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http断点续传简单实现(java)

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/* >8~+[e  
**SiteFileFetch.java h1Ca9Z_  
*/ *s/sF@8<X  
package NetFox; ~l%Dcp  
import java.io.*; t+k"$zR  
import java.net.*; #~54t0|Cd>  
 s%Q pb{  
^IuHc_  
public class SiteFileFetch extends Thread { >+=)Q,|R  
\eE0Rnaf-  
M=$y_9#  
SiteInfoBean siteInfoBean = null; //文件信息Bean e*e}X&|(g  
long[] nStartPos; //开始位置 Pq~"`-h7:  
long[] nEndPos; //结束位置 inavi5.  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 IBY3QG  
long nFileLength; //文件长度 3_2(L"S2  
boolean bFirst = true; //是否第一次取文件 ~a8J"Wh  
boolean bStop = false; //停止标志 yOGa W~  
File tmpFile; //文件下载的临时信息 zPU& }7  
DataOutputStream output; //输出到文件的输出流 A+3@N99HeH  
[1'`KJ]  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) x2.G1  
public SiteFileFetch(SiteInfoBean bean) throws IOException e =Vu;  
{ C_?L$3 U0  
siteInfoBean = bean; ]`&EB~K&NY  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); lNQt  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); n *%<!\gJ  
if(tmpFile.exists ())  &(\z  
{ 3=1aMQ  
bFirst = false; 6#O n .Q  
read_nPos(); o|Obl@CSBD  
} mCe,(/>l+  
else v8,+|+3  
{ *KF:  
nStartPos = new long[bean.getNSplitter()]; oYnA 3  
nEndPos = new long[bean.getNSplitter()]; _/ZIDIn  
} 'MPt K  
8zGe5Dn9  
FGBPhH% (8  
gk~.u  
} V^=z\wBZ  
ts3%cRN r  
5UR$Pn2a2  
public void run() JQ'NFl9<  
{ dfGdY"&  
//获得文件长度 ZPn`.Qc  
//分割文件 ]v@#3,BV  
//实例FileSplitterFetch x&tad+T  
//启动FileSplitterFetch线程 ZrnZ7,!@  
//等待子线程返回 v I@Wuu:  
try{ ?7^H1L  
if(bFirst) ePK^v_vBD  
{ H^p ?t=Y  
nFileLength = getFileSize(); Ooz+V;#Q  
if(nFileLength == -1) QP)-O*+AA  
{ ',`iQt!Lx  
System.err.println("File Length is not known!"); 1b E$x^P  
} Z:09 ]r1  
else if(nFileLength == -2) XQ--8G  
{ n[CESo%[  
System.err.println("File is not access!"); s"p}>BjMIC  
} 7NRq5d(lP  
else _(3VzI'G  
{ qiiX49}{  
for(int i=0;i<nStartPos.length;i++) ($' rV!}  
{ Zgt, 'T  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Miqu  
} -<sn+-uE:  
for(int i=0;i<nEndPos.length-1;i++) 3'Q H\t5  
{ b{s_cOr/  
nEndPos = nStartPos[i+1]; /K:M ,q  
} Wu<  
nEndPos[nEndPos.length-1] = nFileLength; 97e fWYj  
} B%Dy;zdWd/  
} lz EF^6I  
$:s1x\ol  
u}D.yI8  
//启动子线程 bQow,vf  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ?3kfh R  
for(int i=0;i<nStartPos.length;i++) K5z*DYT  
{ Y<X%'Wd\  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), FJKt5}`8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), o8BbSZVu  
nStartPos,nEndPos,i); aAF:nyV~~0  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); WZ'8{XY8  
fileSplitterFetch.start(); @a)@1:=Rm  
} kYl$V =  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _\>?.gg$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); NQ !t`  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ,Ww)>O+  
nEndPos = " + nFileLength); nM34zVy  
// fileSplitterFetch[nPos.length-1].start(); "2}04b|"  
;FQAL@"Yj  
*qj @y'1\  
//等待子线程结束 4Z"D F)+}  
//int count = 0; W`^'hka  
//是否结束while循环 pvQw+jX  
boolean breakWhile = false; u1/4WYJeJ  
:h=];^/E  
2)h i(  
while(!bStop) I1BVqIt1i  
{ *L%HH@] %_  
write_nPos(); F:x" RbbF  
Utility.sleep(500); cP`f\\c  
breakWhile = true; vr/V_  
:"g^y6i  
$SRpFz5y$  
for(int i=0;i<nStartPos.length;i++) ] NL-)8u  
{ GN?^7kI  
if(!fileSplitterFetch.bDownOver) vXLiYWo  
{ 63QMv[`,  
breakWhile = false; f{FW7T}O2  
break; y/h~oGxy  
} {*ATY+  
} D3$PvX[f  
if(breakWhile) 3bu VU& ap  
break; @bOhnd#W  
EA|*|o4)  
&Vg+n 0  
//count++; iUFS1SN \  
//if(count>4) $Lv,e\]  
// siteStop(); 7f#e#_sM;  
} >K1)XP  
M9HM:  
_,"T;i  
System.err.println("文件下载结束!"); O&V}T#8n  
} O;9u1,%w  
catch(Exception e){e.printStackTrace ();} *?Nrx=O*  
} MzL^u8  
*r@7:a5  
b4ZZyw  
//获得文件长度 QxH%4 )?  
public long getFileSize() rS\j9@=Y4  
{ fPZt*A__  
int nFileLength = -1; $[T^ S  
try{ ' 7+x,TszI  
URL url = new URL(siteInfoBean.getSSiteURL()); " JFx  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %/"I.\%d  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9cp-Rw<tI  
Urj8v2k  
Xt^ldW  
int responseCode=httpConnection.getResponseCode(); %%)"W n#`  
if(responseCode>=400) >0DQ<@ot:  
{ zUXQl{  
processErrorCode(responseCode); I'HPy.PV  
return -2; //-2 represent access is error Zy|B~.@<j  
} D+P(  
N9tH0  
x2=Bu#Y  
String sHeader; x^Q:U1  
H<#M)8  
bGOOC?[UX  
for(int i=1;;i++) JS <S?j?*/  
{ <qT[  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ?1*Ka  
//Utility.log(in.readLine()); 0_q8t!<xJw  
sHeader=httpConnection.getHeaderFieldKey(i); .T 6 NMIp*  
if(sHeader!=null) =e](eA;  
{ Y<-h#_  
if(sHeader.equals("Content-Length"))  <K;  
{ C]414Ibi  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); *`Swv`  
break; `ltc)$  
} FM;NA{  
} g5M=$y/H  
else $s+/OgG4H  
break; 45. -P  
} v_mk{  
} Y[)b".K  
catch(IOException e){e.printStackTrace ();} S "'0l S   
catch(Exception e){e.printStackTrace ();} ?!^ow5"8  
O 7RIcU  
,% "!8T  
Utility.log(nFileLength); {,NGxqhE  
JJ_b{ao<  
3n;>k9{  
return nFileLength; ]xC#XYE:dy  
} w\,N}'G  
Su?e\7aj  
[p3{d\=*?  
//保存下载信息(文件指针位置) uP, iGA  
private void write_nPos() ( m/uj z  
{ :B{Wf 2<z  
try{ lC/1,Z/M  
output = new DataOutputStream(new FileOutputStream(tmpFile)); |_."U9!Z^  
output.writeInt(nStartPos.length); ?+av9;Kg  
for(int i=0;i<nStartPos.length;i++) ze2%#<  
{ * N>n5B2  
// output.writeLong(nPos); n2} (Pt.  
output.writeLong(fileSplitterFetch.nStartPos); >*s_)IH2  
output.writeLong(fileSplitterFetch.nEndPos); EP,j+^RVf  
} 0DtewN{Z  
output.close(); EyR~VKbJ'  
} '&hz *yk  
catch(IOException e){e.printStackTrace ();} Ak3cE_*Y/  
catch(Exception e){e.printStackTrace ();} j5m KJC  
} !q\MXS($#u  
]QKo>7%[  
YBh|\  
//读取保存的下载信息(文件指针位置) )U12Rshl  
private void read_nPos() ~_Q~AOFM  
{ $mxm?7ZVR  
try{ hr$Wt ?B  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); }`KK  
int nCount = input.readInt(); 5~D(jHY;  
nStartPos = new long[nCount]; ebno:)  
nEndPos = new long[nCount]; '8%jA$o\g  
for(int i=0;i<nStartPos.length;i++) ;)~}/nR<a  
{ PAng(tubl  
nStartPos = input.readLong(); 8tfM,.]_i  
nEndPos = input.readLong(); '41'Gn  
} OQW%nF9~  
input.close(); Kzwbr?&z  
} "DaE(S&  
catch(IOException e){e.printStackTrace ();} "&Hr)yyWG  
catch(Exception e){e.printStackTrace ();} 1lo. X_  
} Q$ +6f,m#W  
P:D;w2'Q  
8\WV.+  
private void processErrorCode(int nErrorCode) RW~!)^  
{ m tU{d^B  
System.err.println("Error Code : " + nErrorCode); {zX]4 1T  
} |RjAp.pm  
nQGl]2  
]K?;XA3dZ  
//停止文件下载 c wNJ{S+  
public void siteStop() U#V&=~-  
{ cWtuI(.  
bStop = true; ES-V'[+jDy  
for(int i=0;i<nStartPos.length;i++) T:T`M:C.  
fileSplitterFetch.splitterStop(); e5RF6roxO  
I(<9e"1O  
/< k&[  
} X)e#=w!fi3  
} d| #&j. "  
//负责部分文件的抓取 |d$4Fu(M~  
**FileSplitterFetch.java ?f}?I`S,  
*/ 1aI&jdJk  
package NetFox; r[?GO"ej5  
$RH.  
_(zZrUHB  
import java.io.*; YMN=1Zuj?  
import java.net.*; *+OS;R1<  
|`ya+/ff+  
?(Se$iTZ  
public class FileSplitterFetch extends Thread { :V3z`}Rl  
{Qi J-[q  
:)Pj()Os|  
String sURL; //File URL zu3Fi = |0  
long nStartPos; //File Snippet Start Position H )51J:4  
long nEndPos; //File Snippet End Position (> W \Nf  
int nThreadID; //Thread's ID l~]D|92  
boolean bDownOver = false; //Downing is over '-U&S  
boolean bStop = false; //Stop identical ]p8 zT|bv  
FileAccessI fileAccessI = null; //File Access interface zmU@ k  
SZ29B  
r<$o [,W  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4#CHX^De  
{ >.M>,m\  
this.sURL = sURL; y2W|,=Vd  
this.nStartPos = nStart;  nU4to  
this.nEndPos = nEnd; Rk,'ujc  
nThreadID = id; beaSvhPU  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 =t^jlb  
} O 1D|T"@  
rFUR9O.{E  
cJMi`PQ;  
public void run() ?7>"ZGDe>  
{ Ptz## o'{5  
while(nStartPos < nEndPos && !bStop) fat;5XL@  
{ 3eg6 CdT  
^T:L6:  
!&xci})7a  
try{ G6QD`ED  
URL url = new URL(sURL); fy]c=:EmD  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); jDb"|l  
httpConnection.setRequestProperty("User-Agent","NetFox"); T|8:_4/l  
String sProperty = "bytes="+nStartPos+"-"; <UF0Xc&X'  
httpConnection.setRequestProperty("RANGE",sProperty); iC3C~?,7  
Utility.log(sProperty); |Fz ^(US  
o$eo\X?J?  
;4U"y8PVTh  
InputStream input = httpConnection.getInputStream(); l?QA;9_R'  
//logResponseHead(httpConnection); +OqEe[Wk#  
8>@JW]  
jST4O"DjM  
byte[] b = new byte[1024]; #dKy{Q3he  
int nRead; Vm8@ LA  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) eF]8Ar1  
{ CY*o"@-o5)  
nStartPos += fileAccessI.write(b,0,nRead); -)Bvx>8fq-  
//if(nThreadID == 1) MVnN0K4  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); > 23$_'2  
} *|<T@BXn  
IU<lF)PF$  
(i L*1f   
Utility.log("Thread " + nThreadID + " is over!"); {G0=A~  
bDownOver = true; c<,LE@ V  
//nPos = fileAccessI.write (b,0,nRead); NXQ=8o9,9  
} -%5#0Ogh M  
catch(Exception e){e.printStackTrace ();} re_nb)4g  
} 81"` B2  
} }K8e(i6z  
LPBa!fq  
Ui!l3_O  
//打印回应的头信息 d)S`.Q  
public void logResponseHead(HttpURLConnection con) RyP MzxV  
{ I?S t}Tl  
for(int i=1;;i++) 5D.Sg;\  
{ ~Th,<w*o  
String header=con.getHeaderFieldKey(i); mogmr  
if(header!=null) lP*n%Pn)  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); m";..V  
Utility.log(header+" : "+con.getHeaderField(header)); 9Vqy<7i1  
else >s 6ye  
break; .dMdb7  
} V*ao@;sD  
} 76"4Q!  
r<vy6  
VP>*J`'H  
public void splitterStop() [zBi*%5O  
{ a _+?#m  
bStop = true; y+T[="W  
} 9@ YKx0  
zBlv?JwG  
Cdib{y<ji  
} ax>j3HKi  
m3BL  
5L:-Xr{  
/* jQzl!f1c3  
**FileAccess.java Db<#gH  
*//文件访问(定位,写) @J&korU  
package NetFox; X3a9-  
import java.io.*; 'prHXzi(h  
%0}^M1  
c\2rKqFD8  
public class FileAccessI implements Serializable{ g\fj6  
);':aX j  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 +^lB"OcOX@  
RandomAccessFile oSavedFile; ?WHf%Ie2(  
long nPos; #H w(w  
iX6>u4~(  
Vn4wk>b}$2  
public FileAccessI() throws IOException E0R6qS:'  
{ *s*Y uY%y  
this("",0); ')!X1A{  
} Oo@o$\+v  
i4,p\rE0  
BH1h2OEe#  
public FileAccessI(String sName,long nPos) throws IOException w^ut,`yW R  
{ Jr( =Y@Z '  
oSavedFile = new RandomAccessFile(sName,"rw"); VO8rd>b4  
this.nPos = nPos; jOVF+9M  
oSavedFile.seek(nPos); cu($mjC@T  
} xsB0LUt  
vo`&  
O`c50yY  
public synchronized int write(byte[] b,int nStart,int nLen) Hl0" zS[  
{ =K18|Q0m  
int n = -1; E{&MmrlL,  
try{ .a]#AFX  
oSavedFile.write(b,nStart,nLen); -1,0hmn=+  
n = nLen; /3,Lp-kp  
} >P SO]%mE  
catch(IOException e) q:/df]Ntt  
{ 4lB??`UN  
e.printStackTrace (); /W$i8g  
} =&}_bd/]  
/j$=?Rp  
D<;~eZ'  
return n; <;S$4tux  
} ![^pAEgx  
YND}P9 h  
VFL^-tXnA^  
} "vSKj/]  
NC%hsg^0/  
4}h}`KZZ  
/* yl~_~<s6  
**SiteInfoBean.java ^~;ia7V&2  
*/ +Cw_qS"=  
package NetFox; \4q|Qno8  
qK a}O*  
GYfOwV!zB  
public class SiteInfoBean { [|OII!"  
P[ WkW#  
Gv &G2^  
private String sSiteURL; //Site's URL w!7ApEH1  
private String sFilePath; //Saved File's Path @|SeabN^-  
private String sFileName; //Saved File's Name t\K (zE  
private int nSplitter; //Count of Splited Downloading File h6 {vbYj  
Nv7-6C6<  
}+9?)f{?@  
public SiteInfoBean() KOS0Du  
{//nSplitter的缺省值为5 H\R a*EO~j  
//default value of nSplitter is 5 8u+kA mI  
this("","","",5); N s+g9+<A  
} LigB!M  
fz=?QEG  
{siOa%;*  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) G kjfDY:  
{ 172G  
sSiteURL= sURL; 8|i'~BFHs  
sFilePath = sPath; 4w^o !  
sFileName = sName; yV!4Im.>  
this.nSplitter = nSpiltter; 2bNOn%!  
Cf=H~&`Z  
[i`  
} LpU}.  
HU $"o6ap  
=0=#M(w  
public String getSSiteURL() q@ -B+  
{ PC_!  
return sSiteURL; 'w+]kt-  
} 'dwT&v]@  
-I|xW  
0 N,<v7PX  
public void setSSiteURL(String value) s1D<R,J|H  
{ JpC'(N  
sSiteURL = value; 7y'":1  
} R&Y_  
< '5~p$  
HY)xT$/J  
public String getSFilePath() <: v+<)K  
{ 8%7%[WC#  
return sFilePath; KS$t  
} _6NUtU  
K3?5bT_{  
Y<xqws  
public void setSFilePath(String value) S/'0czDMW  
{ a;HAuy`M x  
sFilePath = value; E 5&Z={  
} :(n<c  
|h]V9=  
fg^25g'_  
public String getSFileName() j>\c > U  
{ r<UVO$N  
return sFileName; AHb_BgOU*  
} VL9wRu;  
{]HiTpn  
_ Op%H)  
public void setSFileName(String value) :jiuu@<  
{ qVn<c,8#  
sFileName = value; nje7?Vz  
} |p6d]#z3  
rwF$aR>9  
TEC^|U`G  
public int getNSplitter() c{=Sy;i@  
{ $o[-xNn1  
return nSplitter; J/je/PC  
} &h334N|4{  
h Qn?qJy%W  
*-T.xo  
public void setNSplitter(int nCount) cE]z Tu?!  
{  =}`d  
nSplitter = nCount; ic2 D$`M  
} u&:N`f  
} = l`)b  
NIV}hf YF  
b>07t!;  
/* f7=MgFi  
**Utility.java YXA@ c  
*/ NHd@s#@  
package NetFox;  T~[:oil  
hFIh<m=C?Y  
cbJgeif  
public class Utility { "V|Rq]_+%  
V\L;EHtc$  
is<:}z  
public Utility() .vu7$~7  
{ \o>-L\`O  
/q9I^ztV  
A,~3oQV  
} B7 %,D}  
FuHBzBoM=  
//线程睡眠 %ih\|jR t  
public static void sleep(int nSecond) i KSRr#/  
{ % N8I'*u  
try{ f8Hq&_Pn   
Thread.sleep(nSecond); ~apt, hl  
} b'z $S+  
catch(Exception e) C>Ik ;  
{ 7hk)I`o65  
e.printStackTrace (); |bnd92fvks  
} ]v ${k  
} A({czHLhN5  
xs"i_se  
//日志 h"`\'(,X  
public static void log(String sMsg) fCY|iO0.t  
{ #w{`6}p  
System.err.println(sMsg); I{IB>j}8  
} '.|}  
1w>[&#7  
y3o q{Z>  
public static void log(int sMsg) |J&\/8Q  
{ Cd%5XD^  
System.err.println(sMsg); , 'pYR]3  
} L ]')=J+  
} KXPCkNIN!  
i2qN 0?n  
?0Q3F  
/* ;As~TGiT  
**TestMethod.java %S312=w  
*/ C @Ts\);^  
package NetFox; P y'BMk  
Z518J46o  
[+[ W\6  
public class TestMethod { y_WC"  
Oc)n,D)0  
:,8y8z$+  
public TestMethod() ]j&m\'-s  
{ ///xx/weblogic60b2_win.exe ioi/`iQR  
try{ e9p/y8gC  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); >k @t.PeoV  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?'V78N sA  
SiteFileFetch fileFetch = new SiteFileFetch(bean); RRO@r}A!y  
fileFetch.start(); 0}i 9`p  
} lU1SN/'zx  
catch(Exception e){e.printStackTrace ();} ?1\5X<|,  
k5RzW4zq;  
SzLlJUVX  
} |r@;ulO  
O@$>'Z  
2-F7tcya|  
public static void main(String[] args) xU\!UVQ/  
{ /E6)>y66  
new TestMethod(); r6S  
} TXB!Y!RG#  
} Z_ElLY  
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