1. 异常：
[console_demo][WARN] [2016-12-15 19:49:35] org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver.handleHttpMessageNotWritable(407) | Failed to write HTTP message: org.springframework.http.converter.HttpMessageNotWritableException: Could not write content: No serializer found for class org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS) (through reference chain: java.util.HashMap["ckRequirePartLists"]->java.util.ArrayList[0]->com.dyoon.cmms.pojo.CkRequirePartList["ckPurchaseBill"]->com.dyoon.cmms.pojo.CkPurchaseBill["applyOperator"]->com.dyoon.cmms.pojo.UserOperator_
2. 原因：
使用注解@ResponseBody返回由Hibernate DAO直接获得的pojo对象内存在Lazy关联对象，执行Jason转换时，会从数据库加载该对象，而此时session已关闭，导致加载失败，进而导致Jason转换失败。
3 解决：
方法一：在不影响数据完整性的情况下，使用set方法手动置空pojo类的Lazy关联对象。（这样如果关联的对象比较多，可能漏的。）
方法二：使用@JsonIgnore注释掉pojo类的Lazy关联对象。（这种如果在其他的地方需要用关联的对象转json,这样就会导致失效。）
方法三：自定义类，二次封装所需的pojo对象的属性。
4. 事例：以下对第三种方法做展示
jsp页面：
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function showPartDetails(purchBillId){
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$.ajax({
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type:"post",
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url:"${rootPath }/depot/purchase/getPartByPurchBillId?purchBillId="+purchBillId,
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success : function(data){
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alert(data.requirePartListBeans[0].partName);
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}
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});
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}
常规下的controller如下：
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@RequestMapping(value =
"/getPartByPurchBillId")
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@ResponseBody
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public Map<String,Object> getPartByPurchBillId(@RequestParam(value="purchBillId") Integer purchBillId) throws JsonProcessingException {
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Map<String, Object> map =
new HashMap<>();
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List<CkRequirePartList> ckRequirePartLists = purchaseService.getPartByPurchBillId(purchBillId);
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map.put(
"requirePartListBeans", ckRequirePartLists);
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return map;
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}
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public
class RequirePartListBean {
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private String partNumber;
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private String partName;
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private BigDecimal partQuantity;
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public String getPartNumber() {
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return partNumber;
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}
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public void setPartNumber(String partNumber) {
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this.partNumber = partNumber;
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}
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public String getPartName() {
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return partName;
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}
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public void setPartName(String partName) {
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this.partName = partName;
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}
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public BigDecimal getPartQuantity() {
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return partQuantity;
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}
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public void setPartQuantity(BigDecimal partQuantity) {
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this.partQuantity = partQuantity;
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}
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}
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@RequestMapping(value =
"/getPartByPurchBillId")
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@ResponseBody
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public Map<String,Object> getPartByPurchBillId(@RequestParam(value="purchBillId") Integer purchBillId) throws JsonProcessingException {
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Map<String, Object> map =
new HashMap<>();
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List<CkRequirePartList> ckRequirePartLists = purchaseService.getPartByPurchBillId(purchBillId);
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RequirePartListBean r =
null;
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List<RequirePartListBean> requirePartListBeans =
new ArrayList<>();
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for (CkRequirePartList ckRequirePartList : ckRequirePartLists) {
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r =
new RequirePartListBean();
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r.setPartName(ckRequirePartList.getModPartCatalog().getPartName());
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r.setPartNumber(ckRequirePartList.getModPartCatalog().getPartNumber());
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r.setPartQuantity(ckRequirePartList.getPartQuantity());
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requirePartListBeans.add(r);
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}
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map.put(
"requirePartListBeans", requirePartListBeans);
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return map;
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}
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success : function(data){
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alert(data.requirePartListBeans[0].partName);
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}
至此，问题得到解决。还有问题的可以留言。
原文地址：https://blog.csdn.net/baidu_28283827/article/details/53675121
