问题：
线上运行的lamp服务器，php不支持iconv函数。
解决方法：
安装libiconv，重新编译apache，使php支持iconv函数，实现utf-8和gb2312编码的转换。
具体步骤：
1、下载libiconv
cd /usr/local/src
wget http://ftp.gnu.org/pub/gnu/libiconv/libiconv-1.14.tar.gz #下载
2、安装libiconv
cd /usr/local/src
tar zxvf libiconv-1.14.tar.gz #解压
cd libiconv-1.14 #进入安装目录
./configure --prefix=/usr/local/libiconv #配置
make #编译
make install #安装
3、重新编译php
查找系统之前的php编译参数
cd /usr/local/php/bin #进入php安装目录
./php -i |more #查看php编译参数
如下：
'--with-pdo_sqlite=shared' '--enable-bcmath=shared' '--enable-ftp=shared' '--enable-mbstring=shared' '--with-iconv=shared' '--enable-sockets=shared' '--enable-zip' '--enable-soap=s
hared' '--with-openssl' '--with-zlib' '--with-curl=shared' '--with-gd=shared' '--with-jpeg-dir' '--with-png-dir' '--with-freetype-dir' '--with-mcrypt=shared' '--with-mhash=shared' '--with-mysql=/ho
me/server/mysql' '--with-mysqli=/home/server/mysql/bin/mysql_config' '--with-pdo-mysql=/home/server/mysql/bin/mysql_config' '--without-pear' '--with-libdir=lib64'
对参数进行修改：
如下
./configure --prefix=/usr/local/php --with-config-file-path=/usr/local/php/etc --with-apxs2=/usr/local/apache/bin/apxs --with-gettext=shared --with-sqlite=shared --with-pdo_sqlite=shared --enable-bcmath=shared --enable-ftp=shared --enable-mbstring=shared --with-iconv-dir=/usr/local/libiconv --enable-sockets=shared --enable-zip --enable-soap=shared --with-openssl --with-zlib --with-curl=shared --with-gd=shared --with-jpeg-dir --with-png-dir --with-freetype-dir --with-mcrypt=shared --with-mhash=shared --with-mysql=/home/server/mysql --with-mysqli=/home/server/mysql/bin/mysql_config --with-pdo-mysql=/home/server/mysql/bin/mysql_config --without-pear --with-libdir=lib64
备注：修改部分
取消原来的--with-iconv=shared
替换为：--with-iconv-dir=/usr/local/libiconv
取消参数两边的单引号
其它不变
cd /usr/local/src/php #进入php安装包目录（注意php版本要和之前一样）
./configure --prefix=/usr/local/php --with-config-file-path=/usr/local/php/etc --with-apxs2=/usr/local/apache/bin/apxs --with-gettext=shared --with-sqlite=shared --with-pdo_sqlite=shared --enable-bcmath=shared --enable-ftp=shared --enable-mbstring=shared --with-iconv-dir=/usr/local/libiconv --enable-sockets=shared --enable-zip --enable-soap=shared --with-openssl --with-zlib --with-curl=shared --with-gd=shared --with-jpeg-dir --with-png-dir --with-freetype-dir --with-mcrypt=shared --with-mhash=shared --with-mysql=/home/server/mysql --with-mysqli=/home/server/mysql/bin/mysql_config --with-pdo-mysql=/home/server/mysql/bin/mysql_config --without-pear --with-libdir=lib64 #配置
make #编译
make install #安装
4、重启apache使设置生效
service httpd restart #重启
故障解决！