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http断点续传简单实现(java)

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/* b@nri5noBm  
**SiteFileFetch.java -ET*M<  
*/ *(?U  
package NetFox; :z0s*,QH  
import java.io.*; ]_^"|RJ  
import java.net.*; \_m\U.*  
.V5q$5j  
ib5;f0Qa  
public class SiteFileFetch extends Thread { oV0LJ%  
ga4/,   
e%P+KX  
SiteInfoBean siteInfoBean = null; //文件信息Bean 6F|Hg2tpz  
long[] nStartPos; //开始位置 _n-VgPRn  
long[] nEndPos; //结束位置 3q~":bpAp  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 P!`Q_h6a  
long nFileLength; //文件长度 c8bca`  
boolean bFirst = true; //是否第一次取文件 7\7Brw4  
boolean bStop = false; //停止标志 yt/20a  
File tmpFile; //文件下载的临时信息 6%\7.h  
DataOutputStream output; //输出到文件的输出流 SREDM  
Tf&f`/  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) S5:"_U  
public SiteFileFetch(SiteInfoBean bean) throws IOException |i,zY{GI+2  
{ OqfhCNAY  
siteInfoBean = bean; Bo\a  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); WUE)SVf  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ^kCk^D-Gz  
if(tmpFile.exists ()) -XS+Uv  
{ u)q2YLK8  
bFirst = false; e3yorQ][  
read_nPos(); 5PPPd-'Z_  
} _H~pH7WU  
else @Og\SZhn  
{ 1kB'sc3N!  
nStartPos = new long[bean.getNSplitter()]; x&hvFG3  
nEndPos = new long[bean.getNSplitter()]; Hrd5p+j  
} OPvj{Dv$0  
jRv;D#Hp  
#}[Sj-Vp  
LG/=+[\{E  
} rh:s 7  
TTA{#[=7  
Z^/z  
public void run() VYl_U?D  
{ fWtb mUq  
//获得文件长度 A&NC0K}G!  
//分割文件 I3}HNGvU  
//实例FileSplitterFetch *6 z'+'  
//启动FileSplitterFetch线程 J[j/aDdP  
//等待子线程返回 ue6/EN;}  
try{ ,$MWk(S  
if(bFirst) bm|Jb"T0b  
{ Nt`F0 9S  
nFileLength = getFileSize(); W,9k0t  
if(nFileLength == -1) &.cGj @1!J  
{ Dg9--wI}I9  
System.err.println("File Length is not known!"); ;ZxK3/(7  
} rQd1Ch  
else if(nFileLength == -2) M-&^   
{ ?J^IAF y  
System.err.println("File is not access!"); }$&T O$LX  
} mr{k>Un\  
else K^z5x#Yj  
{ Y0P}KPD  
for(int i=0;i<nStartPos.length;i++) Hm+6QgCs  
{ ZXssvjWQV}  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); b:}wR*Adc  
} bik] JIM  
for(int i=0;i<nEndPos.length-1;i++) ?YkO+?}+  
{ "xvV'&lQ  
nEndPos = nStartPos[i+1]; KRnB[$3F1  
}  m+72C]9  
nEndPos[nEndPos.length-1] = nFileLength; 2R_opbw  
} C,OB3y  
} haEZp6Z  
*#prSS  
CO:m]oj  
//启动子线程 bBeFL~  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; I&'S2=s  
for(int i=0;i<nStartPos.length;i++) K^]?@oHO  
{ Mv7w5vTl  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~WYE"(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 75hFyh;u  
nStartPos,nEndPos,i); .v #0cQX+.  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8T>3@kF  
fileSplitterFetch.start(); y]QQvCJr3d  
} M/8#&RycQ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,%)WT>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); &;NNU T>Q  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", |k7ts&2  
nEndPos = " + nFileLength); Q ^1#xBd  
// fileSplitterFetch[nPos.length-1].start(); MQ9M%>  
,z0~mN  
vjs|!O=oH  
//等待子线程结束 gNEzlx8A  
//int count = 0; H649J)v+m  
//是否结束while循环 ;i-D~Np|  
boolean breakWhile = false; ^huBqEs  
VuO)  
HonAK  
while(!bStop) 3 2iWYN  
{ #cp$ltY  
write_nPos(); PoBu kOv  
Utility.sleep(500); NR;S3-Iq(  
breakWhile = true; G(7\<x:  
o3TBRn,  
FM;;x(sg  
for(int i=0;i<nStartPos.length;i++) nL7S3  
{ NSiYUAu g  
if(!fileSplitterFetch.bDownOver) 6bRQL}[  
{ k<j)?_=`  
breakWhile = false; i)`zKbK  
break; *mK);@pL  
} xy z\;3  
} lvz:UWo  
if(breakWhile) b]so9aCz  
break; "b1R5(Ar  
K;ry4/Vap  
%`s9yRk9>E  
//count++; ,h wf  
//if(count>4) pxCGE[@`  
// siteStop(); {*ko=77$*  
} V%{ 9o  
]mO+<{{4X  
 jKb=Zkd  
System.err.println("文件下载结束!"); d9[6kQ]  
} H z < M  
catch(Exception e){e.printStackTrace ();} Skk3M?  
} vUIK4uR.  
tI!R5q;k  
X/;"CM  
//获得文件长度 [hv3o0".  
public long getFileSize() g*w-"%"O  
{ .2(@jx,[  
int nFileLength = -1; >ihe|WN  
try{ 9TXm Z  
URL url = new URL(siteInfoBean.getSSiteURL()); +}G>M=t::  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); k.? T.9  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8tFyNl`c  
$CQwBsYb=  
v;F+fOo  
int responseCode=httpConnection.getResponseCode(); ,rl <ye*&  
if(responseCode>=400) rY_C3;B  
{ -JyODW#j  
processErrorCode(responseCode); bbPd&7  
return -2; //-2 represent access is error i_ODgc`H  
} )Ido|!]0d  
si mX  
z7l;|T  
String sHeader; `aWwF} +Y  
NM.f0{:cj  
^kR^ QL$  
for(int i=1;;i++) n'ca*E(  
{ ->"h5h  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); gU 2c--`  
//Utility.log(in.readLine()); ae(]9VW  
sHeader=httpConnection.getHeaderFieldKey(i); f@. Q%+!4  
if(sHeader!=null) kAQ\t?`x  
{ Vp-OGX[  
if(sHeader.equals("Content-Length")) <2@<r t{  
{ <hF~L k ,  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); @9kk f{?  
break; RWh}?vs_  
} W!Ct[t  
} hDkqEkq1R  
else  ~NW5+M(u  
break; [2j (\vC!  
} \tw#p k  
} ``YL] <<  
catch(IOException e){e.printStackTrace ();} +KwF U  
catch(Exception e){e.printStackTrace ();} %},S#5L3  
PK`(qK9  
Xde=}9  
Utility.log(nFileLength); r;6YCI=z  
JpHsQ8<  
v,.n/@s|X  
return nFileLength; 1.d9{LO[-  
} MPEBinE?  
7Hkf7\JY  
Xi`U`7?D(=  
//保存下载信息(文件指针位置) 2.&V  
private void write_nPos() 1oW]O@R  
{ Vqp.jF1|  
try{ d<cbp [3F  
output = new DataOutputStream(new FileOutputStream(tmpFile)); uxJiec`&  
output.writeInt(nStartPos.length); [\M?8R$)  
for(int i=0;i<nStartPos.length;i++) ! {o+B^^  
{ AFhG{G'W  
// output.writeLong(nPos); ` Ehgn?6'  
output.writeLong(fileSplitterFetch.nStartPos); 8/kO9'.P  
output.writeLong(fileSplitterFetch.nEndPos); b yreleWo  
} o  >4>7  
output.close(); Zz*mf+  
} [6gHi.`p'  
catch(IOException e){e.printStackTrace ();} .j<B5/+  
catch(Exception e){e.printStackTrace ();} Hr,lA(  
} 0v)mgrl=,  
?bYQZJ>&  
PH4bM  
//读取保存的下载信息(文件指针位置) Qs[EA_  
private void read_nPos() C%7)sLWjJS  
{ X1z0'gvh  
try{ 4y}a,  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ^d $e^cU  
int nCount = input.readInt(); U &k 3  
nStartPos = new long[nCount]; ?}Ptb&Vk(  
nEndPos = new long[nCount]; o?hw2-mH  
for(int i=0;i<nStartPos.length;i++) VKfHN_m*  
{ \C\y' H5  
nStartPos = input.readLong(); A)a+LW'=u  
nEndPos = input.readLong(); cz~11j#  
} Ecl7=-y  
input.close(); 2+Y`pz47W  
} [Ik B/Xbw|  
catch(IOException e){e.printStackTrace ();} BL^Hj  
catch(Exception e){e.printStackTrace ();} PaI63 !  
} o|n0?bThS-  
9d(v^T  
<EN[s  
private void processErrorCode(int nErrorCode) ( 2(;u1  
{ :;u]Y7  
System.err.println("Error Code : " + nErrorCode); ej53O/hP  
} /@}# K P=  
cZF;f{t  
,^[37/S  
//停止文件下载 0$h$7'a  
public void siteStop() 6]A\8Ty  
{ 7 ,~Krzv  
bStop = true; ,ui'^8{gK  
for(int i=0;i<nStartPos.length;i++) jN{xpd  
fileSplitterFetch.splitterStop(); Jj!tRZT  
;HwJw\fo  
T ]nR XW$  
} -ns a3P  
}  X_S]8Aa  
//负责部分文件的抓取 Fm~}A4  
**FileSplitterFetch.java mNB ]e5 ;N  
*/ %z_b/yG  
package NetFox; -@?>nLQb  
bN %MT#X  
1ucUnNkcV  
import java.io.*; U1tPw`0h  
import java.net.*; TK?N^ly  
z#67rh {  
D(?#oCCA  
public class FileSplitterFetch extends Thread { nE$ V<Co}  
d"uM7PMs7x  
05zdy-Fb  
String sURL; //File URL TbM*?\7  
long nStartPos; //File Snippet Start Position `.Q3s?1F  
long nEndPos; //File Snippet End Position } j@@  
int nThreadID; //Thread's ID \>k#]4@rp  
boolean bDownOver = false; //Downing is over |L-juT X9  
boolean bStop = false; //Stop identical (D3m5fO  
FileAccessI fileAccessI = null; //File Access interface l zkn B  
3nGK674;z  
A^7Zy79  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException %cjav  
{ l_IX+4(@b|  
this.sURL = sURL; 9e*poG  
this.nStartPos = nStart; z]_CFo1'l  
this.nEndPos = nEnd; 9cPucKuj  
nThreadID = id; "Z?":|%7  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 pl/$@K?L  
} S$:S*6M@"  
'B:De"_(N  
Q%d[ U4@  
public void run() E*"E{E7  
{ v^E2!X  
while(nStartPos < nEndPos && !bStop) td$Jx}'A  
{ #Ih(2T i  
Z4sjH1W  
TyXOd,%zl  
try{ IUG .q8  
URL url = new URL(sURL); Efd[ZJxS6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +@v} (  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2xm?,p`  
String sProperty = "bytes="+nStartPos+"-"; d u )G)~  
httpConnection.setRequestProperty("RANGE",sProperty); #Jb$AA! z  
Utility.log(sProperty); :|( B[  
+& Qqu`)?F  
@2O\M ,g5  
InputStream input = httpConnection.getInputStream(); 6% axbB  
//logResponseHead(httpConnection); K?eo)|4)DB  
IMEoov-x  
+T;qvx6  
byte[] b = new byte[1024]; }Ec"&  
int nRead; lK@r?w|<M  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) '*.};t~;"d  
{ n-WvIy  
nStartPos += fileAccessI.write(b,0,nRead); >qZRIDE5$  
//if(nThreadID == 1) mJqP#Unik  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =~*u(0sJa  
} -p~B -,  
K|!)<6ZsG7  
P1jkoJ  
Utility.log("Thread " + nThreadID + " is over!"); c3mlO [(  
bDownOver = true; _Y~?.hs^  
//nPos = fileAccessI.write (b,0,nRead); v:b%G?o  
} |9JYg7<  
catch(Exception e){e.printStackTrace ();} LRgk9*@,  
} 94/}@<d-=  
} o4795r,jz  
IC42O_^  
69L&H!<i:  
//打印回应的头信息 ]kvE+m&p}^  
public void logResponseHead(HttpURLConnection con) '93&?  
{ Q5ao2-\   
for(int i=1;;i++) Ric$Xmu  
{ b`=rd 4cpU  
String header=con.getHeaderFieldKey(i); M?97F!\U  
if(header!=null) 8i"fhN3?Y  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); xbIA97g-O,  
Utility.log(header+" : "+con.getHeaderField(header)); 5$w1[}UUd  
else _E7eJSM.  
break; @n3PCH6:Ao  
} }%|OnEk"  
} <9vkiEo  
y3GIR f;>  
C<ljBz`,t  
public void splitterStop() ~a Rq\fx{  
{ W3kilhZ  
bStop = true; nwYeOa/t  
} ,kI1"@Tu  
m-]"I8 [  
Z m>69gl  
} 1owoh,V6  
6ZJQ '9f  
<z PyID`  
/* FUqiP(A  
**FileAccess.java s,= ^V/c  
*//文件访问(定位,写) 7va%-&.&t  
package NetFox; >@o*v*25  
import java.io.*; .l!Z=n|  
^ TS\x/P  
] a()siT  
public class FileAccessI implements Serializable{ u^$ CR  
%8/$CR  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 LgYzGlJp  
RandomAccessFile oSavedFile; P7!Sc  
long nPos; IG\\RYr  
aJ ts  
>#Y q&@G  
public FileAccessI() throws IOException Bf.RYLsh6  
{ xYq8\9Qb  
this("",0); qYs6PLC  
} 1zffPC8jl  
c1f6RCu$b  
'_%Jw:4k  
public FileAccessI(String sName,long nPos) throws IOException 1Ppzch7  
{ K`sm  
oSavedFile = new RandomAccessFile(sName,"rw"); ' =kX   
this.nPos = nPos; :0l(Ll KD  
oSavedFile.seek(nPos); ))vwofkw4  
} l%O-c}X  
3`y:W9!u  
A{k@V!A%  
public synchronized int write(byte[] b,int nStart,int nLen) {u5@Yp  
{ ? "gy`oCv  
int n = -1; 6r`g+Js/  
try{ +}!eAMQ  
oSavedFile.write(b,nStart,nLen); 8MdKH7  
n = nLen; c}lgWu~  
} >X]<s^  
catch(IOException e) s?G@ k}{  
{ , /pE*Yk  
e.printStackTrace (); /:DxB00  
} b< rM3P;  
\]D;HR`vo  
e-WaK0Ep  
return n; )8_0d)  
} [ kknY+n1  
Ptg73Gm&R  
'nul{RE*  
} UkC\[$-"\  
cjL!$OE6  
K{c^.&6D  
/* 2;3q](d   
**SiteInfoBean.java =[$*PTe  
*/ ^s-3U  
package NetFox; kF5}S8B  
xiiZ'U  
p ,!`8c6  
public class SiteInfoBean { DI\^ +P  
9f "*O j  
CfAqMH*ip  
private String sSiteURL; //Site's URL T"z!S0I  
private String sFilePath; //Saved File's Path tPUQ"S  
private String sFileName; //Saved File's Name qy !G&  
private int nSplitter; //Count of Splited Downloading File er_aol e  
SaNx;xgi  
$]vR,E  
public SiteInfoBean() J]%P fWV  
{//nSplitter的缺省值为5 ^a]:GPc  
//default value of nSplitter is 5 nL$tXm-x  
this("","","",5); Au {`o xD  
} zAH+{4lC+  
biJU r^n  
%ug`dZ/  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 5H79) n>  
{ OygYP  
sSiteURL= sURL; |(/"IS]  
sFilePath = sPath; F"q3p4-<>  
sFileName = sName; 1)%o:Xy o  
this.nSplitter = nSpiltter; </fnbyGR  
w-KtxG(  
QM IQy  
} _CgD7d  
$6_J` 7  
\6N\6=t!A  
public String getSSiteURL() YC$pT  
{ 6O"0?wG+  
return sSiteURL; e'jR<ln|  
} 2`z+_DA  
E?;W@MJi  
m'S-h'a  
public void setSSiteURL(String value) BH}u\K  
{ N\p3*#M  
sSiteURL = value; .RT5sj\d  
} 5Hr"}|J<8  
UkdQ#b1  
[~J4:yDd=  
public String getSFilePath() R_^:<F0  
{ :( `Q4D~l  
return sFilePath; .{Xi&[jw  
} k~?@~xm,R  
Awj`6GeJ  
f_ ::?  
public void setSFilePath(String value) -Ju!2by  
{ xGA%/dy,;  
sFilePath = value; 6 2LZ}yn_"  
} 0]Li "Wb  
]t,ppFC#  
qn<~ LxQ  
public String getSFileName() ^Ab|\ 5^3  
{ Oz+>I ^Q  
return sFileName; ]!f=b\-Av  
} _K9jj  
A_[65'*b  
=.uE(L`]NA  
public void setSFileName(String value) }NUP[%  
{ 8T%z{A1T  
sFileName = value; old}}>_  
} +pE-Yn`YS  
O9qEKW)a  
vX{]_  
public int getNSplitter() $GcVC (]  
{ lAoH@+dyA+  
return nSplitter; DukCXyB*l  
} ?(mlt"tPk  
-O ej6sILO  
?&Lb6(}e  
public void setNSplitter(int nCount) /JvNJ f  
{ kY*D s;  
nSplitter = nCount; Pp}j=$&j\  
} `=FfzL  
} X&K1>dgWP  
$FD0MrB_+  
N[AX29  
/* . [C ~a  
**Utility.java xL mo?Y*  
*/ fFsA[@5tul  
package NetFox; 2"NJt9w  
?gTY! ;$P  
3.8d"  
public class Utility { [1N*mY;  
2r1., 1  
s:Memvf  
public Utility() zX)uC<  
{ L"AZ,|wIk  
&'R\yX<J)  
b,I$.&BD  
} Yw./V0Z{@  
'(ql7  
//线程睡眠 q),yY]5  
public static void sleep(int nSecond) JD,/oL.KA  
{ A9[l5E  
try{ 32dR`qb  
Thread.sleep(nSecond); 3]V" 9+  
} :]:q=1;c  
catch(Exception e) UE*M\r<  
{ hH%@8'1v  
e.printStackTrace (); 2jA-y!(e  
} JEj.D=@[  
} D;m>9{=  
|o6B:NH,rg  
//日志 58WL8xu  
public static void log(String sMsg) >8EIm  
{ yw2sK7  
System.err.println(sMsg); Yf<6[(6 O  
} lLl^2[4k5  
8M !If  
NKh8'=S  
public static void log(int sMsg) U@DIO/C,m`  
{ H htAD Y  
System.err.println(sMsg); %I?uO( @  
} :H3qa2p  
} @=:( b"Sg  
V D-,)f  
[$f  
/* fm Fh.m.+N  
**TestMethod.java 6/ F]ncwG  
*/ aNw8][  
package NetFox; Y=\;$:L[  
jgbE@IA@!'  
cjp H hoW  
public class TestMethod { n-0RA~5z  
Q`'w)aV  
g"^<LX-  
public TestMethod() 6Xbo:#  
{ ///xx/weblogic60b2_win.exe $SA8$!:  
try{ {p-&8-  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); N"@aisi)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); yMB*/vs  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 0escp~\Z  
fileFetch.start(); !-)Hog5\  
} 9+_SG/@  
catch(Exception e){e.printStackTrace ();} -ich N/U]s  
gWL'Fl}H  
$0=f9+@5  
} Z2!O)8  
wgp{P>oBX  
9Eu.Y  
public static void main(String[] args) 3%p^>D\  
{ 4At{(fw W  
new TestMethod(); |Q[[WHqj2f  
} t&*X~(Yb!  
} -YPUrU[)  
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