http断点续传简单实现（java)

/* )F%zT[Auph  
**SiteFileFetch.java BPC>  
*/ n,%/cUl  
package NetFox; jg=}l1M"  
import java.io.*; UJrN+RtL  
import java.net.*; `:EU
~4s\  
IFF3gh42.  
(Z at|R.F  
public class SiteFileFetch extends Thread { ;%$wA5"2M  
G'6f6i|<I@  
`'/1Ij+  
SiteInfoBean siteInfoBean = null; //文件信息Bean >twog}%  
long[] nStartPos; //开始位置 6g%~~hX
 
long[] nEndPos; //结束位置 ^ &VN=Y6z  
FileSplitterFetch[] fileSplitterFetch; //子线程对象  uE3xzF  
long nFileLength; //文件长度 .jbT+hhM  
boolean bFirst = true; //是否第一次取文件 3("E5lI(g:  
boolean bStop = false; //停止标志 AR5)Uws  
File tmpFile; //文件下载的临时信息 lX%e  
DataOutputStream output; //输出到文件的输出流 MD=!
a5'  
<+e&E9;>6  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） m7m)BX%O  
public SiteFileFetch(SiteInfoBean bean) throws IOException S *K0OUq  
{ YC d  
siteInfoBean = bean; >I;J!{  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); %scQP{%aD  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); A<[X@o}92  
if(tmpFile.exists ()) qc@v"pIz'S  
{ 6ragRS/'x  
bFirst = false; G0pqiU6  
read_nPos(); -owap-Va  
} n_46;lD  
else p$@l,4@{  
{ "0Yb 2>F  
nStartPos = new long[bean.getNSplitter()]; Rln@9muXA  
nEndPos = new long[bean.getNSplitter()]; "!_,N@\t  
} rd4mAX6@  
P(Q}r7F~(  
3"iJ/Hc}9  
o.KE=zp&z  
} m[6c{$A/w  
zr[|~-  
DO9_o9'  
public void run() 4W36VtQ@E  
{ I"r[4>>B>0  
//获得文件长度 *aS[^iX?s  
//分割文件 5Z(#)sa0Og  
//实例FileSplitterFetch L QA6iZBP  
//启动FileSplitterFetch线程 AWz|HF#-  
//等待子线程返回 [HSN*LXe  
try{ JD{AwE
@Ro  
if(bFirst) .vhEm6wJUM  
{ EF[I@voc  
nFileLength = getFileSize(); oq9gG)F  
if(nFileLength == -1) bKP@-<:]  
{ X16r$~Pb  
System.err.println("File Length is not known!"); C?lZu\L  
} uy oEMT#u  
else if(nFileLength == -2) E
bytvs,w  
{ Ue2k^a*Ww
 
System.err.println("File is not access!"); C'xWRSDO  
} Q(ec>+oi  
else 5u
&hp  
{ "y$s`n4Mj  
for(int i=0;i<nStartPos.length;i++) ThJ`-Ro  
{ ^<QF*!  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); QDJe:\n  
} +]jJ:V  
for(int i=0;i<nEndPos.length-1;i++) 4+4C0/$Y  
{ $BWA=2$  
nEndPos = nStartPos[i+1]; fd*<m8  
} ;0]s:0WD0P  
nEndPos[nEndPos.length-1] = nFileLength; :tcqb2p  
} ({kOgOeC  
} {^*D5  
OA{PKC  
d}(b!q9  
//启动子线程 p)w{}@%r  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; `ls^fnJTpf  
for(int i=0;i<nStartPos.length;i++) y`p(}X`>  
{ &U0Y#11Cx  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5qQ\H}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Gjo&~*;  
nStartPos,nEndPos,i); nj5Hls  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); l\1_v7s  
fileSplitterFetch.start(); &1,{.:@e  
} #wP$LKk  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q'
K[?W|C  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);  o C#W  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", _Q6` Wp6m  
nEndPos = " + nFileLength); b<"LUM*;  
// fileSplitterFetch[nPos.length-1].start(); <-Q0s%mNj,  
[gxH,=Pb  
N"&qy3F  
//等待子线程结束 pm k;5 d  
//int count = 0; 37nGFH`K2m  
//是否结束while循环 \K(QE ~y'W  
boolean breakWhile = false; OysO55
i  
|g8Q.*"l[  
n`2LGc[rP  
while(!bStop) ^9A,j}>o-  
{ +a}>cAj*  
write_nPos(); BewJ!,A!  
Utility.sleep(500); k#pNk7;MZ  
breakWhile = true; }ec3qZ@  
Trt1M  
,1|0]:  
for(int i=0;i<nStartPos.length;i++) 8/`ij?gn  
{ TOXZl3s5#  
if(!fileSplitterFetch.bDownOver) fT  
{ &VfMv'%x  
breakWhile = false; /dq(Z"O_  
break; b 3i34,  
} #>\%7b59>  
} f~Q]"I8w  
if(breakWhile) Xwt}WSdF`k  
break; /E<:=DD<  
_"c:Z!L  
".Sa[A;~  
//count++; T
xXX}6  
//if(count>4) m.
 "T3K  
// siteStop(); hT?|:!ED.F  
} i.G"21M  
 a5@XD_b  
U((mOm6  
System.err.println("文件下载结束！"); );oE^3]f  
} *ci%c^}V  
catch(Exception e){e.printStackTrace ();} dtd}P~  
} 5;Q9Z1 `  
(|U|>@  
|tqYRWn0  
//获得文件长度 dPCn6  
public long getFileSize() Rg6/6/ IN  
{ J\c\
Ar:  
int nFileLength = -1; gzeTBlXg  
try{ Ki(  
URL url = new URL(siteInfoBean.getSSiteURL()); /aX5G  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Xgyi}~AoaU  
httpConnection.setRequestProperty("User-Agent","NetFox"); z]bcg$m  
Gfy9?sa  
c},wW@SF2W  
int responseCode=httpConnection.getResponseCode(); ]q CCCI`  
if(responseCode>=400) ^F4h:  
{ bA8RoC  
processErrorCode(responseCode); RI#o9d"x}  
return -2; //-2 represent access is error t'im\_$F  
} ~5sH`w~vQ  
c&;Xjy  
[ %:%C]4  
String sHeader; XL!^tMk  
pCt0[R;?  
Z2^B.r
#  
for(int i=1;;i++) `=JGlN7  
{ Ch,%xs.)G  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); m(eR Wx&pZ  
//Utility.log(in.readLine()); KG9FR*"  
sHeader=httpConnection.getHeaderFieldKey(i); DfV'1s4y  
if(sHeader!=null) >{@:p`*  
{ Ab/KVB  
if(sHeader.equals("Content-Length")) Gn}^BJN  
{ GG$&=.$  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); V/W{d[86G  
break; ~ w,hJ `  
} fNaboNj[  
} E{W(5.kb;i  
else ]?A-D,!(  
break; F uJ=]T  
} SJXP}JB_  
} >P[BwL]  
catch(IOException e){e.printStackTrace ();}
:1,xse  
catch(Exception e){e.printStackTrace ();} T }^2IJ]  
TU}./b@F  
2"C,u V@F!  
Utility.log(nFileLength); I4%25=0?  
]#t5e>o|  
WSV[)-=:  
return nFileLength; `;H3['~$  
} y~/i{a;1y  
[y(AdZ0*  
c?XqSK`',Z  
//保存下载信息（文件指针位置） 0|D l/
1  
private void write_nPos() PuoN<9 #  
{ ZKco  
try{ ?Y|*EH  
output = new DataOutputStream(new FileOutputStream(tmpFile)); C:$pAE(  
output.writeInt(nStartPos.length); 9Ls=T=96  
for(int i=0;i<nStartPos.length;i++) kRH;c,E@  
{ G;Thz  
// output.writeLong(nPos); !:|[?M.`  
output.writeLong(fileSplitterFetch.nStartPos); 7R5!(g  
output.writeLong(fileSplitterFetch.nEndPos); #;~dA  
} tDwj~{a~  
output.close(); A.
@
Af+  
} '
&j]~m  
catch(IOException e){e.printStackTrace ();} >S=,ype~G  
catch(Exception e){e.printStackTrace ();} rtY4B~_  
} ]/y69ou  
~u+|NtF  
#uHl
 
//读取保存的下载信息（文件指针位置） EaXDY<  
private void read_nPos() ug.'OR  
{ os~}5QJ  
try{ %x zgTZ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); kFo&!  
int nCount = input.readInt(); 7<p?E7  
nStartPos = new long[nCount]; 8bP4  
nEndPos = new long[nCount]; > g=u Y{Rf  
for(int i=0;i<nStartPos.length;i++) 9a;8^?Ld%S  
{ OJ2I (8P  
nStartPos = input.readLong(); bJ6@ B<  
nEndPos = input.readLong(); bhg OLh#  
} ;_<K>r*  
input.close(); gP 6`q  
} c0M>CaKD  
catch(IOException e){e.printStackTrace ();} J0a#QvX!  
catch(Exception e){e.printStackTrace ();} z(dX<  
} Zk#?.z}  
<rAk"R^  
jFThW N  
private void processErrorCode(int nErrorCode) iz pFl@WS  
{ ajMI7j^G  
System.err.println("Error Code : " + nErrorCode); g7),si*  
} 6K 6uB ~  
KXTx{R  
4bZ +nQgLu  
//停止文件下载 .e8S^
lSl  
public void siteStop() xPJ kadu  
{ P<GHX~nB  
bStop = true; %*`yd.L0W  
for(int i=0;i<nStartPos.length;i++) :U$U:e  
fileSplitterFetch.splitterStop(); Vj{}cL"MR  
X=d;WT4,,  
LwL\CE_6+  
} }2-p=Y:6  
} u{"@ 4  
//负责部分文件的抓取 rGxX]  
**FileSplitterFetch.java RS`~i8e'  
*/ sB>ZN3ptH^  
package NetFox; YMEI J}  
?g~g GQV  
Z6XP..  
import java.io.*; ^&-H"jF  
import java.net.*; )TFBb\f>v  
Q0cr^24/  
6 SosVE>Z  
public class FileSplitterFetch extends Thread { q|fZdTw  
!NfN16  
LUjev\Re  
String sURL; //File URL L_4ZxsIv  
long nStartPos; //File Snippet Start Position F6h|AF|"  
long nEndPos; //File Snippet End Position ;r}>1LhN  
int nThreadID; //Thread's ID 3x{2Dhi  
boolean bDownOver = false; //Downing is over QC\][I>  
boolean bStop = false; //Stop identical d3|oKP6  
FileAccessI fileAccessI = null; //File Access interface E?+MM0  
Q]]5\C.  
I N'a5&..  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ; 3WA-nn  
{ &^W91C?<6  
this.sURL = sURL; \dIQhF%%2  
this.nStartPos = nStart; %Kq`8  
this.nEndPos = nEnd; &QL!Y{=Y6  
nThreadID = id; l[J'FR:  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 z nc'  
} m+m,0Ey5H  
A/4
HR]  
)|@ H#kv?  
public void run() [# '38  
{ 0u'qu2mV  
while(nStartPos < nEndPos && !bStop) B "z`X!\  
{ T]fu[yRVvg  
p#Vh[UTl^  
mtON dI  
try{ <Y9xHn&  
URL url = new URL(sURL); Uc3-n`C  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); URFp3qE  
httpConnection.setRequestProperty("User-Agent","NetFox"); WhR j@y  
String sProperty = "bytes="+nStartPos+"-"; -OS&(7  
httpConnection.setRequestProperty("RANGE",sProperty); 02~+$R]L  
Utility.log(sProperty); ZAG iaq  
JM@}+pX  
Vp'Zm:
 
InputStream input = httpConnection.getInputStream(); UA
|A>c  
//logResponseHead(httpConnection); x1}7c9nK  
E\(dyq/  
PmGW\E[ni  
byte[] b = new byte[1024]; %;E/{gO  
int nRead; d,G:+  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) vNhi5EU  
{ @L-3&~=  
nStartPos += fileAccessI.write(b,0,nRead); O,kzU,zOs  
//if(nThreadID == 1) h
o7L@NR  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9N[PZD  
} hK,e<?N^  
m"<Sb,"x!  
ORV~F0d<  
Utility.log("Thread " + nThreadID + " is over!"); SJtQK-%wK>  
bDownOver = true; Qv%"iSe~J  
//nPos = fileAccessI.write (b,0,nRead); to1{7q  
} |-HV@c]  
catch(Exception e){e.printStackTrace ();} {1Z`'.FU  
} YFVNkBO%  
} ^0/FZ)V8  
+%'S>g0W=  
cVt MCgx  
//打印回应的头信息 ]Fc<%wzp  
public void logResponseHead(HttpURLConnection con) G 1rsd  
{ "i\rhX  
for(int i=1;;i++) 93-UA.+g  
{ ) /kf  
String header=con.getHeaderFieldKey(i); ' {L5 3cH=  
if(header!=null) S`Jo^!VJ4  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); cu4&*{  
Utility.log(header+" : "+con.getHeaderField(header)); 8X@p?43  
else S0\
;FmLIc  
break; bm>,$GW(  
}
QQso<.d&  
} v>FsP$p4yE  
'E{n1[b  
@?$x  
public void splitterStop() +mQMzZZTZ  
{ 9y(75Bn9  
bStop = true; NW'rqgG  
} Q2c|sK8  
W)dQyZ>J  
ad "yo=%1  
} R^
PPgE6!$  
OSk+l  
[i18$q5D  
/* prvvr;Ib  
**FileAccess.java phu`/1;
p  
*//文件访问(定位，写) @_Ko<fKSX  
package NetFox; _;G. QwHr  
import java.io.*; ,9I %t%sb  
uXX3IE[  
B>&Q]J+

R  
public class FileAccessI implements Serializable{ hjVct r  
GJ:65)KU  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ^tS{a*Yn  
RandomAccessFile oSavedFile; Z*EK56.b  
long nPos; VQ5D?^'0/  
>+iJ(jqq  
*;QIAd  
public FileAccessI() throws IOException b^wL{q  
{ &_-,Nxsf  
this("",0); l^ P[nQDH  
} eSNwAExm  
}Ut*Y*  
Lo^0VD!O  
public FileAccessI(String sName,long nPos) throws IOException |H`}w2U[j  
{ "|?zQ?E  
oSavedFile = new RandomAccessFile(sName,"rw"); @6eM{3E.  
this.nPos = nPos; nRYHp7`  
oSavedFile.seek(nPos); v71j1Q}6  
} "~R,%sYb(  
f}JiYZ  
h0}=C_.^  
public synchronized int write(byte[] b,int nStart,int nLen) F)ak5  
{ {:U zW\5l)  
int n = -1; O)y|G%O  
try{ `nAR/Ye  
oSavedFile.write(b,nStart,nLen); 8$k`bZ  
n = nLen; B?BB  
} J#h2~Hz!  
catch(IOException e) = GN1l[X  
{ 3/rEXKS  
e.printStackTrace (); 0p"l}Fu@`  
} < Y5pAStg  
^}JGWGib=+  
"gD]K=  
return n; E8_j?X1  
} i3bH^WwE&k  
?b?6/_W~R  
({XB,Rm  
} h<)YZ
[;x  
nQe
^Bn  
o~Jce$X  
/* b-Q*!Ut  
**SiteInfoBean.java =Q\z*.5j.  
*/ Rra3)i`
*  
package NetFox; %49P<vo`?  
%w+"MkH _  
c/:d$o-  
public class SiteInfoBean { ;DQ{6(  
$AGW8"  
n}KF)W=  
private String sSiteURL; //Site's URL &I8Q'  
private String sFilePath; //Saved File's Path :<
t%Sf  
private String sFileName; //Saved File's Name cK()_RB#  
private int nSplitter; //Count of Splited Downloading File sGg=4(D  
}BTK+Tk8  
0;Lt  
public SiteInfoBean() ,8=`Y9#  
{//nSplitter的缺省值为5 /WvF}y  
//default value of nSplitter is 5 m=g\@&N  
this("","","",5); 1(S0hm[ov  
} N4]Sp v  
]i$
<<u  
0:NCIsIm<  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) RKIBFP8.  
{ &hTe-Es  
sSiteURL= sURL; .[%
^~q7  
sFilePath = sPath; UH8q:jOi  
sFileName = sName; S511}KPbm/  
this.nSplitter = nSpiltter; Gi=sJV  
N*J!<vY"  
]]sy+$@~  
} `^:>sU  
r#8t@W  
1 u[a713O  
public String getSSiteURL() 1L~y!il  
{ U*P&O+(1'  
return sSiteURL; pr\wI?:k  
} $w,O[PIi  
'?j[hhfB-  
;kW+  
public void setSSiteURL(String value) F0.Rv):  
{ WruSL|4iH  
sSiteURL = value; cSbyVC[r  
} HPGIz!o  
V/p+Xv(Zt  
c(@(j8@S  
public String getSFilePath() s5`CV$bz  
{ !hMD>B2Z  
return sFilePath; eo#2n8I>=1  
} j{8;5 ?x  
Th\
w#%'N  
@2yoy&IO  
public void setSFilePath(String value) S*aVcyDEP  
{ 6_G[&   
sFilePath = value; yj:<3_-C*  
} /$z(BX/  
/nPNHO>U  
xbVvK+  
public String getSFileName() 8fI]QW  
{ nj90`O.K  
return sFileName; Z.^DJ9E<1  
} ";kwh8wB  
g6AEMer  
P
Z#\O  
public void setSFileName(String value)
3]46qk'  
{ ^ gy"$F3{`  
sFileName = value; be<7Vy]j  
} hFW{qWP  
J!\Cs1!f  
]'.D@vFGO  
public int getNSplitter() Kia34 ~W  
{ DB=^Z%%Z  
return nSplitter; }s@ i  
} \!51I./Q/  
(WCczXm)  
a)o-6  
public void setNSplitter(int nCount) q0m>NA   
{ b] EC+.  
nSplitter = nCount; {)CN.z:O  
} T{CCZ"Fv  
} 9Sb[5_Q  
e) \PW1b  
n<)gS7  
/* yQ [n7du  
**Utility.java )yl
;i  
*/ ln1QY"g  
package NetFox; M?g
c&2Y  
G7qB
  
pdw;SIoC  
public class Utility { |//D|-2  
vkjHh.  
(kYwD  
public Utility() J<9;Ix8R  
{ dED&-e#  
vY"i^
a`f  
'NAC4to;;  
} \yE*nZ  
&6@#W]_  
//线程睡眠 zObrp  
public static void sleep(int nSecond) #0*oj/  
{ JS!`eO/8  
try{ -"CXBKHb  
Thread.sleep(nSecond); E,}(jAq7  
} %a=^T?8  
catch(Exception e) n>XfXt =  
{ *SmR|Qy  
e.printStackTrace (); XU*4MU^'  
} eZ G#op  
} [uLpm*7  
i)1013b  
//日志 -V F*h.'  
public static void log(String sMsg) W#bOx0  
{ GbwqrH+  
System.err.println(sMsg); PAy/"R9DT-  
} Dk^T_7{  
WJ&a9]&C  
gucgNpX  
public static void log(int sMsg) P+Q}bTb8  
{ OpLo[Y\  
System.err.println(sMsg); l
JJ`aYDp  
} !+)5?o  
} v.!e1ke8D*  
Q/%]%d  
0s72BcP  
/* WNK)IC~c  
**TestMethod.java th^&wp  
*/ eia>Y$  
package NetFox; bjr()NM1  
4(%LG)a4S  
~7$jW[i  
public class TestMethod { 4>NmJrh  
oXgi#(y  
([ODmZHv  
public TestMethod() e6i m_ Tk  
{ ///xx/weblogic60b2_win.exe s
= bP@[Gj  
try{ :\"V5  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,Zva^5  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5);  nJ|M  
SiteFileFetch fileFetch = new SiteFileFetch(bean); d "%6S*dL  
fileFetch.start(); ]j+J^g  
} ,382O$C  
catch(Exception e){e.printStackTrace ();} 9YvK<i&I  
<i ";5+  
"KKw\
i  
} w!r
w%  
s?7"iE  
J,D^fVIw  
public static void main(String[] args) =5q_aK#i  
{ &Vy.)0  
new TestMethod(); 'pHxO,vo  
} fo_*Uva_  
} *q*$%H  
点击下载更多相关资料