Java專案跨域問題解決方案總結
阿新 • • 發佈：2019-01-31
import java.io.IOException;
import javax.servlet.http.HttpServletRequest;
import org.apache.commons.io.IOUtils;
import org.apache.commons.lang3.StringUtils;
import org.springframework.http.HttpOutputMessage;
import org.springframework.http.converter.HttpMessageNotWritableException;
import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
import com.fasterxml.jackson.core.JsonEncoding;
import com.fasterxml.jackson.core.JsonProcessingException;
public class CallbackMappingJackson2HttpMessageConverter extends MappingJackson2HttpMessageConverter {
// 做jsonp的支援的標識，在請求引數中加該引數
private String callbackName;
@Override
protected void writeInternal(Object object, HttpOutputMessage outputMessage) throws IOException, HttpMessageNotWritableException {
// 從threadLocal中獲取當前的Request物件
HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.currentRequestAttributes()).getRequest();
String callbackParam = request.getParameter(callbackName);
if(StringUtils.isEmpty(callbackParam)){
// 沒有找到callback引數，直接返回json資料
super.writeInternal(object, outputMessage);
}else{
JsonEncoding encoding = getJsonEncoding(outputMessage.getHeaders().getContentType());
try {
String result =callbackParam+"("+super.getObjectMapper().writeValueAsString(object)+");";
IOUtils.write(result, outputMessage.getBody(),encoding.getJavaName());
}
catch (JsonProcessingException ex) {
throw new HttpMessageNotWritableException("Could not write JSON: " + ex.getMessage(), ex);
}
}
}
public String getCallbackName() {
return callbackName;
}
public void setCallbackName(String callbackName) {
this.callbackName = callbackName;
}
}