http断点续传简单实现（java)

/* 4Pe%*WTX  
**SiteFileFetch.java S3EY9:^C  
*/ v{Al>v}}n  
package NetFox; *9y)B|P^  
import java.io.*; Hgu$)yhlj  
import java.net.*; KPSFy<  
~ P"@^cq  
^.p({6H  
public class SiteFileFetch extends Thread { +w[vYKSZm  
F{0Z  
g(B&A P_e  
SiteInfoBean siteInfoBean = null; //文件信息Bean NQz*P.q  
long[] nStartPos; //开始位置 4='Xhm  
long[] nEndPos; //结束位置 f_Ma~'3  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 m_zl*s*6  
long nFileLength; //文件长度 Oq@+/UWX
 
boolean bFirst = true; //是否第一次取文件
;{EIx*<d  
boolean bStop = false; //停止标志 =5/ow!u8  
File tmpFile; //文件下载的临时信息 {^=T&aCYdS  
DataOutputStream output; //输出到文件的输出流 Atc9[<~WG  
)'+" y~  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） %V71W3>6WS  
public SiteFileFetch(SiteInfoBean bean) throws IOException EudX^L5U<d  
{ \(2w/~  
siteInfoBean = bean;  a?S5 =  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); G d~ v _  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); nF>41 K  
if(tmpFile.exists ()) Swz{5 J2C  
{ O 7RIcU  
bFirst = false; a?jUm.  
read_nPos(); pqe7a3jr  
} U;`
C%vHff  
else WJWi'
|C4  
{ 86Hg?!<i.  
nStartPos = new long[bean.getNSplitter()]; Q
,R>dkS  
nEndPos = new long[bean.getNSplitter()]; :B{Wf 2<z  
} NIgqdEu1
 
%]
7'2  
M.fAFL  
Z,zkm{9*  
} Ha~F&H|"O  
W*S}^6ZT`  
\4Uhc3  
public void run() +7\$wc_1I@  
{ & "i4og<  
//获得文件长度 "uCO?hv0  
//分割文件 2[|52+zhc  
//实例FileSplitterFetch R!i\-C1 S  
//启动FileSplitterFetch线程 5~D(jHY;  
//等待子线程返回 A0hKzj  
try{ ;)~}/nR<a  
if(bFirst) Z$?(~ln  
{ "5<:Dj/W  
nFileLength = getFileSize(); i>z_6Gax*[  
if(nFileLength == -1) 1WjNFi  
{ Q^\m@7O :  
System.err.println("File Length is not known!"); &!P'
M  
} 8\WV.+  
else if(nFileLength == -2) 0N;~(Vt2  
{ q QcQnd2K  
System.err.println("File is not access!"); }NjZfBQW`  
} c wNJ{S+  
else "C0?s7Y  
{ T:T`M:C.  
for(int i=0;i<nStartPos.length;i++) >$$z6A[  
{ r>: ~!o*  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); [)+wke9  
} vf&_ N  
for(int i=0;i<nEndPos.length-1;i++) J':X$>
E|  
{ QyghNImp  
nEndPos = nStartPos[i+1]; _(zZrUHB  
} hrNB"W|?x  
nEndPos[nEndPos.length-1] = nFileLength; uMx6:  
} {N3&JL5\"E  
} }y%c.  
l1bkhA b  
&(7=NAQsE  
//启动子线程 cY5w,.Q/!  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; i0:1+^3^U  
for(int i=0;i<nStartPos.length;i++) =cpUc]~  
{ ?g\emhG  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), d-3.7nJ:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),  nU4to  
nStartPos,nEndPos,i); ]_BH"ng}  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]A;.}1'  
fileSplitterFetch.start(); %pIP#y[4  
} -MRX@a^1  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?7>"ZGDe>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ]]0Yh  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", q<j9l'dHG  
nEndPos = " + nFileLength); @U3:9~Q  
// fileSplitterFetch[nPos.length-1].start(); v,C~5J3h)  
zauDwV=  
EugRC  
//等待子线程结束 UX+vU@Co[  
//int count = 0; |kH.o=  
//是否结束while循环 ;L,i">_%u[  
boolean breakWhile = false; o\F>K'  
u^G Y7gah  
m]vS"AdX  
while(!bStop) 2eHVl.C5  
{ jST4O"DjM  
write_nPos(); RL:B.Lv/W  
Utility.sleep(500); 55'  
breakWhile = true;
/oW]? 9  
[UXN= 76N  
>23$_'2  
for(int i=0;i<nStartPos.length;i++) m.p$f$A_  
{ (i L*1f   
if(!fileSplitterFetch.bDownOver) :hT.L3n,  
{ k3H0$1  
breakWhile = false; "={*0P  
break; /o%VjP"<  
} {nXygg J  
} WW.@&#S5  
if(breakWhile) Um}AV  
break; ;DSH$'1i  
Ml$<x"Q  
S2DG=hi`GK  
//count++; e pp04~  
//if(count>4) ;p2b^q'  
// siteStop(); 9Vqy<7i1  
} ywl=@  
pmUf*u-
 
d&CpaOSu  
System.err.println("文件下载结束！"); 3
<Zp+rD  
} i(pHJP:a:  
catch(Exception e){e.printStackTrace ();} (:qc[,m  
} 3rB0H   
z~X/.>  
8 eK8-R$  
//获得文件长度 O>pv/Ns  
public long getFileSize() t[J=8rhER  
{ Vi:^bv  
int nFileLength = -1; (w#t V*  
try{ /W)A[jR  
URL url = new URL(siteInfoBean.getSSiteURL()); Y*$>d/E  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); R2n 2mQ<  
httpConnection.setRequestProperty("User-Agent","NetFox"); vjS=ZinN"  
m)} 01N4  
&}[P{53sr  
int responseCode=httpConnection.getResponseCode(); u*v<dsGQ  
if(responseCode>=400) Bp_R"DS7A  
{ *s*Y uY%y  
processErrorCode(responseCode); 6IG?t  
return -2; //-2 represent access is error MNWI%*0LO  
} {='Bd6_=  
UL-_z++G  
l>}f{az-T  
String sHeader; EC;>-s  
}1e4u{  
'"fJA/O  
for(int i=1;;i++) ]vlBYAW'  
{ 6ki2/ Q  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); a3<:F2=~\  
//Utility.log(in.readLine()); +ZM,E8  
sHeader=httpConnection.getHeaderFieldKey(i); NDP" @  
if(sHeader!=null) #M16qOEw  
{ bO2?DszT5  
if(sHeader.equals("Content-Length")) 8s$6R|ti  
{ GeTk/tU  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ##=$$1Ki  
break; uy'seJ  
} 7bzm5w@v  
} s:}?rSI  
else <'~m1l#2  
break; ZrTB%  
} qK a}O*  
} )pH
+ibR  
catch(IOException e){e.printStackTrace ();} teg5g|*  
catch(Exception e){e.printStackTrace ();} &bW,N  
^PTf8o  
 /ooGyF  
Utility.log(nFileLength); :J`@@H  
k0e}`#t  
J+`aj8_B  
return nFileLength; e~SK*vR%]  
} N $) G8  
z6iKIw $  
{h@\C|nF  
//保存下载信息（文件指针位置） _-TplGSO=c  
private void write_nPos() jr4xh{Z`  
{ W
FOJg&  
try{ ;>v.(0FE6  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ~\_VWXXvIW  
output.writeInt(nStartPos.length); f1MRmp-f'  
for(int i=0;i<nStartPos.length;i++) :+,;5  
{ "l56?@-x  
// output.writeLong(nPos); B`B=bn+4  
output.writeLong(fileSplitterFetch.nStartPos); s$R /!,c  
output.writeLong(fileSplitterFetch.nEndPos); (`.OS)&  
} 7y'":1  
output.close(); R+M=)Z  
} ~?F,kmO}?  
catch(IOException e){e.printStackTrace ();} dH^6K0J  
catch(Exception e){e.printStackTrace ();} zFq%[X  
} =%X."i1A  
/| v.A\:  
fwFJe(.  
//读取保存的下载信息（文件指针位置） 2tq2   
private void read_nPos() fCr2'+O"b  
{ ;5j|B|v  
try{ gJ6`Kl985O  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Z+El(f x  
int nCount = input.readInt(); =Zq6iMD  
nStartPos = new long[nCount]; OIrm9D#  
nEndPos = new long[nCount]; M~taZt4  
for(int i=0;i<nStartPos.length;i++) ~Ru\Z-q1  
{ :,l7e  
nStartPos = input.readLong(); TpKAdrY  
nEndPos = input.readLong(); PM\Ju]  
}  =_dM@j  
input.close(); .k,j64 r  
} (9]Uuvfp6"  
catch(IOException e){e.printStackTrace ();} #rlgeHG!fs  
catch(Exception e){e.printStackTrace ();} D\Ak-$kJ^  
} [3m\~JtS  
Pd91<L  
3B1\-ry1M  
private void processErrorCode(int nErrorCode) 75# 8P?i  
{ URsx>yx  
System.err.println("Error Code : " + nErrorCode); 8Qg10Yjy  
} Q|(}rIWOQA  
P@7>R7
gS  
fkxkf^g)  
//停止文件下载 cJo%j -AM  
public void siteStop() a"vzC$Hxd  
{ ]Z!Y*v  
bStop = true; C >*z^6Gz  
for(int i=0;i<nStartPos.length;i++) F!vrvlD`s  
fileSplitterFetch.splitterStop(); J>Ar(p  
W'./p"2g  
fs!dI  
} mfraw2H  
} 9Dx~!(  
//负责部分文件的抓取 ReaZg ?:h  
**FileSplitterFetch.java t<!m4Yd|#  
*/ 7hk)I`o65  
package NetFox; qed_PsI  
,>j3zjf^  
q[$>\Nfg>B  
import java.io.*; fCY|iO0.t  
import java.net.*; m%|\AZBA#  
'.|}  

IK -vcG  
public class FileSplitterFetch extends Thread { _^<vp  
\Id8X`,eD  
L ]')=J+  
String sURL; //File URL 8SjCU+V  
long nStartPos; //File Snippet Start Position ?0Q3F  
long nEndPos; //File Snippet End Position 4E''pW]8  
int nThreadID; //Thread's ID u3h(EAH>  
boolean bDownOver = false; //Downing is over (qAF2&  
boolean bStop = false; //Stop identical ZX_QnSNZ?  
FileAccessI fileAccessI = null; //File Access interface 392V\qtS  
q`e0%^U  
e9p/y8gC  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException RZz?_1'  
{ c&D+=   
this.sURL = sURL; oiyvKMHz7  
this.nStartPos = nStart; k=)U  
this.nEndPos = nEnd; k5RzW4zq;  
nThreadID = id; 0]>bNbLB"  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 %pZT3dcK  
} 30h[&
Oc  
Ec7xwPk  
SqAz((  
public void run() "5JMk -2k  
{ e{8C0=  
while(nStartPos < nEndPos && !bStop) \KV.lG!  
{ $ DN.  
ihkZs3}  
0hS&4nW  
try{ ZRhk2DA#FF  
URL url = new URL(sURL); oypLE=H  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); B} qRz  
httpConnection.setRequestProperty("User-Agent","NetFox"); ],c0nz^%BR  
String sProperty = "bytes="+nStartPos+"-"; {JWixbA  
httpConnection.setRequestProperty("RANGE",sProperty); v=^^Mr"Z^  
Utility.log(sProperty); yK{P%oh)  
!MSa -  
&wNr2PHd#  
InputStream input = httpConnection.getInputStream(); Pr>$m{ Z  
//logResponseHead(httpConnection); B+FTkJ0t+G  
-IIrrY O  
I85wP}c(  
byte[] b = new byte[1024]; CQ!D{o=  
int nRead; >(:3H+  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) !jP[=  
{ IiKU=^~w  
nStartPos += fileAccessI.write(b,0,nRead); ,vR>hy
M  
//if(nThreadID == 1) DvWBvs,  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0Cc3NNdz  
} Va[&~lA)  
?~ybFrc  
>u%Bn\G  
Utility.log("Thread " + nThreadID + " is over!"); Fmn_fW6  
bDownOver = true; 2zo>`;l  
//nPos = fileAccessI.write (b,0,nRead);
c'$y_]  
} n(A;:)W{  
catch(Exception e){e.printStackTrace ();} ^C,rN;mX'  
} Ps! \k%FUl  
} C4E*q3[Y  
E=.J*7  
S?DMeZ{:  
//打印回应的头信息 H( LK}[  
public void logResponseHead(HttpURLConnection con) k8Dk;N  
{ VU\G49  
for(int i=1;;i++) ddYb=L+_b  
{ 0>Kgz!I  
String header=con.getHeaderFieldKey(i); J?p|Vy|9  
if(header!=null) W__$ i<1  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 0>,i] |Y  
Utility.log(header+" : "+con.getHeaderField(header)); jcePSps]  
else sVO|Ghy65  
break; B \V;{:  
} @$b7 eu  
} *R&77 o7  
H1evW  
Lxa<zy~b  
public void splitterStop() X56.Y.  
{ T5[(vTp  
bStop = true; @ /e{-Q  
} %AMF6l[  
b^Do
[o}5  
787i4h:71  
} |$T?P*pI.  
V" 5rIk  
+SFo2Wdr43  
/* k%RQf0`T  
**FileAccess.java 17rg!'+   
*//文件访问(定位，写) voN,u>U  
package NetFox;
neWx-O  
import java.io.*; :2L-Nf  
)q7!CG'oY  
;S2/n$Ju_  
public class FileAccessI implements Serializable{ X)Rh&ui  
K
`R  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 9@(V!G  
RandomAccessFile oSavedFile; 5X`m.lhUc  
long nPos; (Sj?BZjC  
*fDhNmQ `  
=sXk,I;  
public FileAccessI() throws IOException 6r5<uZ9w_X  
{ BfvvJh_  
this("",0); orF8%  
} O~bzTn
 
|A u+^#:;  
,|R\ Z,s  
public FileAccessI(String sName,long nPos) throws IOException K30{Fcb< h  
{ WGMEZx  
oSavedFile = new RandomAccessFile(sName,"rw"); cr{f*U6`  
this.nPos = nPos; ]+78 "(  
oSavedFile.seek(nPos); "Kn%|\YL@4  
} n ^C"v6X  
DmpD`^?-L  
`oH6'+fT`;  
public synchronized int write(byte[] b,int nStart,int nLen) p?sC</R  
{ 8<g9 ~L  
int n = -1; z/S}z4o/  
try{ U{.yX7  
oSavedFile.write(b,nStart,nLen); t'Pn*  
n = nLen; *1b)Va8v*  
} n|I5ylt  
catch(IOException e) )KD*G;<O]L  
{ ~Wj. 4b*  
e.printStackTrace (); 6<C|O-  
} ],
ISWb  
4Q(GX.5  
r5aOQ  
return n; Sy`7})[  
} ]PjJy/vkjj  
<-m[0zgq  
t5WW3$Nf  
} ).1F0T  
R<x~KJ11c  
<2{-ey]  
/* 0T7""^'&  
**SiteInfoBean.java dBMr%6tz  
*/ .+ g8zbD4  
package NetFox; DF!*S{)  
w0L+Sj db  
$4a;R I  
public class SiteInfoBean { u3ns-e  
S4FR=QuVQC  
1x~dsM;q  
private String sSiteURL; //Site's URL yd4\%%]  
private String sFilePath; //Saved File's Path m_g2Cep  
private String sFileName; //Saved File's Name =;?afUj  
private int nSplitter; //Count of Splited Downloading File Wc qUF"A  
7awh__@  
m3i+b  
public SiteInfoBean() P4S]bPIp  
{//nSplitter的缺省值为5 L1J~D?q  
//default value of nSplitter is 5 R9`37(c9+  
this("","","",5); SV0h'd(b  
} yvp$s  
dGY:?mf&  
rsgTd\b  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)  &@h(6  
{ ic(`Ev  
sSiteURL= sURL; #XPY\n^k  
sFilePath = sPath; ^>ICycJ  
sFileName = sName; &3_.k  
this.nSplitter = nSpiltter; [uD G;We=  

51&K  
+<o}@hefY2  
} jZ\a:K?  
ydm2'aV  
L
aCVI  
public String getSSiteURL() M4`.[P4  
{ LW '3m5  
return sSiteURL; nWz7$O  
} @nOj6b  
-.=:@H}r  
iu+r=sp  
public void setSSiteURL(String value) 82*nC!P3E  
{ bs9X4n5  
sSiteURL = value; ZtLZW/`  
} U1^3 &N8  
O-jpS?@  
1HS43!  
public String getSFilePath() I->BDNk  
{ WAqH*LB  
return sFilePath; &b:SDl6  
} zi
TE*rNJ  
1@S(v L3a  
DO{Lj#@  
public void setSFilePath(String value) bDADFitSo  
{ aF]cEe  
sFilePath = value; ~,O&A B
  
} V krjs0  
P4{!
/&/  
9T;DFUM  
public String getSFileName() e[l#r>NT  
{ W|-<ekH_u  
return sFileName; >,}SP;  
} V3v/hV:  
G'IRqO*]  
Nm4 h  
public void setSFileName(String value) GA+#'R  
{ &X&
msEM  
sFileName = value; T6M=BkcP  
} Or<OmxJg  
.6HHUy  
/n-!dXi  
public int getNSplitter() %Rm`+  
{ A3eus
 
return nSplitter; Scd_tw.]|  
} w 21g&  
CKy/gTN  
LVe[N-K  
public void setNSplitter(int nCount) W'"p:Uhq  
{
T0v{qQ  
nSplitter = nCount; n@_aTY  
} [5i}C K_=  
} Ju"K"  
B2T=O%  
=.(~`ici~  
/* jeWI<ms  
**Utility.java ,-`A6ehg  
*/ 12LGWhDp  
package NetFox; /zg|I?$>Z4  
>SHP,><H/  
-=4{X R3  
public class Utility { D]'/5]~z<  
z$Z
{ LR  
i{biQ|,.sL  
public Utility() 'mYUAVmSC#  
{ )QAS7w#k  
<~}NxY\5  
{66P-4Ev(  
} |"aop|  
^8V8,C)  
//线程睡眠 )NmYgd~%  
public static void sleep(int nSecond) :CGh$d] +  
{ Wxa</n8S[n  
try{ H:]'r5sw  
Thread.sleep(nSecond); Wa
<SYJ  
} $ #bWh  
catch(Exception e) o2R&s@%0@B  
{ }9~U5UXWU  
e.printStackTrace (); i;fU],aK!  
} se*!OiOt  
} =4#p|
OZP  
h@j
k3J9^  
//日志 I78Q8W(5  
public static void log(String sMsg) Xq%ijo  
{ JYrOE"!h  
System.err.println(sMsg); iC4rzgq  
} z-JYzxL9  
6kHuKxY,  
=y0h\<[  
public static void log(int sMsg) kE854Ej  
{ PYyT#AcW2  
System.err.println(sMsg); gB])@O%/  
} n'83P%x  
} *T2kxN,Ik  
^_t7{z%sA[  
hVW1l&s  
/* uJU;C.LX  
**TestMethod.java oT i$@q  
*/ B8>3GZi  
package NetFox; 4VP$,|a  
9`cj9zz7  
V-ONC
  
public class TestMethod { tZygTvK/S  
" nLWvV1  
FL[w\&fp  
public TestMethod() R= .UbY  
{ ///xx/weblogic60b2_win.exe #Yx /ubg6  
try{ bA07zI2  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 7T?T0x3>  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); uQ3W =  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ^C~t)U  
fileFetch.start();  t: 03  
} ;!B>b)%  
catch(Exception e){e.printStackTrace ();} V
(M7d>N5G  
>'v{o{k|C  
$fwj8S7$  
} B~`:?f9ny5  
BHR(B]EI  
P.3kcZ   
public static void main(String[] args) WD|pG;Gq  
{ & sgzSX  
new TestMethod(); +<'>~lDg  
} LRPdA "Z
 
} ;RS^^vDm  
点击下载更多相关资料