import问题 大家好,小弟编程时遇到一个问题,大家帮帮忙,谢谢import java.io.FileWriter 这样导入编译正常,运行正常但import java.io.*; 这样导入就报找不到FileWriter类这是为什么啊,谢谢大家 解决方案 » 免费领取超大流量手机卡,每月29元包185G流量+100分钟通话, 中国电信官方发货 .....试验了一下没问题啊。把代码发出来看一下!package edu.practice.JDBC.test_clob;import java.io.BufferedReader;import java.io.BufferedWriter;import java.io.File;import java.io.FileReader;import java.io.*;import java.io.IOException;import java.io.Reader;import java.io.Writer;import java.sql.Clob;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import edu.practice.JDBC.JDBC_MySQL_Utils;import edu.practice.JDBC.JDBC_MySQL_Utils_Sing1;public class TestClob { private final static String SQL_QUERY = "SELECT CLOB_TEXT FROM CLOB_TEXT WHERE ID=?"; private final static String SQL_INSERT = "INSERT INTO CLOB_TEXT (CLOB_TEXT) VALUES (?)"; public static void main(String[] args) throws IOException { jdbcTemplate1(1); } public static void jdbcTemplate1(int id) throws IOException { Connection conn = null; PreparedStatement ps = null; ResultSet rs = null; try { conn = JDBC_MySQL_Utils.getConnection(); ps = conn.prepareStatement(SQL_QUERY); ps.setInt(1, id); rs = ps.executeQuery(); while (rs.next()) { Clob clob = rs.getClob("CLOB_TEXT"); Reader reader = clob.getCharacterStream(); // rs.getCharacterStream("CLOB_TEXT"); File file = new File("GetPracticeProperties_bak1.java"); Writer writer = new BufferedWriter(new FileWriter(file)); char buff[] = new char[1024]; for (int i = 0; (i = reader.read(buff)) > 0;) { writer.write(buff, 0, i); } writer.close(); reader.close(); } } catch (SQLException e) { e.printStackTrace(); } finally { JDBC_MySQL_Utils.free(rs, ps, conn); } } public static void jdbcTemplate2() throws IOException { Connection conn = null; PreparedStatement ps = null; ResultSet rs = null; try { conn = JDBC_MySQL_Utils_Sing1.getJDBCMySQLUtilsSing1Instance() .getConnection(); ps = conn.prepareStatement(SQL_INSERT); File file = new File( "src/edu/practice/getProperties/GetPracticeProperties.java"); Reader reader = new BufferedReader(new FileReader(file)); ps.setCharacterStream(1, reader, (int) file.length()); int i = ps.executeUpdate(); reader.close(); System.out.println(i); } catch (SQLException e) { e.printStackTrace(); } finally { JDBC_MySQL_Utils_Sing1.getJDBCMySQLUtilsSing1Instance().free(rs, ps, conn); } }} 楼主说的我也遇到过,每次都是把需要引入的类 路径完整写出来, 怀疑是IDE 的问题, 另外,不管什么理由, 最好不要使用import java.io.*; 这样导入其下所有类, 会占用不必要的系统资源,不是个好习惯 是不是你的类名写成了FileWriter了?? 代码如下,谢谢大家了。package IO;import java.util.ArrayList;import java.io.FileWriter;//import java.io.*;public class WriteFile { public void writeFiler(String str,String fileName){ FileWriter fw = null; try{ fw = new FileWriter(fileName,true); fw.write(str+"\r\n"); fw.close(); }catch(Exception e){ e.printStackTrace(); }finally{ try{ fw.close(); } catch (Exception e) { e.printStackTrace(); } } } /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub String fileName="c:/my.txt"; ArrayList newList =new ArrayList(); String[] arr=new String[100000]; WriteFile wf=new WriteFile(); for(int i=0;i<arr.length;i++){ arr[i]="测试数据"+i; wf.writeFiler(arr[i],fileName); } String str1="bbb"; System.out.println("导入结束"+fileName); }} 如果是IDE问题,有办法解决吗 有时候是有些莫名其妙的问题老出现,楼上这位说得在理,另外我们用Eclipse,它导入类时,也是完整路径,不是* 前几天看到过这样一种情况:swing.List和util.List (我记不清了),如果没有注明,编译的时候会出错的 struts2 action如何接收页面传来的布尔值 压力测试会把当前的domain压夸吗? 关于JavaScript的一个问题,等待高手解答 怎样对一个方法进行事务控制,方法里不只是sql操作 计算器 如何用EL表达式取出该作用域中Set集合的元素 作为一个j2ee的初学者,我想说“为什么j2ee的环境配置这么麻烦呢?” Base64Binary数据类型的读取 [java新手求教]公司中一般搭建怎么样的环境来开发J2EE项目? 什么样的项目需要用j2ee? 救命啊,eclipse的debug工具的问题,恳请各位高手赐答 解惑 有关 PayPal的用户认证
package edu.practice.JDBC.test_clob;import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.*;
import java.io.IOException;
import java.io.Reader;
import java.io.Writer;
import java.sql.Clob;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;import edu.practice.JDBC.JDBC_MySQL_Utils;
import edu.practice.JDBC.JDBC_MySQL_Utils_Sing1;public class TestClob { private final static String SQL_QUERY = "SELECT CLOB_TEXT FROM CLOB_TEXT WHERE ID=?"; private final static String SQL_INSERT = "INSERT INTO CLOB_TEXT (CLOB_TEXT) VALUES (?)"; public static void main(String[] args) throws IOException {
jdbcTemplate1(1);
} public static void jdbcTemplate1(int id) throws IOException {
Connection conn = null;
PreparedStatement ps = null;
ResultSet rs = null;
try {
conn = JDBC_MySQL_Utils.getConnection();
ps = conn.prepareStatement(SQL_QUERY);
ps.setInt(1, id);
rs = ps.executeQuery();
while (rs.next()) {
Clob clob = rs.getClob("CLOB_TEXT");
Reader reader = clob.getCharacterStream();
// rs.getCharacterStream("CLOB_TEXT");
File file = new File("GetPracticeProperties_bak1.java");
Writer writer = new BufferedWriter(new FileWriter(file));
char buff[] = new char[1024];
for (int i = 0; (i = reader.read(buff)) > 0;) {
writer.write(buff, 0, i);
}
writer.close();
reader.close();
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
JDBC_MySQL_Utils.free(rs, ps, conn);
}
} public static void jdbcTemplate2() throws IOException {
Connection conn = null;
PreparedStatement ps = null;
ResultSet rs = null;
try {
conn = JDBC_MySQL_Utils_Sing1.getJDBCMySQLUtilsSing1Instance()
.getConnection();
ps = conn.prepareStatement(SQL_INSERT);
File file = new File(
"src/edu/practice/getProperties/GetPracticeProperties.java");
Reader reader = new BufferedReader(new FileReader(file));
ps.setCharacterStream(1, reader, (int) file.length());
int i = ps.executeUpdate();
reader.close();
System.out.println(i);
} catch (SQLException e) {
e.printStackTrace();
} finally {
JDBC_MySQL_Utils_Sing1.getJDBCMySQLUtilsSing1Instance().free(rs,
ps, conn);
}
}
}
import java.io.*; 这样导入其下所有类, 会占用不必要的系统资源,不是个好习惯
import java.io.FileWriter;
//import java.io.*;public class WriteFile {
public void writeFiler(String str,String fileName){
FileWriter fw = null;
try{
fw = new FileWriter(fileName,true);
fw.write(str+"\r\n");
fw.close();
}catch(Exception e){
e.printStackTrace();
}finally{
try{
fw.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
String fileName="c:/my.txt";
ArrayList newList =new ArrayList();
String[] arr=new String[100000];
WriteFile wf=new WriteFile();
for(int i=0;i<arr.length;i++){
arr[i]="测试数据"+i;
wf.writeFiler(arr[i],fileName);
}
String str1="bbb";
System.out.println("导入结束"+fileName);
}}
如果是IDE问题,有办法解决吗
有时候是有些莫名其妙的问题老出现,楼上这位说得在理,另外我们用Eclipse,它导入类时,也是完整路径,不是*