json复杂数据与Java对象的转换

</pre><pre name="code" class="java">	private static JsonGenerator jsonGenerator = null;
private static ObjectMapper objectMapper = null;
static OutputStream out;

public static void init() {

objectMapper = new ObjectMapper();
try {
out = new ByteArrayOutputStream();
jsonGenerator = objectMapper.getJsonFactory().createJsonGenerator(
out, JsonEncoding.UTF8);
} catch (IOException e) {
e.printStackTrace();
}
}

public static void destory() {
try {
if (jsonGenerator != null) {
jsonGenerator.flush();
}
if (!jsonGenerator.isClosed()) {
jsonGenerator.close();
}
jsonGenerator = null;
objectMapper = null;
System.gc();
} catch (IOException e) {
e.printStackTrace();
}
}

public static String writeObject(Object o) throws JsonGenerationException,
IOException {
init();
jsonGenerator.writeObject(o);
out.toString();
destory();
return out.toString();
}

public static String writeObject(String str, Object o)
throws JsonGenerationException, IOException {
init();
jsonGenerator.writeStartObject();// {
jsonGenerator.writeObjectField(str, o);// user:{bean}
jsonGenerator.writeEndObject();// }
out.toString();
destory();
return out.toString();
}
public static <T> Object TowriteObject(String str, Class<T> o)
throws JsonGenerationException, IOException {
init();
Object obj=objectMapper.readValue(str, o);
destory();
return obj;
}