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http断点续传简单实现(java)

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/* X0FTD':f  
**SiteFileFetch.java ;*+wg5|  
*/ hiT&QJB` _  
package NetFox; H@|h Nn$@  
import java.io.*; /TEE<\"  
import java.net.*; j'IZetT  
@1c[<3xJ T  
g.,_E4L  
public class SiteFileFetch extends Thread { q0t}  
eVRPjVzQ'Q  
9_Ws8nE  
SiteInfoBean siteInfoBean = null; //文件信息Bean ov$S   
long[] nStartPos; //开始位置 wk9qyv<  
long[] nEndPos; //结束位置 ]K0G!TR<  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 j 3t,Cx  
long nFileLength; //文件长度 _48@o^{  
boolean bFirst = true; //是否第一次取文件 Y[~Dj@Q<  
boolean bStop = false; //停止标志 zm~sq_=^  
File tmpFile; //文件下载的临时信息 |#i|BVnoE  
DataOutputStream output; //输出到文件的输出流 <>71;%e;'  
+eUWf{(_  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) i8nzPKF2$3  
public SiteFileFetch(SiteInfoBean bean) throws IOException BbC aIt  
{ bCfw,V{sce  
siteInfoBean = bean; T8t_+| ( G  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 07 E9[U[  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); d_] sV4[  
if(tmpFile.exists ()) pP|LSr Y!  
{ A6S|pO1)3  
bFirst = false; L]e@. /C$  
read_nPos(); \2#j1/d4  
} O'.sK pXe  
else xf|vz|J?y  
{ {kOTQG?y  
nStartPos = new long[bean.getNSplitter()]; *]K/8MbiF  
nEndPos = new long[bean.getNSplitter()]; o=)["V  
} Dkyw3*LCn%  
;N?raz2mEi  
 8 ?4/  
s2kom)  
} :ceT8-PBRx  
/w/um>>K.  
GNX`~%3KYc  
public void run() Ox%.We 5  
{ 7=`_UqCV  
//获得文件长度 Cj5=UUnO  
//分割文件 ir<K"wi(2  
//实例FileSplitterFetch L (@".{T  
//启动FileSplitterFetch线程 EC8Fapy  
//等待子线程返回 \Y$@$)   
try{ D:=Q)Uh0I  
if(bFirst) 2t}^8  
{ P.Gmj;  
nFileLength = getFileSize(); g;-6Hg'  
if(nFileLength == -1) w:3CWF4q]  
{ phP%  
System.err.println("File Length is not known!"); 6|10OTVu`  
} c[zGWF#1>  
else if(nFileLength == -2) f+V^q4  
{ /oC@:7  
System.err.println("File is not access!"); LUKt!I0l  
} L43]0k  
else `)n/J+g  
{ aS/MlMf  
for(int i=0;i<nStartPos.length;i++) 8S#TOeQ  
{ []<N@a6VA>  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); DP6>fzsl  
} s$ZKd  
for(int i=0;i<nEndPos.length-1;i++) n eBcS[  
{ /I~(*X  
nEndPos = nStartPos[i+1]; $,8}3R5}  
} 8;<3Tyjzu  
nEndPos[nEndPos.length-1] = nFileLength; "NvB@>S  
} g$T% C?  
} HLb`'TC3r+  
zW:r7 P.  
+2JC**)I  
//启动子线程 %(ms74R+  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; e3=-7FU  
for(int i=0;i<nStartPos.length;i++) 20`QA u)'  
{ r}M2t$nv  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9?I?;l{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), EXizRL-9o  
nStartPos,nEndPos,i); uGY(`  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); LA4,o@V`  
fileSplitterFetch.start(); vT;~\,M  
} Cm%xI& Y  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `%$l b:e  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); w\%AR1,rs  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", c +N\uG4  
nEndPos = " + nFileLength); !n`Y^  
// fileSplitterFetch[nPos.length-1].start(); E6+ 6  
+z O.|`+  
z+{Q(8'b]  
//等待子线程结束 0NMmN_Lr  
//int count = 0; ]EfM;'j[  
//是否结束while循环 ,r,$x4*  
boolean breakWhile = false; ;dqu ld+q  
8],tGMu  
q{2 +Inf#:  
while(!bStop) -`ss7j&b3  
{ Co^GsUJ  
write_nPos(); LNOz.2fr>  
Utility.sleep(500); -:|t^RM;FT  
breakWhile = true; 4Ixu%  
h: Hpz  
v{O(}@  
for(int i=0;i<nStartPos.length;i++) &H:2TL!  
{ 'M=V{.8U  
if(!fileSplitterFetch.bDownOver) r%FfJM@!  
{ c3!YA"5  
breakWhile = false; &w{: qBa  
break; =q<t,UP8  
} wvPS0]  
} ^-g-]?q  
if(breakWhile) B j z@X  
break; 8^5@J) R8  
m:]60koz]o  
LLd5Z44v  
//count++; z c&i 4K  
//if(count>4) (3QG  
// siteStop(); >"<<hjKJ  
} 8?G534*r@2  
7"p%c`*;  
[w?v !8l  
System.err.println("文件下载结束!"); uU!}/mbo  
} "#=WD  
catch(Exception e){e.printStackTrace ();}  li  
} fT0+i nRG  
*ulkqpO  
;{Tf:j'g  
//获得文件长度 }HxC ~J"  
public long getFileSize() W3]?>sLE*  
{ 6GsB*hW  
int nFileLength = -1; kA{eT  
try{ 9k3RC}dEr  
URL url = new URL(siteInfoBean.getSSiteURL()); gi JjE  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); p&W{g $D>  
httpConnection.setRequestProperty("User-Agent","NetFox"); f!13Ob<8r  
.Gn-`  
* %w8bB  
int responseCode=httpConnection.getResponseCode(); I0v4TjHH  
if(responseCode>=400) UY/qI%#L#,  
{ FV5~sy  
processErrorCode(responseCode); 2i~zAD'  
return -2; //-2 represent access is error N&]_U%#Q  
} +J  <<me4  
2A(IsUtqO:  
DNGj81'c  
String sHeader; Fg^Z g\X3  
+W^$my)<  
4&wwmAp^  
for(int i=1;;i++) g%%j"Cz1  
{ df7 xpV  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); oWV^o8& GH  
//Utility.log(in.readLine()); /m8&E*+T1  
sHeader=httpConnection.getHeaderFieldKey(i);  b =R9@!  
if(sHeader!=null) K yDPD'  
{ yN9setw*,M  
if(sHeader.equals("Content-Length")) a"whg~  
{ DUWSY?^c  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); aSQvtv)91  
break; ;\rKkH"K8n  
} {:ZsUnzm  
} OJXK]dZ  
else \>)#cEX5  
break; 1MxO((k  
} #GIjU1-  
} )|IMhB+4  
catch(IOException e){e.printStackTrace ();} (x/xqDpmBS  
catch(Exception e){e.printStackTrace ();} ]C5/-J,F  
2M*84oh8P  
LNI]IITx/  
Utility.log(nFileLength); lJdwbuB6  
^u$?& #  
1wt(pkNk  
return nFileLength; _OvIi~KW+  
} H\<^p",`  
=O'>H](Q  
TmUN@h  
//保存下载信息(文件指针位置) n--w-1  
private void write_nPos() `Uy4>?  
{ 1D2Yued  
try{ ,&0iFUwN_  
output = new DataOutputStream(new FileOutputStream(tmpFile)); U_ *K%h\m  
output.writeInt(nStartPos.length); _aK4[*jnqh  
for(int i=0;i<nStartPos.length;i++) S%2qX"8  
{ }o2e&.$4d  
// output.writeLong(nPos); +~!\;71:f  
output.writeLong(fileSplitterFetch.nStartPos); M}qrF~   
output.writeLong(fileSplitterFetch.nEndPos); d D;r35h=  
} :y3e-lr  
output.close(); o 76QQ+hP  
} OE5JA8/H  
catch(IOException e){e.printStackTrace ();} [hXnw'Im/  
catch(Exception e){e.printStackTrace ();} F8>J(7On  
} K&UTs$_cI  
31`Eq*Y)4  
lWWy|r'il  
//读取保存的下载信息(文件指针位置) fSw6nEXn  
private void read_nPos() B'~CFj0W%=  
{ kqt.?iJw  
try{ YZQF*fj  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ]hjA,p@Q  
int nCount = input.readInt(); X'.*I])  
nStartPos = new long[nCount]; *k<{nj@y  
nEndPos = new long[nCount]; +WB';D  
for(int i=0;i<nStartPos.length;i++) Y^9b>H\2  
{ 9P\R?~3  
nStartPos = input.readLong(); K4j2xSGeo  
nEndPos = input.readLong(); CyV(+KBe_  
}   7)  
input.close(); ZFa<{J<2  
} -| YDKcL  
catch(IOException e){e.printStackTrace ();} mxkv{;ad  
catch(Exception e){e.printStackTrace ();} f1 TYQ?e  
} CZ}%\2>-v  
g"|Z1iy|9  
V jZx{1kCR  
private void processErrorCode(int nErrorCode) 8bW,.to(?x  
{ iYBp"+#2  
System.err.println("Error Code : " + nErrorCode); CT#u+]T  
} P=PVOt@ b  
VY_<c98v  
2/.I6IbL  
//停止文件下载 drW}w+ !  
public void siteStop() KdU&q+C^  
{ ,'^^OLez  
bStop = true; `cn}}1Lg]  
for(int i=0;i<nStartPos.length;i++) i[rXs/]  
fileSplitterFetch.splitterStop(); Lk:Sju  
{>8u/  
L__J(6,V2  
} Q|i`s=|  
} O&ZVu>`g  
//负责部分文件的抓取 #SIIhpjA(  
**FileSplitterFetch.java ZGbY  
*/ lMRy6fzI  
package NetFox; x&YcF78  
y)#=8oci  
aW@J]slg  
import java.io.*; " UxKG+   
import java.net.*; M;zJ1  
z2Kvp"-}  
0VwmV_6'<W  
public class FileSplitterFetch extends Thread { ;1Zz-@  
7@l.ZECJ1  
!a<}Mpeg  
String sURL; //File URL |"o/GUI~  
long nStartPos; //File Snippet Start Position Ld$e  -dB  
long nEndPos; //File Snippet End Position o%V%@q H  
int nThreadID; //Thread's ID $ITh)#Nj  
boolean bDownOver = false; //Downing is over HqKI|^  
boolean bStop = false; //Stop identical *7:HO{P>Y  
FileAccessI fileAccessI = null; //File Access interface j/*4Wj[  
jO+#$=C  
wTK>U`o  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException { ((|IvP`  
{ t?6_^ 08  
this.sURL = sURL; a?5R ;I B  
this.nStartPos = nStart; i.Jk(%c  
this.nEndPos = nEnd; EL+P,q/b  
nThreadID = id; 0DgEOW9H  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ?VP07 dQTe  
} H;=++Dh  
RY9h^q*  
FNB4YZ6  
public void run() aK4ZH}XHE"  
{ ``9`Xq  
while(nStartPos < nEndPos && !bStop) =BNS3W6  
{ [7*$Sd  
4E~!$Ustx  
04wO9L;  
try{ BkcA_a:W  
URL url = new URL(sURL); \V/;i.ng  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); />[X k  
httpConnection.setRequestProperty("User-Agent","NetFox"); YKWts y  
String sProperty = "bytes="+nStartPos+"-"; h:l4:{A64  
httpConnection.setRequestProperty("RANGE",sProperty); |\iJ6m;a  
Utility.log(sProperty); 3,4m|Z2)  
fx `oe  
B jsF5~+\  
InputStream input = httpConnection.getInputStream(); jpI=B  
//logResponseHead(httpConnection); jZLD^@AP  
1Z| {3W  
gW(7jFl  
byte[] b = new byte[1024]; nD/; Gq  
int nRead; (TQhO$,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) C#Y_La  
{ ]v6s](CE  
nStartPos += fileAccessI.write(b,0,nRead); g?=|kp  
//if(nThreadID == 1) %}x$YD O  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =V(|3?N  
} Wp0L!X=0  
!w #x@6yq  
\]gUX-  
Utility.log("Thread " + nThreadID + " is over!"); wjnQK  
bDownOver = true; LYvjqNC&4  
//nPos = fileAccessI.write (b,0,nRead); !3 j@gi2  
} pXBlTZf  
catch(Exception e){e.printStackTrace ();} Z{gJm9  
} p@Ng.HE  
} f1}am<  
6l|,J`G  
;&8  
//打印回应的头信息 i!k5P".o^  
public void logResponseHead(HttpURLConnection con) O2 sAt3'  
{ bQelU  
for(int i=1;;i++) (iO8[  
{ g (:%E  
String header=con.getHeaderFieldKey(i); bL9EX$P  
if(header!=null) ?!d\c(5Gt  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 0z1UF{{  
Utility.log(header+" : "+con.getHeaderField(header)); k),!%6\(  
else N5Rda2m  
break; :SD^?.W\iT  
} 7B| #*IZe  
} Fy'/8Yv#L  
U#{^29ik=o  
ZlxJY%o eu  
public void splitterStop() ^:F |2  
{ U9ZWSDs  
bStop = true; yQ{xRtNO  
} c4AkH|  
qJ8@A}}8  
13v#  
} C% )Xz  
c5f8pa *  
1O{x9a5Z?O  
/* 7g a|4j3%  
**FileAccess.java *4<Kz{NF  
*//文件访问(定位,写) _Boe"   
package NetFox; Sy?O(BMo  
import java.io.*; +_h1JE_}D  
L dyTB@  
!J@!P?0. C  
public class FileAccessI implements Serializable{ alB[/.1  
P pF"n[j  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 (g>>   
RandomAccessFile oSavedFile; +>,4d  
long nPos; bw\a\/Dw  
eJv_`#R&Of  
Q\ AM] U  
public FileAccessI() throws IOException D3BNA]P\2@  
{ f6d:5 X_  
this("",0); n,+/%IZ  
} `*`@ro  
MsL*\)*s  
aOr'OeG(=e  
public FileAccessI(String sName,long nPos) throws IOException F7r!zKXZ  
{ 0M^v%2 2  
oSavedFile = new RandomAccessFile(sName,"rw"); xct{Tv[FO  
this.nPos = nPos; ?%Pd:~4D  
oSavedFile.seek(nPos); lNw8eT~2  
} D:yj#&I  
/y.+N`_  
(g8<"< N?  
public synchronized int write(byte[] b,int nStart,int nLen) S3oSc<&2  
{ (4WAoye|  
int n = -1; 3TDjWW;#~  
try{ r?l7_aBv3  
oSavedFile.write(b,nStart,nLen); D0f.XWd  
n = nLen; NWt`X!  
} (6*CORE   
catch(IOException e) .*bu:FuDE  
{ r- :u*  
e.printStackTrace (); 8LMO2Wyq  
} uIO<6p)  
}{(dG7G+  
1oSrhUTy  
return n; $%3"@$  
} :s}6a23  
v9t26>{~  
[1\k'5rp  
} !M&Qca2  
PDEeb.(.  
!&n'1gJ)kd  
/* o JLpFL  
**SiteInfoBean.java {vf"`#Q9  
*/ R2 I 7d'|v  
package NetFox; kX2bU$1Q,i  
/2n-q_  
S?M'JoYy  
public class SiteInfoBean { C" W,  
 )Uk!;b  
H:d@@/  
private String sSiteURL; //Site's URL gC+PpY#2h  
private String sFilePath; //Saved File's Path ?Bdhn{_  
private String sFileName; //Saved File's Name !FqJP OGm  
private int nSplitter; //Count of Splited Downloading File Pr%Y!|  
bAsoIra  
8-2e4^ g(  
public SiteInfoBean() $@[`v0y*  
{//nSplitter的缺省值为5 c89+}]mGq  
//default value of nSplitter is 5 ds*N1[ *  
this("","","",5); R.FC3<TTv  
} }KBz8M5  
`}Of'i   
#c?xJ&bh  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) l. 9 i `  
{ ;9+[t8Y)D  
sSiteURL= sURL; lD%Fk3  
sFilePath = sPath; !m* YPY31  
sFileName = sName; w Bi'KS  
this.nSplitter = nSpiltter; $hn=MOMc  
j0XS12eM  
Y M <8>d  
} vH^6O:V  
'K L" i  
nI63Ns  
public String getSSiteURL() N}j]S{j}'  
{ -8r';zR  
return sSiteURL; &7i o/d\/  
} s?:&#  
c,K)*HB  
gyz#:z$p^  
public void setSSiteURL(String value) Q (3Na6  
{ %a_ rYrL  
sSiteURL = value; w=ib@_:f  
} bK\Mn95]  
|[RoR  
YPV@/n[N  
public String getSFilePath() /Vg=+FEO  
{ eNwF<0}  
return sFilePath; ~6)A/]6  
} x'4q`xDa  
.d JX,^  
GV+K] KDI  
public void setSFilePath(String value) kgq"b)  
{ y .O%  
sFilePath = value; <? Z[X{  
} \ r^#a  
*[P"2b#  
g[NmVY-o  
public String getSFileName() 8zMt&5jD  
{ +PlA#DZu  
return sFileName;  $:7 T  
} i1(}E#  
mM[!g'*  
X\ -IAv  
public void setSFileName(String value) _V jfH2Y  
{ {CO]wqEj  
sFileName = value; u["3| `C5  
} R;G"LT  
7z_EX8^  
JJHfg)  
public int getNSplitter() IzuYkl}  
{ 8(6(,WwP}  
return nSplitter; <WHu</  
} A>?_\<Gp  
j5rB+  
Yq$KYB j  
public void setNSplitter(int nCount) <r@w`G  
{ xF#'+Y  
nSplitter = nCount; H n^)Xw  
} *&=sL  
} ag_RKlM3  
sbju3nvk  
W<QMUu  
/* q)m0n237P  
**Utility.java hR g?H  
*/ /:+f5\"-b  
package NetFox; fLtN-w6t  
j$<sq  
Z7="on4  
public class Utility { \Nvu[P  
}MCh$  
1(q &(p  
public Utility() Z8Jrt3l{2  
{ )w t mc4'  
R7nT,7k.  
'4"9f]:  
} `X:o]t@  
V,*<E&+  
//线程睡眠 RZ6[+Ygn  
public static void sleep(int nSecond) (uxe<'Co|  
{ $ouw *|<  
try{ |= o)|z2  
Thread.sleep(nSecond); L&I8lG  
} I*SrK Zb  
catch(Exception e) :rBPgrt  
{ U5iyvU=UG  
e.printStackTrace (); j_ \?ampF  
} MR?5p8S#g  
} 5Al1u|;HB  
N4xC Zb  
//日志 1@i|[dq  
public static void log(String sMsg) `<"@&N^d  
{ YUGEGXw  
System.err.println(sMsg); H,{WrWA  
} B%.vEk)*  
G[bWjw86O  
}%T8?d]  
public static void log(int sMsg) C-}@.wr(  
{ S{0iPdUC  
System.err.println(sMsg); PX} ~  
} nB &[R  
} z>6hK:27  
4GN  
\Fs+H,S<  
/* NKSK+ll2  
**TestMethod.java ;UAi>//#   
*/ Qvx[F:#Tk  
package NetFox; P4VMGP  
)Z"  
zUIh^hbFf  
public class TestMethod { [Zpx :r}  
l!d |luqbA  
&>xd6-  
public TestMethod() (v)/h>vS  
{ ///xx/weblogic60b2_win.exe DD?zbN0X  
try{ }g9g]\.!a  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }3TTtd7  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); $!ATj`}kb  
SiteFileFetch fileFetch = new SiteFileFetch(bean); `xq/<U;i  
fileFetch.start(); Fs3rsig  
} -_KO}_  
catch(Exception e){e.printStackTrace ();} 9'5`0$,|^  
9*<=K  
PsMp &~^  
} 0D s W1  
'Zket=Sm;  
r3BQo[ 't  
public static void main(String[] args) y"L7.B  
{ hHsN(v  
new TestMethod(); X1C &;5  
} ]_EJ "'x  
} \,ko'4 8@  
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