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http断点续传简单实现(java)

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/* } q8ASYNc  
**SiteFileFetch.java Q;rX;p^W  
*/ "chDg(jMZ  
package NetFox; Wne@<+mX  
import java.io.*; f-Z/t fC  
import java.net.*; 26h21Z16q  
eSq.GtI  
b \2 ds,  
public class SiteFileFetch extends Thread { ~4'$yWG  
FZn w0tMq  
3!]rmZ-W  
SiteInfoBean siteInfoBean = null; //文件信息Bean (GfZ*  
long[] nStartPos; //开始位置 =Xr.'(U  
long[] nEndPos; //结束位置 KZf+MSq? B  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Q~Wqy~tS  
long nFileLength; //文件长度 s$j,9uRr  
boolean bFirst = true; //是否第一次取文件 InI$:kJ  
boolean bStop = false; //停止标志 ww1[rCh\+  
File tmpFile; //文件下载的临时信息 :V||c5B+  
DataOutputStream output; //输出到文件的输出流 d2$IH#~9B  
OneY_<*a<  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Q=$2c[Uk  
public SiteFileFetch(SiteInfoBean bean) throws IOException J|73.&B  
{ >hIu2jm  
siteInfoBean = bean; &};zvo~P.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); +N U G  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); abVmkdP_s  
if(tmpFile.exists ()) eHUOU>&P]  
{ ZN0P:==  
bFirst = false; ~P-mC@C  
read_nPos(); CrTw@AW9)  
} v]UwJz3<  
else /)O"l@ }U  
{ ~k5W@`"W  
nStartPos = new long[bean.getNSplitter()]; JxU5 fe  
nEndPos = new long[bean.getNSplitter()]; QMm%@zH  
} [$UI8tV  
t]G:L}AOl  
J{G?-+`  
@H8EWTZ  
} d<Tc7vg4|U  
{' H(g[k  
\  Cj7k^  
public void run() Y'X%Aw;`  
{ T)_hpt.  
//获得文件长度 >H ,*H;6  
//分割文件 BiBOr}ZQ  
//实例FileSplitterFetch 9M c ae 31  
//启动FileSplitterFetch线程 &K,i f  
//等待子线程返回 R4d=S4 i  
try{ Tlr v={  
if(bFirst) Xch~ 1K  
{ .=; ;  
nFileLength = getFileSize(); `Pnoxm'  
if(nFileLength == -1) ~g t@P  
{ dj%!I:Q>u  
System.err.println("File Length is not known!"); W2!+z{:m  
} A3*!"3nU  
else if(nFileLength == -2) Y_P!B^z3  
{ |y!A&d=xYn  
System.err.println("File is not access!"); V=3b&TkE  
} Flb&B1  
else ],].zlN  
{ % & bY]w  
for(int i=0;i<nStartPos.length;i++) 3Zh)]^  
{ lu/ (4ED  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); BJ(M2|VH  
} 08{@rOr  
for(int i=0;i<nEndPos.length-1;i++) Etm?'  
{ g9F?z2^  
nEndPos = nStartPos[i+1]; #`s"WnP9'!  
} \l3h0R  
nEndPos[nEndPos.length-1] = nFileLength; m#p'iU*va,  
} N{>n$ v}  
} > Nr#O  
Rf 1x`wml  
akQ7K  
//启动子线程 }ad|g6i`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ovV'VcUs  
for(int i=0;i<nStartPos.length;i++) RG`1en  
{ =g|FT  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =tY T8Q;al  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), |Q>IrT  
nStartPos,nEndPos,i); IE~ |iQ?-  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >LuYHr  
fileSplitterFetch.start(); #_lDss  
} e>7i_4(C  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), T[j,UkgGo  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); u#SWj,X  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", rrv%~giU  
nEndPos = " + nFileLength); vfo~27T{(  
// fileSplitterFetch[nPos.length-1].start(); rVsJ`+L  
Af{"pzY  
Rx}Gz$   
//等待子线程结束 vr^qWn  
//int count = 0; ,Y48[_ymm  
//是否结束while循环 Du){rVY^d  
boolean breakWhile = false; Lj;2\]  
<0?W{3NqI  
DlNX 3  
while(!bStop) igAtRX%Qx  
{ _J[P[(ab  
write_nPos(); xkR0  
Utility.sleep(500); GuL<Z1<c  
breakWhile = true; >F&47Yn  
Sa5G.^ XI  
)\^-2[;  
for(int i=0;i<nStartPos.length;i++) `@s^(hc7i  
{ X\ F|Tk3_  
if(!fileSplitterFetch.bDownOver) 5/z/>D;  
{ =nHgDrA_  
breakWhile = false; gPc=2  
break; t&DEb_"De  
} Ti&z1_u  
} KY] C6kh  
if(breakWhile) Om {'1  
break; 9~YMyg(Z  
O|UC ?]6  
{FTqu.  
//count++; !0E&@X:-  
//if(count>4) WOf 4o  
// siteStop(); 7J&4akT{9  
} SK.: Q5:  
pY$Q  
<b<j=_3  
System.err.println("文件下载结束!"); GowH]MO  
} [PKR2UEe]  
catch(Exception e){e.printStackTrace ();} dAe')N:KPI  
} H 7 ^/q7  
D|#E9OQzs  
o%*xvH*A  
//获得文件长度 6\S~P/PkE  
public long getFileSize() 2VCI 1E  
{ *HB-QIl  
int nFileLength = -1; #LN`X8Wz'  
try{ *4_Bd=5(U  
URL url = new URL(siteInfoBean.getSSiteURL()); s(roJbJ_;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); S`?!G&[!>  
httpConnection.setRequestProperty("User-Agent","NetFox"); dGTsc/$  
8e"gW >f  
O<W_fx8_'  
int responseCode=httpConnection.getResponseCode(); -s'-eQF J  
if(responseCode>=400) ?P c'C  
{ pFz`}?c0  
processErrorCode(responseCode); 8sK9G` k  
return -2; //-2 represent access is error e<q?e}>?  
} {cw /!B  
q6X1P" %.  
$xdy&  
String sHeader; y L~W.H  
gbagi+8s`%  
dcWD(-  
for(int i=1;;i++) jm r"D>  
{ ##4HYQ%E  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Mh 7DV  
//Utility.log(in.readLine()); {T~#?v(  
sHeader=httpConnection.getHeaderFieldKey(i); -RK- Fu<e  
if(sHeader!=null) m<2M4u   
{ BJo*'US-Q  
if(sHeader.equals("Content-Length")) ?5 [=(\/.  
{ W'u>#  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); vEz"xz1j!]  
break; ib791  
} xFg>SJ7]  
} wo 5   
else ZWp(GC1NA  
break; c-FcEW  
} t.\dpBq  
} i<g-+Qs  
catch(IOException e){e.printStackTrace ();} %BB%pC  
catch(Exception e){e.printStackTrace ();} ^D-/`d  
w917N 4$  
|)/aGZ+  
Utility.log(nFileLength); sds"%]r g  
QoH6  
@49S`  
return nFileLength; KRKCD4  
} &~U ]~;@  
N_q|\S>t/  
('p5:d  
//保存下载信息(文件指针位置) P J[`|  
private void write_nPos() R0  
{ K@w{"7}  
try{ 0NX,QD  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 4tmAzD  
output.writeInt(nStartPos.length); l0i^uMS  
for(int i=0;i<nStartPos.length;i++) delu1r  
{ g5r(>,vY  
// output.writeLong(nPos); ! #2{hQRu  
output.writeLong(fileSplitterFetch.nStartPos); K8Y=S12Ti  
output.writeLong(fileSplitterFetch.nEndPos); uOdl*|T?  
} c<$OA=n  
output.close(); EI^C{ $Y  
} G[q$QB+  
catch(IOException e){e.printStackTrace ();} `%WU8Yv  
catch(Exception e){e.printStackTrace ();} cD'V>[h  
} 2WYPO"q  
fvxu#m=  
:tv,]05t  
//读取保存的下载信息(文件指针位置) C'}KTXiRW  
private void read_nPos() W#3Q ^Z?  
{ v^+Sh|z/  
try{ Qv/=&_6  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 3I-MdApT  
int nCount = input.readInt(); UN<]N76!  
nStartPos = new long[nCount]; qPfQy  
nEndPos = new long[nCount]; lQkQ9##*   
for(int i=0;i<nStartPos.length;i++) 2x0<&Xy#P  
{ hODWB&b  
nStartPos = input.readLong(); 'Ne@e)s9  
nEndPos = input.readLong(); 0}q uG^%_  
} aPbE;" f  
input.close(); Q^txVUL  
} dL )<% o  
catch(IOException e){e.printStackTrace ();} l8#EM1g-  
catch(Exception e){e.printStackTrace ();} ]f9Cx\d:k  
} `$ aZ0+  
WbqWG^W  
Czu\RXJR  
private void processErrorCode(int nErrorCode) 8StgsM  
{ _/5H l`  
System.err.println("Error Code : " + nErrorCode); Pw!MS5=r  
} Otm0(+YB 7  
-Wi` G  
 p|D/;Mk  
//停止文件下载 9|CN8x-  
public void siteStop() LOV)3{m  
{ Z Sd4z:/  
bStop = true; Pce;r*9  
for(int i=0;i<nStartPos.length;i++) i9][N5\$  
fileSplitterFetch.splitterStop(); t"/q]G5  
l$bu%SZ  
#';:2Nyq  
} xbYi.  
} * *G9H  
//负责部分文件的抓取 {8,J@9NU  
**FileSplitterFetch.java Y#$%iF  
*/ B%+T2=&$7  
package NetFox; IG9VdDj  
~|xA4u5LG  
yhA6i  
import java.io.*; )+t0:GwP`:  
import java.net.*; H-fX(9  
3]3|  
v9O~@v{=  
public class FileSplitterFetch extends Thread { Q%mB |i|  
':m,)G5&  
ly3\e_z:G  
String sURL; //File URL HYSIN^<oy  
long nStartPos; //File Snippet Start Position tr}Loq\y  
long nEndPos; //File Snippet End Position *CTlOy  
int nThreadID; //Thread's ID (|1A?@sJ#h  
boolean bDownOver = false; //Downing is over nq8C'Fo!6T  
boolean bStop = false; //Stop identical 2Gaa(rJ5o  
FileAccessI fileAccessI = null; //File Access interface 6]%sFy2  
* U=s\  
;&-k#PE]/H  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 'o>B'$  
{ rK]Cr9WM  
this.sURL = sURL; =CVBBuVy  
this.nStartPos = nStart; }"!I[Ek> y  
this.nEndPos = nEnd; q\p:X"j|  
nThreadID = id; tQYM&6g  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 +@k+2?] FO  
} RcU}}V  
' x35=@  
!s?nJ(p  
public void run() I( 7NQ8H x  
{ VYImI>.t{  
while(nStartPos < nEndPos && !bStop) Ob`d  
{ !AfHk|  
@;?p&.W`D  
Opc ZU{4 b  
try{ |kV*Jc k  
URL url = new URL(sURL); q6`b26  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); mah JSz(3  
httpConnection.setRequestProperty("User-Agent","NetFox"); c?&X?<  
String sProperty = "bytes="+nStartPos+"-"; s6.M\^  
httpConnection.setRequestProperty("RANGE",sProperty); @Y<bwv  
Utility.log(sProperty); ;{tj2m,  
x%!s:LVX  
f-G :uI_  
InputStream input = httpConnection.getInputStream(); h2J/c#Qvh  
//logResponseHead(httpConnection); 8~z~_TD6m@  
6){]1h"  
8MzVOF{"  
byte[] b = new byte[1024]; )@Yf]qx+Y<  
int nRead; mtmjZP(w   
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Y^}Z>  
{ 3L}!RB  
nStartPos += fileAccessI.write(b,0,nRead); `q*M4,  
//if(nThreadID == 1) 64G[|" j D  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (VEpVn3{  
} \VyZ  
"8^ Ch{G-  
sAS:-wp  
Utility.log("Thread " + nThreadID + " is over!"); z Q`jP$2  
bDownOver = true; sjwo/+2  
//nPos = fileAccessI.write (b,0,nRead); >$7v ;Q  
} f"SD/]q-  
catch(Exception e){e.printStackTrace ();} m\r@@!  
} ^c4@(]v'G  
} *><F'   
?+W 9az]+  
VZymM<O  
//打印回应的头信息 y8!4q  
public void logResponseHead(HttpURLConnection con) ADP%QTdqFJ  
{ Et/\xL  
for(int i=1;;i++) @As[k2  
{ c[4i9I3v  
String header=con.getHeaderFieldKey(i); VE {3}S  
if(header!=null) EGzzHIZ`!  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ( b~T]3Es  
Utility.log(header+" : "+con.getHeaderField(header)); 6ZG+ZHUC&  
else !1DKLQ  
break; b TM{l.Aq3  
} %GA"GYL9'  
} evAMJ=  
-Rd/G x  
#_J@-f7^  
public void splitterStop() pg.ri64H<  
{ >qjq=Ege  
bStop = true; b8"?VS5-"  
} LO khjHR  
Ix!Iw[CNd  
L>W'LNXCv  
} n%C>E.Tq  
NS%xTLow-  
IE&!YP(U(  
/* y7 3VFb  
**FileAccess.java n}_JB>i~  
*//文件访问(定位,写) ?Exv|e  
package NetFox; B~JwHwIhA  
import java.io.*; ~&8^9E a  
_w/EP  
A3no~)wZn  
public class FileAccessI implements Serializable{ g-H N  
UAFwi%@!-q  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 x:>wUhzZ  
RandomAccessFile oSavedFile; E^lvbLh'  
long nPos; Wm"4Ae:B  
+ SFVv_n  
I)cFG{~L  
public FileAccessI() throws IOException f3&[#%  
{ iZNts%Y]  
this("",0); D 38$`j  
} Y/ >&0wj)d  
X4AyX.p  
ujaG Ng?,  
public FileAccessI(String sName,long nPos) throws IOException !2A:"2Kys:  
{ +!z{5:  
oSavedFile = new RandomAccessFile(sName,"rw"); RIXMJ7e7  
this.nPos = nPos; RHq/JD-  
oSavedFile.seek(nPos); Z!@~>i  
} *-q"3 D`  
Nq` C.&  
P8>d6;o($  
public synchronized int write(byte[] b,int nStart,int nLen) Nz+9 49X  
{ rI>aAW'  
int n = -1; 8lb%eb]U  
try{ SAK!z!t  
oSavedFile.write(b,nStart,nLen); ang~<  
n = nLen; Xr2ou5zAn  
} . DR<Te  
catch(IOException e) %K` % *D  
{ ~ ! 3I2  
e.printStackTrace (); J'fQW<T4wU  
} O QT;zqup  
Fpa ;^F  
jm0- y%  
return n; P%=#^T&`}  
} '0uh D.|G  
HA`@7I  
`V"sOTb  
} =%gRW5R%  
W4e5Rb4~f"  
RIE5KCrGB  
/* iz?tu: \v&  
**SiteInfoBean.java /yF QeE  
*/ 2Sp=rI  
package NetFox; CkD#/  
;SaX;!`39+  
Y&_&s7z  
public class SiteInfoBean { NqEA4C  
dBe`p5Z  
oiyzHx  
private String sSiteURL; //Site's URL Tp?y8r  
private String sFilePath; //Saved File's Path x.zbD8l/9  
private String sFileName; //Saved File's Name (v|} \?L  
private int nSplitter; //Count of Splited Downloading File WxJf{=-  
DrBUe'RH:M  
_ozg_E  
public SiteInfoBean() ?a8(a zn  
{//nSplitter的缺省值为5 ]Xf% ,iu  
//default value of nSplitter is 5 @` Eg(  
this("","","",5); XC "'Q+  
} .YnFH$;$  
:.d:9Z|_  
\&3"<6xA  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) f=!VsR2o  
{ MpqZH{:?G  
sSiteURL= sURL; CI :`<PZ\-  
sFilePath = sPath; t" 7yNs(I  
sFileName = sName; ;VNMD 6H  
this.nSplitter = nSpiltter; OhmQ,  
7&"n`@(.!  
}X_;X_\3;'  
} T4 N~(Fi)  
)aao[_ZS  
VX+jadYdq  
public String getSSiteURL() MJCzo |w  
{ hL;8pE8  
return sSiteURL; ""h)LUrl  
} )a3J9a;ZS0  
L%$|^T=%  
f{i8w!O"~  
public void setSSiteURL(String value) N, *m ,  
{ a/U2xq{x  
sSiteURL = value; PN<C=gAe  
} bb`':3%  
P<2 +L|X?}  
|vMpXiMxxT  
public String getSFilePath() saAxGG  
{ +:-57  
return sFilePath; ^1x*lLf  
} {}m PEd b  
U{$1[,f  
EVUq--)~  
public void setSFilePath(String value) 3ZZV<SS  
{ iQ6epg1wB  
sFilePath = value; lz0TK)kuC  
} TO*BH^5R  
qdG~!h7j  
h:)Ci!D;  
public String getSFileName() [kzd(u  
{ kWb2F7m  
return sFileName; ;v~-'*0  
} (N K9vW4F  
t"lyvI[  
p,<&zHb>K  
public void setSFileName(String value) `)h6j)xiQ  
{ jWO/ xX  
sFileName = value; GK}'R=   
} !W'Ui 9uX  
~!d/8?!   
y}K\%;`[a  
public int getNSplitter() s(LT  
{ ~i_Tw#}  
return nSplitter; (j"(  
} Rek -`ki5F  
"ZHtR/;  
\[>9UC%  
public void setNSplitter(int nCount) %|l8f>3[  
{ %q322->Z  
nSplitter = nCount; hv$m4,0WB  
} f8<o8*`7  
} R%H$%cnj  
1?Aga,~k:a  
ph|ZG6:  
/* Ei3zBS?J)  
**Utility.java ia{c  
*/ vN OH&ja-s  
package NetFox; 0Hw-59MK  
#W2[  
Y'3}G<'%  
public class Utility { asgF1?r  
FNQX7O52  
Gy Qm/I  
public Utility() \#x}q'BC4  
{ qxJQPz  
9H]Lpi^OH  
=}fd6ea(o  
} @C-dG7U.P  
uH^ PQ  
//线程睡眠 Hv<'dt$|  
public static void sleep(int nSecond)  `}no9$l~  
{ XfzVcap  
try{ PaCzr5!~f  
Thread.sleep(nSecond); jSQ9.%4  
} 5NXt$k5  
catch(Exception e) ZDYJhJ.  
{ Zz |MIGHm  
e.printStackTrace (); Bl1Z4` 3  
} rn:!dV[  
} 6`"M  
SnTDLa  
//日志 ])#\_' fg  
public static void log(String sMsg) %im#ww L%  
{ ,rwuy[Q8  
System.err.println(sMsg); w[Ep*-yeI  
} x q-$\#O  
=]Hs|{  
}98>5%Uv  
public static void log(int sMsg) agOk*wH5  
{ D 0]a\,aZ  
System.err.println(sMsg); g#K'6VK{  
} y466A]|  
} i(wgB\9i4  
o8FXqTUcs4  
q cA`)j  
/* qturd7  
**TestMethod.java Y ZaP  
*/ Y &r]lD  
package NetFox; h#Ce_,o  
Cw,D{  
h:Ndzp{  
public class TestMethod { ;<G<1+  
;+I4&VieK  
vV`|!5x  
public TestMethod() C;\VO)]t  
{ ///xx/weblogic60b2_win.exe Y5!b)vke  
try{ cf[vf!vi  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 3@O0^v-  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); jV7&Y.$zF]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); JK~ m(oQ  
fileFetch.start(); P-JfV7(O8  
} {rkn q_;0  
catch(Exception e){e.printStackTrace ();} WA.\*Nqze  
kJ: 2;t=  
ZAg;q#z j  
} 3On JWuVfZ  
q:HoKJv4  
Ew^ @Aq  
public static void main(String[] args) WY)^1Gb$ux  
{ s"0b%0?A  
new TestMethod(); o;-<|W>  
} G\Q9IcJ0dY  
} %XXkVK`  
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