http断点续传简单实现（java)

/* j&N {j_M
 
**SiteFileFetch.java C>:,\=y%  
*/ o#Viz:  
package NetFox; u]z87#4  
import java.io.*; PY@BgL=/  
import java.net.*; 5Ic'6AIz  
@*<`*W  
'PqKb%B|  
public class SiteFileFetch extends Thread { ~Fe$/*v  
+:_;K_h  
KXiStwS  
SiteInfoBean siteInfoBean = null; //文件信息Bean 0'ge}2^  
long[] nStartPos; //开始位置 KSYHG  
long[] nEndPos; //结束位置 W%wc@.P  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 U^;|as  
long nFileLength; //文件长度 )z_5I (?&  
boolean bFirst = true; //是否第一次取文件 <\'aUfF v  
boolean bStop = false; //停止标志 Y6E0-bL@Fe  
File tmpFile; //文件下载的临时信息 *'n L[]  
DataOutputStream output; //输出到文件的输出流 .WVIdVO7  
3Fg{?C_l  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） wVmQE  
public SiteFileFetch(SiteInfoBean bean) throws IOException ?Q[b1:;Lm  
{ xG1(vn83gq  
siteInfoBean = bean; ri1;i= W  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 3+/^  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ;)ku SH  
if(tmpFile.exists ()) Bfu/w  
{ VvUP;o&/  
bFirst = false; eyzXHS*s;L  
read_nPos(); W,5_i7vr  
}  X@Bg_9\i  
else m7|S'{+!  
{ +Ym#!"  
nStartPos = new long[bean.getNSplitter()]; [$D%]]/,  
nEndPos = new long[bean.getNSplitter()]; IcA]B?+  
} 7NMy1'-q  
}3/|;0j$  
;r BbLM`  
6ltV}Wt-  
} _oE 7<  
C({r1l4[D  
hEA;5-m  
public void run() {rzvZ0-j}  
{ `$Y%c1;  
//获得文件长度 <64#J9T^  
//分割文件 _&RGhA  
//实例FileSplitterFetch fP/;t61Z  
//启动FileSplitterFetch线程 ;3\'}2^|l  
//等待子线程返回 8xt8kf*k  
try{ 4jw q
$G  
if(bFirst) f%/6kz  
{ @;X#/dZe  
nFileLength = getFileSize(); !q1XyQX  
if(nFileLength == -1) E^B3MyS^^  
{ \HL66%b[  
System.err.println("File Length is not known!"); RN2z/FUf  
} Fu>;hx]s  
else if(nFileLength == -2) G2dPm}sZG  
{ nH
}V:C  
System.err.println("File is not access!"); (7C$'T-ZK  
} i 2 ='>  
else p+;;01Z+_  
{ 6~O;t'd  
for(int i=0;i<nStartPos.length;i++) f{-,"6Y1  
{ z .+J\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); #G\Ae
:O  
} a/n~#5-  
for(int i=0;i<nEndPos.length-1;i++) ETm:KbS  
{ ~g}blv0q+B  
nEndPos = nStartPos[i+1]; v)aV(Oa  
} r-_-/O"l  
nEndPos[nEndPos.length-1] = nFileLength; 0v|qP  
} $+ORq3  
} XPLm`Q|1#t  
qu0
q LM  
^ f[^.k$3d  
//启动子线程 /jSb^1\  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ~m4LL[  
for(int i=0;i<nStartPos.length;i++) n]8*yoge  
{
{S`Rr/E|%  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5`QfysR5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), kyf(V)APPu  
nStartPos,nEndPos,i); x@*?~1ai  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); y*E{X  
fileSplitterFetch.start(); G_}oI|B  
} Ckhwd  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), AZ SaI  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ,xutI  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", L7"<a2J  
nEndPos = " + nFileLength); C'PHbo:  
// fileSplitterFetch[nPos.length-1].start(); ab[V->>%  
s$~H{za  
F(`Q62o@  
//等待子线程结束 65GC7 >[  
//int count = 0; g&\;62lV%  
//是否结束while循环 (!a\23  
boolean breakWhile = false; _ucixM#  
^97[(89G9  
Ky*xAx:  
while(!bStop) ,=2)1I]  
{ dKmPKeJM  
write_nPos(); rIX 40,`  
Utility.sleep(500); !Pu7%nV.  
breakWhile = true; x[R?hS,0t  
X;v{,P=J  
MfraTUxIo/  
for(int i=0;i<nStartPos.length;i++) <
bJ~Ol  
{ ]UrlFiR  
if(!fileSplitterFetch.bDownOver) GS*_m4.Ry6  
{ G+WCE*  
breakWhile = false; /U>8vV+C  
break; t&-c?&FO\;  
} fO837  
} D=)qd@,K  
if(breakWhile) ie/QSte  
break; '.e5Ku  
{JM3drnw  
*7qa]i^]  
//count++; )O\l3h
"  
//if(count>4) n65fT+;  
// siteStop(); JEfhr  
} 7o-}86x#  
J?Rp  
Up>,~bs]  
System.err.println("文件下载结束！"); #+^l3hMK  
} qz 29f  
catch(Exception e){e.printStackTrace ();} hDbZ62DDN  
}
1?r$Rx<R  
}dSFv   

<JZa  
//获得文件长度 `Mo%)I<`=  
public long getFileSize()
zu1gP/  
{ Xg;q\GS/<i  
int nFileLength = -1; II.Wa&w}  
try{ tAb3ejCo?  
URL url = new URL(siteInfoBean.getSSiteURL()); O>ZJOKe  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &<hk&B  
httpConnection.setRequestProperty("User-Agent","NetFox"); hG3RZN#ejq  
<4;f?
eu  
`U
;V-  
int responseCode=httpConnection.getResponseCode(); ]xhH:kW4  
if(responseCode>=400) %Jn5M(myC  
{ d_98%U+u  
processErrorCode(responseCode); 5hB2:$C  
return -2; //-2 represent access is error DE?@8k  
} =OR&,xt  
7.C]ZcU  
^Cg@'R9  
String sHeader; }80n5X<9  
,-> P+m5  
7wqD_Xr  
for(int i=1;;i++) Z8pZm`g)T  
{ Kw>gg  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); E}]SGU"  
//Utility.log(in.readLine()); _xdttO^N  
sHeader=httpConnection.getHeaderFieldKey(i); ;~s@_}&  
if(sHeader!=null) 73M;-qnU  
{ *kDV ^RBfq  
if(sHeader.equals("Content-Length")) <pUc( tPoz  
{ j MA%`*r  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); _[ `"E'  
break; s_,&"->  
} <zu)=W'R]  
} qj?I*peK)  
else wJF$<f7P  
break; 9a.[>4}  
} td+[Na0d  
} 5gPAX $jH  
catch(IOException e){e.printStackTrace ();} >2)!w  
catch(Exception e){e.printStackTrace ();} zyI4E\  
&l~=c2  
=`%%
*  
Utility.log(nFileLength); 3*b!]^d:D  
&S#bLE  
$w<~W1\:  
return nFileLength; }Z\+Qc<<  
} g/,O51f'  
i)e)FhEY6  
O11.wLNH  
//保存下载信息（文件指针位置） v aaZ  
private void write_nPos() upH%-)%'  
{ H %PIE1_  
try{ vGPaWYV  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )5bdWJ>l  
output.writeInt(nStartPos.length);  ,#
-^  
for(int i=0;i<nStartPos.length;i++) 9a_(_g>S  
{ /t?(IcP5  
// output.writeLong(nPos); iAWoKW  
output.writeLong(fileSplitterFetch.nStartPos); sfNAGez  
output.writeLong(fileSplitterFetch.nEndPos); BcoE&I?[m|  
} <kor;exeJ  
output.close(); %u|qAF2uS  
} O~&l.>??  
catch(IOException e){e.printStackTrace ();} k)USLA  
catch(Exception e){e.printStackTrace ();} oDas~0<oh  
} 8%#uZG\}  
BF6H_g  
Jh:-<xy)  
//读取保存的下载信息（文件指针位置） 3'2}F%!Mv  
private void read_nPos() 1')/BM2  
{   s/
'gl  
try{ _'oy C(:}  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); <`m.Vbvm"  
int nCount = input.readInt(); -.WVuc`  
nStartPos = new long[nCount]; `+/[0B=.  
nEndPos = new long[nCount]; h Tn^:%(  
for(int i=0;i<nStartPos.length;i++) B[MZPv)  
{ @.i
OFY  
nStartPos = input.readLong(); >heih%Ar0J  
nEndPos = input.readLong(); z*>CP  
} JGD{cr[S  
input.close(); !ZV#~t:)  
} XsHl%o8,z  
catch(IOException e){e.printStackTrace ();} HIeMV,.QN  
catch(Exception e){e.printStackTrace ();} (;h]'I@  
} 5cQBqH]   
9tC8|~Q  
UwQ3q  
private void processErrorCode(int nErrorCode) ;3sT>UB  
{ $Y0bjS2J  
System.err.println("Error Code : " + nErrorCode); o6KBJx  
} *id|za
|:k  
FZmYv%J  
(^Do#3  
//停止文件下载 0QIocha  
public void siteStop() Bv@m)$9\+3  
{ y$V{yh[:  
bStop = true; aLXA9?  
for(int i=0;i<nStartPos.length;i++) e@,,;YO#4  
fileSplitterFetch.splitterStop(); cmN0ya  
|I+E`,n"b  
25ZGuM  
} Da-(D<[0  
} Ef`LBAfOO  
//负责部分文件的抓取 $'FPst8Q<  
**FileSplitterFetch.java :g9z^ $g  
*/ v V^GIWK  
package NetFox; c[y=K)<Z  
pmW=l/6+V3  
Ft.BfgJ$  
import java.io.*; Sc~kO4  
import java.net.*; ?s"v0cg+  
EShakV  

S s`0;D1  
public class FileSplitterFetch extends Thread { ^]R0d3
?>\  
Eq<#pX6  
=OZ_\vO  
String sURL; //File URL C${TC+z  
long nStartPos; //File Snippet Start Position r&3fSx9  
long nEndPos; //File Snippet End Position t2Y~MyT/  
int nThreadID; //Thread's ID |b3/63Ri-0  
boolean bDownOver = false; //Downing is over usTCn3u  
boolean bStop = false; //Stop identical V!<#
E)-?<  
FileAccessI fileAccessI = null; //File Access interface l*:p==  
B=c^ma
  
.RWBn~b#I  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException eu:_V+  
{ ;W*$<~_  
this.sURL = sURL; ( L6`_)  
this.nStartPos = nStart; #*]= %-A  
this.nEndPos = nEnd; `A^} X  
nThreadID = id; TQ2Tt"  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 8c|IGC  
} \4p<;$'  
F_Pd\Aq8  
t@HE.h  
public void run() anwn!Eqk"  
{ 4 z`5W,  
while(nStartPos < nEndPos && !bStop) YWZF*,4  
{ hB+ t pa  
+{w&ksk  
SA7,]&Zb  
try{ kv4J@  
URL url = new URL(sURL); T?ZMmUE  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6e*b;{d  
httpConnection.setRequestProperty("User-Agent","NetFox"); <C{5(=
X{  
String sProperty = "bytes="+nStartPos+"-"; _/=ZkI5  
httpConnection.setRequestProperty("RANGE",sProperty); N_DgnZ7*  
Utility.log(sProperty); tj&A@\/  
=
% JDo  
sq^"bLw  
InputStream input = httpConnection.getInputStream(); M#>GU<4"  
//logResponseHead(httpConnection); -/qrEKQ0U?  
FTenXJ/c  
dCK-"#T!  
byte[] b = new byte[1024]; ]/']{*T1  
int nRead; %%>?<4t  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ZF/KV\Ag)  
{ .eAC!R  
nStartPos += fileAccessI.write(b,0,nRead); *j* WE\  
//if(nThreadID == 1) fytx({I .a  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~Iu09t|a  
} D/Wuan?yPN  

NE4fQi?3  
W*m[t&;  
Utility.log("Thread " + nThreadID + " is over!"); 2yZ6:U~  
bDownOver = true; o|W? a#_\  
//nPos = fileAccessI.write (b,0,nRead); wg1pt1 `  
} HlSuhbi'@  
catch(Exception e){e.printStackTrace ();} wm8x1+P  
} GT.^u#r  
} }a1UOScO0  
1m)/_y~1 k  
yi?&^nX@9,  
//打印回应的头信息 7a<qP=J  
public void logResponseHead(HttpURLConnection con) N [
u Xo  
{ &F}+U#H  
for(int i=1;;i++) Chup %F  
{ w0!,1 Ry  
String header=con.getHeaderFieldKey(i); S\ZAcz4  
if(header!=null) Mg$9'a"[\
 
//responseHeaders.put(header,httpConnection.getHeaderField(header)); >i%w'uU  
Utility.log(header+" : "+con.getHeaderField(header)); t>2^!vl  
else | dwxe
a  
break; VW
v0\:,G  
} srLr~^$j[  
} &^_(xgJL  
(O2HB-<rY  
eeZysCy+DY  
public void splitterStop() N0[I2'^.  
{ Ol9fwd  
bStop = true; 36a~!  
} PuJ{!S\T7  
Vcq?>mH&T  
BfT,  
} 88$Y-g5*  
uFWgq::\  
tJPRR_nZv  
/* )X;cS} yp  
**FileAccess.java )<F\IM  
*//文件访问(定位，写) }Xi#x*-D  
package NetFox; 7yTe]O  
import java.io.*; Xh"iP%  
qo-F9u1J  
8M9\<k6  
public class FileAccessI implements Serializable{ ^&H=dYcV>/  
S "Pj1  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 w
PJRp]FA  
RandomAccessFile oSavedFile; #cG479X"  
long nPos; -3tBN*0+  
QCf
pDE}  
`;CU[Ps?]  
public FileAccessI() throws IOException 7$W;4!BN*  
{ .p(l+  
this("",0); \_AEuz3 F  
} &AcFa<U  
u^zitW!X$  
YB~t|m65  
public FileAccessI(String sName,long nPos) throws IOException 6QXQ<ah"  
{ 6.s?  
oSavedFile = new RandomAccessFile(sName,"rw"); wrYQ=u#Z  
this.nPos = nPos; rDX'oP:  
oSavedFile.seek(nPos); {IHK<aW  
} 5MY}(w  
;nKHm  
B8AzN9v&"N  
public synchronized int write(byte[] b,int nStart,int nLen) SM+fG:4d  
{ kdh9ftm*\  
int n = -1; 4F,Ql"ae(  
try{ 4<<bk_7'  
oSavedFile.write(b,nStart,nLen); L?27q  
n = nLen; u?;Vxh3@|  
} rHgdvDc  
catch(IOException e) Gj19KQ1G  
{ a@y5JxFAy  
e.printStackTrace (); +c8AbEewg  
} 0nn]]B@l  
yCCw<?  
TUUE(sLA  
return n; .q`H`(QM  
} S?7V "LF  
C<t'f(4s`u  
-^4bA<dCCE  
} >2CusT2  
b]<HhU  
VNrO(j DUv  
/* rgdQR^!l6  
**SiteInfoBean.java %y\eBfW,/  
*/ RC{Z)M{~  
package NetFox; aXbNDj ][  
B UQn+;be  
D5!K<G?-K  
public class SiteInfoBean { %7>AcTN~  
(vAv^A*i}  
|1+(Ny.%k  
private String sSiteURL; //Site's URL gJ5
wAK+?  
private String sFilePath; //Saved File's Path bV$8 >[`  
private String sFileName; //Saved File's Name 3$N %iE
6  
private int nSplitter; //Count of Splited Downloading File ^jha:d  
i<wU.JX&h  
B >u,)  
public SiteInfoBean() D<bU~Gd,P  
{//nSplitter的缺省值为5 .D,?u"fk|  
//default value of nSplitter is 5 [Ba2b: l6v  
this("","","",5); W`u$7k]$  
} =Etwa  
|5~wwL@LW7  
f']sU/c=  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) <L/M`(:=k  
{ XK%W^a*x
 
sSiteURL= sURL; }or2 $\>m  
sFilePath = sPath; L+L"$  
sFileName = sName; K)Zkj"y  
this.nSplitter = nSpiltter; *hZ~i{c,7  
;Lsjh#  
Vo9>o@FlLM  
} }*.:Hv"  
j!S1Y0CV  
w`j*W$82
  
public String getSSiteURL() [T4 pgt'H  
{ lj EB  
return sSiteURL; Bzu(XQ
 
}
/1 US,  
pymx\Hd,  
?..i4  
public void setSSiteURL(String value) ]PlY}VOY  
{ K=tx5{V
 
sSiteURL = value; 8Da(tS  
} *9dV/TT~f[  
gp$EXJ=  
}$|%/Y  
public String getSFilePath() 3q#"i&  
{ z[qdmx^  
return sFilePath; ?-8y4 Ex  
} K5!";V  
3s?v(1 {)  
_b0S  
public void setSFilePath(String value) C|4
U78f{  
{ &@4.;u  
sFilePath = value; NWJcFj_  
} Z[#I"-Q~:  
 Iys6R?~  
HZDk <aU/!  
public String getSFileName() { r6]MS#l1  
{ O1?B{F/ e  
return sFileName; 5;FP.{+  
} FgOUe  
pxw{  
:3a&Pb*PL  
public void setSFileName(String value) ;23=p=/h  
{ n2n00%Wu[  
sFileName = value; #"Eks79s  
} t
7|MkX1  
OgEUq''  
|?x^8e<*  
public int getNSplitter() 7$+P|U
 
{ >oft :7p  
return nSplitter; :%/\1$3P  
} W il{FcHY  
u}Ei_ O<z  
20rN,@2<  
public void setNSplitter(int nCount) n> MD\ZS  
{ N@cMM1  
nSplitter = nCount; 5mI?p
fm  
} 3D 9N:c  
} Az9X#h.vf  
x*unye7  
rD0k%-{{  
/* M MAA
Ho  
**Utility.java ?_VRfeztw  
*/ _Fy4DVCg  
package NetFox; #04{(G|~+E  
"?i>p z  
5U0ytDZ2/(  
public class Utility { '"` Lv/  
[#7y[<.P  
lir&e 9I+  
public Utility() D3%l4.h  
{ T@(6hEmP,  
PqT"jOF]n  
0fn
ZR$PB  
} |yLk5e~@-  
G$cxDGo  
//线程睡眠 HG3.~ 6X  
public static void sleep(int nSecond) sL)Rg(rkx  
{ 5{')GTdX>  
try{ uyL72($  
Thread.sleep(nSecond); &}zRH}s;  
} w`M]0'zls  
catch(Exception e) OYBotk]{1  
{ &nQRa?3,   
e.printStackTrace (); +->\79<#V(  
} Dp!;7e s|  
} yrO?Np  
Jf
_]Z  
//日志 c`-YIz)W  
public static void log(String sMsg) De;,=BSp  
{ (tJ91SBl  
System.err.println(sMsg); Qn*6D  
}
G-2EQ.  
DZJeup?Z  
^[en3aQ  
public static void log(int sMsg) 6/|U  
{ c2/FHI0J;  
System.err.println(sMsg); wOjv[@d  
} DWu
RJ  
} ?#4+r_dP  
bKYY{V55  
~Y% : 3  
/* ,MRvuw0P  
**TestMethod.java * !X4&#xP  
*/ 5QR}IxQ  
package NetFox; GXO4x|08F  
=Wj{]&`  
O-Dc[t%  
public class TestMethod { gyC^K3}  
HH7[tGF  
_]P a>8X*  
public TestMethod() _=uviMuE  
{ ///xx/weblogic60b2_win.exe %=BtOM_2  
try{ . /Y&\<  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); m+H%g"Zj  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 60'6/3  
SiteFileFetch fileFetch = new SiteFileFetch(bean); _~PO  
fileFetch.start(); s){Q&E~X  
} H;qJH1EdD  
catch(Exception e){e.printStackTrace ();} :H{Bb{B%  
_ ~|Q4AJ  
{-Yee[d<
?  
} <p09oZ{6  
[qiOd!  
INOH{`}Ew  
public static void main(String[] args) M]1;  
{ GN0duV  
new TestMethod(); N.jA 8X  
} rrAqI$6  
} O"qR}W  
点击下载更多相关资料