首先引入依赖包
<dependency>
<groupId>org.codehaus.jackson</groupId>
<artifactId>jackson-mapper-asl</artifactId>
<version>1.9.12</version>
</dependency>
Java代码如下
import java.text.SimpleDateFormat;
import java.util.HashMap;
import java.util.Map;
import org.apache.commons.lang3.StringUtils;
import org.codehaus.jackson.map.DeserializationConfig;
import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.map.SerializationConfig;
import org.codehaus.jackson.map.annotate.JsonSerialize.Inclusion;
import org.codehaus.jackson.type.JavaType;
import org.codehaus.jackson.type.TypeReference;
public class JsonUtil {
private static ObjectMapper objectMapper = new ObjectMapper();
static {
// 对象的所有字段全部列入
objectMapper.setSerializationInclusion(Inclusion.ALWAYS);
// 取消默认转换timestamps形式
objectMapper.configure(SerializationConfig.Feature.WRITE_DATES_AS_TIMESTAMPS, false);
// 忽略空Bean转json的错误
objectMapper.configure(SerializationConfig.Feature.FAIL_ON_EMPTY_BEANS, false);
// 所有的日期格式都统一为以下的样式,即yyyy-MM-dd HH:mm:ss
objectMapper.setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));
// 忽略 在json字符串中存在,但是在java对象中不存在对应属性的情况。防止错误
objectMapper.configure(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES, false);
}
public static <T> String obj2String(T obj) {
if (obj == null) {
return null;
}
try {
return obj instanceof String ? (String) obj : objectMapper.writeValueAsString(obj);
} catch (Exception e) {
System.err.println("Parse Object to String error");
return null;
}
}
public static <T> String obj2StringPretty(T obj) {
if (obj == null) {
return null;
}
try {
return obj instanceof String ? (String) obj
: objectMapper.writerWithDefaultPrettyPrinter().writeValueAsString(obj);
} catch (Exception e) {
System.err.println("Parse Object to String error");
return null;
}
}
public static <T> T string2Obj(String str, Class<T> clazz) {
if (StringUtils.isEmpty(str) || clazz == null) {
return null;
}
try {
return clazz.equals(String.class) ? (T) str : objectMapper.readValue(str, clazz);
} catch (Exception e) {
System.err.println("Parse String to Object error");
return null;
}
}
public static <T> T string2Obj(String str, TypeReference<T> typeReference) {
if (StringUtils.isEmpty(str) || typeReference == null) {
return null;
}
try {
return (T) (typeReference.getType().equals(String.class) ? str
: objectMapper.readValue(str, typeReference));
} catch (Exception e) {
System.err.println("Parse String to Object error");
return null;
}
}
public static <T> T string2Obj(String str, Class<?> collectionClass, Class<?>... elementClasses) {
JavaType javaType = objectMapper.getTypeFactory().constructParametricType(collectionClass, elementClasses);
try {
return objectMapper.readValue(str, javaType);
} catch (Exception e) {
System.err.println("Parse String to Object error");
return null;
}
}
public static void main(String[] args) {
String jsonStr = "{\"id\":\"2001\",\"name\":\"iphone\"}";
Map testPojoObject = JsonUtil.string2Obj(jsonStr, HashMap.class);
System.out.println(testPojoObject);
}
}