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http断点续传简单实现(java)

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/* o\`>c:.  
**SiteFileFetch.java +<.\5+  
*/ #Y93y\  
package NetFox; dp5f7>]:(  
import java.io.*; sLcFt1  
import java.net.*; R 4wr  
Z?^"\u-  
@ 2_<,;$  
public class SiteFileFetch extends Thread { aj ~bt-cE  
]bgY6@M  
j}+5vB|0  
SiteInfoBean siteInfoBean = null; //文件信息Bean [WB{T3j  
long[] nStartPos; //开始位置 33~qgK1>  
long[] nEndPos; //结束位置 "Jy~PcJZ1  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 H<ZU#U0FZf  
long nFileLength; //文件长度 Sg] J7;]  
boolean bFirst = true; //是否第一次取文件 S='syq>Aok  
boolean bStop = false; //停止标志 me\cLFw  
File tmpFile; //文件下载的临时信息 "%@uO)A /  
DataOutputStream output; //输出到文件的输出流 -Y:ROoFOZ  
DJQglt}~  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 8@M'[jT  
public SiteFileFetch(SiteInfoBean bean) throws IOException N8!TZ~1$  
{ S^f:`9ab9  
siteInfoBean = bean; df=z F.5  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); eeUp 1g  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); R: aYL~  
if(tmpFile.exists ()) -qebQv  
{ l SkEuN  
bFirst = false; 3^.8.q(6  
read_nPos(); \NXQ  
} M0-,M/]l  
else QMk+RM8U  
{  yu ,h\  
nStartPos = new long[bean.getNSplitter()]; BN@,/m9OQ%  
nEndPos = new long[bean.getNSplitter()]; mEQ!-p   
} ?A7Yk4Y.?N  
c[0oh.  
-)<m S  
~ H[%vdR  
} ., :uZyG  
4?/7 bc  
cCxi{a1uo  
public void run() aEx(rLd+  
{ idJh^YD  
//获得文件长度 .}9FEn 8  
//分割文件 nd+?O7~}(  
//实例FileSplitterFetch 1.R kIB  
//启动FileSplitterFetch线程 X^< >6|)  
//等待子线程返回 vZajT!h  
try{ LW39YMw<  
if(bFirst) LxT rG)4  
{ aQcN&UA@  
nFileLength = getFileSize(); kd;'}x=5yP  
if(nFileLength == -1) Zj-BuE&@f  
{ A1*4*  
System.err.println("File Length is not known!"); agaq`^[(P  
} 7CrpUh  
else if(nFileLength == -2) 1. SkIu%  
{ H/+{e,SW"  
System.err.println("File is not access!"); wq4nMY:#  
} '1]7zWbW  
else ;IC'Gq  
{ kb|eQtH  
for(int i=0;i<nStartPos.length;i++) " OGdE_E  
{ IM ad$AKc  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); JJl7JwSTW  
} Q @2(aR  
for(int i=0;i<nEndPos.length-1;i++) :HW>9nD.  
{ wO"GtVd  
nEndPos = nStartPos[i+1]; i<u9:W  
} y3yvZD  
nEndPos[nEndPos.length-1] = nFileLength; G[q9A$yw  
} 0RyFv+  
} PZ34*q  
7Qh_8M  
?mOg@) wx  
//启动子线程 <pOl[5v]  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; *fP(6e#G,  
for(int i=0;i<nStartPos.length;i++) >QI~`MiI  
{ .v,bXU$@YG  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6s,2NeVWa  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Z5>V{o  
nStartPos,nEndPos,i); j, t~  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); e d;"bb  
fileSplitterFetch.start(); L#j |2H|  
} 6;JP76PD  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ozxYH],  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Z( #Ln  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", |mj# 0  
nEndPos = " + nFileLength); +t>XxYScx  
// fileSplitterFetch[nPos.length-1].start(); T _~KxQ  
M5Wl3tZL  
=hcPTU-QU  
//等待子线程结束 UE)fUTS  
//int count = 0; ~Oh=   
//是否结束while循环 g+9v$[!  
boolean breakWhile = false; !BRcq~-.  
@*_ZoO7{  
XOxB (0@  
while(!bStop) ?f@ 9nph  
{ .&chdVcxyS  
write_nPos(); kV 1vb  
Utility.sleep(500); QV/";A3k  
breakWhile = true; d +xA:  
P Ey/k.  
C*O ,rm}  
for(int i=0;i<nStartPos.length;i++) bpMl =_  
{ n{{ P 3f  
if(!fileSplitterFetch.bDownOver) M;qb7Mu  
{ /:Y9sz uW`  
breakWhile = false; F; a3  
break; vpafru4  
} WFj*nS^~l  
} DoG%T(M!a9  
if(breakWhile)  ,F}r@  
break;  i_y:4  
sVcdj|j  
\c68n  
//count++; > i`8R  
//if(count>4) }3sN+4  
// siteStop(); gV.f*E1C  
} 3"vRK5Bf  
SW;HjQ>V  
!3HsI| $<G  
System.err.println("文件下载结束!"); 7(@(Hm  
} &<=e_0zT  
catch(Exception e){e.printStackTrace ();} `A"Q3sf%  
} A: c]1  
ixzTJ]yu  
;ct)H* y  
//获得文件长度 QmHwn)Ly  
public long getFileSize() 7&px+155  
{ Q!x`M4   
int nFileLength = -1; tO4):i1  
try{ (h|ch#  
URL url = new URL(siteInfoBean.getSSiteURL()); =Pj@g/25u  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); s@ z{dmL  
httpConnection.setRequestProperty("User-Agent","NetFox"); U,38qKE  
S"{GlRpd  
\2Xx%SX  
int responseCode=httpConnection.getResponseCode(); vQy$[D*  
if(responseCode>=400) 08O7F  
{ 3/l\ <{  
processErrorCode(responseCode); u6p5:oJj,  
return -2; //-2 represent access is error ,,}sK  
} ,wlbIl~  
1w bTqc  
($:y\,5(9I  
String sHeader; 0IpST  
iz$FcA]  
& L3UlL  
for(int i=1;;i++) t5n2eOy~T  
{ &!6DC5  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); T|!D>l'  
//Utility.log(in.readLine()); . Jb?]n  
sHeader=httpConnection.getHeaderFieldKey(i); 2pjW,I!`  
if(sHeader!=null) 33,;i E  
{ r/^tzH's  
if(sHeader.equals("Content-Length")) 0w'|d@*wV  
{ }ymc5-  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ;fj9 n-  
break; IJldN6&\q  
} 2 mSD"[%  
} 7:h<`_HT(X  
else #TIX_RXh  
break; ^IYJEqK  
} q`cEA<~S  
}  *[VEF  
catch(IOException e){e.printStackTrace ();} PK_Fx';ke^  
catch(Exception e){e.printStackTrace ();} K`~BL=KI  
Vj/fAHR`>'  
^W5>i[  
Utility.log(nFileLength); QP+c?ct}hF  
'xsbm^n6a&  
:cEd[Jm9  
return nFileLength; G{/;AK  
} pK<%<dIc  
,;7`{Nab  
E3LBPXK  
//保存下载信息(文件指针位置) W\'Nv/L  
private void write_nPos() 1Jl{1;c  
{ 7F=2t_2O  
try{ P&,hiGTDi  
output = new DataOutputStream(new FileOutputStream(tmpFile)); >/8ru*Oc  
output.writeInt(nStartPos.length); I'xC+nL@  
for(int i=0;i<nStartPos.length;i++) R04.K !  
{ .r7D )xNa@  
// output.writeLong(nPos); Q6eN+i2 ;  
output.writeLong(fileSplitterFetch.nStartPos); y{YXf! AS  
output.writeLong(fileSplitterFetch.nEndPos); v3?kFd7%H~  
} hTDV!B-_(  
output.close(); " \`BPN  
} W0C{~|e  
catch(IOException e){e.printStackTrace ();} HgYc@P*b  
catch(Exception e){e.printStackTrace ();} @l)\?IEF@f  
} (rAiDRQ[  
)\D2\1e(c  
dFx2>6AZt  
//读取保存的下载信息(文件指针位置) f V*}c`  
private void read_nPos() Go-wAJ>  
{ E]\D>[0O  
try{ :m]/u( /N  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); #NW Zk.S  
int nCount = input.readInt(); O >nK ,.  
nStartPos = new long[nCount]; ZGA)r0] P`  
nEndPos = new long[nCount]; :jBZK=3F>  
for(int i=0;i<nStartPos.length;i++) T!Xm")d  
{ 1]_?$)$T  
nStartPos = input.readLong(); <"hb#Tn  
nEndPos = input.readLong();  <V7SSm  
} j.<:00<  
input.close(); 5?Uo&e  
} Tt{U"EFO  
catch(IOException e){e.printStackTrace ();} A*rZQh b[  
catch(Exception e){e.printStackTrace ();} u82h6s<'W  
} IO^:FnJJv  
~g*Y, Y  
@bc[ eas  
private void processErrorCode(int nErrorCode) 79 TPg  
{ +.S#=  
System.err.println("Error Code : " + nErrorCode); J 5Wz4`'  
} j?Cr31  
y>>vGU;  
qUifw @  
//停止文件下载 _{lx*dq  
public void siteStop() @c6"RHG9  
{ \s.1R/TyD  
bStop = true; P#w}3^  
for(int i=0;i<nStartPos.length;i++) r hiS  
fileSplitterFetch.splitterStop(); m$7x#8gF  
+8Of-ZUx  
m5X3{[a :  
} u+I3IdU3  
} wy,Jw3  
//负责部分文件的抓取 J"/ JRn  
**FileSplitterFetch.java 5dg-d\ 6S  
*/ UN-T ^  
package NetFox; BjH~Ml2  
=Dh$yC-Zr  
<P|`7wfxE  
import java.io.*; Ko1AaX(I'+  
import java.net.*; [u/zrpTk  
' 9IP;  
zY]Bu-S3  
public class FileSplitterFetch extends Thread { CWE Ejl  
@*CAn(@#N  
;[;)P tFz\  
String sURL; //File URL LN@lrC7X  
long nStartPos; //File Snippet Start Position C$$"{FfgU"  
long nEndPos; //File Snippet End Position q :TZ=bs^  
int nThreadID; //Thread's ID fn1 ?Qp|  
boolean bDownOver = false; //Downing is over H;b8I  
boolean bStop = false; //Stop identical cYZwWMzp  
FileAccessI fileAccessI = null; //File Access interface wrz+2EP`  
\Ku9"x  
'dmp4VT3  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException "}S9`-Wd|  
{ [54@irH  
this.sURL = sURL; IW5*9)N?  
this.nStartPos = nStart; [>b  '}4  
this.nEndPos = nEnd; 2q`)GCES~  
nThreadID = id; +CsI,Uf4*  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 >v^2^$^u  
} c+@d'yR  
o,*folL  
4y|xUO:  
public void run() 4(` 2#  
{ 9X 5*{f Y  
while(nStartPos < nEndPos && !bStop) a/`c ef  
{ T)b3N| ONB  
iifc;62  
a"`g"ZRx  
try{ ) 1lJ<g#  
URL url = new URL(sURL); Iq4Kgc  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4 ?9soc  
httpConnection.setRequestProperty("User-Agent","NetFox"); (Wm/$P;  
String sProperty = "bytes="+nStartPos+"-"; &,W_#l{  
httpConnection.setRequestProperty("RANGE",sProperty); D}zOuB,S  
Utility.log(sProperty); gGtep*k  
SRA|7g}7W  
1Pud,!\%q  
InputStream input = httpConnection.getInputStream(); pieU|?fQ  
//logResponseHead(httpConnection); p<Zs*  @  
Jo6~r-  
]I{qp~^#n  
byte[] b = new byte[1024]; n.2E8m/  
int nRead; vDu0  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) tb-OKZq  
{ }4bB7,j  
nStartPos += fileAccessI.write(b,0,nRead); p{mxk)A  
//if(nThreadID == 1) '#cT4_D^lI  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zznPD%#Sc  
} K$MJ#Zx^  
s=H/b$v  
F|]o9&/<]  
Utility.log("Thread " + nThreadID + " is over!"); ATYQ6E[{MV  
bDownOver = true; O ,Pl7x%tK  
//nPos = fileAccessI.write (b,0,nRead); ,omp F$%  
} MZUF! B  
catch(Exception e){e.printStackTrace ();} ) xfc-Q  
} hRuo,FS#:  
} 2x<Qt2"  
l }2%?d  
;kyL>mV{  
//打印回应的头信息 xJ[k#?T'  
public void logResponseHead(HttpURLConnection con) ,<uiitOo  
{ GL;x:2XA  
for(int i=1;;i++) w8m8r`h  
{ ?)Czl4J  
String header=con.getHeaderFieldKey(i); Sy+]SeF&  
if(header!=null) j61BP8E  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); cXLV"d  
Utility.log(header+" : "+con.getHeaderField(header)); E<zT  
else 48 c D3w  
break; w-0O j  
} y~]I Vl"  
} C0t+Q  
c:?#zX  
c:h.J4mv  
public void splitterStop() DJ mQZ+{2  
{ Z!]U&Ax`Z  
bStop = true; 9%3 r-U=  
} -CU7u=*b  
zulf%aaL  
I |<+'G  
} 6yu*a_  
G!e}j @@  
ga{25q}"  
/* X5L(_0?F1  
**FileAccess.java (2O} B.6  
*//文件访问(定位,写) LRCS)UBY(.  
package NetFox; r7Q:l ?F2  
import java.io.*; |L.~Am d  
Mk'n~.mb  
#5ohmp,u  
public class FileAccessI implements Serializable{ I7q?V1f u4  
,rH)}C<Q+  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 +]S;U&vQ  
RandomAccessFile oSavedFile; EMW4<na[  
long nPos; JR a*;_  
S0Bl?XsD_  
d5sGkR`(  
public FileAccessI() throws IOException XC$+ `?  
{ 8)-t91hkL  
this("",0); -;@5Ua1uf  
} VH7iH|eW  
_~w V{ yp  
O&?CoA?  
public FileAccessI(String sName,long nPos) throws IOException 1(:=j Ofk  
{ rd"]@ ~v1  
oSavedFile = new RandomAccessFile(sName,"rw"); F;MT4*4  
this.nPos = nPos; <_sT]?N #  
oSavedFile.seek(nPos); RZV1:hNN  
} 8Snq75Q<   
)HzITsFZKT  
ek{PA!9Sk  
public synchronized int write(byte[] b,int nStart,int nLen) 2,XqslB)  
{ ]:E! i^C`Z  
int n = -1; ?CUp&L0-"  
try{ :S+U}Sm[  
oSavedFile.write(b,nStart,nLen); -YRL>]1  
n = nLen; YW$x:  
} d WB8  
catch(IOException e) jzJ1+/9  
{ 2;?wN`}5g=  
e.printStackTrace (); "mP*}VF  
} ' ! UF&  
|Z7bd^  
tls6rto  
return n; 9Pob|UA  
} bF Y)o Z  
eZ.0,A*1B1  
8F\Msx  
} 6B;_uIq5  
h&k ^l,  
Lx:9@3'7'  
/* 9CU6o:'fW  
**SiteInfoBean.java E=1/  
*/ Q!+{MsZ  
package NetFox; &v9PT!R~  
dT@SO  
SE}RP3dF!  
public class SiteInfoBean { sO4}kxZ  
9uq+Ve>  
8apKp?~yW  
private String sSiteURL; //Site's URL Hj4w i|  
private String sFilePath; //Saved File's Path x+:,b~Skk  
private String sFileName; //Saved File's Name 2wuW5H8w{  
private int nSplitter; //Count of Splited Downloading File Q0"F> %Cn  
fddbXs0Sn  
QWW7I.9r  
public SiteInfoBean() (Q]Y> '  
{//nSplitter的缺省值为5 4\'81"e i  
//default value of nSplitter is 5 Z=t#*"J  
this("","","",5); q(ET)xCeD  
} pffw5Tc  
Z Lio8  
MoR-8vnJ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) _M]rH<h  
{ K^qUlyv  
sSiteURL= sURL; \PMKmJ X0O  
sFilePath = sPath; > %cWTC  
sFileName = sName; 9@z|2z2\G  
this.nSplitter = nSpiltter; $?A Uk  
dZiWVa  
u*-<5& X  
} rNzhP*Fw  
s)DNLx  
m6Cd^'J9^  
public String getSSiteURL() /'=^^%&:B  
{ 89- 8v^ Pq  
return sSiteURL; ~CdseSo 9  
} ?eVuz x  
k -DB~-L  
&Cpxo9-  
public void setSSiteURL(String value) *DI:MBJY  
{ }!7DF  
sSiteURL = value; k$x 'v#  
} 8 8 =c3^  
E0B2>V  
R6@~   
public String getSFilePath() a~eLkWnh<k  
{ @?cXa: tX  
return sFilePath; <<zz*;RJJ  
} 6M vR R  
7 }MJK)  
-0IFPL8  
public void setSFilePath(String value) V45Udwp ^  
{ |e; z"-3  
sFilePath = value; >iWf7-:  
} Cv(N5mA2  
Ho8.-QSG  
Yl~?MOk  
public String getSFileName() 2c`=S5  
{ ?gMrcc/{  
return sFileName; RqjDMN:  
} TN@JPoH  
+-YuBVHL  
T&MS_E&;  
public void setSFileName(String value) M*@ aA XM  
{ H{Y=&#%d  
sFileName = value; rbZ6V :  
} OO+#KyU   
v4a4*rBI"  
#~-&&S4a.J  
public int getNSplitter() CJtjn  
{ `1}?{ud  
return nSplitter; FITaL@{c  
} n zrCOMld  
KPe.AK,8  
;Owu:}   
public void setNSplitter(int nCount) 'CAukk|  
{ i|{nj\6w^  
nSplitter = nCount; 0uJzff!|  
} DCzPm/#b  
} lJY=*KB(6  
<RVtLTd/  
{1U*: @j  
/* *k]S{]Y  
**Utility.java z2q5f :d8  
*/ 7^TXlW n^G  
package NetFox; \bQ!> l\  
R*{?4NKG  
$yqq.#1  
public class Utility { Ty:Ir  
YYr&r.6  
Q|z06_3i  
public Utility() p#BvlS=D  
{ =(5GU<}  
i[^lJ)[>N  
&j@J<*k  
} 5Zm_^IS  
l@J|p#0q  
//线程睡眠 RGuHXf  
public static void sleep(int nSecond) j3-6WUO  
{ >^GCSPe  
try{ GE+csnA2  
Thread.sleep(nSecond); K 0H!Ds9  
} J6Nw-qF  
catch(Exception e) T*~)9o  
{ "?&bh@P&  
e.printStackTrace (); 29657k8  
} 4 Wd5Goe:  
} Hz3X*G\5b  
!!O{ ppM  
//日志 z\d2T%^:g(  
public static void log(String sMsg) VgTI2  
{ NWN)b&}  
System.err.println(sMsg); `(suRp8!  
} `+;oo B  
zP'pfBgbJW  
< LAD  
public static void log(int sMsg) LVl0:!>~  
{ w} q@VVB%  
System.err.println(sMsg); >6834e  
} Y]Vc}-a(h  
} }lpm Hvs  
2Wf qgR[3  
,[1`'nN@g  
/* koY8=lh/  
**TestMethod.java q0Lt[*q3R  
*/ o(NyOC  
package NetFox; tsVhPo]e0  
cB=u;$k@*  
3CPOZZ  
public class TestMethod { @W- f{V  
lj*913aFh  
Z9~Wlt'?  
public TestMethod() [F{a-i-  
{ ///xx/weblogic60b2_win.exe )K3 vzX  
try{ tg3JU\  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); U(LR('-h  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); |L{dQ)-'l  
SiteFileFetch fileFetch = new SiteFileFetch(bean); =e{KtX.  
fileFetch.start(); &'\+Z  
} gt(nZ  
catch(Exception e){e.printStackTrace ();} A8(PI)Ic.  
qk1D#1vl  
&7u Ra1/R  
} # h|< >  
\9zC?Cw  
yP]W\W'  
public static void main(String[] args) R3`W#`  
{ x#mk[SV  
new TestMethod(); IjAity.Xrq  
} zN JyF;3  
} ulo7d1OVkJ  
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