[Y@  
ru&RL HFV  
public void setSFilePath(String value) !"kvXxp^  
{ Fri5_rxLl  
sFilePath = value; lbPxZ'YO#  
} TcC=_je460  
9#p^Z)[)-  
_FV.}%W<u  
public String getSFileName() Rm RV8 WJ6  
{ ;r y{cq  
return sFileName; H|^4e   
} +SJ aE] $  
%[0"[<1a  
#yqcUbJY0R  
public void setSFileName(String value) bY<"$);s  
{ jC oZm(bi  
sFileName = value; M;E&@[5  
} I9MI}0}7  
%nIjRmqM~  
t!k 0n&P  
public int getNSplitter() 9we=aX5  
{ rEViw?^KT  
return nSplitter; S.I<Hs  
} <[q)2 5RL  
A-~)7-  
gp}S 1  
public void setNSplitter(int nCount) oH;Y}h  
{ #\jPBLc  
nSplitter = nCount; H0Tt(:.&  
} T&c[m!}X|t  
} 7+c@pEU]  
r'8e"pTi  
4e:hKv,+4  
/* Wj3H  y4  
**Utility.java A;g[G>J  
*/ pSAXp# g  
package NetFox; B<)(7GTv7"  
8dpVB#]pp,  
-&&mkK B!  
public class Utility { P)H%dJ ^l  
TQ BL!w  
WlY%f}l n  
public Utility() lRrOoON  
{ V6!oe^a7'  
; R67a V,  
^,X+ n5q;m  
} >ko;CQR  
/i]Gg \)  
//线程睡眠 eI[z%j[Y*  
public static void sleep(int nSecond) NZ_45/(dx  
{ 4M:oa#gh@  
try{ a}fW3+>  
Thread.sleep(nSecond); <sTa Xaq?  
} T4UY%E!0  
catch(Exception e) Y}Ov`ZM!r  
{ &8(2U-  
e.printStackTrace (); G0^PnE0-  
} f ZISwr  
} _E~uuFMn*R  
OS!47Z /q  
//日志 ]/a?:24[  
public static void log(String sMsg) ^cY5!W.q8  
{ c(~M<nL0  
System.err.println(sMsg); 5E%W;$3Pb  
} HiWZ?G  
:\>UZ9h #  
o;O_N^_W  
public static void log(int sMsg) B<o i,S  
{ Ywni2-)<  
System.err.println(sMsg); 3w-0v"j U  
} mF_/Rhu  
} $q+7 ,,"  
snK/,lm.  
[Nq4<NK  
/* H95VU"  
**TestMethod.java hIdGQKr>V  
*/ 9KP+  
package NetFox; x&f?c=\F  
> 1r>cZn  
7#RW4ZM  
public class TestMethod { Ghj6&K%b0  
,^'Y7"  
KLxg  
public TestMethod() wCdUYgsPT"  
{ ///xx/weblogic60b2_win.exe ubgq8@;  
try{ "XH]B  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); hP|5q&wX  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?GFVV->i  
SiteFileFetch fileFetch = new SiteFileFetch(bean); -wO`o<  
fileFetch.start(); # ><.zZ  
} Ao,lEjNI  
catch(Exception e){e.printStackTrace ();} {!,+C0  
='mqfGRi>  
k'{lo _  
} u-?&~WA  
a E#s#Kv   
=e4,)Wd9&  
public static void main(String[] args) ve>8vw2  
{ Ar\`OhR  
new TestMethod(); #3qkG)  
} {u!,TDt*  
} g'IS8@  
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