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http断点续传简单实现(java)

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/* x6iT"\MO  
**SiteFileFetch.java #U ?=D/  
*/ U#gv ~)\k  
package NetFox; D//uwom  
import java.io.*; gZ 6Hj62D  
import java.net.*; ,!I'0x1OR  
Y(97},  
i-W!`1LH'  
public class SiteFileFetch extends Thread { 6$'0^Ftm'  
Qh{]gw-6  
".|?A9m_  
SiteInfoBean siteInfoBean = null; //文件信息Bean  XKEbK\  
long[] nStartPos; //开始位置 hcrx(oJ5  
long[] nEndPos; //结束位置 w=}R'O;k  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 PvkHlb^x%  
long nFileLength; //文件长度 4+2hj*I  
boolean bFirst = true; //是否第一次取文件  Z5[f  
boolean bStop = false; //停止标志 %:=Jr#a  
File tmpFile; //文件下载的临时信息 S!{Kn ;@  
DataOutputStream output; //输出到文件的输出流 tLc~]G*\`s  
jHx)q|2\  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ?S0gazZm  
public SiteFileFetch(SiteInfoBean bean) throws IOException 48W-Tf6v|  
{ 5#}wI~U;  
siteInfoBean = bean; $?Yw{%W  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); A6AIkKjzq  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ffibS0aM  
if(tmpFile.exists ()) `7o(CcF6H  
{ yq,% ey8  
bFirst = false; )u}MyFl.  
read_nPos(); !vwx0  
} d_!l RQ^N  
else ,].S~6IM  
{ RXWS,rF  
nStartPos = new long[bean.getNSplitter()]; oP`yBX  
nEndPos = new long[bean.getNSplitter()]; \-scGemH  
} uJ_"gPO  
@;T?R  
1Zi(5S)  
W:XN!  
} 6( ~DS9  
nq3B(  
99mo]1_  
public void run() 7nOn^f D  
{ AOVoOd+6  
//获得文件长度 A_}%YHb  
//分割文件 Jz Z9ua  
//实例FileSplitterFetch B_uAa5'  
//启动FileSplitterFetch线程 oHj64fE9  
//等待子线程返回 U.0bbr  
try{ \[5mBuk  
if(bFirst) Ymr\8CG/  
{ >x 6$F*:W}  
nFileLength = getFileSize(); K" U!SWv  
if(nFileLength == -1) a8[Q1Fa4|  
{ DUOSL  
System.err.println("File Length is not known!"); TU,k( `tn<  
} =S|^pN  
else if(nFileLength == -2) Kj`sq":Je0  
{ o7#Mr`6H  
System.err.println("File is not access!"); S&w(H'4N  
} 8QaF(?  
else AXOR<Ns`  
{ @[] A&)B  
for(int i=0;i<nStartPos.length;i++) cc|"^-j-7  
{ Ze>Pg.k+  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 'RjMwJy{  
} M~ ^ {S[o  
for(int i=0;i<nEndPos.length-1;i++) ZPolE_P7  
{ JJn+H&[B  
nEndPos = nStartPos[i+1]; 7IV:X _y  
} 9e xHR&>{  
nEndPos[nEndPos.length-1] = nFileLength; i@|.1dWh  
} xgQ]#{ tG  
} KJLK]lf}d  
ko<iG]Dv'  
-ip fGb  
//启动子线程 zMI0W&P M  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ( O>oN~  
for(int i=0;i<nStartPos.length;i++) OJH:k~]0!  
{ eODprFkt}  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^68BxYUoD\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), c?1 :='MC  
nStartPos,nEndPos,i); xw%'R-  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %hqhi@q#  
fileSplitterFetch.start(); NA`EG,2  
} xK8R![x  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), S3(2.c~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); >|e>=  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", t<Z)D0.  
nEndPos = " + nFileLength); \p&a c&]  
// fileSplitterFetch[nPos.length-1].start(); }:5>1FfX=  
;*8nd-\  
!Ho=(6V  
//等待子线程结束 mp x/~`c  
//int count = 0; Q(e3-a  
//是否结束while循环 0Q_@2  
boolean breakWhile = false; al3[Ph5G  
nPj/C7j  
L beMP  
while(!bStop) 0- 'f1 1S  
{ ,B<Tt|'  
write_nPos(); &3;yho8v@  
Utility.sleep(500); G$buZspL'd  
breakWhile = true; 389puDjy  
`*1059   
^9Je8 @Yu  
for(int i=0;i<nStartPos.length;i++) "[LSDE"(  
{ VC6S4FU4K  
if(!fileSplitterFetch.bDownOver) @$(/6]4p  
{ +yYv"J  
breakWhile = false; 8'kA",P  
break; &2!F:L  
} .7nr:P  
} &$ ?i  
if(breakWhile) "w\Iz]  
break; ]GS@ub  
.2jG~_W[  
pSq3\#Twr  
//count++; #^bkM)pc  
//if(count>4) [@qUQ,Ie  
// siteStop(); bh8IF,@a  
} 32f lOi:  
Odo"S;)  
')ErXLP_  
System.err.println("文件下载结束!"); &dV|~xA6N  
} FB0y  
catch(Exception e){e.printStackTrace ();} I2!0,1Q  
} Yz?1]<X  
1/bu}?a  
mYudUn4Wo  
//获得文件长度 c9dH ^t  
public long getFileSize() ~la=rh3  
{ Wh,{|R[  
int nFileLength = -1; :q2tda  
try{ cJ%u&2J_  
URL url = new URL(siteInfoBean.getSSiteURL()); .+H8c.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ='7n  
httpConnection.setRequestProperty("User-Agent","NetFox"); USnKj_e  
.bm#|X)RO  
<9S?wju4W'  
int responseCode=httpConnection.getResponseCode(); KJwkkCE/=  
if(responseCode>=400) I]`>m3SJ  
{ ~[i,f0O,  
processErrorCode(responseCode); z:aT5D  
return -2; //-2 represent access is error COw]1 R  
} 9 GdrJ~h  
S!GjCog^J  
'U)|m  
String sHeader; *XmOWV2Y_  
+|OkT  
Bu'PDy~W,  
for(int i=1;;i++) / 4K*iq  
{ 3:rH1vG.m  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); j/bebR}X  
//Utility.log(in.readLine()); sBuVm<H  
sHeader=httpConnection.getHeaderFieldKey(i); F*QD\sG:  
if(sHeader!=null) sX3Vr&r  
{ j~G^J  
if(sHeader.equals("Content-Length")) F6T@YSP  
{ bp6 La`+  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); $a6&OH/  
break; @NXGVmY1}  
} $J #}3;a  
} \<VwGbzFi  
else ?S8cl7;+  
break; Y962rZ  
} j\nnx8`7  
} RGGP6SDc  
catch(IOException e){e.printStackTrace ();} &50Kn[  
catch(Exception e){e.printStackTrace ();} )S$!36Ni[  
E0c5c  
}TRr*] P<%  
Utility.log(nFileLength); W|T"'M_  
.ukP)rGe  
[&rW+/  
return nFileLength; 0>-l {4srs  
} l%"eQ   
`}F=Zjy  
0+O)~>v  
//保存下载信息(文件指针位置) J-fU,*Bk  
private void write_nPos() c7IgndVAV  
{ jow^~   
try{ \PzC:H  
output = new DataOutputStream(new FileOutputStream(tmpFile)); &_&])V)<\S  
output.writeInt(nStartPos.length); `X]-blHo  
for(int i=0;i<nStartPos.length;i++) F'Fc)9qFa<  
{ WjGv%^?  
// output.writeLong(nPos); J%xp1/= 2  
output.writeLong(fileSplitterFetch.nStartPos); .9 WUp>  
output.writeLong(fileSplitterFetch.nEndPos); |rf\]3 F  
} ~aH*ZA*f  
output.close(); 5/mW:G,&  
} "HVwm>qEi  
catch(IOException e){e.printStackTrace ();} pi5Al)0  
catch(Exception e){e.printStackTrace ();} SGH"m/ e  
} ?M7nbfy[A@  
V0L^pDLOV  
"8Pxf=   
//读取保存的下载信息(文件指针位置) U;KHF{Vm  
private void read_nPos() j2#Vdw|j  
{ qo.~5   
try{ 6(oGU4  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); L5cNCWpo  
int nCount = input.readInt(); y]?%2ud/=  
nStartPos = new long[nCount]; 9L?EhDcDV  
nEndPos = new long[nCount]; <l5{!g  
for(int i=0;i<nStartPos.length;i++) &P!^k0NJR  
{ p&_a kQj  
nStartPos = input.readLong(); 0(3t#  
nEndPos = input.readLong(); G4s!q1H  
} *E .{i   
input.close(); (EU X>IJ  
} K;-:C9@  
catch(IOException e){e.printStackTrace ();} YFLWkdqAY  
catch(Exception e){e.printStackTrace ();} -MHu BgYJ-  
} gSu+]N  
.gT@_.ZD9  
e\.|d<N?  
private void processErrorCode(int nErrorCode) pZGs o  
{ 5cyl:1Ln  
System.err.println("Error Code : " + nErrorCode); .4F(Y_c  
} t2+m7*76  
nI.#A  
rN{&$+"2  
//停止文件下载 #>~$`Sg  
public void siteStop() h&yaug,.  
{ Y*f7& '[  
bStop = true; >K-O2dry*  
for(int i=0;i<nStartPos.length;i++) %9BC%w]y  
fileSplitterFetch.splitterStop(); C-_u; NEu  
#B'WT{B$/~  
zv#i\8h^p  
} &66G  
} uz Z|w+3O  
//负责部分文件的抓取 GWA_,/jS%  
**FileSplitterFetch.java fylW)W4C  
*/ |fTQ\q]W  
package NetFox; r9s1\7]x  
V}9wx%v  
\s<iM2]Kl  
import java.io.*; G~4^`[elB  
import java.net.*; X.Z?Ie  
v_5DeaMF'  
":"M/v%F  
public class FileSplitterFetch extends Thread { sNX$ =<E  
R,Tw0@{O*  
,3GM'e{hV  
String sURL; //File URL $j{ynh)^  
long nStartPos; //File Snippet Start Position R) @ k|  
long nEndPos; //File Snippet End Position d-N<VVcy\  
int nThreadID; //Thread's ID ])~*)I~Y  
boolean bDownOver = false; //Downing is over Q6%m}R  
boolean bStop = false; //Stop identical K]kL?-A#'  
FileAccessI fileAccessI = null; //File Access interface )CdglPK  
O:lD>A4{  
f 21w`Uk48  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1 ,D2][  
{ "!Mu5Ga  
this.sURL = sURL; uaJ5'*  
this.nStartPos = nStart; A7|"0*62  
this.nEndPos = nEnd; #wM0p:<  
nThreadID = id; .D4 D!!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 $!obpZ~}  
} v l{hE~  
o{UwUMw5`  
3O#7OL68v  
public void run() 4sZ^:h,1  
{ >454Yir0Mk  
while(nStartPos < nEndPos && !bStop) T| 4c\  
{ L?9Vz&8]  
m> NRIEA6  
s|,gn5  
try{ X[Y!=e4z  
URL url = new URL(sURL); ]vT  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); fRrHWE+  
httpConnection.setRequestProperty("User-Agent","NetFox"); XJ@ /r,2  
String sProperty = "bytes="+nStartPos+"-"; fEQ<L!'  
httpConnection.setRequestProperty("RANGE",sProperty); !0Q(x  
Utility.log(sProperty); k92X)/ll'  
C(,s_Ks  
um3 M4>K  
InputStream input = httpConnection.getInputStream(); o"n^zG  
//logResponseHead(httpConnection); -Qn:6M>w^  
0^[ " &K/  
YuPgsJ[m  
byte[] b = new byte[1024]; *[yCcqN.  
int nRead; YT:<AJm  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) qU2>V  
{ C 7+TnJ  
nStartPos += fileAccessI.write(b,0,nRead); k9R1E/;  
//if(nThreadID == 1) 1Tiq2+hmf  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); pd7FU~-  
} >Q5 SJZ/  
]E=JUYf0  
oTx#e[8f{  
Utility.log("Thread " + nThreadID + " is over!"); lc5NC;JR  
bDownOver = true; aL=VNZ!Pqc  
//nPos = fileAccessI.write (b,0,nRead); a-QHm;_S  
} o@pM??&x  
catch(Exception e){e.printStackTrace ();} Rut6m5>  
} / m?Z!  
} j/Bzbjq"  
5@Py`  
Nr(WbD[T  
//打印回应的头信息 8sbS7*#  
public void logResponseHead(HttpURLConnection con) m,up37-{  
{ %eT/:I  
for(int i=1;;i++) x!YfZ*  
{ qHHWe<}OT  
String header=con.getHeaderFieldKey(i); ,vN#U&RS  
if(header!=null) ( I,V+v+{Y  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;H\,w /E9  
Utility.log(header+" : "+con.getHeaderField(header)); #d|.BxH  
else 1^Caz-  
break; d[$1:V  
} ^R<= }  
} y"9TS,lmK  
9Hc#[Ml  
9MXauTKI  
public void splitterStop() C)ChF`Ru':  
{ w[|!$J?  
bStop = true; 1m ![;Pg3  
} ' GW@P  
#x%O0  
{UPIdQ'g  
} HQUL?URt  
41C=O@9m  
?xG #4P<C=  
/* OdR  
**FileAccess.java MPGQ4vi&  
*//文件访问(定位,写) 7rr5$,Mv  
package NetFox; ZjI^0D8  
import java.io.*; <XLATS8Y  
|Xu7cCh$me  
]\3dJ^q|%  
public class FileAccessI implements Serializable{ iySmNI  
;hZ(20  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ~;`i&s  
RandomAccessFile oSavedFile; BM3)`40[]  
long nPos; Jhut>8  
XM=`(e o  
nwkhGQ  
public FileAccessI() throws IOException P4N{lQ.>  
{ oNEU?+  
this("",0); ] 2b@mX  
} ?3z x?>sG  
4l3N#U0Q  
twN(]w}Ps|  
public FileAccessI(String sName,long nPos) throws IOException CRqa[boU*  
{ MBwp{ET!p  
oSavedFile = new RandomAccessFile(sName,"rw"); Fvv6<E  
this.nPos = nPos; XSD7~X/:  
oSavedFile.seek(nPos); Xg%zE  
} 2]C0d8=*?  
j<gnh  
#pVk%5N  
public synchronized int write(byte[] b,int nStart,int nLen) >5N}ZIN  
{ iL\\JuY  
int n = -1; >i ~zG6H  
try{ Y}WO`+Vf5  
oSavedFile.write(b,nStart,nLen); Lh,<q >t  
n = nLen; Jq; }q63:  
} /y-P) 3_  
catch(IOException e) X:!%"K%}  
{ "xO`&a{  
e.printStackTrace (); VtmUK$k}I  
} [ z&y]~  
}0!\%7-Q  
8t7hN?,t  
return n; AV&eg e  
} =AAH}  
nv8,O=#s  
+,KuYa{lu  
} +X- k)9  
![V<vIy  
+0a',`yc  
/* p1D-Q7F  
**SiteInfoBean.java !C+25vup  
*/ Wx-{F  
package NetFox; J7maG|S(DF  
h*KhH>\  
Ln: y|t  
public class SiteInfoBean { Gs9jX/ #  
u*U?VZ5  
Y{S/A*X  
private String sSiteURL; //Site's URL );*GOLka  
private String sFilePath; //Saved File's Path D0-e,)G}V,  
private String sFileName; //Saved File's Name IQ~()/;3d  
private int nSplitter; //Count of Splited Downloading File >/n/n{{  
w5|"cD#8A  
vTP_vsdeG  
public SiteInfoBean() )a6i8b3  
{//nSplitter的缺省值为5 |On6?5((e  
//default value of nSplitter is 5 mPh;  
this("","","",5);  K A<  
} H _2hr[  
<zUmcZ  
TRiB|b]8Q#  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) +GGj*sD  
{ \"*l:x-u  
sSiteURL= sURL; 'nLv0.7*  
sFilePath = sPath; Ga h e-%J  
sFileName = sName; Kfr?sX  
this.nSplitter = nSpiltter; N" 8o0>  
aL`pvsnF  
t3WlVUtq3  
} L\B+j+~  
] x Kmz  
xpnnWHdaq  
public String getSSiteURL() [_~U<   
{ DUtpd|  
return sSiteURL; #}gc6T~0  
} ox*Ka]  
|~/{lE=I  
{u1t .+  
public void setSSiteURL(String value) *83+!DV|  
{ 7+fik0F  
sSiteURL = value; ,yT4(cMBk?  
} jgYiuM3c\  
$@NZ*m%?JQ  
N7;2BUIXJ  
public String getSFilePath() M-Js"cB[  
{ Pf!K()<uJ  
return sFilePath; w9oiu$7),  
} qzLRA.#f^  
X}Csl~W8in  
(0][hdI~B  
public void setSFilePath(String value) oT_,k}LIX  
{ OW.ckYt%  
sFilePath = value; l nZ=< T  
} vKW%l  
;L`'xFo>>  
1zM`g_(#  
public String getSFileName() t (1z+  
{ (PNvv/A  
return sFileName; h%O`,iD2  
} olJ9Kfc0  
EbW7Av  
j` x9z_  
public void setSFileName(String value) <)}*S  
{ a0n F U  
sFileName = value; sv[)?1S  
} Oo0$n]*;W  
<E ^:{J95  
x?%vqg^r  
public int getNSplitter() tsk}]@W  
{ QL)UPf>Kp  
return nSplitter; I?PKc'b  
} GM%|mFqeu  
z#\Z|OKU  
S38D cWIw  
public void setNSplitter(int nCount) +]__zm/^  
{ %d>Ktf  
nSplitter = nCount; "au"\}   
} z XvWo6  
} ,Bta)  
@#V{@@3$  
0>'1|8+`(z  
/* YcGqT2oLP  
**Utility.java =thgNMDm"  
*/ tQ)8HVKF  
package NetFox; e"b F"L  
-1{N#c/U  
5|Y4GQVz  
public class Utility { b+C>p2%  
dv,8iOL  
IlE! zRA  
public Utility() p7k0pSt  
{ Q`oi=O YB  
a"v D+r7Ol  
dFUsQ_]<  
} IOJfv8  
s<5t}{x  
//线程睡眠 x,>=X` T  
public static void sleep(int nSecond) 2M;{|U  
{ mr/^lnO  
try{ 1xx-}AIH#  
Thread.sleep(nSecond); T.{I~_  
} tVe*J@i\$  
catch(Exception e) ,:#prT[P"  
{ K.cNx  
e.printStackTrace (); <1@_MY o  
} GJW1|Fk  
} E:i3 /Ep?  
KctD=6  
//日志 ^C'k.pV n~  
public static void log(String sMsg) 4Q]+tXes  
{ "_(o% \"7  
System.err.println(sMsg); kL&^/([9  
} v/^2K,[0>  
y/PEm)=Tt  
n3)g{K^  
public static void log(int sMsg) ~U^0z|.  
{ # v v k7  
System.err.println(sMsg); -_2= NA?t  
} RuHJk\T+  
} a-YK*  
p<![JeV  
wRuJein#  
/* LAr6J  
**TestMethod.java YY.;J3C  
*/ 2=#O4k.@  
package NetFox; `R; ct4-  
{g);HnmPN  
o30PI  
public class TestMethod { v5*SoUOF  
1.';:/~(  
ckTnb  
public TestMethod() u?aq' "t  
{ ///xx/weblogic60b2_win.exe B0YY7od  
try{ Fc nR}TE  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); plp).Gq  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); xi.;`Q^#  
SiteFileFetch fileFetch = new SiteFileFetch(bean); hTy#Q.=  
fileFetch.start(); 7?kvrIuY&  
} s{CSU3vYmi  
catch(Exception e){e.printStackTrace ();} Z1>pOJm  
 ,{.&xJ$  
EJ86k>]  
} KcSvf;sx  
(K2 p3M^  
CUYp(GU  
public static void main(String[] args) zZDr=6|r_  
{ ."H5.'  
new TestMethod(); hZ%Ie%~n  
} ;/YSQt)rc>  
} Cd (Ov5%  
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