http断点续传简单实现（java)

/* nms8@[4-  
**SiteFileFetch.java mI1H!  
*/ p*3; hGp6  
package NetFox; Sv[5NZn0&  
import java.io.*; &(pjqV  
import java.net.*; KLWDo%%u  
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public class SiteFileFetch extends Thread { # TkR  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Ri*3ySyb  
long[] nStartPos; //开始位置 2[yBD-":  
long[] nEndPos; //结束位置 5]Ajf;W\  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 }FqA ppr  
long nFileLength; //文件长度 r?$?;%|C  
boolean bFirst = true; //是否第一次取文件 ))h6~1`  
boolean bStop = false; //停止标志 dFXc/VH')  
File tmpFile; //文件下载的临时信息 W7No
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DataOutputStream output; //输出到文件的输出流 ki]ti={12  
k ]a*&me  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 9)dfL?x8V{  
public SiteFileFetch(SiteInfoBean bean) throws IOException $%k1fa C  
{ $4=
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siteInfoBean = bean; AONDx3[   
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 2'0K WYM  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); uKr1Z2  
if(tmpFile.exists ()) |AZ
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{ mh/n.*E7  
bFirst = false; R!\EKH  
read_nPos(); .p` pG3  
} u'~;Y.@i'  
else 9"{W,'r&d  
{ j7QX,_Q  
nStartPos = new long[bean.getNSplitter()]; `TLzVB-j3  
nEndPos = new long[bean.getNSplitter()]; {tP%epQ  
} +K",^6%1  
/
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^C)n$L>C0  
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} g=@_Z"  
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public void run() lEjwgk {  
{ Pt,
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//获得文件长度 CB\{!  
//分割文件 sN=6gCau  
//实例FileSplitterFetch jH;Du2w  
//启动FileSplitterFetch线程 `6=-WEo  
//等待子线程返回 &]6)
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try{ gxNL_(A  
if(bFirst) <=K qcHb  
{ gk0.zz([  
nFileLength = getFileSize(); 6aft$A}XnD  
if(nFileLength == -1) _o3e]{  
{ nSx8E7 |V  
System.err.println("File Length is not known!"); (t^n'V  
} ~EiH-z4U  
else if(nFileLength == -2) PyC0Q\$%  
{ (?)7)5H  
System.err.println("File is not access!"); \;5\
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} U\@
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else I&yVx8aH}  
{ Wzq>JNny  
for(int i=0;i<nStartPos.length;i++) -Yi,_#3{  
{ )Q;978:  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); M)-6T{[IT  
} {2d_"lHBt  
for(int i=0;i<nEndPos.length-1;i++) $
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{ Sb2v_o  
nEndPos = nStartPos[i+1]; +xv!$gJEj  
}
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nEndPos[nEndPos.length-1] = nFileLength; oih5B<&f#  
} {^)70Vz>PE  
} Pn.bVV:  
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AEirj /  
//启动子线程 "d/s5sP|S  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; '_s}o<  
for(int i=0;i<nStartPos.length;i++) {Bvj"mL]j  
{ ,Z9>h[JF  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), iOw3MfO  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), *hhmTc#  
nStartPos,nEndPos,i); /hWd/H]  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !\ND(  
fileSplitterFetch.start(); V)M1YZV{  
} ]:]H:U]p  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +]xFoH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); )P&9A)8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", y8Xv~4qQW  
nEndPos = " + nFileLength); 5i6
hp;=  
// fileSplitterFetch[nPos.length-1].start(); >T3H qYX5W  
&Nl2sey  
M6|I6M<  
//等待子线程结束 5E\#%K[  
//int count = 0; FVsj;  
//是否结束while循环 >>Ar$  
boolean breakWhile = false; b}9[s  
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le)DgIT>=  
while(!bStop) y7\"[<E`(V  
{ Fqq6^um  
write_nPos(); n^(A=G  
Utility.sleep(500); km5~Gc}  
breakWhile = true; qNgd33u1  
%y[1H5)3<  
A?!I/|E^;  
for(int i=0;i<nStartPos.length;i++) WKM)*@#,  
{
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if(!fileSplitterFetch.bDownOver) .9G<y 4  
{ 4R%*Z~  
breakWhile = false; \YJy#2K  
break; tq50fq'  
} l;X|=eu'  
} ?9MVM~$  
if(breakWhile) Ds8 EMtS  
break; sRHA."A!8  
'X
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8iQ[9  
//count++; mABe'"8  
//if(count>4) _W!p8cB  
// siteStop(); \uOdALZ  
} h[tix:  
`s#Hq\C  
m`?MV\^  
System.err.println("文件下载结束！"); A~(l{g  
} 2(!fg4#+  
catch(Exception e){e.printStackTrace ();} zdun,`6  
} 3:/'n  
9%)=`W  
y %8op:'  
//获得文件长度 H5>hx{  
public long getFileSize() 9.O8/0w7LV  
{ k,Qskd-N]  
int nFileLength = -1; M[

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try{ ks;%*d  
URL url = new URL(siteInfoBean.getSSiteURL()); +#J,BKul  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \$*$='6"  
httpConnection.setRequestProperty("User-Agent","NetFox"); &O\(;mFc  
Kr`]_m  
+V862R4,o  
int responseCode=httpConnection.getResponseCode(); D<{{ :7n  
if(responseCode>=400) !G5a*8]  
{ ~|Y>:M+0Z  
processErrorCode(responseCode); &:B<Q$g#  
return -2; //-2 represent access is error .y5,x\Pq(  
} ._:nw=Y0<}  
g&/p*c_  
6&U+6gb  
String sHeader; ZUXr!v/R:1  
#%3rTU  
=4!nFi  
for(int i=1;;i++) "O>n@Q|  
{ 7EhN u@5-  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); N)8HR9[!  
//Utility.log(in.readLine()); cp Ear  
sHeader=httpConnection.getHeaderFieldKey(i); qAkx<u  
if(sHeader!=null) xvLn'8H.  
{ N6QVt f.  
if(sHeader.equals("Content-Length")) wmr-}Y!9u%  
{ 4b]a&_-}  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); %~|HFYd  
break; `'_m\uo  
} SU_SU".  
} BZK`O/  
else 4pz|1Hw7  
break; -_VG;$,jE  
} }f>H\iJe  
} #b0{#^S:  
catch(IOException e){e.printStackTrace ();} 8t"~Om5sG  
catch(Exception e){e.printStackTrace ();} lt'I,Xt  
Eu<1Bse;  
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Utility.log(nFileLength); #Sg\q8(O  
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return nFileLength; `:{B(+6  
} p^m5`{1]x  
0Sl]!PZR1  
u<ySd?  
//保存下载信息（文件指针位置） 3+7^uR$/I4  
private void write_nPos() w]j+9-._  
{ 1{"ll
D  
try{ CENVp"C/`  
output = new DataOutputStream(new FileOutputStream(tmpFile)); lVH<lp_ZtK  
output.writeInt(nStartPos.length); cX!Pz.C  
for(int i=0;i<nStartPos.length;i++) or ;f&![w  
{ ~rbIMF4T`]  
// output.writeLong(nPos); 7[v%GoE  
output.writeLong(fileSplitterFetch.nStartPos); bJr[I  
output.writeLong(fileSplitterFetch.nEndPos); ug 7o>PX  
} 1MkI0OZE  
output.close(); `xS{0P{uj  
} t-%Q`V=[  
catch(IOException e){e.printStackTrace ();} $9 p!Y}  
catch(Exception e){e.printStackTrace ();} &(rWwOo6  
} {0\,0*^p  
Y o
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=(AtfW^H  
//读取保存的下载信息（文件指针位置） n_K~vD  
private void read_nPos() T>>YNaUL  
{   \J^  
try{ 2+8#H.  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); FeJr\|FT  
int nCount = input.readInt(); tYW>t9  
nStartPos = new long[nCount];
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nEndPos = new long[nCount]; FXKF\1`(H  
for(int i=0;i<nStartPos.length;i++) "HMP$)d  
{ nCg66-3A  
nStartPos = input.readLong(); EEy$w1ec  
nEndPos = input.readLong(); d4[(8} x$/  
} 01a-{&   
input.close(); u8
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} !,$i6gm  
catch(IOException e){e.printStackTrace ();} 1nj(hg  
catch(Exception e){e.printStackTrace ();} qf'm=efRyu  
} uw\1b.r'B  
{WN(&eax  
[ANuBNF  
private void processErrorCode(int nErrorCode) w6|9|f/  
{ 6x{<e4<n  
System.err.println("Error Code : " + nErrorCode); K5Wg"^AHY/  
} I lR\  #  
u}hF8eD  
,M !tm7  
//停止文件下载 G* %t'jX9  
public void siteStop() wl=61Mb  
{ tEd.'D8 s  
bStop = true; sf}Dh  
for(int i=0;i<nStartPos.length;i++) %u{W7  
fileSplitterFetch.splitterStop(); JD>d\z2QC  
igf)Hb;5  
Ha>*?`?yI  
} $Byj}^;1  
} iSRpfU  
//负责部分文件的抓取 &tR(n$M@>  
**FileSplitterFetch.java EfLO5$?rm  
*/ td2/9|Q  
package NetFox; @=S}=cl  
R  
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import java.io.*; 8Chj w wB  
import java.net.*; !4@G3Ae22  
4fV3Ear=j  
KP;(Q+qTx  
public class FileSplitterFetch extends Thread { Huw\&E  
}'"Gr%jf(  
PrQ?PvA<L  
String sURL; //File URL vEM(bT=H  
long nStartPos; //File Snippet Start Position [a[/_Sf{  
long nEndPos; //File Snippet End Position D:\g,\Z  
int nThreadID; //Thread's ID t5k!W7C  
boolean bDownOver = false; //Downing is over %3;Fgky  
boolean bStop = false; //Stop identical !4"sX+z9  
FileAccessI fileAccessI = null; //File Access interface 5@Bu99`  
]36sZ *  
;.sl*q1A  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException t,)N('m}=  
{ ^he=)rBb?  
this.sURL = sURL; >M
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this.nStartPos = nStart; _GQz!YA  
this.nEndPos = nEnd; dGfVZDs
r]  
nThreadID = id; gxPx&Z6jF  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Q\ ^[!|  
} UCrh/bTm  
3CjL\pIC  
7)rWw<mY  
public void run() l7(!`NPbC  
{ gJt`?8t  
while(nStartPos < nEndPos && !bStop) 6~:Sgt nU  
{ jdeV|H} u  
}G46g#_6d>  
stl 1QO(h  
try{ c47")2/yO  
URL url = new URL(sURL); `pZs T ^G[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %wV>0gQTf  
httpConnection.setRequestProperty("User-Agent","NetFox"); ExSe=4q#  
String sProperty = "bytes="+nStartPos+"-"; G}@#u9  
httpConnection.setRequestProperty("RANGE",sProperty); j Ib  
Utility.log(sProperty); cR-~)UyrO  
#BK9 k>i  
y]..=z_ql  
InputStream input = httpConnection.getInputStream(); >C WKH~  
//logResponseHead(httpConnection); 5(2|tJw-H;  
lor8@Qz  
3LR p2(A  
byte[] b = new byte[1024]; ~d{.ng 4K  
int nRead; (fD ;g9  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 'J*<iA*W  
{ BIaDY<j90  
nStartPos += fileAccessI.write(b,0,nRead); ln*icaDqf  
//if(nThreadID == 1) ~sQjl]  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?zJpD8e  
} fqz28aHh  
C`rLj5E%  
Oh.ZPG=  
Utility.log("Thread " + nThreadID + " is over!"); *x~xWg9^  
bDownOver = true; 1RLY $M  
//nPos = fileAccessI.write (b,0,nRead); #yseiVm;  
} (LvS :?T}  
catch(Exception e){e.printStackTrace ();} iVtl72O  
} 2s*#u<I  
} ~pk(L[G  
}y%`)lz~;  
:H6FPV78  
//打印回应的头信息 HC {XX>F^  
public void logResponseHead(HttpURLConnection con) +^aFs S  
{ "Y`3DxXz  
for(int i=1;;i++) B(k=oXDF  
{ wmNHT _  
String header=con.getHeaderFieldKey(i); Yw3oJf&  
if(header!=null) wo2@hav  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `i,_aFB|  
Utility.log(header+" : "+con.getHeaderField(header)); )|j[uh6wo  
else v4Zb? Yb  
break; }g+;y  
} :qhpL-ER  
} @ufo$?D  
[@<sFP;g  
>$677  
public void splitterStop() DVZdClAL  
{ >!e<}84b  
bStop = true; c97{Pu  
} uaw~r2  
?[TfpAtQ`  
dCYCHHHF  
} Zt -1h{7  
+ Y.1)i}  
h[KvhbD3
 
/* 7T``-:`[  
**FileAccess.java @r(Z%j7  
*//文件访问(定位，写) 3:/'t{ ^B  
package NetFox; xVB;s.'!  
import java.io.*; 3FSqd<t;D  
#mR4fst  
S 6,4PP  
public class FileAccessI implements Serializable{
HysS_/t~  
Z#d&|5Xj  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ?rVy2!  
RandomAccessFile oSavedFile; eO=s-]mk  
long nPos; h+.{2^x  
=rA~7+}  
/gcEw!JS  
public FileAccessI() throws IOException a/Q$cOs  
{ qL$a c}`  
this("",0); ?,P3)&3g  
} <Tw>|cFT  
})xp%<`  
p=GWq(S6  
public FileAccessI(String sName,long nPos) throws IOException TQX)?^Ft  
{ v dbO(  
oSavedFile = new RandomAccessFile(sName,"rw"); a?} .Fs  
this.nPos = nPos; zIC;7 5#  
oSavedFile.seek(nPos); E9\vA*a  
} '#NcZy  
B0$:b!  
_CBWb  
public synchronized int write(byte[] b,int nStart,int nLen) `=+^|Y}  
{ ]=rht9),"  
int n = -1;
hDP/JN8y  
try{ d4:
`@*
 
oSavedFile.write(b,nStart,nLen); CQ7{1,?2  
n = nLen; qs\2Z@;  
} 9Gy  
catch(IOException e) +:=(#Y  
{ (YBMsh  
e.printStackTrace (); ( m\$hX  
} C`=p+2I]  
r;9 r!$d  
7*Qk`*Ii  
return n; y4Z&@,_{  
} $CTSnlPq  
*b *G2f^  
682Z}"I0  
} eg<bi@C1|  
m p<1yY]  
&wd;EGGT!q  
/* "q}FPJ^l_N  
**SiteInfoBean.java bawJ$_O_  
*/ "xcX'F^  
package NetFox; N#V.1<Y  
m^'uipa\  
lN,/3\B  
public class SiteInfoBean { H|ozDA  
Y^Nuz/  
]3
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private String sSiteURL; //Site's URL r
`&-9"+  
private String sFilePath; //Saved File's Path ?1L
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private String sFileName; //Saved File's Name  [=O/1T  
private int nSplitter; //Count of Splited Downloading File rn DCqv!'P  
HCK|~k  
n%h^o  
public SiteInfoBean() V$0dtvGvH  
{//nSplitter的缺省值为5 I`[i;U{CK  
//default value of nSplitter is 5 i| \6JpNA:  
this("","","",5); o:Qv JcB  
} Qjx?ri//  
s?8<50s  
9[!,c`pw  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) u&G.4QQF  
{ (>J4^``x=  
sSiteURL= sURL; $VAx:Y|  
sFilePath = sPath; 6s,uXn  
sFileName = sName; ^@P1 JNe  
this.nSplitter = nSpiltter; I8oo~2Qw  
a`Gx=8  
8eA+d5k\.  
} Vz14j_  
%1pYEHn  
"~UUx"Y  
public String getSSiteURL() -(#I3h;I  
{ EM>}0V  
return sSiteURL; %h1N3\y9i(  
} yx V:!gl  
IUR<.Y`  
t+oJV+@  
public void setSSiteURL(String value) &`b "a!  
{ d0'JC*  
sSiteURL = value; "5cM54Z0  
} k6`6Mjbc  
L 
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(F7(^.MG  
public String getSFilePath() b~dIk5>O  
{ yH][(o=2  
return sFilePath; 9nu3+.&P  
} J0zn-  
+C7 ~b~ %  
NM)k/?fA  
public void setSFilePath(String value) **69rN  
{ {M,,npl  
sFilePath = value; ^Rm  
} (&$VxuJ+6y  
!lo/xQ<  
}b1cLchl  
public String getSFileName() CJ}5T]WZ  
{ :JlP[I  
return sFileName; 6TP7b|  
} 4Llo`K4  
lKk/p^:  
d[rv1s>i  
public void setSFileName(String value) a>\vUv*  
{ Ym;*Y !~[  
sFileName = value; cqxVAzb  
} UH7jP#W%=  
8[6o (  
y qtKy  
public int getNSplitter() Jk,;JQ  
{ = k\J<  
return nSplitter; :qC'$dO!
 
} r1RGTEkD  
+{
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s/089jlc  
public void setNSplitter(int nCount) hY`\&@  
{ \h8
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nSplitter = nCount; Z"unF9`"1  
} g^zs,4pPU<  
} fhB}9i^]tg  
{v3P9s(  
yDNOtC|  
/* HSq}7S&U  
**Utility.java A 7[:5$  
*/ Cu6%h>@K$  
package NetFox; $1SUU F\.  
 TX  
SwZA6R&  
public class Utility { e{Z &d  
{k rswh3  
;#Q%j%J  
public Utility() 3_A *$  
{ hMtf.3S7c  
s+>:,U<A  
arf8xqR-U]  
} +^;JS3p@\  
<$JaWL  
//线程睡眠 s(W|f|R  
public static void sleep(int nSecond) +{
/  
{ >M&3Y XC  
try{ ](|\whI
 
Thread.sleep(nSecond); ID/F  
} HV<Lf 6gE  
catch(Exception e) 1'?4m0W1  
{ R:B^  
e.printStackTrace (); _UuC,Pl3  
} `-LGU7~+  
} (Cqn6dWK  

:%IoME   
//日志 irjP>3_e  
public static void log(String sMsg) m#=z7.XrX  
{ $ `7^+8vHV  
System.err.println(sMsg); 7 [0L9\xm  
} sJNFFOz  
$ MC)}l  
5atYOep  
public static void log(int sMsg) )p*}e8
L  
{ .1LCXW=  
System.err.println(sMsg); $8BPlqBIZ  
} i~r l o^  
} z;y:9l  
3po:xMY  
|fo0  
/* 5eWwgA  
**TestMethod.java }l=xiAF  
*/ XC+A_"w)  
package NetFox; S{3nM<  
JfPD}w  
G}p\8Q}'  
public class TestMethod { 'F3)9&M  
Z@r.pRr'  
6^DR0sO  
public TestMethod() m4*@o?Ow  
{ ///xx/weblogic60b2_win.exe G z)NwD  
try{ f7}*X|_Y  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Dl}$pN  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); a0Zv p>Ft  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [+P#
tIL  
fileFetch.start(); jVq(?Gc  
} o6p98Dpg   
catch(Exception e){e.printStackTrace ();} PdvqDa8  
4f<$4d^md  
Q%f|~Kl-hd  
} <m'ow  
M8u<qj&<O  
N?.%?0l  
public static void main(String[] args) 9+pmS#>_  
{ IH"6? 9nd  
new TestMethod(); Nv"EV;$  
} )RcL/n  
} ]~3U  
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