我编的一段Java代码 有错误请给改正下

题目是：从键盘中读入两个字符串。将比较长的写入到Hello.txt文件中（用续写的方式）。如果同样长 比较大小。写入较大的那个。下面是我写的代码，有错误。请高手指出并改正 最好加注释说明为什么错了 谢谢

import java.io.*;
public class Test1
{
String s1,s2;
int a,b;
InputStreamReader is;
BufferedReader br;
File file1;
FileWriter out;
public void Test1()throws IOException
{
is=new InputStreamReader(System.in);
br=new BufferedReader(is);
s1=br.readLine();
s2=br.readLine();
a=s1.length;
b=s2.length;
file1=new File("F://java//hello.txt");
out=new FileWriter(file1,true);
if(a>b){
out.writer(s1);
}
if(a<b){
out.writer(s2);
}
if(a=b){
if(s1.compareTo(s2)>0)
{
out.writer(s1);
}
if(s1.compareTo(s2)<0)
{
out.writer(s2);
}
}
System.out.println("已完成写入!");
out.close();
}
public static void main(String args[])throws IOException
{
Test1 t1=new Test1();
}
}

public class Test1 {
String s1,s2;
int a,b;
InputStreamReader is;
BufferedReader br;
File file1;
FileWriter out;
public void Test1()throws IOException
{
is=new InputStreamReader(System.in);
br=new BufferedReader(is);
s1=br.readLine();
s2=br.readLine();
a=s1.length();
b=s2.length();
file1=new File("F://java//hello.txt");
out=new FileWriter(file1,true);
if(a>b){
out.write(s1);
}
if(a<b){
out.write(s2);
}
if(a==b){
if(s1.compareTo(s2)>0)
{
out.write(s1);
}
if(s1.compareTo(s2)<0)
{
out.write(s2);
}
}
System.out.println("已完成写入!");
out.close();
}
public static void main(String args[])throws IOException
{
Test1 t1=new Test1();
}

}

在字符串中只有length方法 数组中才有length属性

FileWriter 中写入数据的方法是write 不是writer

//下面是你的程序，我把语法错误的地方改过来了，写了注释，你自己看看...

import java.io.*; public class Test1 { String s1,s2; int a,b; InputStreamReader is; BufferedReader br; File file1; FileWriter out; public void Test1()throws IOException { is=new InputStreamReader(System.in); br=new BufferedReader(is); s1=br.readLine(); s2=br.readLine(); a=s1.length();//字符串没有length属性，只有length()方法; b=s2.length();//字符串没有length属性，只有length()方法; file1=new File("F://java//hello.txt"); out=new FileWriter(file1,true); if(a>b){ out.write(s1);//不是writer; } if(a<b){ out.write(s2);//不是writer; } if(a==b){//比较int类型是否相等用==不是=; if(s1.compareTo(s2)>0) { out.write(s1);//不是writer; } if(s1.compareTo(s2)<0) { out.write(s2);//不是writer; } } System.out.println("已完成写入!"); out.close(); } public static void main(String args[])throws IOException { Test1 t1=new Test1(); } }