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http断点续传简单实现(java)

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/* kWL.ewTiex  
**SiteFileFetch.java ZPO|<uR  
*/ KJh,,xI>by  
package NetFox; mm[SBiFO\  
import java.io.*; otr>3a*'  
import java.net.*; B@t'U=@7  
"tu*YNP\Q  
5Qa zHlJ  
public class SiteFileFetch extends Thread { :0 ^s0l  
5j^NV&/_  
rt4Z;  
SiteInfoBean siteInfoBean = null; //文件信息Bean g4&jo_3:p  
long[] nStartPos; //开始位置 H4<Nnd\   
long[] nEndPos; //结束位置 C!%:o/  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ;sPzOS9  
long nFileLength; //文件长度 #[ -\lU|  
boolean bFirst = true; //是否第一次取文件 @5<CXTdF9c  
boolean bStop = false; //停止标志 N/~N7MwJj  
File tmpFile; //文件下载的临时信息 Zk? =  
DataOutputStream output; //输出到文件的输出流 QH@>icAb  
.px:e)iW  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) S KXD^OH  
public SiteFileFetch(SiteInfoBean bean) throws IOException uDayBaR  
{ .ve *Vp  
siteInfoBean = bean; ]hTb@.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); qv+R:YYOq  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); =%qEf   
if(tmpFile.exists ()) G&9#*<F$c  
{ -_8*41  
bFirst = false; Qv#]81i(1  
read_nPos(); |M5-5)  
} 7#-y-B]l  
else :w-`PY J%G  
{ Jb(Y,LO^  
nStartPos = new long[bean.getNSplitter()]; sR_xe}-  
nEndPos = new long[bean.getNSplitter()]; {'bip`U.  
} 7*+TP~WI  
j"7 JLe*  
\4bWWy  
v[S-Pi1  
} 'Ud| Ex@A9  
l]#!+@  
MagMZR  
public void run()  6sxz_f  
{ wu~hqd  
//获得文件长度 ?S#\K^  
//分割文件 8+'C_t/0i  
//实例FileSplitterFetch 'ks{D(`  
//启动FileSplitterFetch线程 HKmcQM  
//等待子线程返回 (36K3=Qa  
try{ P-Su5F  
if(bFirst) Z(Q2Ue;}&  
{ KCR N}`^  
nFileLength = getFileSize(); ' UMFS  
if(nFileLength == -1) ]~c+'E`  
{ Ruaur]  
System.err.println("File Length is not known!"); RR|\- 8;  
} \54}T 4R  
else if(nFileLength == -2) YD[H  
{ pSAR/':eg  
System.err.println("File is not access!"); HW_& !ye  
} R>)MiHcCg  
else t[C1z  
{ h)x_zZ%>o  
for(int i=0;i<nStartPos.length;i++) Nhf~PO({&  
{ FJS'G^  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); pP/@  
} ')#,X^   
for(int i=0;i<nEndPos.length-1;i++) TZB+lj1  
{ x8[MP?Wz  
nEndPos = nStartPos[i+1]; =dH$2W)G  
} HFtf  
nEndPos[nEndPos.length-1] = nFileLength; UTk r.T+2X  
} lrEj/"M  
} 6m`{Z`c$  
%w"nDu2Gcv  
ae`|ic  
//启动子线程 UQ8bN I7  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Omyt2`q  
for(int i=0;i<nStartPos.length;i++) IF_DZ   
{ \7 a4uc  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), J)x3\[}Ye  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), r6.N4eW.L  
nStartPos,nEndPos,i); 3fkk [U  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^PqF<d6  
fileSplitterFetch.start(); %5B%KCCN  
} {]/8skov5]  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), wD9a#AgEd  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); KS<Jv;  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", xAdq+$><  
nEndPos = " + nFileLength); d>i13d AI  
// fileSplitterFetch[nPos.length-1].start(); Z`_.x &Y  
{BV4h%P]:  
q~Jq/E"f  
//等待子线程结束 Dz&+PES_k  
//int count = 0; jPJAWXB4a  
//是否结束while循环 Fwfo2   
boolean breakWhile = false; *y7 $xa4  
Y94MI1O5$  
H5xzD9K;/C  
while(!bStop) x0+glQrNN  
{ Oh!(@  
write_nPos(); #@//7Bf%  
Utility.sleep(500); ClUSrSp  
breakWhile = true; )|]dm Q-  
&7[[h+Lb  
=nRuY '  
for(int i=0;i<nStartPos.length;i++) }C#3O{5  
{ oyeG$mpg  
if(!fileSplitterFetch.bDownOver) YD_]!HK}  
{ AFm1t2,+;  
breakWhile = false; Y 62r  
break; 8A2 z 5Aa  
} ;#QhQx  
} W|R-J  
if(breakWhile) uofLhy!  
break; f(Hu {c5yV  
+=fKT,-*G!  
h4`9Cfrq,  
//count++; tYe:z:7l?<  
//if(count>4) !]b@RUU  
// siteStop(); L* |1/  
} $@uU@fLB  
+;gsRhWk  
HnZPw&*  
System.err.println("文件下载结束!"); Ijo(^v@  
} ?[= U%sPu=  
catch(Exception e){e.printStackTrace ();} 6?gi_3g  
} uP|FJLY  
SkP[|g'56  
j%tEZ"H  
//获得文件长度 JF9Hfs/jS  
public long getFileSize() [ ]p"3 i  
{ a6nlt? 1?D  
int nFileLength = -1; 5P ke8K  
try{ 32>x^>G=>  
URL url = new URL(siteInfoBean.getSSiteURL()); _l&ucA  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `wO}Hz  
httpConnection.setRequestProperty("User-Agent","NetFox");  ]PX}b  
2*OxA%QELM  
>&K!VQ{g  
int responseCode=httpConnection.getResponseCode(); 5h^[^*A?  
if(responseCode>=400) ]Yz'8uts  
{ !#WqA9<  
processErrorCode(responseCode); +zO]N&  
return -2; //-2 represent access is error .Ff_s  
} 1f//wk|  
8wFn}lw&  
P6Xp<^%E  
String sHeader; w|Qd`  
!nw [  
q=0 pQ1>  
for(int i=1;;i++) pXW`+<g0  
{ 8(lCi$  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); p\D >z("  
//Utility.log(in.readLine()); Fd8hGj1  
sHeader=httpConnection.getHeaderFieldKey(i); d*-Xuv  
if(sHeader!=null) =AkX4k  
{ 3,$iG e  
if(sHeader.equals("Content-Length")) WU\m^!`w=F  
{ F`& >NQb  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 2d&^Sp&11  
break; kL;t8{n  
}  W"qL-KW  
} O E|+R4M  
else K H}t:m+h  
break; uPDaq ]A  
} 3$_2weZxYn  
} UR:n5V4  
catch(IOException e){e.printStackTrace ();} A{`]& K1u  
catch(Exception e){e.printStackTrace ();} 6>B \|  
fPz=KoN  
>\bPZf)tJ)  
Utility.log(nFileLength); /'&v4C^y>  
`d`&R.'  
!-(J-45  
return nFileLength; {B^pnLc  
} 4ftj>O  
zoXuFg  
l1RlYl5  
//保存下载信息(文件指针位置) `|,tCM&-  
private void write_nPos() AM/lbMr  
{ l<N?'&  
try{  -$R5  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^[TOZXL`:  
output.writeInt(nStartPos.length); vKkf2 7  
for(int i=0;i<nStartPos.length;i++) RKk"  
{ &kx\W)  
// output.writeLong(nPos);  N|N/)  
output.writeLong(fileSplitterFetch.nStartPos); .v l="<  
output.writeLong(fileSplitterFetch.nEndPos); p JX, n  
} v=MzI#0L  
output.close(); \e0x ,2  
} _IKQ36=  
catch(IOException e){e.printStackTrace ();} ca}S{"  
catch(Exception e){e.printStackTrace ();} llqDT-cp  
} M6x;BjrV  
G5+]DogS  
Eq7gcDQ  
//读取保存的下载信息(文件指针位置) G>j "cj  
private void read_nPos() y`+<X{V5L  
{ n|Ma&qs  
try{ g TD%4V  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); STRyW Ml  
int nCount = input.readInt(); ZjavD^ky  
nStartPos = new long[nCount]; HnK/A0jM  
nEndPos = new long[nCount]; dw99FA6  
for(int i=0;i<nStartPos.length;i++) 4ioN A/E  
{ u2om5e:  
nStartPos = input.readLong(); rr4 _8Rf  
nEndPos = input.readLong(); -W6V,+of  
} hhj ,rcsi  
input.close(); J{x##p<F$  
} cuNq9y;[  
catch(IOException e){e.printStackTrace ();} >rRjm+vg  
catch(Exception e){e.printStackTrace ();} )#mW7m9M#  
} !$XO U'n  
1W7 iip,  
98ayA$  
private void processErrorCode(int nErrorCode) cWc$ yE'  
{ t5A[o7BS  
System.err.println("Error Code : " + nErrorCode); /gF]s_  
} BDnBBbBrz  
EyPy*_A  
i&5!9m`Cw  
//停止文件下载 9Mut p4#  
public void siteStop()  nFVbQa~  
{ 14;Av{Xt  
bStop = true; '9Qd.q7s|b  
for(int i=0;i<nStartPos.length;i++) GMyoSe%1/  
fileSplitterFetch.splitterStop(); Q.uR<C6)v  
Ic_tc  
,Zr  YJ<  
} WVsK rFZT  
} tTE3H_   
//负责部分文件的抓取 n *Q4G}p  
**FileSplitterFetch.java _i#@t7  
*/ Mj,2\ijNM  
package NetFox; P'gT6*an,"  
v3 !byN^  
jCam,$oE  
import java.io.*; fCs\Q  
import java.net.*; [v~Uy$d\  
dcM+ylB  
Z,(%v.d  
public class FileSplitterFetch extends Thread { 0FN~$+t)H  
]Oig ..LJ  
d+1L5}Jn  
String sURL; //File URL +}`p"<'u  
long nStartPos; //File Snippet Start Position ?Of{c,2 .  
long nEndPos; //File Snippet End Position av7q>NEZ!1  
int nThreadID; //Thread's ID v] W1F,u  
boolean bDownOver = false; //Downing is over GR_p1 C\  
boolean bStop = false; //Stop identical k-;.0!D^  
FileAccessI fileAccessI = null; //File Access interface o&*1U"6D  
{Nzmb|&  
P] {B^,E  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException xu0;a  
{ Y+}OClS  
this.sURL = sURL; 5mDVFb 3a  
this.nStartPos = nStart; ]i9H_K  
this.nEndPos = nEnd; aEV|>K=6Y'  
nThreadID = id; M ^ 0w/  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 *#3voJjV(  
} b0rt.XB  
Z 5{*? 2  
|F8;+nAVF#  
public void run() 1"*Nb5s  
{ WXRHG)nvL  
while(nStartPos < nEndPos && !bStop) {[H4G,QK  
{ \5j22L9S  
Q'>_59  
' |h./.K  
try{ P6.)P|n7=  
URL url = new URL(sURL); rHA/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]Hv*^Bak  
httpConnection.setRequestProperty("User-Agent","NetFox"); (UbR%A|v;  
String sProperty = "bytes="+nStartPos+"-"; Q-H =wJ4R  
httpConnection.setRequestProperty("RANGE",sProperty); 7"h=MB_  
Utility.log(sProperty); ^F;Z%5P=  
\H"/2o%l")  
Oi+Qy[y2  
InputStream input = httpConnection.getInputStream(); Y)@oo=oG  
//logResponseHead(httpConnection); =[v2   
s\F EA"w/  
1o"y%*"  
byte[] b = new byte[1024]; LRfFn^FPM  
int nRead; /It.>1~2@  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) FE^?U%:u@  
{ D0,oml  
nStartPos += fileAccessI.write(b,0,nRead); }bj,&c  
//if(nThreadID == 1) )w3XN A_V  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); i2\\!s  
} &kmd<  
/cn/[O9  
3P=Eb!qtdD  
Utility.log("Thread " + nThreadID + " is over!"); Wb*T   
bDownOver = true; 6c;?`C  
//nPos = fileAccessI.write (b,0,nRead); 'T #<OR  
} (STWAwK-  
catch(Exception e){e.printStackTrace ();} g&5pfrC [  
} _s*uF_: 3  
} hx2!YNx !  
PHE;  
&~D.")Dz  
//打印回应的头信息 Nys'4kx7  
public void logResponseHead(HttpURLConnection con) z}Mb4{d1  
{ & Q|f*T  
for(int i=1;;i++) iZVT% A+q  
{ ;]8p:ME  
String header=con.getHeaderFieldKey(i); HY%6eUhj  
if(header!=null) PN)TX~}  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); U:T5o]P<  
Utility.log(header+" : "+con.getHeaderField(header)); b(.o|d/P  
else SOi(5]  
break; ~ 33@H  
} t9=|* =;9)  
} RvgAI`T7$  
=*U%j  
mF$jC:Tb  
public void splitterStop() d/-0B<ts  
{ @)!1#^(}%  
bStop = true; ?!Th-Cc&m  
} tpy :o(H  
}lQn]q  
n"`SL<K1  
} ~[bMfkc3  
G~mB=]  
E l8.D3  
/* P^d . ,  
**FileAccess.java lk *QV  
*//文件访问(定位,写) +{l3#Y  
package NetFox; #,|_d>p:  
import java.io.*; O(WMTa'%  
EJSgTtp 2  
5{x[EXE'  
public class FileAccessI implements Serializable{ WZy6K(18"'  
P.2.Ge|  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 B39PDJ]hu  
RandomAccessFile oSavedFile; {)dEO0 p  
long nPos; 4UX]S\X  
 p% YvP  
+~v3D^L15  
public FileAccessI() throws IOException 4s+J-l  
{  TVEF+t  
this("",0); 8Jly! =Qm5  
} +cplM5X  
L"zgBB?K6  
e]y=]}A3{  
public FileAccessI(String sName,long nPos) throws IOException 8G^B%h]  
{ qI/r_  
oSavedFile = new RandomAccessFile(sName,"rw"); :."n@sA@  
this.nPos = nPos; l Ib>t  
oSavedFile.seek(nPos); <` VJU2  
} k-Hfip[ro  
sMe~C>RD  
:!it7vZ  
public synchronized int write(byte[] b,int nStart,int nLen) +^% &8<  
{ 9#$V1(}?  
int n = -1; o dQ&0d  
try{ :?of./Df|  
oSavedFile.write(b,nStart,nLen); WaZ@  
n = nLen; w<^2h}5  
} ]NhWhJ:  
catch(IOException e) n;T  
{ V%KW[v<G<  
e.printStackTrace (); UBk 5O&  
} wQ/@+$>  
fw~%^*  
z_iyuLRdb  
return n; /iJhCB[QZ  
} ?ia[KLt"  
m_O=X8uj"D  
'MM~ ~:  
} Q9'V&jm  
l\l]9Z6%  
L08;z  
/* VDI S`E  
**SiteInfoBean.java lNp:2P  
*/ [g 68O*  
package NetFox; `  vmk  
Ta5iY }  
)k<~}wvQ0  
public class SiteInfoBean { {*P7)  
TKutO0  
MM)/B>cQt  
private String sSiteURL; //Site's URL F$.s6Hh.  
private String sFilePath; //Saved File's Path tf}Q%)`f  
private String sFileName; //Saved File's Name :zy'hu;  
private int nSplitter; //Count of Splited Downloading File thboHPml{  
nf@u7*# 6  
`U>b6 {K  
public SiteInfoBean() !(AFT!  
{//nSplitter的缺省值为5 MvwJ(3  
//default value of nSplitter is 5 -(,6w?  
this("","","",5); K`Zb;R X  
}  G6ES]  
p:n^c5  
&ZFAUE,[  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) /M c"K  
{ ~G^doj3|+  
sSiteURL= sURL; F[giq 1#  
sFilePath = sPath; D`@U[`Sw  
sFileName = sName; g<5Pc,  
this.nSplitter = nSpiltter; [ESs?v$  
aV%rq9Tp  
|(8h:g  
} "TNUw&ih  
.T>}O0L"  
*X55:yha  
public String getSSiteURL() G~L#v AY  
{ ^\9G{}VY  
return sSiteURL; . zMM86c  
} t# {>y1[29  
!d@`r1t  
)/^$JYz  
public void setSSiteURL(String value) H/I`c>Zn  
{ e-av@a3  
sSiteURL = value; Hjkgy%N  
} u1Yp5jp^K  
IYC#H}  
c&W.slE6  
public String getSFilePath() 7VBw@Rh  
{ 7anpz%  
return sFilePath; dNt|"9~&  
} c324@o^V  
&Rt]K  
#IwB  
public void setSFilePath(String value) 2= mD  
{ 6b)UoJxj  
sFilePath = value; muq|^Hfb  
} @S:/6__  
zQ _[wM-  
$q+`GXc-  
public String getSFileName() ^*W<$A_  
{ aRP+?}b">  
return sFileName; hjT1SW\I  
} UL"3skV   
1"6k5wrIA  
[63;8l}  
public void setSFileName(String value) .ai9PsZ?V  
{ (}8 ;3pp  
sFileName = value; K)@Buu&,p  
} tAi9mm;k  
: seL=  
B+ sqEj-  
public int getNSplitter() <}1%">RA  
{ 7y7y<`)I5  
return nSplitter; :_zKUv]  
} .?j8{>  
+yI^<BH  
m~B=C>r}t  
public void setNSplitter(int nCount) DNe^_v)]|  
{ E e&$9 )t  
nSplitter = nCount; { "c,P:S]  
} __c_JU  
} #OTsD+2Za=  
o>tT!8rH  
eP?|U.on  
/* &Hxr3[+$  
**Utility.java *p!dd?8  
*/ Z`KmH.l!  
package NetFox; N|LVLsK  
S7Fxb+{6D  
vsR ^aVwVZ  
public class Utility { bb/MnhB  
A'EA!  
<`qo*__1  
public Utility() Fgk/Ph3r  
{ ,;18:  
BI]t}7  
d`/{0:F  
} XQ+hTtP  
-9"Ls?Cu  
//线程睡眠 |L&V-f&K  
public static void sleep(int nSecond) 3MVZ*'1QM\  
{ I,;)pWX=@  
try{ )O Cr6UR  
Thread.sleep(nSecond); t |hmEHUk  
} bwFc>{Wo5  
catch(Exception e) !Ua#smZ  
{ u<zDZ{jt)  
e.printStackTrace (); 78-:hk  
} -~k2Gy;E  
} '*; rm*n  
~s_$a8  
//日志 ^B9wmxe  
public static void log(String sMsg) 3!L)7Z/  
{ 'c D"ZVm1  
System.err.println(sMsg); 8<xy *=%  
} ffVYlNQ7L  
!%@{S8IP.v  
Gov{jksr  
public static void log(int sMsg) B!v1 gh  
{ QPEv@laM  
System.err.println(sMsg); d6VKUAk'7>  
} ;}qCIyuO]  
} +h/$_5  
ijB,Q>TgO  
`h'^S,'*  
/* 2LdV=ifq2S  
**TestMethod.java ngjbE+  
*/ RFdN13sJ v  
package NetFox; M ~IiJ9{  
u4'Lm+&O  
\ck3y]a[  
public class TestMethod { 6eD[)_?]y  
67eo~~nUtg  
L"a#Uu8  
public TestMethod() 4o8!p\a  
{ ///xx/weblogic60b2_win.exe 8] *{ i  
try{ ? 6l::M  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); :jPAA`,  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); T9^i#8-^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); N\?iU8w=  
fileFetch.start(); Y>+D\|%Q  
} c#DTL/8"DO  
catch(Exception e){e.printStackTrace ();} ZU|nKt<GK  
:U s-^zVr  
itU01  
} l O^h)hrR  
QWkw$mcf  
k <qQ+\X  
public static void main(String[] args) MqqS3   
{ a#1X)ot  
new TestMethod(); AN;?`AM;  
} WA/\x  
} @'<|B. f  
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