http断点续传简单实现（java)

/* ,SyUr/D  
**SiteFileFetch.java C}h@El  
*/ 7XDV=PQ[  
package NetFox; Gtg)%`  
import java.io.*; KyyG8;G%  
import java.net.*; ,Mhe:^3  
C^%zV>o  
9_Re,h  
public class SiteFileFetch extends Thread { "pZ3  
g&"(- :  
87K)qsv8  
SiteInfoBean siteInfoBean = null; //文件信息Bean ]v{fFmL  
long[] nStartPos; //开始位置 NVjJ/  
long[] nEndPos; //结束位置 V{h@nhq  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Ft7a\vn*B  
long nFileLength; //文件长度 N-r
mk  
boolean bFirst = true; //是否第一次取文件 Z0=m:h  
boolean bStop = false; //停止标志 +hg\DqO^M  
File tmpFile; //文件下载的临时信息 Y/S3)o  
DataOutputStream output; //输出到文件的输出流
HL
e
^|  
$CmX &%L=  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） vaj66nV  
public SiteFileFetch(SiteInfoBean bean) throws IOException &5.~XM;  
{  4Z}bw#  
siteInfoBean = bean; tqQ0lv^J  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 2\w=U,;(  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 8`G{1
lr4o  
if(tmpFile.exists ()) 30_un  
{ MA+-2pMc|7  
bFirst = false; ;-?ZI$  
read_nPos(); {}pqxouE  
} kppRQ Q*[  
else }iSakq'  
{ |"yf@^kdC  
nStartPos = new long[bean.getNSplitter()]; S/-7Zo&w+  
nEndPos = new long[bean.getNSplitter()]; V./w06;0  
} {F:v$ K  
iw fp'  
YC]YX
H  
~9?U_ahfVt  
} gOyY#]g  
^Q=y^fx1  
olMO+-USP  
public void run() DnHAm q]  
{ Q H_W\W  
//获得文件长度 Tdwwtbe  
//分割文件 B~>cNj<  
//实例FileSplitterFetch =YGP%}_.p{  
//启动FileSplitterFetch线程 + |qfgi  
//等待子线程返回 EyPJvs  
try{ Zva  
if(bFirst) &^IcL!t[  
{ EB>B,#  
nFileLength = getFileSize(); ]zyX@=mM  
if(nFileLength == -1) bw<w u}ED  
{ }[z<iij4  
System.err.println("File Length is not known!"); v1r_Z($  
} )_v\{N  
else if(nFileLength == -2) )@qup _M@  
{ (a}
  
System.err.println("File is not access!"); P=^#%7J/l  
} ;:Z=%R$wJ  
else P;[Y42\z|  
{ Blbq3y+Sq  
for(int i=0;i<nStartPos.length;i++) hoR=%pC*  
{ 3l%,D: ?  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); {KDgK  
} 9U)t@b  
for(int i=0;i<nEndPos.length-1;i++) ahtYSz_FM  
{ 0i\',h}9  
nEndPos = nStartPos[i+1]; 8*yo7q&  
} EF=dXm/\  
nEndPos[nEndPos.length-1] = nFileLength; 7"q+"0G  
} ~*!u  
} x48'1&m  
7B(bH8  
tKZ&1
E  
//启动子线程 `\jTpDV_W  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ISS\uj63M  
for(int i=0;i<nStartPos.length;i++) s8_aL)@f  
{ |=cCv_y  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), zBt`L,^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), BMNr<P2li  
nStartPos,nEndPos,i); 9&%#nN4`8  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); n}A?jOSAe  
fileSplitterFetch.start(); xHB/]Vd-  
} GVG!sMmnX  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8PBU~mr  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); r!$'!lCR  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", nG"n-$A?<  
nEndPos = " + nFileLength); !&`}]qQZ  
// fileSplitterFetch[nPos.length-1].start(); f<89$/w
 
>+ ]R4  
f]8!DXEA  
//等待子线程结束 ejklpa ./  
//int count = 0; sS2_-X[_  
//是否结束while循环 uuSR%KK]|  
boolean breakWhile = false; SFn 3$ rh  
8?7kIin  
O4EIE)c  
while(!bStop) a*Ss -y  
{ RzS|dGNQE  
write_nPos(); YOV :  
Utility.sleep(500); st?gA"5w  
breakWhile = true; dk_,YU'z  
$;Vc@mYGW;  
kG1;]1tT#  
for(int i=0;i<nStartPos.length;i++) [q-;/ed  
{ M!
gBmQZ1  
if(!fileSplitterFetch.bDownOver) mz\NFC<  
{ R-pH Quu3  
breakWhile = false; u 1ZJHry  
break; mX&xn2}qZ"  
} Hz?!BV0  
} >z=Ou<,  
if(breakWhile) ptpW41t}^  
break; |3{+6cg  
tAqA^f*{  
~BZXt7DE  
//count++; 3ai (x1%  
//if(count>4) QCOLC2I  
// siteStop(); hH%,!tSx  
} -J,Q;tj  
B0oxCc/'sZ  
<%z@  
System.err.println("文件下载结束！"); 1E8H%2$ V  
} S_!hsY  
catch(Exception e){e.printStackTrace ();} 99e*]')A%  
} XFW5AP  

HU &)  
HG2GZ}~^1  
//获得文件长度 m0A#6=<  
public long getFileSize() i&`!|X-=R  
{ fVe@YqNa  
int nFileLength = -1; AnNPTi  
try{ Y4#y34We  
URL url = new URL(siteInfoBean.getSSiteURL()); s^w
\zzYb  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9ilM@SR  
httpConnection.setRequestProperty("User-Agent","NetFox"); )Zas x6`  
-(*nSD9  
vwKw?Z0%J  
int responseCode=httpConnection.getResponseCode(); ]cIu|bRO  
if(responseCode>=400) ~,ynJ]_aJB  
{ ?g2zmI!U  
processErrorCode(responseCode); {o
dA[H  
return -2; //-2 represent access is error 0 y<k][  
} .f>,6?  
Dg~ [#C-  

.nEs:yn  
String sHeader; Is13:  
2H[ ; v+  
{Eu'v$c!  
for(int i=1;;i++) ~m=$VDWm  
{ 4O!E|/`wO  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); F>N+<Z  
//Utility.log(in.readLine()); nfX12y_SXL  
sHeader=httpConnection.getHeaderFieldKey(i); 2"@Ft()]  
if(sHeader!=null) .Gh%p`<  
{ lop uf/U0  
if(sHeader.equals("Content-Length")) B{p4G`$i1  
{ Fn!SGX~kx$  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ibJl;sJ
 
break; 7JI:=yY!>:  
} f=o4I2Y[  
} <Nex8fiJ9  
else pI>*u ]x  
break; R:A'&;S  
} I!0JG`&  
} $jG4pPG  
catch(IOException e){e.printStackTrace ();} b3\B8:XFo|  
catch(Exception e){e.printStackTrace ();} xP{-19s1]  
D`Gt  
^agj4$  
Utility.log(nFileLength); =EW3&+Lt  
vX+.e1m  
qD-fw-,:  
return nFileLength; ?E<c[*F05  
} QH~Jy*\+PX  

.+yW%~0  
j0FW8!!-g  
//保存下载信息（文件指针位置） R&#tSL  
private void write_nPos() 7^MX l  
{ zDDK  
try{ P16YS8$  
output = new DataOutputStream(new FileOutputStream(tmpFile)); BwxnDeG)  
output.writeInt(nStartPos.length); _A 2Lv]vfV  
for(int i=0;i<nStartPos.length;i++) V^n0GJNo  
{ JrDHRIkgm  
// output.writeLong(nPos); B3mS]  
output.writeLong(fileSplitterFetch.nStartPos); Uk,g> LG
  
output.writeLong(fileSplitterFetch.nEndPos); LkBZlh_  
} #~k[6YR 0  
output.close(); >)Gd:636+  
} +`.,| |Mq  
catch(IOException e){e.printStackTrace ();} F;u_7OM  
catch(Exception e){e.printStackTrace ();} x=]S.XI  
} l~J*' m2  
IU#x[P!  
5ZK&fKeCF  
//读取保存的下载信息（文件指针位置） /p)F>WR  
private void read_nPos() Zu21L3  
{ P~RhUKfd  
try{ -7%X]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); yNa;\UF  
int nCount = input.readInt(); ffE#^|  
nStartPos = new long[nCount]; GK?4@<fY  
nEndPos = new long[nCount]; I@\+l6&#;  
for(int i=0;i<nStartPos.length;i++) 5G(E&>~  
{ k_aW  
nStartPos = input.readLong(); DM),|Nq"  
nEndPos = input.readLong(); c?K~/bx.  
} uWjU OJEe  
input.close(); s;Y<BD  
} ^.goO]  
catch(IOException e){e.printStackTrace ();} Izo!rC  
catch(Exception e){e.printStackTrace ();} %NajFjBI  
} nt ,7u(  
T8XY fcc*h  
U O<:.6"  
private void processErrorCode(int nErrorCode) g97]Y1g  
{ 2f{T6=SK  
System.err.println("Error Code : " + nErrorCode); i sW\MB]  
} a1c1k}  
@dgH50o[  
t-7og;^8k  
//停止文件下载 p[v#EyoC  
public void siteStop() {]kaJ{U>  
{ U)D[]BVg  
bStop = true; cCiI{  
for(int i=0;i<nStartPos.length;i++) >w|*ei:@S  
fileSplitterFetch.splitterStop(); @r;wobt  
)TJS4?  
2e1]}wlK  
} x83a!9  
} )oU)}asY  
//负责部分文件的抓取 2.lgT|p  
**FileSplitterFetch.java 5`-UMz<
]  
*/ PJLR<9  
package NetFox; ]@ M5_%p  
vF4]ux&  
|L
::bx(  
import java.io.*; g|%L"-%gJ  
import java.net.*; u[oUCTY  

SO{p;g  
L":bI&V?:  
public class FileSplitterFetch extends Thread { _P7tnXww  
1S:|3W  
CN&  
String sURL; //File URL *>q/WLR  
long nStartPos; //File Snippet Start Position Bh]!WMAw.  
long nEndPos; //File Snippet End Position 'Ot,H_pE  
int nThreadID; //Thread's ID a|_p,_  
boolean bDownOver = false; //Downing is over ~i~%~doa  
boolean bStop = false; //Stop identical @jy41eIo  
FileAccessI fileAccessI = null; //File Access interface K#mOSY;}  
gfa[4 z  
Q2|p\rO  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException uQqWew8l+  
{ Pbu{'y3J  
this.sURL = sURL; gTf|^?vd  
this.nStartPos = nStart; oPQtGl p  
this.nEndPos = nEnd; ?KE$r
~dn  
nThreadID = id; OMrc_)he\  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 `>lzlEhKV  
} ,0N94pKy  
.12aUXo(  
</"4 zD|  
public void run() $_;e>*+x  
{ )?aaBaN$  
while(nStartPos < nEndPos && !bStop) C$yq\C+I  
{ :t("L-GPW  
&^".2)zU  
O;9?(:_  
try{ ExBUpDQc  
URL url = new URL(sURL); Ms^dRe)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]j<Bo4~Il  
httpConnection.setRequestProperty("User-Agent","NetFox"); 39i
9wrP  
String sProperty = "bytes="+nStartPos+"-"; ^jE8+h  
httpConnection.setRequestProperty("RANGE",sProperty); 9~\kF5Q"  
Utility.log(sProperty); ^
K(^I*q  
NH A5e<  
b1#dz]  
InputStream input = httpConnection.getInputStream(); e [h8}F  
//logResponseHead(httpConnection); UUe#{6Jx_  
v`PY>c6~  
H^%lDz  
byte[] b = new byte[1024]; L1{GL #qV  
int nRead; *fMpZ+;[m  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) AyKMhac  
{ NAC_pM&B  
nStartPos += fileAccessI.write(b,0,nRead); fwR_OB:$  
//if(nThreadID == 1) 7- d.ZG  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A^\.Z4=d"  
} 4u;9
J*r4  
*/qtzt  
~uWOdm-"[  
Utility.log("Thread " + nThreadID + " is over!"); 13k !'P  
bDownOver = true; Sjj>#}U  
//nPos = fileAccessI.write (b,0,nRead); 2
1X`h3+=  
} Dim> 7Wbh  
catch(Exception e){e.printStackTrace ();} /1UOT\8U
 
} \Q?ip&R  
} rqPo)AL  
d*8 $>GA  
@$^bMIj@W  
//打印回应的头信息 DTRJ/@t  
public void logResponseHead(HttpURLConnection con) 1Na@|yY  
{ ^2D1`,|N  
for(int i=1;;i++) "ww|&-W9  
{ gmKGy@]
 
String header=con.getHeaderFieldKey(i); =WbOwI)u  
if(header!=null) Bq\F?zk<  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); p9!"O  
Utility.log(header+" : "+con.getHeaderField(header)); Jzji&A~  
else t_z>Cl^u  
break; %M F;`;1  
} K7knK  
}
fEf_F r  
$``1PJoi  
!LMN[3M_  
public void splitterStop() olB)p$aH#  
{ 1@48BN8cm'  
bStop = true; "Mw[P [w*  
}
7"F*u :  
#AkV/1Y  
h0--B]f@  
} @}p2aV59  
H(c72]@Vg  
lf{e[!ML'  
/* ~)LH='|h\}  
**FileAccess.java E907fX[R~  
*//文件访问(定位，写) Ix@&$!'k  
package NetFox; e1(Q(3  
import java.io.*; f),TO  
Ei}/iBG@  
U@ ?LP  
public class FileAccessI implements Serializable{ `+'rib5  
x9/H/'
 
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 iXu]e;6  
RandomAccessFile oSavedFile; RpWTp
T1  
long nPos; '|]e<Mt-  
00I}o%akO  
Ars687WB  
public FileAccessI() throws IOException s4Sd>D7  
{ KH)D08  
this("",0); LZJA4?C  
} Ee)[\Qjn  
=L%DX#8  
FMNm,O]  
public FileAccessI(String sName,long nPos) throws IOException ~CB[9D=  
{ .7'kw]{/  
oSavedFile = new RandomAccessFile(sName,"rw"); 0N[&3Ee8  
this.nPos = nPos; d2oh/j6`TA  
oSavedFile.seek(nPos); WARb"8Kg  
} \P} p5k[  
H1<>NWm!v7  
v(*C%.M)  
public synchronized int write(byte[] b,int nStart,int nLen) 9CA^B2u  
{ f.aSKQD  
int n = -1; q{s(.Uq$&  
try{ M;cO0UIwO  
oSavedFile.write(b,nStart,nLen); 0&qr  
n = nLen; GoA4f3  
} 3G.5724,  
catch(IOException e) :tIC~GG]_)  
{ IDkWGh  
e.printStackTrace (); Zfk*HV#\  
} R1nJUOE4w^  
]{"Br
$  
Q9I j\HbA"  
return n; sK{l 9  
} +iRq8aS_  
.Ha'p.  
A+y  
} ;\
EiM;Q]  
WZOY)>K  
l"\~yNgk  
/* ]
k9)G*  
**SiteInfoBean.java mNmLyU=d  
*/ k(zsm"<q  
package NetFox; ?9l [y  
$0bjKy  
6KD `oUx
 
public class SiteInfoBean { <%xS{!'}  
;Yi4Xva@  
)jq?lw'&  
private String sSiteURL; //Site's URL V"p!Bf  
private String sFilePath; //Saved File's Path
1;Pv0&[q/  
private String sFileName; //Saved File's Name >zDF2Y[  
private int nSplitter; //Count of Splited Downloading File h;=6VgXZ  
: ^ 8  
(`SR
J$~f  
public SiteInfoBean() USFDy  
{//nSplitter的缺省值为5 bSVlk`  
//default value of nSplitter is 5 :2nj
p%  
this("","","",5); e]jH+IR:>  
} Bo<>e~6P  
R!l:O=[<  
u:aW 8  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) lKEkXO  
{ ;7N Z<k  
sSiteURL= sURL; AuR$g7z  
sFilePath = sPath;
d Le
-nF  
sFileName = sName; .{;Y'Zc14S  
this.nSplitter = nSpiltter; "NgoaG~!YO  
PrudhUI^  
: tWU .f#  
} MxyN\Mq'  
J8Yd1.Qj  
`
%09xMPu  
public String getSSiteURL() mhW-J6u*  
{ )'*5R<#  
return sSiteURL; 9-]i.y  
} k`GA\&zt  
^$&k5e/}C  
@ym/27cRE  
public void setSSiteURL(String value) ]7;\E\o  
{ 0* /{4)r  
sSiteURL = value; BTM), w2  
} `/HUV&i"S  
6U^\{<h_c  
qF 9NQ;  
public String getSFilePath() k</%YKk  
{ s?ko?qN(  
return sFilePath; $T :un.TM  
} g;ZxvR)ZJk  
1SrJ6W @j[  
q~o,WZG  
public void setSFilePath(String value) +za8=`2o  
{ XQ4G)  
sFilePath = value; Z}|(FRVk  
} %*#n d  
;<0LXYL;  
'R&uD~Q  
public String getSFileName() SZJ$w-<z  
{ z<.?x%4O  
return sFileName; Mwgu93?  
} lo'W1p  
hDV20&hq  
:>itXD!  
public void setSFileName(String value) *6 _tQ9G  
{ "*,XL uv>  
sFileName = value; QXF aAb=(7  
} P>9aI/d9  
h^j?01*Et  
1^i Pji/  
public int getNSplitter() M>M`baM1  
{ erVO|<%=R  
return nSplitter; TNQP"9[?  
} s}pIk.4ot!  
D1nq2GwS  
w,R[C\#J  
public void setNSplitter(int nCount) P;pl,~  
{ 2< hAa9y  
nSplitter = nCount; 3BpZX`l*p  
} au,t%8AC  
} ^<X@s1^#  
t<n"-Tqu  
.(Qx{r$  
/* ,RN:^5 p  
**Utility.java $ "Bh]
-  
*/ pHoEa7:  
package NetFox; 4nAa`(62  
7}jW
BK  
!ZU2{  
public class Utility { 7z~_/mAI  
-R{V-   
y1=NF  
public Utility() b,KcB
Q.  
{ qH['09/F6  
`Y?87f:SP  
<, 3ROo76  
} c^`]`xiX  
/*|oL#hK  
//线程睡眠 ~{}#)gGU  
public static void sleep(int nSecond) Y<0 4RV  
{ xnE|Umz  
try{ HNL42\Kz!  
Thread.sleep(nSecond); cWajrLw  
} 1,5E`J  
catch(Exception e) h=_mNG>R)  
{ @(C1_  
e.printStackTrace (); GElvz'S~  
} K!,<7[MBg  
} U?.9D  
^fz+41lE\  
//日志
L],f3<  
public static void log(String sMsg) Q]o C47(  
{ ItVugI(^ C  
System.err.println(sMsg); _j_x1.l  
} 'H7x L  
d,$d~alY  
,.gQ^^+=  
public static void log(int sMsg) 'EFyIVezg9  
{ } G<rt  
System.err.println(sMsg); ?aW^+3i   
} <LRey%{q  
} ^9-&o  
X>?b#Eva  

n&A'C\  
/* ^T~gEv  
**TestMethod.java CIVnCy z  
*/ >c-fI$]  
package NetFox; E\;ikX&1  
+/D>|loRC  
>3u]OSb  
public class TestMethod { Dz./w  
TE )gVE]  
`mT$s,:h  
public TestMethod() 7Ol}EPf#  
{ ///xx/weblogic60b2_win.exe H:H6b  
try{ OCy0
#aPRS  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); BnRN;bu  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `]Ppau  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 0P>OJYFr'  
fileFetch.start(); ps$7bN C  
} LK"  bC  
catch(Exception e){e.printStackTrace ();} fIGFH
Zy,  
e|4&b@  
*._|
-L  
} 5'a3huRtV  
b3YO!cJ  
|y<),j6  
public static void main(String[] args) #.[AK_S5&  
{ 8.bKb<y  
new TestMethod(); m
?HZ;  
} P,=+W(s9}  
} w:'dhr':  
点击下载更多相关资料