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http断点续传简单实现(java)

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/* F$sDmk#  
**SiteFileFetch.java " "@kBY1C  
*/ En9>onJ  
package NetFox; `VrQ? s  
import java.io.*; O7"16~ a  
import java.net.*; 56?RFnZ&j  
%f?Z/Wn  
fsjCu!  
public class SiteFileFetch extends Thread { eKUP,y;[I  
~tc,p  
!AXt6z cZ  
SiteInfoBean siteInfoBean = null; //文件信息Bean b!<\#[ A4  
long[] nStartPos; //开始位置 drQI@sPp  
long[] nEndPos; //结束位置 .fgVzDR|+  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 >~;= j~  
long nFileLength; //文件长度 V8hmfV~=]P  
boolean bFirst = true; //是否第一次取文件 diWi0@  
boolean bStop = false; //停止标志 OZR{+YrB^  
File tmpFile; //文件下载的临时信息 ( 5 BZZ  
DataOutputStream output; //输出到文件的输出流 ^ 'ws/(  
h-<Qj,L{W  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) "h5.^5E6  
public SiteFileFetch(SiteInfoBean bean) throws IOException /jl/SV+  
{ MBqw{cy  
siteInfoBean = bean; |SfCuV#g/<  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 7_Op(C4,nC  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); .3'U(U  
if(tmpFile.exists ()) oLS/  
{ [gDl<6a#4  
bFirst = false; RsW4 '5  
read_nPos(); Ya &\b 6  
} oCxy(q'y  
else #9glGPR(  
{ +>ld  
nStartPos = new long[bean.getNSplitter()]; K=Z.<f  
nEndPos = new long[bean.getNSplitter()]; kQ`p\}7_  
} "-Yj~  
Ys0N+  
mb>8=hMg  
"s.hO0Z  
} \ZtKaEXnx  
J(:y-U  
W)<t7q+  
public void run() \4KV9wm  
{  u]OYu  
//获得文件长度 ||))gI`3a  
//分割文件 v,kvLjqt  
//实例FileSplitterFetch lhPxMMS`j  
//启动FileSplitterFetch线程 (]` rri*^  
//等待子线程返回 C~IE_E&Q`  
try{ 6HZVBZhM  
if(bFirst) z?@N+||,.  
{ Qb5@e#  
nFileLength = getFileSize(); >9NC2%61S  
if(nFileLength == -1) OtbPr F5  
{ [:zP]l.|  
System.err.println("File Length is not known!"); ?=im  ~  
} p^1~o/  
else if(nFileLength == -2) :=*V i`  
{ 3RF`F i  
System.err.println("File is not access!"); 0DFVB%JdI  
} #5=W[+4eN  
else _\gCdNrD  
{ {rwT4]4  
for(int i=0;i<nStartPos.length;i++) F!fsW9  
{ 7&dK_x,a  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 6!se,SCvw  
} (((|vI3 <  
for(int i=0;i<nEndPos.length-1;i++) =ea.+  
{ uvAJJIae'  
nEndPos = nStartPos[i+1]; DkSs^ym  
} uu.}<VM.1  
nEndPos[nEndPos.length-1] = nFileLength; ?G<ISiABQC  
} sDY+J(Z  
} u@;e`-@  
z+{xW7  
y\ })C-&  
//启动子线程 gT(8.<h8  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; -Jf}3$Ra  
for(int i=0;i<nStartPos.length;i++) 1aZGt2;  
{ <I#M^}`  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +`iJ+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ((&5F!+\-  
nStartPos,nEndPos,i); 1Ko4O)L]&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); & WeN{  
fileSplitterFetch.start(); ROXa/  
} ~uV(/?o%  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1IlOU|4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); PuhvJHT  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Z6-ZAS(>m  
nEndPos = " + nFileLength); M!D6i5k,   
// fileSplitterFetch[nPos.length-1].start(); gWL`J=DiU  
vOLa.%X]h  
5,4m_fBoW  
//等待子线程结束 {9@u:(<X9  
//int count = 0; <xe_t=N  
//是否结束while循环 Cg|\UKfy$  
boolean breakWhile = false; LIrebz  
0 6M?ecN  
|MOz> 1<a  
while(!bStop) ddN G :  
{ :>/6:c?atG  
write_nPos(); CYlS8j  
Utility.sleep(500); LJom+PxF$x  
breakWhile = true; f-634KuP  
>FKwFwT4D  
80`$F{xcX  
for(int i=0;i<nStartPos.length;i++) /\;m/cwrl"  
{ 'c_K[p$  
if(!fileSplitterFetch.bDownOver) l|{[vZpT  
{ nW} s  
breakWhile = false; xQ2: tY#?  
break; )Ay9 0Wt  
} <s7cCpUFP  
} &r,)4q+  
if(breakWhile) g~$UU(HX  
break; |fIyq}{7  
f$tm<:)Y  
T:Ovh.$  
//count++; mYj)![  
//if(count>4) GwfCl{l  
// siteStop(); +KD7Di91<K  
} ;4(}e{  
x7Gf):,LK  
j@w1S[vt  
System.err.println("文件下载结束!"); :`E p#[Wvo  
} Br15S};Ce  
catch(Exception e){e.printStackTrace ();} z{FFTb^B  
} o(H.1ESk  
Vh>cV  
=R~zD4{"  
//获得文件长度 2gZ nrU  
public long getFileSize() HTv#2WX  
{ #0hqfs  
int nFileLength = -1; qE|syA9  
try{ .ANR|G  
URL url = new URL(siteInfoBean.getSSiteURL()); QQ_7Q^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2P)O 0j\/  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1q@R04i  
4P"bOt5izR  
kN78j  
int responseCode=httpConnection.getResponseCode(); f0j]!g  
if(responseCode>=400) "*.N'J\  
{ GmaNi  
processErrorCode(responseCode); lG Bg8/[  
return -2; //-2 represent access is error Lr 5{c5M  
} <,rOsE6  
y4LUC;[n  
ggiy{CdR  
String sHeader; <9piKtb|L  
lSW'qgh  
f$6N  
for(int i=1;;i++) h6OQeZ.  
{ zA8@'`Id  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); wpN3-D  
//Utility.log(in.readLine()); d6 ef)mw  
sHeader=httpConnection.getHeaderFieldKey(i); vV*J;%MO  
if(sHeader!=null) fU?#^Lg  
{ Lt=32SvTn  
if(sHeader.equals("Content-Length")) \/?J)k3H.  
{ Rw%?@X3m]  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); l_yF;5|?z  
break; u '/)l}  
} Nh_\{ &r  
} aK95&Jyw&  
else hc+B+-,  
break; N%xCyZ  
} ,ofE*Wt  
} -egnMc67  
catch(IOException e){e.printStackTrace ();} DyCzRkH  
catch(Exception e){e.printStackTrace ();} e,VF;Br  
,z>-_HOnw  
86N,04  
Utility.log(nFileLength); fZ5 UFq_~s  
83SK<V6  
IQ~qiFCf  
return nFileLength; }8#Ed;%K  
} bT&{8a  
u~j H  
R:YVmqd  
//保存下载信息(文件指针位置) %),u0:go  
private void write_nPos() ;nP(S`'  
{ 5cinI^x)f  
try{ :;yrYAyT3  
output = new DataOutputStream(new FileOutputStream(tmpFile)); }O>1tauI  
output.writeInt(nStartPos.length); j&_>_*.y  
for(int i=0;i<nStartPos.length;i++) }`Ya;  
{ 7/51_=%kR  
// output.writeLong(nPos); P1T {5u!T  
output.writeLong(fileSplitterFetch.nStartPos); pR93T+X  
output.writeLong(fileSplitterFetch.nEndPos); NWvIwt{  
} _<FUS'"  
output.close(); h=gtuaR4  
} Wp8>Gfb2  
catch(IOException e){e.printStackTrace ();} "q+Z*   
catch(Exception e){e.printStackTrace ();} c8"Qmy  
} #gO[di0WhC  
c/A?-9  
05T?c{ ;  
//读取保存的下载信息(文件指针位置) q,@# cQBV  
private void read_nPos() W/xPVmnV  
{ 6bhb_U'f  
try{ CvE^t#Bok  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); *c[w9(fU  
int nCount = input.readInt(); 8|=C/k  
nStartPos = new long[nCount]; (w)%2vZ^  
nEndPos = new long[nCount]; y zp#  
for(int i=0;i<nStartPos.length;i++) x@Z{5w_a  
{ #f24a?n|  
nStartPos = input.readLong(); v$Fz^<Na  
nEndPos = input.readLong(); T`fT[BaY  
} #jg-q|nd  
input.close(); ,^8':X"A{!  
} `1(ED= |  
catch(IOException e){e.printStackTrace ();} `| ?<KF164  
catch(Exception e){e.printStackTrace ();} <I34@;R c  
} [B;okW  
W j^@Zq#  
/~w*)e)  
private void processErrorCode(int nErrorCode) QrK%DN  
{ B os`+Y  
System.err.println("Error Code : " + nErrorCode); CU\gx*=E  
} {%u^O/M  
`x/i1^/_@  
ah,f~.X_|  
//停止文件下载 ' Xj^cX  
public void siteStop() d=qVIpZ  
{ PHqg~q;*  
bStop = true; /qy6YF8;y  
for(int i=0;i<nStartPos.length;i++) m\XsU?SuX  
fileSplitterFetch.splitterStop(); !>> A@3  
%K|f,w=m  
$.4A?,d  
} RVttk )Ny  
} TG$ #aX\'  
//负责部分文件的抓取 >"b W'  
**FileSplitterFetch.java iSezrN  
*/ d; YKw1  
package NetFox; Slg *[r#  
n({%|O<|  
F<g&t|@  
import java.io.*; 6c-3+,Y"#  
import java.net.*; ?[zw5fUDS  
AF"7 _  
6_KvS  
public class FileSplitterFetch extends Thread { {:!>Y1w>  
gR# k'   
l1k&@1"  
String sURL; //File URL tUx H 6IS  
long nStartPos; //File Snippet Start Position 9gw;MFP)D  
long nEndPos; //File Snippet End Position z+Fu{<#(  
int nThreadID; //Thread's ID eZ(ThA*2=t  
boolean bDownOver = false; //Downing is over Gm:s;w-;v  
boolean bStop = false; //Stop identical %6uZb sa  
FileAccessI fileAccessI = null; //File Access interface 4vWiOcJF!O  
SkmTW@v  
CYy=f-  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException -_t4A *  
{ XJeWhk3R9  
this.sURL = sURL; ptT-{vG  
this.nStartPos = nStart; :Q("  
this.nEndPos = nEnd; Ue 9Y+'-x  
nThreadID = id; iKrk?B<  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 2H.g!( Oza  
} /}~=)QHH  
7yyX8p>  
3W[?D8yi)  
public void run() D tZ?sG  
{ a)pc+w#  
while(nStartPos < nEndPos && !bStop) mbkt7. ,P  
{ a($7J6]M  
KF+r25uy[+  
aUEr& $  
try{ AH&RabH2  
URL url = new URL(sURL); uthW AT &  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); r+C4<-dT  
httpConnection.setRequestProperty("User-Agent","NetFox"); z8t;jw  
String sProperty = "bytes="+nStartPos+"-"; Fnak:R0  
httpConnection.setRequestProperty("RANGE",sProperty); Ez|NQ:o  
Utility.log(sProperty); 3JQ7Cc>  
xtP:Q9!N  
d%0Gsga}  
InputStream input = httpConnection.getInputStream(); vO2WZ7E!  
//logResponseHead(httpConnection); H%Gz"  
G$TO'Ciu:  
Xrb7.Y0d  
byte[] b = new byte[1024];  ?{"r(  
int nRead; ^PNDxtd|v  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) k5aB|xo  
{ ]>(pj9)  
nStartPos += fileAccessI.write(b,0,nRead); J";N^OR{A%  
//if(nThreadID == 1) hQj@D\}  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Gl'G;F$Y-  
} W/BPf{U  
;]grbqXVE  
:5CyR3P  
Utility.log("Thread " + nThreadID + " is over!"); o-H?q!  
bDownOver = true; v%T'!(0j/  
//nPos = fileAccessI.write (b,0,nRead); q{9 \hEeb  
} $?W2'Xm!V  
catch(Exception e){e.printStackTrace ();} EB!ne)X  
} nX3?7"v  
} ?lD)J?j  
`OMX 9i  
b;jdk w|  
//打印回应的头信息 $k0(iFzR1  
public void logResponseHead(HttpURLConnection con) H; \C7w|  
{ q,)V0Ffe[|  
for(int i=1;;i++) K\9CW%W  
{ E} XmZxHV  
String header=con.getHeaderFieldKey(i); 0ex.~S_Oj4  
if(header!=null) J78.-J5 j0  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); vwu/33  
Utility.log(header+" : "+con.getHeaderField(header)); Wj,s/Yr:  
else R&Nl!QTJj  
break; H@@ 4n%MK  
} asYk #;z\"  
} ~;CNWJtcf(  
\ZADY.ha  
q&z'S  
public void splitterStop() oB5\^V$  
{ F|> 3gW  
bStop = true; G!$~'o%/  
} 3ArHaAv{y  
_N|%i J5  
A{q%sp:3~  
} ,o n]Fts  
C5V}L  
Z qn$>mG-  
/* 7P3pjgh  
**FileAccess.java @U=y}vi8  
*//文件访问(定位,写) %r1#G.2YW  
package NetFox; &,G2<2_b  
import java.io.*; ZH\t0YhrVe  
(4 ZeyG@  
b3-j2`#  
public class FileAccessI implements Serializable{ +7w5m  
rZdOU?U  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 })^eaLBR4  
RandomAccessFile oSavedFile; 5]I)qij q  
long nPos; ' F.^ 8/>  
;=0mL,  
W;I{4ed6  
public FileAccessI() throws IOException F_:zR,P%#  
{ X,VI5$  
this("",0); nm#23@uZ4K  
} WRu(F54Sk  
9R8q+2  
0,RYO :`  
public FileAccessI(String sName,long nPos) throws IOException 5@>hjXi"Y  
{ ?[ )}N _o#  
oSavedFile = new RandomAccessFile(sName,"rw"); r]cq|Nv8:  
this.nPos = nPos; hOk9y=  
oSavedFile.seek(nPos); ,e'm@d$Q*  
} z[J=WI  
rd0Fd+t/  
vVo'f|fW  
public synchronized int write(byte[] b,int nStart,int nLen) 3?V'O6  
{ G@ ot^n3  
int n = -1; trrNu  
try{ .q MxShUU  
oSavedFile.write(b,nStart,nLen); &j:prc[W  
n = nLen; 'e]>lRZ  
} 8[J%TWq%9  
catch(IOException e) cy,6^d  
{ n(Nu  
e.printStackTrace (); :1qLRr  
} K!CVS7  
?1\I/ 'E9  
#Q7:Mu+  
return n; q-Z<.GTq  
} 8m' f8.x  
1(Vv-bq$  
I= :yfW  
} wX)'1H):T  
zNo,PERG  
V.`hk^V,  
/* J&\Q3_vro9  
**SiteInfoBean.java \wz^Z{U  
*/ IQ\!wWKmY  
package NetFox; ^}$t(t  
>4wigc  
iWjNK"W  
public class SiteInfoBean { 'Iw`+=iVz  
>mA]2gV<a  
Y<W9LF  
private String sSiteURL; //Site's URL Bv~^keuj3t  
private String sFilePath; //Saved File's Path ,X_3#!y  
private String sFileName; //Saved File's Name &cyB}Gv  
private int nSplitter; //Count of Splited Downloading File 16Ka>=G  
Fu{VO~w  
geK;r0(f  
public SiteInfoBean() !%R):^R8  
{//nSplitter的缺省值为5 Ld_uMe?Z  
//default value of nSplitter is 5 %_:L_VD@  
this("","","",5); 19GF%+L ,  
} <$?#P#A  
sT1OAK\^  
83vZRQw  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) .CEC g*f  
{ I_f%%N%  
sSiteURL= sURL; Zex~ $r  
sFilePath = sPath; g0biw?  
sFileName = sName; fsOlg9  
this.nSplitter = nSpiltter; dl=)\mSFjF  
fIpS P@$<  
/'{vDxZf R  
} <fBJ@>  
tBzE(vW  
[K #$W  
public String getSSiteURL() XO?WxL9k]  
{ L>/$l(  
return sSiteURL; zZ-/S~l  
} g~21|Sa$[  
/xgC`]-  
T$MXsq  
public void setSSiteURL(String value) ph b ;D  
{ )OQm,5F1  
sSiteURL = value; Oi|cTZ@A-  
} 5w>TCx  
V$DB4YM1k  
 Yf[Cmn  
public String getSFilePath() $G0e1)D  
{ %9zpPr WF  
return sFilePath; DmgDhNXKq  
} lv] U)p  
.=}\yYGe   
{@Lun6\  
public void setSFilePath(String value) +~F>:v?Rh  
{ #"A`:bjG  
sFilePath = value; 5);"()g32  
} .mrv"k\<  
iDDq<a.A  
>j]Gz-wC  
public String getSFileName() tC1'IE-h  
{ %Jl6e}!  
return sFileName; >N! Xey  
} E5S(1Z}]p{  
T)22P<M8  
FB?V<x  
public void setSFileName(String value) uh 9b!8  
{ V 7~9z\lW  
sFileName = value; z I9jxwXU  
} ysp,:)-%G@  
=1>G * ,  
c9H6\&  
public int getNSplitter() 7C2Xy>d~  
{ |;V-;e*  
return nSplitter; ,>(X}Q  
} zuMz6#aCC8  
`TF3Ho\MC  
-[>J"l  
public void setNSplitter(int nCount) sDgo G  
{ .yTo)t  
nSplitter = nCount;  3k6Dbz  
} ZiKO|U@/  
} uHf1b?W  
.I{u[ "  
K ..Pn 17t  
/* DZESvIES  
**Utility.java ffB<qf)?G  
*/ Z 5 .cfI[  
package NetFox; , =*^XlO=c  
kN<;*jHV  
,lCFe0>k!=  
public class Utility { b-`P-  
Y -BZV |  
KIuj;|!q  
public Utility() U\{I09@E 0  
{ _^eA1}3  
~PpU'[  
&j'k9C2p  
} 4u2_xbT  
 k_^ 4NU  
//线程睡眠 ='Oxy  
public static void sleep(int nSecond) g-x;a0MQx  
{ e7Gb7c~  
try{ <#Fex'4  
Thread.sleep(nSecond); mT j  
} lzFg(Ds!f  
catch(Exception e) HF&d HD2f  
{ G'HLnx}Yi  
e.printStackTrace (); (7~vOWs:[  
} Iw$T'I+4W  
} rw@N=`4P  
"$"<AKCwS  
//日志 ^^xzaF  
public static void log(String sMsg) g*9&3ov  
{ )i-`AJK-'v  
System.err.println(sMsg); YSZ[~?+  
} oqK: 5|  
``Um$i~e%  
Ex}TDmTu  
public static void log(int sMsg) H 0Sm4  
{ 3WfZzb+  
System.err.println(sMsg); Y8mv[+Z  
}  >qI:  
} ZkMHy1  
Np~qtR  
h^ K>(x  
/* m|Z[8Tup  
**TestMethod.java i-k(/Y0  
*/ 7` XECIh  
package NetFox; </fTn_{2s8  
<PO-S\N  
1-!|_<EW1  
public class TestMethod { kl&_O8E+K  
iIo>]\Pw  
9FT==>  
public TestMethod() 3fop.%(  
{ ///xx/weblogic60b2_win.exe b` 9Zin  
try{ Ki)hr%UFw  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); \\"CgH-  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); .= 8Es#  
SiteFileFetch fileFetch = new SiteFileFetch(bean); !\&4,l(  
fileFetch.start(); H/G;hk  
} 3bugVJ9 3  
catch(Exception e){e.printStackTrace ();} )4+uM'2%  
J2`OJsMwWe  
O_SM!!,  
} 6& 9q6IIy  
?N%5c%oF  
mvtuV`  
public static void main(String[] args) } 4>#s$.2  
{ URTJA<r8D  
new TestMethod(); 61TL]S8  
} S7hfwu&7F  
} ! }awlv;  
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