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http断点续传简单实现(java)

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/* {*4Z9.2c*  
**SiteFileFetch.java DZ|/#- k  
*/ N" oJ3-~  
package NetFox; 'MIM_m)H  
import java.io.*; 7kidPAhY  
import java.net.*; ,1e@Y~eZ  
1uhSP!b  
G{oM2`c'#8  
public class SiteFileFetch extends Thread { 9L9mi<,  
& |o V\L  
SkA"MhX  
SiteInfoBean siteInfoBean = null; //文件信息Bean Aaix? |XN  
long[] nStartPos; //开始位置 GEi^3UD  
long[] nEndPos; //结束位置 V?cUQghHg  
FileSplitterFetch[] fileSplitterFetch; //子线程对象  6@ )bZ|  
long nFileLength; //文件长度 \(ZOt.3!J  
boolean bFirst = true; //是否第一次取文件 r7p>`>_Q\  
boolean bStop = false; //停止标志 sQe>LNp,G  
File tmpFile; //文件下载的临时信息 "A9 c]  
DataOutputStream output; //输出到文件的输出流 l,3[hx  
c}FZb$q#  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) wD&b[i  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1{S" axSL  
{ n-_-;TYH  
siteInfoBean = bean; /c1FFkq|K  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); I*K~GXWs#  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); >j$CM:w  
if(tmpFile.exists ()) ysiBru[u  
{ ?5 d3k%  
bFirst = false; #VEHyz6P  
read_nPos(); WChJ <[]W  
} 2xd G&}$fa  
else ",T-'>h$2R  
{ `W8dayZt  
nStartPos = new long[bean.getNSplitter()]; _\LAWQ|M4[  
nEndPos = new long[bean.getNSplitter()]; j7 D\O  
} I(Yyg,1Z  
*^u5?{$l(  
Tce2]"^;  
y(8AxsROp  
} Pw'3ya8  
I.\fhNxHY  
.r?-O{2t  
public void run() ( Qw"^lE3  
{ Y75,{1\l0  
//获得文件长度  P-QZ=dm  
//分割文件 v7/qJ9l  
//实例FileSplitterFetch e;<=aa)}?  
//启动FileSplitterFetch线程 j xr~cp?4  
//等待子线程返回 igsJa1F  
try{ m>'sM1s  
if(bFirst) [x 5T7=  
{ ?t+Kp 9@aZ  
nFileLength = getFileSize(); /nRi19a%xU  
if(nFileLength == -1) g Xvuv^  
{ M:qeqn+  
System.err.println("File Length is not known!"); @%K@oDL  
} Jn. WbS  
else if(nFileLength == -2) r"a0!]n  
{ `Q*L!/K+  
System.err.println("File is not access!"); Sf)VQ5U!Y  
} wbzAX  
else wg*2mo  
{ YZdp/X6x  
for(int i=0;i<nStartPos.length;i++) ajW[}/)  
{ :0j9  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); |jniI(  
} WLEjRx  
for(int i=0;i<nEndPos.length-1;i++) s3W)hU)  
{ C9U~lcIS  
nEndPos = nStartPos[i+1]; wz5xJ:Tj  
} :~pPB#)nk  
nEndPos[nEndPos.length-1] = nFileLength; Q9Wa@gi|  
} x5k6yHn  
} J A ]s  
T2 0dZ8{y  
e;56}w  
//启动子线程 g6k@E,cI_  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; jAmAT /1  
for(int i=0;i<nStartPos.length;i++) ojzO?z  
{ 1y l2i|m+  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Aq}]{gfQ1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ;GO>#yg4Eh  
nStartPos,nEndPos,i); 74rz~ZM 5  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  [ottUS@  
fileSplitterFetch.start(); C+$dm)M/q  
} `(<XdlOj  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <SUjz}_Oa:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); K.n #;|  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", [>Kkj;*  
nEndPos = " + nFileLength); BDyOX6  
// fileSplitterFetch[nPos.length-1].start(); s"<k) Xi  
-@-cG\{  
R 28v5  
//等待子线程结束 Zi[@xG8dm  
//int count = 0; SY_T\ }  
//是否结束while循环 9`+c<j4/B  
boolean breakWhile = false; a1B_w#?8  
&96I4su  
>Qz#;HI  
while(!bStop) .R;HH_  
{ F_U3+J>  
write_nPos(); |AW[4Yn>  
Utility.sleep(500); &F*s.gL  
breakWhile = true; .{LFc|Z[  
)V%xbDdS  
={-\)j  
for(int i=0;i<nStartPos.length;i++) =xWZJ:UnU  
{ hV])\t=yf  
if(!fileSplitterFetch.bDownOver) Ap !lQ>p  
{ .|=\z9_7S8  
breakWhile = false; ItCv.yv35  
break; @ .KGfNu  
} O H7FkR  
} \Og+c%  
if(breakWhile) I 2DpRMy  
break; H[|~/0?K  
L rPkxmR  
.sA.C] f  
//count++; =Runf +}  
//if(count>4) G / 5%.Bf@  
// siteStop(); t:c.LFrF  
} 'm9` 12 H  
t >sE x:  
6zn5UW#q  
System.err.println("文件下载结束!"); Er[A X.3  
} 6@Y|"b  
catch(Exception e){e.printStackTrace ();} ?hM64jI|  
} iR0y"Cii  
,2)6s\]/b  
R GX=)  
//获得文件长度 DeYV$W B  
public long getFileSize() P }uOJVQ_  
{ HorDNRyu  
int nFileLength = -1; U%<Inb}ad  
try{ [8*)8jP3  
URL url = new URL(siteInfoBean.getSSiteURL()); -{+}@?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *9i{,I@  
httpConnection.setRequestProperty("User-Agent","NetFox"); PxE3K-S)G  
>OK^D+v"j  
v9UD%@tZ  
int responseCode=httpConnection.getResponseCode(); -!9G0h&i|  
if(responseCode>=400) o? $.fhD   
{ ;UP$yM;  
processErrorCode(responseCode); [fIg{Q  
return -2; //-2 represent access is error Tac$LS\Q  
} 3D(0=$ W  
 RX5dO%  
t()c=8qF|u  
String sHeader; d`6 ' Z  
Hq 188<  
Xs?o{]Fe  
for(int i=1;;i++) 5 u0HI  
{ $tS}LN_!  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); MqUH',\3  
//Utility.log(in.readLine()); k# rBB  
sHeader=httpConnection.getHeaderFieldKey(i); ! v0LBe4  
if(sHeader!=null) .6'qoo_N  
{ &8 x-o,  
if(sHeader.equals("Content-Length")) {.\TtE  
{ (!N|Kl  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); m9Hit8f@Q  
break; >e"#'K0?\  
} ;d9QAN&0}  
} !GGkdg*-*9  
else # N cK X  
break; Z)aUt Srf  
} 4_cqT/  
} # 4PVVu<  
catch(IOException e){e.printStackTrace ();} E+w<RNBmz  
catch(Exception e){e.printStackTrace ();} N*&1GT#9  
8pgEix/M5o  
9 |vLwQ  
Utility.log(nFileLength); ox (%5c)b|  
,nB5/Lx  
/gkX38  
return nFileLength; N' `A?&2ru  
} /RC7"QzL  
0=E]cQwh  
 !=P1%  
//保存下载信息(文件指针位置) <yFu*(Q  
private void write_nPos() C-[eaHJ'$  
{ Gk /fBs  
try{ OH(waKq2I  
output = new DataOutputStream(new FileOutputStream(tmpFile)); J6FV]Gpv  
output.writeInt(nStartPos.length); kq,ucU%>p  
for(int i=0;i<nStartPos.length;i++) KNIn:K^/  
{ Da&]y  
// output.writeLong(nPos); ah+iZ}E%  
output.writeLong(fileSplitterFetch.nStartPos); $@"g^,n  
output.writeLong(fileSplitterFetch.nEndPos); EA]U50L(  
} ` v@m-j6  
output.close(); b 7?hI  
} @7j AL-  
catch(IOException e){e.printStackTrace ();} K}MK<2vU  
catch(Exception e){e.printStackTrace ();} h|{]B,.Lh  
} JHTSUq  
Vt&2z)Zz  
Y^EcQzLw  
//读取保存的下载信息(文件指针位置) =.]4;z  
private void read_nPos() S2VA{9:m  
{ s{\8om '-  
try{ T !WT;A  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); F%D.zvKN  
int nCount = input.readInt(); EVC]sUT  
nStartPos = new long[nCount]; &H/'rd0M  
nEndPos = new long[nCount]; '=8d?aeF  
for(int i=0;i<nStartPos.length;i++) qm8B8&-  
{ Fgh_9S9J  
nStartPos = input.readLong(); \B,@`dw  
nEndPos = input.readLong(); ~^fZx5  
} My[pr_xg  
input.close(); JL}_72gs  
} c>:wd@w  
catch(IOException e){e.printStackTrace ();} 62o:,IcoG  
catch(Exception e){e.printStackTrace ();} k],Q9  
} $OkBg0  
iYm-tsER;  
>T3-  
private void processErrorCode(int nErrorCode) 3z9d!I^>k  
{ -g Sa_8R  
System.err.println("Error Code : " + nErrorCode); /quc}"__  
} Tg)| or/ %  
[KaAXv .X  
$f=J2&D,Cz  
//停止文件下载 Wk4s reB  
public void siteStop() Pz|>"'  
{ J76kkW`5  
bStop = true; Jg\zdi:t  
for(int i=0;i<nStartPos.length;i++) ~{B7 k:  
fileSplitterFetch.splitterStop(); u9GQU  
9gEwh<  
KNpl:g3{<Q  
} u4F5h PO]  
} lC("y' ::  
//负责部分文件的抓取 ~>Fu5i $i  
**FileSplitterFetch.java i8[t=6Rm@  
*/ 5Y'qaIFR  
package NetFox; ?o4C;  
Qu"\wE^.`  
ag#S6E^%S  
import java.io.*; ,+vy,<e&  
import java.net.*; ith 3 =`3  
[OV"}<V  
eH3JyzzP,  
public class FileSplitterFetch extends Thread { aS{n8P6vW  
k,E{C{^M  
5k3b3&  
String sURL; //File URL N~d?WD\^  
long nStartPos; //File Snippet Start Position (Hz^)5(~  
long nEndPos; //File Snippet End Position UkT=W!cq  
int nThreadID; //Thread's ID |\<`Ib4j  
boolean bDownOver = false; //Downing is over eJVjuG  
boolean bStop = false; //Stop identical J^nBdofP  
FileAccessI fileAccessI = null; //File Access interface W*4-.*U8a  
#!qm ZN  
m!4ndO;0vh  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException YX7L?=;.@  
{ 8'.Hyy@;  
this.sURL = sURL; EXwo,?I  
this.nStartPos = nStart; z(exA  
this.nEndPos = nEnd; f/NH:1)y  
nThreadID = id; {3p4:*}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 C:* *;=.  
} -MO#]K3<  
+p_CN*10H  
\H~T>j{N  
public void run() wd^':  
{ |zNX=mAV  
while(nStartPos < nEndPos && !bStop) b#Z{{eLny  
{ 69?wc!  
}DE g-j,F  
[f-?y mmT  
try{ }[};IqVaK  
URL url = new URL(sURL); Ae^~Cz1qz  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); JEwa &  
httpConnection.setRequestProperty("User-Agent","NetFox"); [0[i5'K:  
String sProperty = "bytes="+nStartPos+"-"; @* jz o  
httpConnection.setRequestProperty("RANGE",sProperty); Uq,^Wy  
Utility.log(sProperty); +I:Unp  
cAqLE\h  
(KD RkE|=  
InputStream input = httpConnection.getInputStream(); "f2$w  
//logResponseHead(httpConnection); 9y8&9<#  
3{^9]7UC  
n;Q7X>-f8`  
byte[] b = new byte[1024]; /P3 <"?#k  
int nRead; UWJ8amA  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) V-2(?auZd  
{ Rz:]\jcIT/  
nStartPos += fileAccessI.write(b,0,nRead); ,~$p,ALwN7  
//if(nThreadID == 1) VUGmi]qd  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6|%?tex  
} LTCb@L{^i  
"]x'PI 4J  
@#>rYAb8,  
Utility.log("Thread " + nThreadID + " is over!"); oUr66a/[U  
bDownOver = true; 1 ~*7f>  
//nPos = fileAccessI.write (b,0,nRead); Y;Dp3v !  
} ")5":V~fN  
catch(Exception e){e.printStackTrace ();} 9C9oUtS  
} c?*=|}N  
} 7\[@ m3s  
[z\$?VJspQ  
t%FwXaO#  
//打印回应的头信息 $am$ EU?s  
public void logResponseHead(HttpURLConnection con) cN6X#D  
{ |\t-g" ~sN  
for(int i=1;;i++) f:w?pE  
{ XS{Qnx_#  
String header=con.getHeaderFieldKey(i); JPUW6e07o  
if(header!=null) FFpT~.  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); A#<?4&  
Utility.log(header+" : "+con.getHeaderField(header)); IGQFtO/x  
else su( 1<S}  
break; \fd v]f  
} : /N0!&7  
} >dD@j:Qc  
LEf^cM=>  
(D&3G;0tK  
public void splitterStop() T!kN)#S  
{ RJ&RTo  
bStop = true; E GS)b  
} U&OJXJd j  
iB yf{I>+  
y9GoPC`z  
} s`8= 3]w  
!hy-L_wL]  
gO-  _  
/*  A,<E\  
**FileAccess.java uyWunpT  
*//文件访问(定位,写) =BAr .m+"  
package NetFox;  'KL0@l  
import java.io.*; "m8^zg hL  
'sKk"bi;0  
]:-mbgW  
public class FileAccessI implements Serializable{ P|E| $)m  
..5CC;B  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 !i}w~U<  
RandomAccessFile oSavedFile; Y\P8 v  
long nPos; ueWEc^_>  
&wawr2)}  
 4e7-0}0  
public FileAccessI() throws IOException {\1?ZrCI&  
{ ,w4(kcg%iQ  
this("",0); lfgq=8d  
} eC4[AX6e  
my1@41 H  
ec;o\erPG  
public FileAccessI(String sName,long nPos) throws IOException +TL%-On  
{ !9e=_mY  
oSavedFile = new RandomAccessFile(sName,"rw"); iWkWR"ys y  
this.nPos = nPos; #:_Kws>+  
oSavedFile.seek(nPos); Gb6'n$g  
} Q3~H{)[Kq  
N>`Aw^ _@&  
jB2[(  
public synchronized int write(byte[] b,int nStart,int nLen) eo?bL$A[s  
{ (5YM?QAd  
int n = -1; ^{`exCwM x  
try{ 9$w.9`Py  
oSavedFile.write(b,nStart,nLen); M|h3Wt~7  
n = nLen; <'oQ \eB  
} ]%H`_8<gc  
catch(IOException e) IEi^kJflU  
{ ED gag  
e.printStackTrace ();  mq.`X:e  
} 7n<{tM  
r l%  
2/^3WY1U  
return n; Yj49t_$b  
} Lk8ek}o'  
g3y~bf  
g! |kp?  
} J*M>6Q.)  
J ZS:MFA  
6bC3O4Rw  
/* 6 H$FhJF  
**SiteInfoBean.java 8nV+e~-w  
*/ gH{X?  
package NetFox; I=N;F6  
/zB;1%m-  
&}TfJ=gj  
public class SiteInfoBean { ;g-L2(T05;  
)X8?m <cG  
-uho;  
private String sSiteURL; //Site's URL r*-e~  
private String sFilePath; //Saved File's Path }~8/a3  
private String sFileName; //Saved File's Name @B<B#  
private int nSplitter; //Count of Splited Downloading File A5d(L4Q]a(  
c5>'1L  
V}leEf2'  
public SiteInfoBean() uO4kCK<7C  
{//nSplitter的缺省值为5 |FF"vRi8a7  
//default value of nSplitter is 5 ?q}XD c  
this("","","",5); Hk65c0  
} ~:65e 8K  
o6@Hj+,,  
N8$MAW  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) /0w?"2-  
{ 3 cd5 g  
sSiteURL= sURL; 8J&K_ JC^  
sFilePath = sPath; 9.bMA<X  
sFileName = sName; h6!o,qw"  
this.nSplitter = nSpiltter; +y+-~;5iv  
^7l.!s#$b  
i.4L;(cg  
} B{ i5UhxD  
Z;/"-.i  
NW}kvZ  
public String getSSiteURL() nN|zEw]  
{ &"V%n  
return sSiteURL; X%S9 H^9  
} 8}Pd- .se  
bL=32YS  
ObDcNq/b!  
public void setSSiteURL(String value) "}uPz4  
{ jg ~;s  
sSiteURL = value; B3 mD0   
} ;pU#3e+P8  
Sb&sW?M  
jV_Eyi3  
public String getSFilePath() <{C oM  
{ &Wj %`T{  
return sFilePath; b"Hg4i)  
} dAOmqu, 6  
N=) E$h  
WMB~? EDhv  
public void setSFilePath(String value) 5S PGv}if  
{ %eoO3"//  
sFilePath = value; RH,(8.&>r  
} \ H#zRSbZ  
M ) 9Ss  
=bUVGjr%96  
public String getSFileName() Pnb?NVP!^9  
{ \h6_m)*H4  
return sFileName; 5 ^}zysY`  
} /*Z ,i&eC  
mw<LNnT{8  
tzv&E0 |d  
public void setSFileName(String value)  A_: Bz:  
{ clz6; P  
sFileName = value; M*)}F  
} qyMR0ai-  
Pms"YhyZ7  
]}/LNO*L"  
public int getNSplitter() c ?mCt0Cg  
{ Lwgk}!KR  
return nSplitter; wU_e/+0h  
} 1F'j .1  
>Pv#)qtm  
h?2qX  
public void setNSplitter(int nCount) |+//pGx  
{ :)+|q  
nSplitter = nCount; X:\r )  
} 6\(wU?m'/  
} }p0|.Qu9  
#SQao;>  
#5)E4"m  
/* sHO6y0P  
**Utility.java t&(}`W  
*/ ,Z*?"d  
package NetFox; c@)k#/[[b  
2.O;  
)sG`sET]`f  
public class Utility { ?4wS/_C/  
ny17(Y =  
-~eNC^t;W  
public Utility() A?8f 6  
{ zzi%r=%r&  
[ Y.3miE  
> Zo_-,  
} ]V J$;v'{[  
fkWuSGi  
//线程睡眠 aS?A3h4WM_  
public static void sleep(int nSecond) xuQ$67F`;z  
{ ^R\0<\'  
try{ aoQK.7  
Thread.sleep(nSecond); hZ!N8nWwNR  
} {E!ie{~  
catch(Exception e) &Cp)\`[y  
{ OOS(YP@b  
e.printStackTrace (); QkUq%}_0  
} Z8tQ#Pu{  
} 0 } uEM_a  
 .BJ;}  
//日志 l)GV&V  
public static void log(String sMsg) ^Fgmwa'  
{ vK)^;T ;  
System.err.println(sMsg);  Ko9"mHNB  
} 61>@-55k9  
eAS~>|N#x  
eZR{M\Q  
public static void log(int sMsg) }5-^:}gL   
{ SU9qF73Y  
System.err.println(sMsg); H2`aw3  
} L,V\g^4$K  
} #rM/  
i6M_Gk}  
LL@VR#n"V  
/* _3DRCNvh  
**TestMethod.java G\&4_MS  
*/ Q-fi(UP  
package NetFox; /PF X1hSu  
:a#Mq9ph!  
5CH9m[S  
public class TestMethod { O0Y/y2d  
2i`N26On  
`!Ei H<H}  
public TestMethod() DZKVZ_q  
{ ///xx/weblogic60b2_win.exe 0<75G6wd  
try{ ;*ebq'D([  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Y}%=:Yt  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); {^ 1s  
SiteFileFetch fileFetch = new SiteFileFetch(bean); CJ0j2e/  
fileFetch.start(); YFgQ!\&59  
} JTB_-J-TU  
catch(Exception e){e.printStackTrace ();} ]@_M)[ x  
RGh `=D/yE  
I@~hz%'  
}  N)G.^9  
hyv*+FV;  
+ew2+2  
public static void main(String[] args) bv ,_7UOG  
{ i~:FlW]  
new TestMethod(); @bU(z$eB  
} i3g;B?54  
}  pv1J6  
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