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http断点续传简单实现(java)

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/* `Q{kiy  
**SiteFileFetch.java J|ILG  
*/ 1D*e u  
package NetFox; , vky  
import java.io.*; f6m^pbQFl  
import java.net.*; cJqPcCq(wn  
@p!["v&  
}x%"Oq|2]x  
public class SiteFileFetch extends Thread { 5X  
^wX_@?aKtt  
vv3dr_l:  
SiteInfoBean siteInfoBean = null; //文件信息Bean o?b"B+#  
long[] nStartPos; //开始位置 3{:d$- y  
long[] nEndPos; //结束位置 M~@\x]p >  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 akNJL\b  
long nFileLength; //文件长度 Jus)cO#I  
boolean bFirst = true; //是否第一次取文件 _ p?q/-[4  
boolean bStop = false; //停止标志 { }>"f]3  
File tmpFile; //文件下载的临时信息 sx/g5 ?zh  
DataOutputStream output; //输出到文件的输出流 X=DJOepH'  
SkK=VeD>8  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) xd>2TW l#  
public SiteFileFetch(SiteInfoBean bean) throws IOException 's e 9|:  
{ J +9D/VT  
siteInfoBean = bean; HHX9QebiST  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); A\=:h  AQ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 0AaN  
if(tmpFile.exists ()) %~6+=*(\  
{ "r[Ea|  
bFirst = false; tmm\V7sJ  
read_nPos(); p1 o?^A&  
} wo?C 7,-x  
else [rQ#skf  
{ V,>#!zUv  
nStartPos = new long[bean.getNSplitter()]; / {A]('t  
nEndPos = new long[bean.getNSplitter()]; BkIvoW_  
} {t9U]hX%A[  
)Dv"seH.  
6/GhQ/T%D  
'2%hc\P6P  
} _/KW5  
vK6bpzI 3  
OnG!5b  
public void run() ag] nVE/  
{  R z[-  
//获得文件长度 6R?J.&|  
//分割文件 zis-}K<   
//实例FileSplitterFetch #!<x|N?_<  
//启动FileSplitterFetch线程 u'=#~'6  
//等待子线程返回 SK-|O9Ki  
try{ q6osRK*20  
if(bFirst) K7CiICe  
{ PZ"xW0"-  
nFileLength = getFileSize(); %.Mtn%:I *  
if(nFileLength == -1) 0ai4%=d-  
{ {(t (}-:Z  
System.err.println("File Length is not known!"); f(9w FT  
} h>\}-|Ek  
else if(nFileLength == -2) !FO92 P16  
{ ysL8w"t  
System.err.println("File is not access!"); hzPpw.  
} u<+;]8[o  
else S_\RQB\l  
{ RzyEA3L'  
for(int i=0;i<nStartPos.length;i++) d/7 c#er  
{ $bMeL7CN  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 5m_@s?P[  
} oE5+   
for(int i=0;i<nEndPos.length-1;i++) +[*UC"  
{ }p "HD R>  
nEndPos = nStartPos[i+1]; h; {?z  
} R/P.m~?  
nEndPos[nEndPos.length-1] = nFileLength; 8fdOV&&D~i  
} 2Y$==j  
} :S,#*rPKBK  
1-q\C<Q)  
Q9rE_} Z  
//启动子线程 U~7.aZHPx3  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; $bD!./fl  
for(int i=0;i<nStartPos.length;i++) [J:vSt  
{ !WbQ`]uN/#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Th"7p:SE?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), r"rEVx#1=  
nStartPos,nEndPos,i); ,E/vHI8  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !&#CEF@J  
fileSplitterFetch.start(); xv1$,|^ts  
} $'e.bh  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), QO|ODW+D  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <01MXT-  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", a z`5{hK  
nEndPos = " + nFileLength); 15SIZ:Q  
// fileSplitterFetch[nPos.length-1].start(); CIV6 Qe"<  
'"I"D9;9  
O1/!)E!  
//等待子线程结束 @^`-VF  
//int count = 0; SqEO ] ~  
//是否结束while循环 c-gaK\u}j}  
boolean breakWhile = false; ^B5Hjf9  
QAX+oy  
1)k))w9  
while(!bStop) G|H\(3hHLZ  
{ Y/{Z`}  
write_nPos(); #&DJ3(T  
Utility.sleep(500); ,$CZ (GQ  
breakWhile = true; 3aW4Gs<g  
`L:wx5?  
f!1K GP  
for(int i=0;i<nStartPos.length;i++) u,&Z5S  
{ W+Iln`L  
if(!fileSplitterFetch.bDownOver) @Wdnc/o]  
{ Z#\ \NfR  
breakWhile = false; q^,^tw  
break; UY>{e>/H9  
} 783a Z8  
} ,/Xxj\i  
if(breakWhile)  E?%k  
break; 'zRd?Z>%  
w}7`Vas9  
SUx\qz)  
//count++; *6k (xL  
//if(count>4) c?wFEADn  
// siteStop(); Kz'W |  
} ujDAs%6MZ  
S,J'Z:spf  
M~3(4,  
System.err.println("文件下载结束!"); MLL2V`vBT  
} `t#C0  
catch(Exception e){e.printStackTrace ();} 3{,Mpb@  
} sp AYb<  
c*LnLK/m  
[?;oiEe.|  
//获得文件长度 eeuAo&L&  
public long getFileSize() +>/ Q+nh  
{ ]_#[o S  
int nFileLength = -1; W>s<&Vb  
try{ EEF}Wf$f  
URL url = new URL(siteInfoBean.getSSiteURL()); W*VQ"CW{^]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 48w3gye  
httpConnection.setRequestProperty("User-Agent","NetFox"); m@"!=CTKd  
M*@MkN*u&  
e?F r/n  
int responseCode=httpConnection.getResponseCode(); X/'B*y'=U  
if(responseCode>=400) ?jb7Oq#[  
{ $YL} rM  
processErrorCode(responseCode); Jb_/c``  
return -2; //-2 represent access is error >Utn[']~  
} D|UDLaz~  
<:/V`b3a  
>>&~;PG[  
String sHeader; [<OMv9(l'o  
}8 ,b; Q  
l$PO!JRD  
for(int i=1;;i++) |RHX2sso  
{ cj5p I?@e)  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); :qw:)i  
//Utility.log(in.readLine()); #16)7  
sHeader=httpConnection.getHeaderFieldKey(i); vE{QN<6T  
if(sHeader!=null) %lEPFp  
{ YIjBKh  
if(sHeader.equals("Content-Length")) c9DX  
{ |1rBK.8  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 'gQm%:qU3r  
break; LP.-  
} =]"[?a >  
} *:)#'cenI  
else gl00$}C  
break; `5h$@  
} `s@1'IG;R_  
} qAkx52v6  
catch(IOException e){e.printStackTrace ();} _es>G'S  
catch(Exception e){e.printStackTrace ();} |A &Nv~.)  
YW>|gE  
4dl?US[-  
Utility.log(nFileLength); J6\<>5 A?  
B>-Iv _  
} %rF}>$A  
return nFileLength; 7Nx@eoZ  
} wgfn:LR  
jhK&Z7;  
^Fy) oWS  
//保存下载信息(文件指针位置) 0vDP- qJV-  
private void write_nPos() Fx)]AJ~[t  
{ +)Z,%\)Z  
try{ D3BX[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Sd}fse  
output.writeInt(nStartPos.length); B*K%&w10~  
for(int i=0;i<nStartPos.length;i++) /|BzpIfpN  
{ b- %7@j  
// output.writeLong(nPos); NIQa{R/H  
output.writeLong(fileSplitterFetch.nStartPos); H=7dp%b"  
output.writeLong(fileSplitterFetch.nEndPos); z_r W1?|  
} %k1*&2"1#  
output.close(); C$M^<z  
} '$l*FWOEal  
catch(IOException e){e.printStackTrace ();} (w@|:0t^y[  
catch(Exception e){e.printStackTrace ();} u~% m(  
} (w4#?_  
m[]p IXc(  
P?\rRB  
//读取保存的下载信息(文件指针位置) cXtL3T+  
private void read_nPos() Q >)?_O(  
{ 1*G7Uh@K}  
try{ T3wR0,  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,tmo6D62  
int nCount = input.readInt(); I0GL/a 4s  
nStartPos = new long[nCount]; Eq'YtqU  
nEndPos = new long[nCount]; kRZ(  
for(int i=0;i<nStartPos.length;i++) !X*L<)=nh  
{ rDm>Rm=  
nStartPos = input.readLong(); cb|`)"<HN  
nEndPos = input.readLong(); K)@]vw/\  
} H;Z{R@kf  
input.close(); CM8WI~  
} i8u9~F   
catch(IOException e){e.printStackTrace ();} G8 f7N; D  
catch(Exception e){e.printStackTrace ();} rTW1'@E  
} [ZDJs`h!`  
I3s'44  
i1C]bUXA  
private void processErrorCode(int nErrorCode) '^lrGO6 z7  
{ d<fS52~l  
System.err.println("Error Code : " + nErrorCode); hW _NARA  
} +1F@vag7  
li,kW`j+t  
eAm7*2  
//停止文件下载 &Lk@Xq1  
public void siteStop() Sg')w1  
{ [uZU p*.V  
bStop = true; />.&  
for(int i=0;i<nStartPos.length;i++) 7u o4F= %  
fileSplitterFetch.splitterStop(); mpK|I|-   
t[)z/[ m  
x8tRa0-q  
} \MK)dj5uUJ  
} .#rI9op  
//负责部分文件的抓取 'HPw5 L  
**FileSplitterFetch.java #d(6q$IE  
*/ XlDVJx<&J  
package NetFox; V>4 !fD=  
]wdudvS@6r  
C'*1w  
import java.io.*; #q(BR{A>t  
import java.net.*; R*VZ=i  
7A3e-51 >  
(:M6*RV  
public class FileSplitterFetch extends Thread { \ 1ys2BX  
At+on9&=  
KDg!Y(m{  
String sURL; //File URL rQN+x|dKMb  
long nStartPos; //File Snippet Start Position %+xh  
long nEndPos; //File Snippet End Position lT1*e(I  
int nThreadID; //Thread's ID I{B8'n{cN  
boolean bDownOver = false; //Downing is over klv^310  
boolean bStop = false; //Stop identical Scxf5x-  
FileAccessI fileAccessI = null; //File Access interface Y2<Z"D`  
LEHlfB#z`@  
$P4hNb  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException rbQA6_U 5A  
{ BRD>q4w  
this.sURL = sURL; r$G;^  
this.nStartPos = nStart; lt5~rH2  
this.nEndPos = nEnd; ag[yM  
nThreadID = id; khc5h^0  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 \muyL?  
} B~LB^ n(>@  
;( VJZ_  
M /Bn^A8@  
public void run() pd>EUdbrp&  
{ ^Q2K0'm5  
while(nStartPos < nEndPos && !bStop) ?HZ+fS ,-  
{ :%!=Ej.J  
~A>3k2 N/e  
>:KPvq!0  
try{ 4'G<qJoc  
URL url = new URL(sURL); Lr40rLx;u  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Gd:fWz(  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;y4 "wBX  
String sProperty = "bytes="+nStartPos+"-"; oA_AnD?G+  
httpConnection.setRequestProperty("RANGE",sProperty); eEezd[p  
Utility.log(sProperty); k<8:  
w}oH]jVKL6  
A-c3B+  
InputStream input = httpConnection.getInputStream(); p.8G]pS  
//logResponseHead(httpConnection); }SUe 4r&4}  
pz.<5  
aMh2[I  
byte[] b = new byte[1024]; e?RHf_d3T-  
int nRead; 1u)I}"{W>  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) b3y@!_'c  
{ ]*I&104{  
nStartPos += fileAccessI.write(b,0,nRead); GS< ,adD  
//if(nThreadID == 1)  =Lp0i9c  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^J@Y?CQl\  
} [8O`VSV3  
b`18y cVME  
HO & #Lv  
Utility.log("Thread " + nThreadID + " is over!"); xxiEL2"`>  
bDownOver = true; Ler9~}\D  
//nPos = fileAccessI.write (b,0,nRead); sE-"TNONZ  
} {.Nt#l  
catch(Exception e){e.printStackTrace ();} 0Oe@0L%^3"  
} Z</$~ T  
} ]UFf-  
7NoB   
\u",bMQF  
//打印回应的头信息 6dq5f?w]  
public void logResponseHead(HttpURLConnection con) A3M)yWq  
{ 0m51nw~B  
for(int i=1;;i++) a"#5JcR3  
{ j.AAY?L  
String header=con.getHeaderFieldKey(i); %J2u+K  
if(header!=null) YX@[z 5*  
//responseHeaders.put(header,httpConnection.getHeaderField(header));  mEhVc!  
Utility.log(header+" : "+con.getHeaderField(header)); xjv?Z"X  
else Q 4_j`q  
break; g%[lUxL  
} E]_sl/`{od  
}  5Lm ?  
>|uZIcs 6  
pkBmAJb@  
public void splitterStop() a?\ Au  
{ V4ayewVX  
bStop = true; M^k~w{   
} +r4^oT[-  
GZ*cV3Y`&  
Q6"r^w Wx  
} F9-xp7 T  
8Qek![3^  
f>l}y->-Ug  
/* ^EM##Ss_  
**FileAccess.java Z`q?pE>R  
*//文件访问(定位,写) @/B&R^aVZ  
package NetFox; b.;F)(  
import java.io.*; ks 3<zW(  
e"[o2=v;5  
X;ijCZb3b  
public class FileAccessI implements Serializable{ A2* z  
G#3 O^,m  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 0alm/or  
RandomAccessFile oSavedFile; v34XcA  
long nPos; v7xc01x  
N\<M4 fn  
a:v&pj+|<  
public FileAccessI() throws IOException %k5^n0|*  
{ <|s|6C  
this("",0); /_aFQ>.4n  
} K`PF|=z  
nwHi3ojD:  
Xxp<qIEm  
public FileAccessI(String sName,long nPos) throws IOException 3%!d&j>v  
{ k+&LOb7  
oSavedFile = new RandomAccessFile(sName,"rw"); r5tv9#4]  
this.nPos = nPos; fh}\#WE"  
oSavedFile.seek(nPos); WPpl9)Qc  
} }\P9$D+  
!NjC+ps]  
I tp7X  
public synchronized int write(byte[] b,int nStart,int nLen) Lc0^I<Y  
{ "P"~/<:)  
int n = -1; ?_}[@x  
try{ $>]7NTP  
oSavedFile.write(b,nStart,nLen); bC)d iC  
n = nLen; "*XR'9~7  
} L%U-MOS=  
catch(IOException e) qL UbRp  
{ Ej8EQ% P  
e.printStackTrace (); >&Y8VLcK  
} (lTM^3 }  
7`|$uIM`  
$Rd74;edn  
return n; f9X*bEl9;`  
} 5e6]v2 k  
y]+i. 8[  
yzgDdAM  
} aQ46euth  
Y(-4Agq  
Y!Wz7 C  
/* Mw*R~OX  
**SiteInfoBean.java W6 f*>  
*/ ?b:l.0m  
package NetFox; egK,e?~  
aOA;"jR1  
d^!)',`  
public class SiteInfoBean { 89k9#i X  
~4`LOROC  
 -*M/,O  
private String sSiteURL; //Site's URL 'k{pWfn=<  
private String sFilePath; //Saved File's Path 8{(;s$H~  
private String sFileName; //Saved File's Name p4*VE5[?_+  
private int nSplitter; //Count of Splited Downloading File {ajaM'x  
BXnSkT7  
0[H'l",~  
public SiteInfoBean() Ky|dRbK,  
{//nSplitter的缺省值为5 @s b\0}  
//default value of nSplitter is 5 VSL6tQp  
this("","","",5); G= !Gy.  
} J-au{eP^  
#t>w)`bA-  
&C`t(e  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) AQDT6E:  
{ wm=!tx\`k  
sSiteURL= sURL; =3_I;L w  
sFilePath = sPath; ^Z$%OM,  
sFileName = sName; Y?{L:4cRX  
this.nSplitter = nSpiltter; hdXdz aNS  
hg/G7Ur"  
KtG|m'\D  
} Uw8O"}U8  
CC;T[b&  
Pe EC|&x  
public String getSSiteURL() =EA*h_"q9  
{ oe=^CeW"  
return sSiteURL; PxhB=i!'$  
} kXFgvIpg<  
1 `hj]@.]  
/EZF5_`bT  
public void setSSiteURL(String value) MN}@EQvW==  
{ BA4qQCS;5  
sSiteURL = value; }S\\"SBC  
} }Dc0 Y  
sk5h_[tK  
{0 IEizQ|i  
public String getSFilePath() h# c.HtVE  
{ ,edX;`#  
return sFilePath; )hGRq'WA=  
} wf)T-]e  
Eaf6rjD  
R^.E";/h  
public void setSFilePath(String value) k|(uIU* ]  
{ F *_g3K!!  
sFilePath = value; xc7Wk&{=  
} f02 <u  
K;a]+9C  
*e&OpVn  
public String getSFileName() &U^6N+l9  
{ rvgArFf}]  
return sFileName; ] ?w hx &+  
} 8=Xy19<;t  
s.d }*H-o  
OSY$qL2  
public void setSFileName(String value) 'H+H4(  
{ _WO*N9Iz  
sFileName = value; F'^6 ra9  
} ;7Cb!v1  
tgCEz%  
se(ZiyHp  
public int getNSplitter() P~HzN C  
{ Q(=} PF  
return nSplitter; .Zv@iL5  
} :Q@=;P2  
ZCsL%(  
FH:^<^M  
public void setNSplitter(int nCount) UIPi<_Xa  
{ 9#Gz2u$  
nSplitter = nCount; mxt fKPb  
} Y3KKskhLx  
} .aTu]i3l_  
E&ou(Q={  
? WyL|;b*  
/* s ~c_9,JK  
**Utility.java FRqJ#yd]  
*/ do@`(f3 g  
package NetFox; fG_.&!P  
f86h"#4  
=m]|C1x  
public class Utility { 5$9g4  
ye !}hm=w  
lJ1_Zs `  
public Utility() Z Z|a`U  
{ 53=5xE= `D  
nQm7At  
KKB&)R  
} *S,5  
mux_S2x9m\  
//线程睡眠 nW#UBtZ  
public static void sleep(int nSecond) YL*yiZ9  
{ 4&]Sb}  
try{ `L n,qiA  
Thread.sleep(nSecond); .h O ) R.  
} /E8{:>2  
catch(Exception e) Jse;@K5y  
{ CEbZj z|  
e.printStackTrace (); aly1=j  
} ;n1< 1M>!  
} ]'+PJdA  
c4H5[LPF  
//日志 _nW{Q-nh  
public static void log(String sMsg) a ^wGc+  
{ g+'=#NS}  
System.err.println(sMsg); ai|d`:;  
} D2<(V,h9  
#2AKO/  
XL SYE   
public static void log(int sMsg) W:s`;8iM$  
{ ++{,1wY\  
System.err.println(sMsg); v',%   
} R<wPO-dX  
} BCUn[4Gp  
/~=W3lhY  
[H"\<"1o  
/* .%Pt[VQ  
**TestMethod.java 5MU-Eu|*>  
*/ dZ]['y%  
package NetFox; e0rh~@E  
Qy< ~{6V  
ICq  
public class TestMethod { vq(ElXTO  
fSR+~Vy  
x$p_mWC  
public TestMethod() M`m-@z  
{ ///xx/weblogic60b2_win.exe DNYJR]>  
try{ h zv4+1Wd[  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); MLVrL r t  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 1dsMmD[O  
SiteFileFetch fileFetch = new SiteFileFetch(bean); $Sg5xkV,a  
fileFetch.start(); =]Gw9sge@  
} *SP@`)\D  
catch(Exception e){e.printStackTrace ();} &:Mk^DH5  
[22>)1<(  
`Ckx~'1M:  
} e$ pXnMx7  
LHJ}I5zv  
i"4&UJu1;  
public static void main(String[] args) CSu}_$wC#  
{ Obj?,O  
new TestMethod(); =H8 LBM  
} ?7?hDw_Nk  
} IhRWa|{I  
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