JDBC处理大数据

1、处理大文本

 package com.demo;

 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.FileReader;
 import java.io.FileWriter;
 import java.io.IOException;
 import java.io.Reader;
 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.SQLException;

 import org.junit.Test;

 import com.utils.DButils;

 //jdbc存大文本数据

 public class Demo1 {
     @Test
     public void insert() throws SQLException, FileNotFoundException{
         Connection con = null;
         PreparedStatement st = null;
         ResultSet result = null;
         try {
             con = DButils.getConnection();
             String sql = "insert into testclob(id,resume) values(?,?)";
             st = con.prepareStatement(sql);
             st.setString(1,"1");

             File file = new File("src/1.txt");
             FileReader reader = new FileReader(file);

             //设置大文本的列
             st.setCharacterStream(2, reader, file.length());
             int num = st.executeUpdate();
             if(num>0){
                 System.out.println("插入成功");
             }
         }finally{
             DButils.release(con, st, result);
         }
     }

     //读取大文本数据
     @Test
     public void read() throws SQLException, IOException{
         Connection con = null;
         PreparedStatement st = null;
         ResultSet result = null;

         try {
             con = DButils.getConnection();
             String sql = "select id,resume from testclob where id='1'";
             st = con.prepareStatement(sql);
             result = st.executeQuery();
             if(result.next()){
                 //String resume = result.getString("resume");不能用String保存，占用内存过大
                 Reader reader = result.getCharacterStream("resume");
                 FileWriter writer = new FileWriter("c:\\1.text");
                 try{
                     int len = 0;
                     char buffer[] = new char[1024];
                     while((len=reader.read(buffer))>0){
                         writer.write(buffer, 0, len);
                     }
                 }finally{
                     if(reader!=null){
                         reader.close();
                     }
                     writer.close();
                 }
             }
         }finally{
             DButils.release(con, st, result);
         }
     }

 }

2、处理二进制文件

 package com.demo;

 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.SQLException;

 import org.junit.Test;

 import com.utils.DButils;

 //jdbc存取二进制文件
 public class Demo2 {
     @Test
     public void insert() throws SQLException, FileNotFoundException{
         Connection con = null;
         PreparedStatement st = null;
         ResultSet result = null;
         try{
             con = DButils.getConnection();
             String sql = "insert into testblob(id,image) values(?,?)";
             st = con.prepareStatement(sql);
             st.setString(1, "1");
             File file = new File("src/1.jpg");
             FileInputStream in = new FileInputStream(file);
             st.setBinaryStream(2, in, file.length());
             st.executeUpdate();
         }finally{
             DButils.release(con, st, result);
         }
     }

     @Test
     public void read() throws SQLException, IOException{
         Connection con = null;
         PreparedStatement st = null;
         ResultSet result = null;
         try{
             con = DButils.getConnection();
             String sql = "select id,image from testblob where id='1'";
             st = con.prepareStatement(sql);
             result = st.executeQuery();
             if(result.next()){
51                 InputStream in = result.getBinaryStream("image");
52                 OutputStream out = new FileOutputStream("c:\\1.jpg");
53                 try{
54                      int len = 0;
55                      byte[] buffer = new byte[1024];
56                      while((len=in.read(buffer))>0){
57                          out.write(buffer, 0, len);
58                      }
59                 }finally{
60                     if(in!=null){
61                         in.close();
62                     }
63                     if(out!=null){
64                         out.close();
65                     }
66                 }
67             }
         }finally{
             DButils.release(con, st, result);
         }
     }
 }