package com.alibaba.fastjson; public abstract class JSON { public static final int writeJSONString(OutputStream os, //  Object object, //  SerializerFeature... features) throws IOException; public static final int writeJSONString(OutputStream os, // Charset charset, //  Object object, //  SerializerFeature... features) throws IOException; public static final int writeJSONString(Writer os, //  Object object, //  SerializerFeature... features) throws IOException; }

import com.alibaba.fastjson; import java.nio.charset.Charset; class Model { public int value; } Model model = new Model(); model.value = 1001; OutputStream os = ...; JSON.writeJSONString(os, model); JSON.writeJSONString(os, Charset.from("GB18030"), model); Writer writer = ...; JSON.writeJSONString(os, model);