业务：需要从一个数据库查询百万级数据，在java程序中插入到另一个oracle数据库中

代码：

private final int persize = 1000;

/**

* 推送数据-流程

* @param tableCode 表名

* @param startTime 开始时间

* @param endTime 结束时间

* @return

*/

public boolean pushFrData(String username,String tableCode,String tableName,String startTime,String endTime){

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");

System.out.println("导入数据到名录库！");

boolean boo = false;

//表名集合

String [] str = tableCode.split(",");

String [] names = tableName.split(",");

startTime = startTime==""?"2000-01-01":startTime;

endTime = endTime==""?getCurrentDate():endTime;

//System.out.println("service 时间 "+startTime+" > "+endTime);

String start_Time = "to_date('"+startTime+"','%Y-%m-%d')";

String end_Time = "to_date('"+endTime+"','%Y-%m-%d')";

System.out.println("选择推送 "+str.length+" 张表");

//遍历表名集合

for(int i = 0;i

System.out.println("所选数据表： "+str[i]);

//字段集合

String [] arr = fillService.getIdenCode(str[i]);

String iden_code = "";

//遍历字段

for(int j = 0;j

iden_code += ""+arr[j]+",";

}

//表字段

iden_code = iden_code.substring(0,iden_code.length()-1);

//System.out.println(str[i]+"总共 "+arr.length+" 个字段!");

//得到推送数据集合

String sql = "select count(*) from "+str[i] +" where s_ext_timestamp >= "+start_Time+" and s_ext_timestamp < "+end_Time;

System.out.println(sql);

int table_size = Integer.valueOf(frDao.query(sql).get(0).toString());

//System.out.println(table_size/persize);

int times = table_size%persize==0?table_size/persize:table_size/persize+1;

for(int t = 1; t <= times;t++){

int start = (t-1) * persize;

List lists = getData(str[i], iden_code,startTime,endTime,start);

//推送数据

System.out.println("准备导出第 "+t+" 批数据");

push(lists,str[i],iden_code);

System.out.println("已导出第 "+t+" 批数据");

}

try{

if(table_size > 0){

addLog(username,str[i].toString(),names[i].toString(),table_size,"1",sdf.parse(startTime),sdf.parse(endTime));

}

}catch (ParseException e){

System.out.println("日期格式转换异常");

}

}

return boo;

}

/**

* 推送数据

* @param lists 数据集

* @param table 表名

* @param iden_code 字段集

*/

private int push(List lists,String table,String iden_code){

boolean boo = false;

int count = 0;

//遍历数据结果集

if(lists.size()>0){

for(int k = 0;k < lists.size();k++){

Object [] obj = lists.get(k);

String val = ""; //将数据转换成String类型

for(Object s:obj){

//val += "'"+s.toString()+"',";

if(s != null){

val += "'"+s.toString()+"'|";

}else{

val += "''|";

}

}

val = val.substring(0,val.length()-1);

String etpsid = "";

String [] iden = iden_code.split(",");

String [] value = val.split("\\|");

String val2 = "";//格式化数据(日期)

if(iden.length == value.length){

//格式化sql语句的时间

for(int i = 0;i

//判断字段是否是date类型

if(getDateType(table, iden[i])){

//格式化字符串 防止出现datetime类型 1900-01-01 00:00:00.0的情况

if(value[i].length() > 4){

String vv = value[i].substring(value[i].length()-3,value[i].length());

if(vv.contains(".")){

val2 += "to_date("+value[i].substring(0,value[i].length()-3)+"','YYYY-MM-DD HH24:MI:SS'),";

}else{

val2 += "to_date("+value[i]+",'YYYY-MM-DD HH24:MI:SS'),";

}

}else{

val2 += "'',";

}

}else{

val2 += value[i]+",";

}

if("ETPSID".equals(iden[i])){

etpsid = value[i];

}

}

val2 = val2.substring(0,val2.length()-1);

}else{

/*System.out.println(iden.length+" : "+value.length);

for(int j = 0 ;j< value.length;j++){

System.out.println(value[j]);

}*/

System.out.println("推送数据和字段不一致");

}

String mlk_table = getMlkTable(table);

String mlk_code = getMlkCode(iden_code,table);

//插入数据sql

//String sql = "insert into "+table+"("+iden_code+") values ("+val2+")";

//生成流水号

String uuid = UUID.randomUUID().toString();

uuid = uuid.replace("-","");

val2 += ",'"+uuid+"'";

String sql = "insert into "+mlk_table+"("+mlk_code+") values ("+val2+")";

if(etpsid != ""){

//System.out.println(etpsid);

//工商增量数据按日依"企业唯一标识"为关键字，更新、追加至名录库表中

String s_sql = "select * from "+mlk_table+" where 企业唯一标识 = "+etpsid;

//System.out.println(s_sql);

int s = mlDao.query(s_sql).size();

if (s > 0){

String update_sql = "";

String [] update_code = mlk_code.split(",");

for(int j = 0;j < iden_code.split(",").length;j++){

//判断字段是否是date类型

if(getDateType(table, iden[j])){

//格式化字符串 防止出现datetime类型 1900-01-01 00:00:00.0的情况

if(value[j].length() > 4){

String vv = value[j].substring(value[j].length() - 3, value[j].length());

if(vv.contains(".")){

update_sql += update_code[j]+" = "+ "to_date("+value[j].substring(0, value[j].length() - 3)+"','YYYY-MM-DD HH24:MI:SS'),";

}else{

update_sql += update_code[j]+" = "+ "to_date("+value[j]+",'YYYY-MM-DD HH24:MI:SS'),";

}

}else{

update_sql += update_code[j]+" = "+ "'',";

}

}else{

update_sql += update_code[j]+" = "+ value[j]+",";

}

//update_sql += update_code[j]+" = "+update_val[j]+",";

}

update_sql += "流水号 = '"+uuid+"'";

update_sql = "update "+mlk_table+" set "+update_sql+" where 企业唯一标识 = "+etpsid;

//System.out.println("/// /\n"+update_sql+"\n");

sql = update_sql;

System.out.println("更新 "+mlk_table+" 标识 "+etpsid);

}else{

System.out.println("插入 "+mlk_table+" 标识 "+etpsid);

}

}

//System.out.println(sql);

try{

//循环执行sql

mlDao.execute(sql);

count++;

System.out.println(table+" 推送第 "+count+" 条");

}catch (Exception e){

System.out.println("sql执行异常！");

}

}

System.out.println(table+" 表共插入 "+count+" 条数据!");

}else{

System.out.println(table+" 表共插入 "+count+" 条数据!");

System.out.println("导入数据为空！");

}

return count;

}