http断点续传简单实现（java)

/* i^WIr h3a  
**SiteFileFetch.java !#?8BwnaZ  
*/ AM'gnP>  
package NetFox; *8PN!^  
import java.io.*; ,+se  
import java.net.*; d/S+(<g  
+semfZ)  
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public class SiteFileFetch extends Thread { 4.8nY\_WF  
{7qA&c=  
>8|+%pK8<  
SiteInfoBean siteInfoBean = null; //文件信息Bean `fz,Lh*v  
long[] nStartPos; //开始位置 =`-|&  
long[] nEndPos; //结束位置 =+<d1W`>0  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 j&WL*XP&5  
long nFileLength; //文件长度 G
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boolean bFirst = true; //是否第一次取文件 &UL_bG}  
boolean bStop = false; //停止标志 l4KbTKm7  
File tmpFile; //文件下载的临时信息 Hd*}k6  
DataOutputStream output; //输出到文件的输出流 tjj^O%SV<  
&1_U1  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） FPF6H puV  
public SiteFileFetch(SiteInfoBean bean) throws IOException g`n;R  
{ M'q'$)e  
siteInfoBean = bean; G+VD8]!K1  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ]*3:DU  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); sK&,):"]R  
if(tmpFile.exists ()) X"j>=DEX  
{ kh3<V'k]  
bFirst = false; !2$ z *C2;  
read_nPos(); %k2FPmA6  
} yxwWj>c  
else /Wu|)tx  
{ U'y,YtF@  
nStartPos = new long[bean.getNSplitter()]; :I \9YzSs@  
nEndPos = new long[bean.getNSplitter()]; @DuK#W"E u  
} 03([@d6<
E  
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} -f?Ah  
^,TTwLy-t  

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public void run() =1Z;Ma<;  
{ WhFS2Jl0  
//获得文件长度 rA1
qSG~c  
//分割文件 *P!s{i  
//实例FileSplitterFetch ]CX[7Q
+'  
//启动FileSplitterFetch线程 |CIC$2u  
//等待子线程返回 f@@s1gdb  
try{ y\'P3ihK  
if(bFirst) \~#WY5  
{ EB!daZH,  
nFileLength = getFileSize(); (?3[3w~  
if(nFileLength == -1) SdJ/4&{ !  
{ X3wX`V}

  
System.err.println("File Length is not known!"); 'e@=^FC  
} _dU8'H  
else if(nFileLength == -2) 26L~X[F  
{ MR$>!Nlp  
System.err.println("File is not access!"); O>c$sL0g  
} $*\L4<(  
else R?pRxY  
{ j1q[c,  
for(int i=0;i<nStartPos.length;i++) /YH`4e5g  
{ brSi<  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); _U0$=V  
} {q3:Z{#>7  
for(int i=0;i<nEndPos.length-1;i++) ~e">_;k6  
{ +th%enRB  
nEndPos = nStartPos[i+1]; bA@P}M)X  
} e;VIL 2|  
nEndPos[nEndPos.length-1] = nFileLength; Kesy2mE  
} 0 [8=c&F  
} aDL*W@1S  
*hdC?m._  
<7XT\?%F  
//启动子线程 ,*Z.  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; HjA_g0u  
for(int i=0;i<nStartPos.length;i++) p'f%%#I  
{ % /}WUP^H  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @hif$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), LA%bq_>f  
nStartPos,nEndPos,i); VK:8 Nk_y  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~@4'HM
Q  
fileSplitterFetch.start(); syPWs57pH  
} .lNs4e  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), jb[!E^'&>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); `/n
M[  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", wX,F`e3"/  
nEndPos = " + nFileLength); ;%Hf)F  
// fileSplitterFetch[nPos.length-1].start(); ?LaUed'  
@Uo6>-WF  
kKiA  
//等待子线程结束 L]d-33.c!H  
//int count = 0; EQ<RDhC@b  
//是否结束while循环 nSx]QREL!  
boolean breakWhile = false;  Paj vb-f  
r~7:daG*  
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while(!bStop) zj|WZ=1*Wp  
{ T vtm`Yk\  
write_nPos(); LF*&(NC  
Utility.sleep(500); 6l\FIah@  
breakWhile = true; :G5RYi  
',I0ih#Ls  
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for(int i=0;i<nStartPos.length;i++) .S?pG_n]f  
{ p'94SXO_  
if(!fileSplitterFetch.bDownOver) RA O`i>
@  
{ &miexSNeF  
breakWhile = false; [10zTU
`  
break; en*d/>OVJ  
} o0It82?RN  
} 0N:XIGFa  
if(breakWhile) ]; Wx  
break; 58V[mlW)O0  
nBItO~l  
a W
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//count++; iK()&TNz  
//if(count>4) >[10H8~bI/  
// siteStop(); Q.U$nph\%d  
} P\nC?!Q%c  
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System.err.println("文件下载结束！"); >vbY<HGt  
} #z'uRHx%=0  
catch(Exception e){e.printStackTrace ();} S9| a$3K'  
} 6Jz^  
Li
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I5m][~6.?  
//获得文件长度 ~b~2 >c9  
public long getFileSize() ;gg\;i}^  
{ 13hE}g;.  
int nFileLength = -1; K(}AX+rIg  
try{ ?sz)J3  
URL url = new URL(siteInfoBean.getSSiteURL()); dt}_D={Be  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Zw1U@5}A  
httpConnection.setRequestProperty("User-Agent","NetFox"); M]]pTU((  

#/2$+x  
t2HJsMX  
int responseCode=httpConnection.getResponseCode(); [K/m  
if(responseCode>=400) tWeFEVg  
{ >slm$~rv  
processErrorCode(responseCode); o=J9  
return -2; //-2 represent access is error }J:+{4Yn  
}
DL'iS  
8flOq"uK^  
[U@;\V$  
String sHeader; UBv@+\Y8m  
v *-0M  
vmTs9"ujF,  
for(int i=1;;i++) PQN@JaD  
{ cTTW06^  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 3*UR3!Z9 *  
//Utility.log(in.readLine()); LUX*P7*B  
sHeader=httpConnection.getHeaderFieldKey(i); vQ}6y  
if(sHeader!=null) b75$?_+  
{ 8I;XS
14Q  
if(sHeader.equals("Content-Length")) u"1rF^j6k  
{ $Xm6N@  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); q$(5Vd:  
break; (6l+lru[  
} Cqii}  
} RwI[R)k  
else 6z0@I*  
break; Fs_]RfG  
} uc7Eq45  
} %WTEv?I{Ga  
catch(IOException e){e.printStackTrace ();} d[p;T\?"  
catch(Exception e){e.printStackTrace ();} L|-98]8>  

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s~I6SA&i  
Utility.log(nFileLength); bHLT}x/Gw  
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@yd4$Mv8%  
return nFileLength; ]?O2:X  
} sg
'pO*_&  
/S5|wNu  
<@wj7\pQ  
//保存下载信息（文件指针位置） ~lNsa".c  
private void write_nPos() uiq^|5Z  
{ m7EcnQf  
try{ &k-Vcrcz  
output = new DataOutputStream(new FileOutputStream(tmpFile)); W[EKD 7  
output.writeInt(nStartPos.length); 9O{b]=>wq  
for(int i=0;i<nStartPos.length;i++) l3Njq^T  
{ y[B>~m8$  
// output.writeLong(nPos); HK\~Qnq  
output.writeLong(fileSplitterFetch.nStartPos); ~'37`)]z  
output.writeLong(fileSplitterFetch.nEndPos); =K'cM=WM6  
} QrO\jAZ{Ag  
output.close(); cdqB,]"  
} X\EVTd)@  
catch(IOException e){e.printStackTrace ();} 2(5ebe[
 
catch(Exception e){e.printStackTrace ();} qTZFPfyU  
} Hbv6_H  
kKC9{^%)  
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//读取保存的下载信息（文件指针位置） niB`2J  
private void read_nPos() ARcB'z\r  
{ lL1k.&|5m  
try{ ;XM{o:1Y[  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); F}Vr:~  
int nCount = input.readInt(); 2'=T[<nNB  
nStartPos = new long[nCount]; ifN64`AhRX  
nEndPos = new long[nCount]; uqz]J$
 
for(int i=0;i<nStartPos.length;i++) s0Z uWVip  
{ X7k.zlH7T  
nStartPos = input.readLong(); @(r/dZc  
nEndPos = input.readLong();  hI9  
} __mF?m  
input.close(); (/35pg6\  
} @gY)8xMbA  
catch(IOException e){e.printStackTrace ();} V#VN%{  
catch(Exception e){e.printStackTrace ();} q6YXM  
} )K &(  
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KYzv$oK  
private void processErrorCode(int nErrorCode) F:x [  
{ h=;{oY<V)?  
System.err.println("Error Code : " + nErrorCode); z5ij(RE]  
} H":oNpfb  
%*BlWk!Q  
4apL4E"r  
//停止文件下载 v
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public void siteStop() .\>v0Du  
{ MEB it  
bStop = true; RX/hz|  
for(int i=0;i<nStartPos.length;i++) vWAL^?HUP  
fileSplitterFetch.splitterStop(); I`NjqyTW  
"DYJ21Ut4  
U&O: _>~  
} f^W;A"+  
} 9(QJT}qC  
//负责部分文件的抓取 j?'GZ d"B  
**FileSplitterFetch.java 98^V4maR:  
*/ t!RiUZAo  
package NetFox; 5\z`-)  
 SdD6 ~LS  
k:7(D_  
import java.io.*; ;!yQ  
import java.net.*; A~-b!Grf  
2}8v(%s p  
|\pbir  
public class FileSplitterFetch extends Thread { oq}'}`lw"  
3Z1CWzq(  
s{1sE)_  
String sURL; //File URL `V##Y  
long nStartPos; //File Snippet Start Position .V,@k7U,V  
long nEndPos; //File Snippet End Position FSND>\>  
int nThreadID; //Thread's ID p,#o<W  
boolean bDownOver = false; //Downing is over ob8qe,_'  
boolean bStop = false; //Stop identical 4:FK;~wM&x  
FileAccessI fileAccessI = null; //File Access interface ;+"+3  
\ Yx/(e  
%7|9sQ:  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException `nu''B H  
{ Ofs<EQ
 
this.sURL = sURL; $< JaLS  
this.nStartPos = nStart; _*f`iu:`  
this.nEndPos = nEnd; (!:,+*YY  
nThreadID = id; =i[\-  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 >7 ="8  
} CB^U6ZS  
v/_  
Hm*/C4B`  
public void run() Hl,W=2N  
{ %KLpig  
while(nStartPos < nEndPos && !bStop) #{;k{~;PF  
{ FYpzQ6s~  
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try{ ;0Tx-8l  
URL url = new URL(sURL); uLV#SQ=bZN  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `x*Pof!Io  
httpConnection.setRequestProperty("User-Agent","NetFox"); [TmIVQ!B  
String sProperty = "bytes="+nStartPos+"-"; c24dSNJg,  
httpConnection.setRequestProperty("RANGE",sProperty); ln6d<; M5  
Utility.log(sProperty); ,5h)x"s  
I`!<9OTBj  
6
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InputStream input = httpConnection.getInputStream(); F'21jy&  
//logResponseHead(httpConnection); K|[*t~59  
jWA(C;W  
'd9INz.  
byte[] b = new byte[1024]; @u6B;)'l  
int nRead; a!v1M2>  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) xA$XT[D  
{ 4\iOeZRf  
nStartPos += fileAccessI.write(b,0,nRead); ]Gsv0Xk1  
//if(nThreadID == 1) YpVD2.jy  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); T{-CkHf9Q  
} ~UP[A'9jJ  
A PEE~  
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Utility.log("Thread " + nThreadID + " is over!"); VZKvaxIk
6  
bDownOver = true; Wi)_H$KII  
//nPos = fileAccessI.write (b,0,nRead); .[I
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} |Y,b?*UF  
catch(Exception e){e.printStackTrace ();} Hquc o  
} bKMy|_  
} Hx?;fl'G%  
b0Ps5G\ u  
3`DQo%<  
//打印回应的头信息 g,!L$,/F  
public void logResponseHead(HttpURLConnection con) VAHh~Q6 ;e  
{ 5@~ Q^r:%  
for(int i=1;;i++) V2wb%;q  
{ M/"I2m   
String header=con.getHeaderFieldKey(i); s Z].8.  
if(header!=null) r7%I n^k  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); "ut39si  
Utility.log(header+" : "+con.getHeaderField(header)); z7fp#>uw  
else I 
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break; #Lh;CSS  
} *XIF)Q=<>  
} kaVxT_  
ivJ@=pd)B  
|v3T!  
public void splitterStop() vdc\R?  
{ gCB |DY  
bStop = true; @niHl  
} Swig;`  
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c(xrP/yOwi  
} Ng2twfSl$  
Z 2V.3  
L>Fa^jq5  
/* Yg||{  
**FileAccess.java Ga^"1TZ x  
*//文件访问(定位，写)  iu=7O  
package NetFox; ,/Z%@-rF  
import java.io.*; ;n*.W|Uph  
0ypNUG}   
X^wt3<Kbf  
public class FileAccessI implements Serializable{ 2} /aFR  
a%JuC2  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 f<d`B]$(  
RandomAccessFile oSavedFile; / *#r`A  
long nPos; - M4JJV(  
dO! kk"qn  
T $>&[f$6  
public FileAccessI() throws IOException *av<E  
{ hj*pTuym  
this("",0); %K=?@M9i  
} <l
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*v!9MU9[(  
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public FileAccessI(String sName,long nPos) throws IOException /T0F"e)Ci  
{ 1Y\DJ@lh  
oSavedFile = new RandomAccessFile(sName,"rw"); ) j#`r/  
this.nPos = nPos; 4DI8s4fi  
oSavedFile.seek(nPos); 2*;~S44  
} H)kwQRfu  
9<6;Hr,>G  
]8_NZHld  
public synchronized int write(byte[] b,int nStart,int nLen) 6 $4[gcL'  
{ y}" O U  
int n = -1; l*Gvf_UH  
try{ @<hb6bo,N
 
oSavedFile.write(b,nStart,nLen); -A^_{4X  
n = nLen; +SR+gE\s0  
} P^~yzI  
catch(IOException e) _7Ju  
{ 4yy>jXDG  
e.printStackTrace (); > PRFWO  
} JE"x  
q$d>(vbq  
AUG#_HE]k  
return n; EIP/V  
} @e.C"@G  
X:"i4i[}{9  
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} |.: 
q  
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v!~fs)cdE|  
/*
MS~(D.@ZS  
**SiteInfoBean.java !GjQPAW  
*/ 'x#~'v
*  
package NetFox; QOGvC[*`<T  
i+ ?^8#  
C_}]`[  
public class SiteInfoBean { J5K^^RUR  
@1roe G  
pK>N-/?a  
private String sSiteURL; //Site's URL Cw3a0u  
private String sFilePath; //Saved File's Path ?=sDM& '  
private String sFileName; //Saved File's Name J/y83@  
private int nSplitter; //Count of Splited Downloading File O3,jg|,  
yLvDMPj  
<`=j^LU  
public SiteInfoBean() UERLtSQ  
{//nSplitter的缺省值为5 "<N*"euH  
//default value of nSplitter is 5 AlaW=leTe  
this("","","",5); 5{X<y#vAC0  
} {UI+$/v#  
y%cP1y)  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) g wRZ%.Cn  
{ |tH4:%Q'  
sSiteURL= sURL; Q~ w|#  
sFilePath = sPath; Rsm^Z!sn  
sFileName = sName; W' VslZG  
this.nSplitter = nSpiltter; tCH!m
y_  
L ca}J&x]^  
/hR&8 `\\  
} -=Q*Ml#I  
$t[FH&c(  
9s q  
public String getSSiteURL() Tx# Mn~xD  
{ N#_H6TfMG  
return sSiteURL; kS);xA8s]  
} L~OvY
  
b{&)6M)zo  
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public void setSSiteURL(String value) pz}.9 yI8  
{ %YscBG  
sSiteURL = value; Czu9o;xr  
} 194)QeoFw  
CY5Z{qiX  
)mT<MkP  
public String getSFilePath() S9y}  
{ v@L;x [Q  
return sFilePath; U?Zq6_M&  
} }o(-=lF  
PJ%C N(0  
4xje$/_d  
public void setSFilePath(String value) *w\W/Y  
{ -GrE}L  
sFilePath = value; *L^,|   
} 77f9(~ZnT  
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83_h J  
public String getSFileName() zwjgE6  
{ [}=B8#Jl-C  
return sFileName; e
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} AQvudx
)@"  
6A-|[(NS  
/W<;Z;zk  
public void setSFileName(String value) G5 WVr$  
{ |u<7?)mp  
sFileName = value; wlqksG[B  
} ^6V[=!& H  
"ze|W\Bv!  
SY\ gXO8k  
public int getNSplitter() f.$af4 u  
{ +a+Om73B2  
return nSplitter; *.t7G  
} .W!i7  
(hbyEQhF  
O_7|C\]  
public void setNSplitter(int nCount) VY4yS*y  
{ _]H&,</  
nSplitter = nCount; c-5)QF) z  
} JK5gQ3C[  
} n
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!_)[/q"  
VpDbHAg  
/* h*](a_0  
**Utility.java iqWQ!r^  
*/ ggR.4&<  
package NetFox; gjDHo$  
HIZe0%WPw  
Kn1a>fLaJ_  
public class Utility { E ~<JC"]  
](8[}CeL
 
'5$b-x6F  
public Utility() >|UOz&  
{ %IWPM"  
2FJ*f/  
^<2p~h0 \  
} 3f{3NzN  
lt8|9"9<  
//线程睡眠 @Jw-8Q{  
public static void sleep(int nSecond) SE %pw9  
{ kt:! 7  
try{ D'Q\za  
Thread.sleep(nSecond); EaN6^S=  
} s2'h  
catch(Exception e) -[.[>&`/  
{ cVF"!.  
e.printStackTrace (); ?6WY:Zec@  
} h2d(?vOT  
} wbl&  
t%=tik2|7  
//日志 y}|s&4Sq  
public static void log(String sMsg) S<Xf>-8w  
{ }5"u[Z.  
System.err.println(sMsg); Lp9E:D->  
} UJ   
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vEJbA  
public static void log(int sMsg) k9L;!TH~1K  
{ 9\7en%(M  
System.err.println(sMsg); cbTm'}R(G  
} i9x+A/o[  
} /j.9$H'y  
>4CbwwMA  
_oeS Uzq.  
/* gg2(5FPP  
**TestMethod.java `;egv*!P  
*/ 3^yK!-Wp(  
package NetFox; Nj/ x. X  
jmZI7?<z  
utV_W&  
public class TestMethod { k8zI(5.>
 
+ {'.7#  
uwGc@xOgg,  
public TestMethod() zdam^o  
{ ///xx/weblogic60b2_win.exe Zj'9rXhrM1  
try{ qIT@g"%}t  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 'm$L Ij?@  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); DN6Mo<H  
SiteFileFetch fileFetch = new SiteFileFetch(bean); #%O0[kd  
fileFetch.start(); l.M0`Cn-%  
} U 6)#}
 
catch(Exception e){e.printStackTrace ();} h/Y'<:  
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scV5PUq  
} |2A:eI8 ^  
SOIN']L|V[  
do'GlU oMC  
public static void main(String[] args) 'LDQgC*%  
{ \s\?l(ooq"  
new TestMethod(); wUJcmM;  
} P]C<U aW'!  
} G' 1'/  
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